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Maker Select Plus 3D Printer Head Size Settings for Cura
I want to print multiple objects in a single G-code file on my Maker Select Plus 3D Printer.
On the Cura "Machine>Machine Settings..." menu, what are the correct settings for "Printer head size" in the upper right quadrant?
My best guess is below:

Note 1: I'm particularly concerned that I got the min and max directions correct.  For instance, I just swapped my Y min and Y max values because when I tried them the other way, the print head impacted the first object when printing the second.
Note 1.5: I added 10 mm to my settings because I was concerned that Cura wasn't accounting for the width of the raft that I usually use when I print.
Note 2: From what I've read online before posting this question, this printer may be physically the same as the WanHao Duplicator i3.

TL;DR
The settings that you seem to need can be found here: Print One At a time settings? CURA:

You actually can!
Providing that none of your object is too tall (taller than the Gantry
  clearance). Also the objects cannot be too close from each other (when
  you activate the option and move objects on the bed, you see a gray
  box around them showing this limit).
The reason you cannot use it at the moment is probably because you
  didn't filled the printer head size parameters (Menu "Machine ->
  Machine Settings..."). You will have to measure them, but on mine
  (Australian clone of the i3) I use those values and it works fine:

Head size toward X min: 30
Head size toward Y min: 70
Head size toward X max: 60
Head size toward Y max: 50
Printer gantry height: 35

Those are "conservative" values (a little bigger than the actual
  values). It means I'm losing a little bed space, but I prefer that to
  the risk of having the print head knocking out previous prints if one
  of the measurements is too low :o).
PS: The option will automatically disable itself if some object
  dimension are too big to avoid collisions

To be fair, the rest of the thread is people debating whether you can successfully achieve sequential printing, or not, with the Wanhao Duplicator I3.
However, the setting above seem to be the settings that you are looking for. Apart from Head size toward X max, they also correlate, pretty much, to the settings that you have already determined. As the poster notes, their settings are, somewhat, on the conservative side, which would explain the difference.

Extra detail
If this is so that you can achieve sequential printing1, then this may not be suitable for your printer, unfortunately. Sequential printing works best for printers with a long nozzle with nothing (fans, X-axis gantry, etc.) around it, for example a delta printer with a low hanging nozzle would be ideal. Your printer type has a wide head with attachments, as well as an X-axis gantry, and so the clearance is less than that of an (ideal) delta.
See WanHao Duplicator i3 Printer Head Size Settings for Cura for more details.
If you wish to go ahead and still try it, then from the same link:

The way to measure is lower the nozzle to the bed.
Then measure the space taken up around the nozzle by the heater block, fans, mounting, the motor, and finally, the distance between the X axis rods and the bed "WHEN the nozzle is touching the bed".
That gives you some idea of the clearance you have where an ALREADY printed object can exist on the bed and NOT get slammed into the gantry or moving head when printing a second sequential part.
Just a visual with a moving bed printer and it's not promising.
  Not impossible, but in a 200mm square build area, you might really only get 4 objects at a time in the 4 quadrants.
Even that is height limited because the gantry will slam into it at a certain height.
Maybe some weird staggering pattern.

Also, of use, for obtaining your own measurements, from Ultimaker - Cura 14.07 Printer Head Size:

If I'm not mistaken all measurements are taken from the nozzle tip. So, for the first one, measure the size of your head from the nozzle tip towards the direction in X to where your machine homes.

and

There's a tooltip when you mouse over these settings which describes what they mean.
Gantry height is the vertical clearance between the build plate and your x-y gantry (on the Ultimaker, these are the 6mm shafts which hold the head).
If you print two objects - one after another - then the first object must be shorter in height than the gantry height. Otherwise, the gantry would crash into the first part while printing the second part.

In more detail, paying attention to the placing of the objects can aid with any issues that you have with a low gantry:

If you place multiple parts in a diagonal line across the build-plate so the gantry and head never intersects earlier parts after printing them, you can set the gantry height to an artificially high value, to ignore it, without problems.
I place pieces along a diagonal from right-front to left-rear, to avoid conflict when the head homes after finishing the print. I can fit 3 to 4 small but tall pieces on the build plate that way for sequential printing.

The purpose of these Printer head size settings is to enable Cura to determine the order in which the objects are printed:

... none of those settings are important as long as you only print one STL file at a time. It's when you want to print multiple objects "one at a time" that these numbers have a purpose - it allows Cura to figure out which order to print them in and if it can do them one at a time or if it has to print them all at once.

Footnote
1 Sequential Printing is where one object is completely printed, before moving on to the next object, instead of the usual method of printing all objects simultaneously one layer at a time. This method can give superior quality prints, but not always. The main advantage appears to be reduced "stringing" of filament between objects, and a cleaner surface finish, due to reduced print head movement between objects. The process is detailed in Multi-part printing.

Thank you for taking the time to answer my question. Unfortunately, this is not the information that I'm looking for; I saw that post as well before I asked my question.  I'm looking for official values from the manufacturer, not measurements -- I already made my own measurements because I can't be sure that the other post has the exact same machine as I.

@Gdalya - Ok, that's a shame. It is often a good idea to state, in your original post, what research you have already done (with links) to save others duplicating your effort. You best bet, now, would seem to be to contact the manufacturer of your printer and try to get a definitive answer from them. If you do get a reply, could you post an answer with the correct/recommended values and accept your answer?

Like the OP, I'm confused by this as well. I figured I'd need measurements from the center of the nozzle to the left, right, front, and back of the print head, as well as a height from the print surface to the gantry while the head was homed. I've carefully measured, but things aren't going quite as I expected. In trying to understand this, I see examples like the one here:

Head size toward X min: 30
Head size toward Y min: 70
Head size toward X max: 60
Head size toward Y max: 50

How is 70 a minimum and 50 a maximum? What do these numbers really mean?
Also, I see the shading in the slicer (presumably one is a shadow, the middle one is a minimum, and the darker one is a maximum?) and changing my values don't affect these shadows in the way I'd expect.

If you have a new question, please ask it by clicking the Ask Question button. Include a link to this question if it helps provide context. - From Review

Head size toward "X min" means distance from center of nozzle toward the origin of the X-axis.


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Monoprice Maker Ultimate Extrudes Too Much Filament At Start
Today I received my Monoprice Maker Ultimate 3D Printer. It is a rebranded Wanhao Duplicator 6 for reference. I am using the default settings for a Wanhao Duplicator 6 in Simplify3D.
Here is the Start G-Code that Simplify3D has setup for me via the Configuration Assistant:
G28 ; home all axes
G92 E0 ; zero the extruded length
G1 Z10 ; lower
G1 E20 F200 ; purge nozzle quickly
G1 E10 F60 ; purge nozzle slowly
G92 E0 ; zero the extruded length again
G1 E-1.5 F400 ; retract
G1 X170 Z0 F9000 ; pull away filament
G1 X180 F9000 ; wipe
G1 Y20 F9000 ; wipe
G1 E0 ; feed filament back

The problem is that right before a print, the extruder squeezes out a bunch of filament making a nice little spiral tower. It is a waste of filament. I suspect it is all the purging in the Start Code that is doing it, but I don't know what I should change because I don't know what is necessary, so I am coming here to ask the question before I start experimenting. Has anyone had this problem? Does anyone know the solution?
Update: I tried printing one of the models that came on the SD card with the printer (I think it was created with Cura) and the Start G-code is different.
G21        ;metric values
G90        ;absolute positioning
M82        ;set extruder to absolute mode
M107       ;start with the fan off
G28 X0 Y0  ;move X/Y to min endstops
G28 Z0     ;move Z to min endstops
G1 Z15.0 F4800 ;move the platform down 15mm
G92 E0                  ;zero the extruded length
G1 F200 E3              ;extrude 3mm of feed stock
G92 E0                  ;zero the extruded length again
G1 F4800
;Put printing message on LCD screen
M117 Printing...

It also uses absolute positioning. It got going without purging a bunch of unnecessary filament on that print. Now I am not sure how to combine these two to get the good working starting G-code. Any ideas?

Changing the Simplify3D start script to this will change the nozzle purge to the same length as what was on your SD card.
    G28 ; home all axes
    G92 E0 ; zero the extruded length
    G1 Z10 ; lower
    G1 E20 F200 ; purge nozzle quickly<---------Change E20 to E3, E is the extrusion length
    G1 E10 F60 ; purge nozzle slowly <----------Remove this line
    G92 E0 ; zero the extruded length again
    G1 E-1.5 F400 ; retract
    G1 X170 Z0 F9000 ; pull away filament
    G1 X180 F9000 ; wipe
    G1 Y20 F9000 ; wipe
    G1 E0 ; feed filament back

The rest of it is just moves to try to clean the nozzle.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

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Slic3r settings for flat slopes on top
I am having trouble printing a hollow object using Slic3r. On flat slopes on top, there are gaps that I cannot get fixed. The perimeters of successive layers just don't cover each other.
Cura however adds filament to cover the gaps.
The bottom left bunny is sliced with Slic3r 1.2.9.99.
The top right bunny is sliced with Cura 2.5. Take a closer look at the forehead and the back of the bottom left bunny.
I have "extra perimeters if needed" turned on. But turning it off makes no difference. What am I missing?
So far only adding infill and increase the solid top layer count helps to get a closed surface. But then everything gets stiffer. The bunnies are printed with nylon so they are a bit squishy.

The printer settings in both Cura and Slic3r are:

0.4 mm nozzel;
0.2 mm layer height;
No infill;
2 perimeter walls, and;
3 solid top/bottom layers.

This is very similiar to the issue I had in https://3dprinting.stackexchange.com/questions/3461/why-does-my-domed-print-have-a-thin-shell. I think Slic3r simply can't handle this type of shape properly. In the end, I just use Cura.

true, thats the same issue. I also already tried Slic3r 1.3 beta with the same result. Looks like Cura is the cure for that issue :)

This seems to be a recurring problem with Slic3r.
Slic3r appears to have problems with perimeters that are not attached to infill.  I suspect that it is getting confused on what is the inside and what is the outside.  I know that seems a bit silly; but as you slice an object with indentations (like the bunny's face) then the perimeter can cease to be a simple closed shape and it gets confused.  If you use a viewer to step through the gcode layers around the place it starts having problems you may be able to see what is going wrong.
Here are a couple of examples of why I say this is a recurring problem with slic3r.  I also recall seeing a video that showed the problem but I can't remember where.  That was one of the reasons I don't use slic3r.

Reported on Sic3r Git in 2012 - Can't tell for sure if this was ever fixed
Infill Perimeter issue in 2015

Here are three options that may work

Use a different slicer for this specific condition.  Every product is going to have vulnerabilities - this may be one of slic3r's.
Increase the perimeter and top and bottom layer thicknesses.  Making them thick enough it will bridge the problem areas.  Use a gcode viewer to inspect that area to see if it fixed the problem.  That way you don't waste material on another fail. It sounds like you may have already tried this but you didn't like that it made the model stiffer.
Repair the STL file using an application like Meshmixer.  Maybe you will have to get the file close then tweak it where it doesn't.  Here is good article from PinShape repairing and STL file.

Good luck, hope this helps.

What infill are you using? How flexible do you need the object to be?
I suggest two or three top and bottom layers, and a second or third solid perimeter as well.
The slicer has to determine if a particular path is part of an external perimeter or a top layer, so adding one to each should give a better result.
Thinner layers and a fan cooling the deposited material both help with overhangs like this.

I want the object to be completely hollow, so I used no infill at all in both, Cura and Slic3r. Cura adds more to the inner perimeter walls as they come closer to the problematic area. Slicer however does not. Since I practically used the same basic settings in both, there must be something I can tell Slic3r to do the same.

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How do I get my Wanhao Duplicator 6 / Maker Ultimate to lower bed at end of print?
What would be the end g-code so that I can get my Monoprice Ultimate (Wanhao D6) to lower the bed to midway on the frame or something easier to remove the print? The default end position is very high up at the top.

In your ending script add the line below and change Z200.0 to your max Z height.  This will rapid to the given value using absolute coordinates.  I added G90 in case G91 was previously set so it did not do a relative move.  I'm not positive if G91 is modal in printer firmwares or not but the G90 should not hurt anything.
G90 G0 Z200.0

This will rapid to... should that be raise?

No, G0 uses rapid feed rate.  G1 uses the feed rate given by F.  Also a Z value like this does not mean we are raising something.  The head will raise to 200mm on a printer like the i3 but the bed will lower on a printer like the DaVinci 2.


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PLA filament not feeding correctly with Ultimaker 2+
I've got the following PLA filament that is not feeding correctly into our Ultimaker 2+
It starts to feed and then all of the sudden, the wire 'eats' (read breaks, but not entirely) the plastic filament as you can see on the picture below:

Any hints are more than welcomed.

The photograph and your description indicate that the drive gear is eating the filament because the filament has stopped moving. The least likely problem would be that something is jammed at the spool or between the spool and the entry to the drive mechanism.
The more likely problem is that your nozzle is clogged. It is simple to determine if that is the case. If you have a direct drive mechanism (not a bowden tube type), remove all the filament and release the wheel or bearing that presses the filament against the hobbed pulley, which is the part connected to the motor or driven gear if you have a geared mechanism.
Heat the nozzle up to correct temperature for PLA and attempt to push filament through the nozzle. If it does not move, your nozzle is clogged and has to be cleared.
A nozzle clog can be caused by a too-low temperature or a too-high temperature resulting in burned material becoming jammed in the nozzle.
If you have a 0.40 nozzle, find that size of nozzle tool or use a 0.40 mm drill bit and carefully push and turn it into the nozzle.
Also consider to use nylon cleaning method. This involves heating the nozzle to the correct temperature for melting nylon filament, forcing it into the hot end, then allowing it to cool. Reheating it while pulling on the filament will remove some of the debris. Eventually, it will pass through the nozzle and will also pull out clean, with no debris on the end of the filament. It is suggested to research "nylon cleaning method" to learn correct temperatures.
I have used the nylon cleaning method and have removed debris from overheated filament in the past. I have been able to shine a bright light from below and see the open nozzle after completing the process.
The above steps are identical for bowden type systems and require to remove the bowden tube to access the hot end more effectively. The tube can be removed from either the hot end or the drive end, but force is more effectively applied if the tube is removed from the hot end.

I had a clogged filament. I heated up to 240 C, and pushed a wire up through the nozzle. It took some effort, and much patience is expected. I left the wire inside, as  it helped soften the PLA. Then I pushed the filament by hand from top. After some efforts, the needle moved, indicating the movement of the PLA clog. Once the PLA starts pushing the clogged area, some material comes out the nozzle. Keep pushing and after some hours of effort all is flowing fine! The idea was to transport heat to the clogged PLA by using the needle (from the nozzle end). But it certainly requires patience!

It looks like your nozzle is jammed, since the filament is being chewed. You can fix this by heating the extruder up to around 220 C ( or just about 15 degrees above the recommended printing temp for your filament), then attempting to push some filament through the extruder. If this doesn't work, use a small wire and push it through the nozzle a few times, then run some filament through it.


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E3D V6 underextruding always?
I have an E3D v6 1.75mm bowden.
When I print, there is a gap between infill lines, and also when printing rectilinear/hexagonal infill lines seem to be pretty slim.
My settings:

Slicer: Slic3r
Nozzle size: 0.4mm
Print speed: 30mm/s
First layer print speed: 15mm/s
Travel speed: 90mm/s
Retraction length: 0.8mm
Retraction speed: 40mm/s
Extrude ratio: 1 (tried also with 0.48mm extrusion width, I remember it's the default S3D setting, so I gave it a try)
Print temperature: 220 °C
Material: PLA

Firmware settings:

Firmware: Marlin 1.1.0-1
Motion system: CoreXY
Acceleration: 1000
VMax X: 300
VMax Y: 300
VMax Z: 5
VMax E: 80
Xsteps/mm: 80.05
Ysteps/mm: 80.05
Zsteps/mm: 400
Esteps/mm: 96.5

Disclaimer: I set Esteps/mm to 96.5 because I calibrated the printer as described here, so I'm 100% sure it's an accurate setting. Same for X,Y,Z steps. I printed a cube and calculated the real steps per millimeter, and it's accurate too. The extruder motor works, it's not the issue.
Here you can find some pictures that show what I'm trying to describe:

While printing I tried to release the extruder motor clamp and push the filament by hand: it extruded 1mm thick lines, so the extruder is not clogged and is perfectly capable of extruding the required amount of PLA.
Is it possible that the VMax E parameter is preventing the extruder motor to extrude properly? I mean, could it be that it's trying to extrude at a higher speed than the maximum allowed? Seems weird to me, because comments in Marlin's Configuration.h file say Default Max Feed Rate (mm/s) for that parameter, so if the limit is set to 80mm/s it should extrude just fine. If this is the issue, how should I solve it?

This problem could be related to your slicer.  Have you tried using a different slicer (Cura for example)?  I have seen the  gapping reported several times for slic3r that went away when they used a different slicer.

@markshancock I use Slic3r since more than a year without issue, so I think it should work... I thought about a Marlin issue because this is a printer I assembled with components from another printer that had repetier. Same Slic3r settings which worked perfectly with the old Repetier firmware don't seem to work with Marlin, this is weird... Or maybe it's just that I had a direct extruder before and bowden requires some special settings...?

I am not saying that Slic3r is a bad slicer; but, every product has its vulnerabilities and I have seen several reports where people saw something like this and used a different slicer and they didn't see it; so, I didn't want to claim that as an answer; but, thought you should try it as an experiment to see if it resolves what you are seeing.

Another trick I have hears to workaround this is to lie about your nozzle diameter.

Maybe this would help http://manual.slic3r.org/advanced/flow-math

Look at https://3dprinting.stackexchange.com/questions/4133/slic3r-settings-for-flat-slopes-on-top/4138#4138 for an example of a slic3r specific issue

@markshancock I didn't say that Slic3r is the best slicer out there, I just said that with the exact same components I didn't have issues. Plus, I already sliced and printed the round-shaped model in this question with Slic3r, same filament and my old printer setup, it came out perfect. As I said, issues came after switching to Marlin and E3D V6, so let me think this is not a slicer issue, whatever the slicer is.

Major factors affecting extrusion:

Nozzle diameter
Extrusion ratio
Extrusion stepper calibration
Filament actual diameter
Extrusion width setting
Nozzle temperature

According to the photos, temperature is acceptable (may be a bit high, but it is not a problem in this case). Extrusion ratio is 1 and should not be changed in normal operation. Extrusion width is often set to auto but sometimes calibrating it gives better results in slic3r. If stepper is calibrated properly, then I would check for nozzle and filament diameters. For nozzle it should be enough to verify that 0.4 bit fits in and 0.5 doesn't. Filament can be measured by digital caliper. Difference between 1.75 and 1.73mm may have significant difference resulting in under-extrusion.

Everything is calibrated. Extrusion width is set to 0.4, I also tried 0.48 (because Simplify3D does this by default, so I thought I could try that too), no luck. Stepper is calibrated, as wrote in the question. The filament actual diameter is quite accurate, as I said I never experienced this type of issue with the stock direct extruder and Repetier: all the troubles came when I switched to Marlin + E3D V6

Do you use EEPROM in Marlin? Try to get current parameters via M503 command and check if they are the same as you expect


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Delta printer printing incorrect dimensions in X and Y directions. Z dimensions are correct
I had to pause an ongoing print (because of complicated reasons) and that caused the printer to reboot (I don't know why).
When it rebooted, the Z extents were screwed up. I know this because when I gave the print again, the nozzle hit the print bed and started grinding.
The printer has an auto bed levelling function that runs before every print.
It takes three points on the bed where the sensor needle comes down to contact in a vertical to-and-fro motion. When that runs now, the head starts its vertical to-and-fro motion from a point considerably higher than where it used to start from earlier. The sensor needle does come down to touch the bed but it takes a longer time per point since the distance travelled is more now. (Hope this is clear)
To print again, I compensated for the Z-direction by giving a global offset (2.65 mm) while generating G-code. But I realised later that X and Y dimensions were incorrect (larger by 4.6% to be precise). I tested this by printing cubes of 10, 20, 30 and 100 mm. The Z dimensions are perfect though.
Also, there have been weird "lags" while printing larger objects. The print head stutters and this is causing sharp vertexes in between curves and some little blotching of material.
The printer runs on Repetier 0.92.6 and I've been reading about it but its honestly intimidating to me. Please let me know how to figure out what to change and by how much.
Edit: I agree this is quite similar to scaling issues thread here: Scaling/size issues in delta printers
I just want to know what could've caused this problem, whether there are any other possible solutions, and how to get started with Repetier framework.
Edit2: Attached image is the bottom surface of the 100 mm cube. You might notice slight charring on the bottom right corner. The masking sheet I pasted on the print bed was charred underneath. Also, it's evident that the bottom surface is not as compact at the corners as it is in the center.

What could be the possible reasons for that?

Possible duplicate of Scaling/size issues in delta printers

@Ecnerwal agreed. I just want to know what could've caused it, what are the possible solutions, and what all in repetier would matter in this case

Ah - so you're saying the printer changed from correct size to incorrect size after the reboot? Sounds like it loaded some incorrect values from somewhere (EEPROM, presumably) upon reboot.

Oh okay. So I guess tweaking the firmware is the solution. Referring to your similar question from a month ago, diagonal rod value is all I need to change, right? And what should I do for the incorrect Z height?

I would guess at an incorrect radius value based on the print, assuming it was positioned at the center. That was an interesting trip for me, starting with the set value being ignored .vs. awrong value in the EEPROM on my printer. Radius errors make what should be the "flat plane" in Z warped either up or down - they also affect the overall Z height, which speaks to your other problem. I went through some tedious homing and checking to get mine correct and the correct value stored in EEPROM (as well as written down elsewhere, just in case.)

So I have to tweak just the delta radius or also the diagonal rod value? Also, in which order should I go about changing them? I can't find a good enough tutorial for all of this

Please don't forget to upvote and mark as accepted any answer that has helped you fix your solution. Marking the question as answered will remove it from the Unanswered list, which as we are a beta site, it is important to keep as small as possible. Upvoting rewards people for their time. :-)

As detailed at minow.blogspot.com (which I found very helpful for the most part - it was the first link in the answer to my related question) you need to check/adjust the zero in front of each tower, check the zero in the center, tweak the radius, and repeat (checking the zeros at the edge of the bed in front of each tower again) until it's correct.
After that you adjust the rod length to correct XY size (and recheck all 4 zeros, thus the radius - it makes for a less than exciting day, but is worth it in the long run.)
You either need to turn off EEPROM until you have the right settings, or save the setting to EEPROM each time - depends how worried you are about using up EEPROM write cycles, I guess.
You should also turn off auto-bed-levelling while getting the basic calibration correct, per the same blog instructions.
My fun with figuring out what my EEPROM was doing behind my back is here:
Delta printer not responding to changes in DELTA_RADIUS


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Help understanding bridge settings
I can't understand how to best tune my slicer settings in order to get better bridges...
I've downloaded a simple test off thingiverse and printed at different speeds.
Here are the results, bridging tests (youtube link).
On the left we can see that going at a slow (10 mm/s) speed results in a very poor first layer.
On the right at Slic3r Auto setting which I believe is 60 mm/s is better but there are still a few strings hanging...
The middle one is printed at 30 mm/s and looks the best.
On the one hand I was expecting faster = better because the plastic wouldn't have time to fall, but I once saw a video somewhere off a printer bridging at 10 mm/s and it came out flawless!
So I decided to do some testing of my own and now I'm more confused than before.
Why did the 30 mm/s turn out better than the others and how can I improve my bridging?

Nice video... I edited your question to try to inline the video, but, unfortunately, it doesn't appear to work. see on Meta - Is the “inlining videos” capability turned off on this site?.

The engineering approach is that if 30mm/s is working best on your equipment (at least on that day), you should use it; at least until it doesn't work so well for you. You might also try more different speeds (closer to 30 than to 10 or the assumed 60) in case one works even better than 30mm/s - though you might also want to question the assumed 60 (or test a set 60) since assumptions can bite you.
There's not going to be a fixed speed that's always best independent of the printer - everything is dependent on the printer, and its environment - if the temperature of the room varies a lot, it could change the "best setting" on days of different room temperatures. Perhaps the "10mm/s" that you saw working well was using a more effective cooling fan while bridging, or had other differences from your particular unit - or had different settings (other than speed - nozzle temperature, for instance) which impacted the result.
(note that I have limited tolerance for videos, and have not actually looked at yours, so if you're going to come back with "but I don't have a cooling fan", please post a picture of the printer or results that does not involve needing to sit through a video. And perhaps add a cooling fan...)
As for "understanding how to best tune your slicer settings" - far more testing, and keep track of the results. So, do tests (without altering other parameters) at 20, 25, 35, 40, 45, 50, 55 mm/s.
Depending on the results of those tests, say you find the best results at 35-40mm/s, perhaps you try 47 and compare that. Perhaps there's no real difference between the 3, so it's in that range, but not picky.
Then alter one other thing (nozzle temperature comes to mind first, but perhaps it's "fan speed for bridging" or some other, single, item) and do more testing - likely the best speed will change, so you'll need to re-run a range of speeds at the new setting. And keep track of which results (test prints) go with which settings, so you can go back to the ones that work best. Then alter that parameter more, or alter another parameter.
For the most part, there comes a point where it's good enough, or at least where you're sick of testing for a while and results are good enough until you want to test / tune some more.
If you change many things at once, it's hard to isolate cause and effect. If you test many settings but lose track of which settings were used for what result, it can be hard to progess towards better results consistently. When you find a range that seems to make no difference (and it's as good as it gets), be happy that the parameter is not too sensitive, and tend towards the middle of it.

While I would generally agree with your comment about videos, to be fair to the OP, the video is actually quite interesting, as it has three simultaneous prints shown, side by side.It makes for an interesting watch. Also, there doesn't appear to be a cooling fan, but it is a bit hard to tell as the video is quite dark.

I filmed against the light on purpose, so the filament dropping would be as clear as possible. Also it has a cooling fan and a ring shaped air duct I got off thingiverse.

Even though I tried my best to describe the video, I put it on the question for a reason, which was to give as much information as possible. Your answer seems to be very much "30 mm/s works better because it works better". So even though you give some tips on how to improve bridging the "why" part of the question doesn't seem answered...

One more thing, could you please elaborate on what is a "more effective cooling fan for bridging"? Size, speed, orientation, etc

A "more effective cooling fan" is not some specific set of specs standing in a field by itself - it's one that does a better job than whatever you are currently using - if, indeed, there's even any benefit to bridging 3 times slower than a relatively slow 30mm/s. When tuning a complex system with many variables, (which a typical 3D printer is) many factors impact the outcome. You varied one parameter (rather coarsely), but you had many other parameters - and the fact remains that 30mm/s worked best (of the settings you have tested so far) for where those other parameters were set.

Changing other parameters (nozzle temperature, size, etc.) will most likely alter where the "best" behavior sets in your printer, and would entail further experiments to find those best settings with the changed parameter. You may be running into things like "how fast will the extruder extrude (at a given temperature, with a given filament) as limits in your "faster should be better" direction. But it may also be that "faster is better" is simplistic and not a good hypothesis. I'm improving print quality on my cheap-junk printer by by limiting acceleration, to limit shaking.


text:
Servo vs Stepper
I'm a new one for this community.
This also not directly related with 3D printing.
I searched about this and I couldn't find good answer.
One of my friends told me CNC machining centers (Milling) mostly use servo motors and CNC laser cutter and plasma cutters use stepper motors mostly.
Position controlling is more accurate in servo motors than steppers.
I think position controlling is more important in laser and plasma cutters than CNC machining centers, but laser and plasma cutters use stepper motors.
Why do laser and plasma cutters use steppers without using servo motors?
P.S.
This question has more area than 3D printing and CNC routing.And also, This question asked for more reason for why use steppers in laser cutters,plasma cutters and CNC router.SO, this is not a duplicate of this  one.

Possible duplicate of Reprap variants with servo motors rather than stepper motors?

I think it has to do with the mass in the control loop. Servos don't have a control loop as such, so are simpler to work with, but are more limited in their ability to move a large mass precisely.

@SeanHoulihane, Actually servos do have a control loop (often called a PID loop because of the parameters that drive it).  the loop is the defining nature of what makes it a servo.  Stepper motors on the other hand run open loop because they have no feedback.  In addition, I would say servos are the better choice for controlling a large mass.  Hmm... maybe I'll add this to my answer.

You don't want "position control" if you are moving your tool along a path. The tool (3dprinting hot end, Laser, or whatever) shall move exactly on the path. When you need to drive to a position the "position control" is important. When driving along a part the control loop means deviations from the path.

Servos do have several advantages; but, they are more expensive and more difficult to control.
Generally, a servo motor is a DC motor but with an encoder to provide position feedback.  A circuit (can be a computer) then compares the actual position (from the encoder) against the commanded position and uses the error to determine how much power to put to the motor (usually by PWM).
Some of the advantages of servos:

The encoders on the motor often have thousands of counts per revolution so they are accurate.
They are a great choice for controlling a large mass.  When beginning a motion, the control loop can detect that more power is required when the encoder does not respond as fast as expected thus putting more power to the motor. This will them automatically reduce as the motor reaches speed and no longer needs the acceleration torque. Also, the servo loop can also apply reverse torque when trying to slow down the large mass to limit overshot.

Some of the disadvantages of servos:

The DC Motors used for servos reach peak power at thousands of RPM.  That means to use them on a printer you will need to gear them down.  This adds to the expense.
You need electronics to PWM the power to the DC Motor and to close the servo loop (usually at least 1 KHz).  This can require a lot of the CPU.  Probably would be more than a Melzi could do since it is already maxed out.
The servo loop tuning can cause the motor to buzz when it is holding position on an unloaded axis.  This could cause print issues.

I know you have likely seen cheap servos out there often called "hobby servos". These are often used in RC.  These use a creative trick that allows them to use a cheap potentiometer to create an inexpensive control loop.  The limit to this "trick" is that it CAN NOT rotate a full 360°; thus, it CAN NOT run a continuous axis.  Yes, I know there are hobby servos out there that are called continuous rotation servos; but, they do that by disconnecting the potentiometer.  In that case they are no longer servos.  This is just a way to use the same control interface to control a standard DC motor and the motors are not accurate.
Stepper motors on the other hand:

Are really cheap;
Don't require complicated drive circuits or control loops;
Love to hold position without a load.

Their downside is that their rotational accuracy is limited by the physical poles of the motor.  This can be improved using micro-stepping; but, there are limits.  Also, it is difficult (often impractical) to determine if the motor missed a step.  That can usually be handled by just making sure that the load on the motor is always well below the step torque.  This often involves managing the motor acceleration.
In summary, servos are great for some applications; but, for low cost situations like 3D printing, steppers are hard to beat.  It is likely servos needed for milling CNCs because the cutting head is much more massive than an extruder or laser and the servo control loop is needed to provide accurate motion for the higher mass.

Thanks, I think I fixed it.  When I changed the answer, I wrote based on my memory of the question (which is often not as good as I think it is).  That was exacerbated further by Stack Exchange hidding the question when you are editing and answer.

Thanks for your answer.
According to your explanation of servo and steppers, I can get one reason for why steppers are used for a laser and plasma cutters.
CNC millings have heavy load/weight to handle. So, Accelerating and decelerating is more important than laser cutters. therefore, CNC milling need a servo. Otherwise, laser cutters have low weight load to move. So, position controlling can be reached using steppers.No need more expensive and complicated system using servo.

CNC Machines use AC Servo Motor.

Servomotors can use steppers internally.  The "servo" part refers to closed-loop position control, and any motor can be used to move the mass around.  It's just that usually it's cheaper to put a large BLDC or brushed motor instead of a stepper once you have position control.

@NSiri - Yes, that is what I think too.

@JashJacob I have heard two different ways for a servo being called an "AC Servo".  One type is a DC Servo whose controller uses AC line power input.  Rectified AC line allows for a much higher drive voltage.  The voltage a DC motor runs at limits its max RPM due do back-emf; so, the higher voltage means higher RPM and HP.  Another motor I have heard called an "AC Servo" is an AC induction motor run in a servo control loop.  This requires a more complicated drive; but for high HP, AC induction motors are WAY cheaper than brushless DC motors.

@BryanBoettcher You are correct, stepper motors and servos motors are  both brushless DC motors.  Like a servo, a stepper is more defined by its control scheme than the motor it uses.  A stepper uses the poles within the motor to step the motor around its axis.  The more steps, the more positions you can achieve.  Similarly, servos benefit from more poles as that makes them run smoother.  Thus both schemes typically use the same motors.  Servo control; however, will allow you to push the envelope of the motor further than stepper control can; but, at the cost of more expensive control.

Servo is best when you primarily provide an exact position to go to, sounds like a human arm isn't it? However, number of positions is sometimes overwhelming.
Think about a painting, is it easier to draw point by point or just throwing the pencil relatively with instincts? That is why you need less computing when using stepper motors because they just step locally without worrying about the overall painting. Having said that, it is more costly for a stepper motor to travel far distances because it has to think about its every step.

The main reason why stepper motors are used is their low price. Small stepper motors (NEMA 17 and smaller) are powerful enough for 3D printers because the mass is so small. These motors generally require a maximum of 2 amps of current. 2 amps is small enough that control chips with all the circuitry and drive electronics can be manufactured as an integrated unit. The most common chips in 3D printers are the Allegro line of chips. Since they are so common, the price per chip is extremely low.
Servo motors could have a similar fully integrated chip, but the issue is servos need to be tuned for their specific application. A servo needs to be tuned separately for each axis of each model of a 3D printer (or other CNC device). This makes servos much more difficult to use for hobbyists in particular. If a servo is not tuned properly, it could oscillate dramatically or respond to inputs too slowly. The interface for tuning would probably be a serial interface, which would increase the cost and complexity dramatically.
Additionally, servo motors require an encoder of some type. Often it is an optical encoder, but there are also magnetic encoders and capacitive encoders. The cost of the encoder is essentially constant no matter how powerful the motor is, so when you have a small motor, the cost of the encoder is significant. High resolution magnetic encoders are $3 each in bulk. That would add a lot of cost to the motor, not including the other more expensive drive electronics. Optical encoders can be cheaper; I'm not sure of the specific pricing on those.
Ignoring cost, servo motors with high resolution encoders would definitely be better for 3D printers. I think we will likely see some higher end consumer printers with servos come onto the market soon. Servos would eliminate missed steps, potentially increase acceleration and maximum speed (depending on the size), and would reduce vibrations if properly tuned.
The answer given by markshancock brings up good points too, but I wanted to elaborate on the cost issue.

The basic difference between a traditional stepper and a servo-based system is the type of motor and how it is controlled. Steppers typically use 50 to 100 pole brushless motors while typical servo motors have only 4 to 12 poles.

I cant understand your answer correctly. can you please explain what  are the poles that you said.

Servo for spindle to control rotation speed of cutting bit.
Stepper to control movement and tool position.
All CNC machines.

CNC spindle is controlled by a high RPM motor.Its not suitable servo or stepper most of time.

authors: ธนวัฒน์ อรุณศรี


text:
Prusa i3 Z axis only goes down (even on up command)
I have just finished building a Tronxy P802M Prusa i3.
When I try to move the Z-axis, using the hardware buttons in the LCD menu (without a computer connected), it only goes down, when I both increase, and decrease, the value of Z.
Any suggestions?

See similar issue at https://3dprinting.stackexchange.com/questions/4090/my-prusa-i3s-z-axis-will-only-go-up/4091#4091

Increasing the value of Z makes it go down as well? Does it make any unusual noise? I had to loosen the nut on the right lead screw, otherwise the right motor wouldn't turn when I increased the value for Z

@markshancock - I thought that was similar too, except in this case it moves down for both up and down commands, which is odd.

It could be a hardware fault.
First check, and compare, the control board connections to the motors of the three axes. You don't state it in your question but, presumably, the X and Y axes move correctly? If so, then compare the connections for the Z-axis motors with the connections for the motors of the axes that work as expected.
If they are correct then the problem is likely to be with the firmware.
Have you...

homed the Z-axis yet?
installed the endstops?

From X Y Z axis only move one direction?:

Using Marlin? Before you do a G28 homing the axes will only move
  towards the endstops. But also check your endstops with M119 to make
  sure they are triggered at the right time. On older Marlin, you may
  need to set DISABLE_MAX_ENDSTOPS (on a machine that has no max
  endstops). Newer Marlin uses USE_XMIN_PLUG, etc., to specifically
  set which endstops are connected. If the switches show the opposite
  state (off when triggered) then set the
  [XYZ]_(MIN|MAX)_ENDSTOP_INVERTING flags, as needed.

Likewise, from Building a Prusa I3 3D Printer:

You will probably also find the motor will turn only in one direction. This is normal for now as we don't have end-stops installed and haven't homed the axis - so the software doesn't know how far it can go in one direction or the other.

As Mark states in his comment, the P802M uses a Melzi board. From Github: Repetier-Firmware/boards/Zonestar P802M/:

There are some printers sold under different names like 'Zonestar
  P802M', 'Prusa i3 P802M DIY kit', 'Anet A8-B', etc, which have LCD
  20x4 with 5 keys controller connected to Melzi V2.0 board via 10 wires
  cable. Keys are connected to a single analog input using resistive
  divider.

Thank you guys, it took me a while but it was a faulty cable,
One stepper motor worked but the other did not. But, apparently, both have to work for even one to turn.
The cable had one wire isolation still in place, so there was no connection from the board to the stepper.
I also had another cable with the wires connected in the wrong order, as well.
Bottom line - it is working. And printing well.
Now it seems like I have problem with the z-sensor (stopped working after a few hours of printing). But I'll figure it out tomorrow.
Thank you for your help.


text:
Help with Repetier firmware (probably locked and licensed)
I'm in the process of tweaking the firmware (Repetier 0.92.6) because of some problems mentioned here: Delta printer printing incorrect dimensions in X and Y directions. Z dimensions are correct
But I found out that the printer manufacturer has locked the firmware (probably) and I cannot edit it. So I have to burn a new one (I guess? Correct me if I'm wrong)
Printer name: Dimension Dual Delta
Manufacturer: J Group Robotics
Website: http://www.jgrouprobotics.com/dimension-dual-delta
I have the slicer (Simplify3D) configured with the FFF profile as my printer was working completely fine up until a few weeks ago. I just want to know that if I change the firmware, would I have to change/update the profile as well? If yes, how do I do that?

Here is a screenshot of Repetier host. The "JGR" continues indefinitely:

Here is the actual log text
22:56:00.216 : OpenGL version:4.2.0
22:56:00.218 : OpenGL renderer:GeForce GT 540M/PCIe/SSE2
22:56:00.218 : Using fast VBOs for rendering is possible
22:56:06.634 : Printer reset detected - initalizing
22:56:06.661 : start
22:56:06.662 : Info:External Reset
22:56:06.662 : Info:Autoleveling enabled
22:56:06.662 : Transformation matrix: 0.999994 0.000010 0.003587 0.000000 0.999996 -0.002727 -0.003587 0.002727 0.999990
22:56:06.865 : N1 M110*34
22:56:06.865 : N2 M115*36
22:56:06.865 : N3 M105*36
22:56:06.865 : N4 M114*35
22:56:06.865 : N5 M111 S6*98
22:56:06.869 : N6 T0*60
22:56:06.870 : N7 M20*22
22:56:06.871 : N8 M80*19
22:56:06.872 : N9 M105*46
22:56:08.706 : Free RAM:1002
22:56:08.706 : Autoretract:0
22:56:08.706 : X:0.00 Y:0.00 Z:0.000 E:0.0000
22:56:08.713 : N10 M220 S100*80
22:56:08.713 : N11 M221 S100*80
22:56:08.714 : N12 M111 S6*84
22:56:08.714 : FIRMWARE_NAME:Repetier_0.92.6 FIRMWARE_URL:https://github.com/repetier/Repetier-Firmware/ PROTOCOL_VERSION:1.0 MACHINE_TYPE:Delta EXTRUDER_COUNT:2 REPETIER_PROTOCOL:3
22:56:08.714 : Printed filament:32.75m Printing time:0 days 6 hours 0 min
22:56:08.714 : PrinterMode:FFF
22:56:08.714 : N13 T0*8
22:56:08.745 : X:0.00 Y:0.00 Z:0.000 E:0.0000
22:56:08.745 : Begin file list
22:56:08.746 : End file list
22:56:09.726 : JGR
22:56:09.960 : N14 M105*18
22:56:10.972 : JGR
22:56:11.979 : JGR
22:56:12.969 : JGR
22:56:13.016 : N15 M105*19
22:56:14.028 : JGR
22:56:15.035 : JGR
22:56:16.025 : JGR
22:56:16.072 : N16 M105*16
22:56:17.085 : JGR
22:56:18.091 : JGR
22:56:19.081 : JGR
22:56:19.134 : N17 M105*17
22:56:20.157 : JGR
22:56:21.163 : JGR
22:56:22.154 : JGR
22:56:22.189 : N18 M105*30
22:56:23.202 : JGR
22:56:24.208 : JGR
22:56:25.199 : JGR
22:56:25.245 : N19 M105*31
22:56:26.253 : JGR
22:56:27.261 : JGR
22:56:28.267 : JGR
22:56:28.307 : N20 M105*21
22:56:29.319 : JGR
22:56:30.326 : JGR
22:56:31.316 : JGR
22:56:31.363 : N21 M105*20
22:56:32.376 : JGR
22:56:33.382 : JGR
22:56:34.372 : JGR

Edit: Since it is advisable to get a new controller board and keep the current one as it is, I'm attaching a picture of what my printer is controlled by.

The black box on the green board reads HRD 12008. Google says its a DC-DC SMPS module but mine has some extra connectors than what I could find online.
The black board is a MKS Base v1.3
The other box is a solid state relay.
This is more intimidating than I thought it would be. How do I proceed now? If I get a brand new controller board to play with, which should it be? Also, I can't seem to locate any RAMPS shield.

The reason that you have no RAMPS board is that, on your board, the RAMPS and the Arduino circuitry are merged into one. Any new controller would work, as they all run the same firmware. There are many to choose from. As you are just experimenting (and reverse engineering) at this stage, I personally would buy a cheap Chinese Arduino Mega 2560 and RAMPS board on eBay, for only $10 (if you buy them separately - don't get a combination "deal"), to test your settings. Once you are happy with those settings, then you can spend more money on a better board, should you feel that you need it.

The firmware is not really locked by the OEM1, you just need to upload (or, as you say burn) a new version. This is not unusual2.
Repetier is just like any other firmware that uses Arduino boards. While it may seem intimidating at first, it really is quite easy to regularly upload new firmware to the Arduino Mega 2560 board3. If you are not familiar with Arduino programming at all, then there are a good number of Repetier oriented guides out there, for example, from Repetier's own web site, Repetier-Firmware Documentation.
If are you familiar with Arduino programming, then it really is the same as uploading the Blink sketches, but the base code is just bigger, that is all.
There is too much to detail in a simple answer here and, as I stated above, there are a lot of online guides. However, en bref:

Download and install the Arduino IDE to your Mac/Wintel/Linux PC;
Download the latest Repetier firmware to your Mac/Wintel/Linux PC4;
Connect the Arduino Mega 2560 to your PC using a USB cable;
Change the settings, i.e. Boards and Port settings, in the Arduino IDE, so that your PC can "see" the Arduino Mega 2560;
Open the Reptier firmware, that you have just downloaded, in the Arduino IDE;
Configure the Repetier firmware source code, i.e. make some edits in the Configuration.h file5, with the tweaks that you require (which you mention in your question)6;
Compile the firmware using the Arduino IDE. and (finally);
Upload the firmware to the Arduino Mega 2560.

That is it. Once you have done it a few times, it will become second nature.
Watch a few online youtube videos, as well, before you start, so that you have a better idea of what to do. For example:

Repetier 0 92 8 Firmware Configration. or;
Kossel Mini 3D Printer Repetier Firmware and Calibration.
As an aside, for gaining a basic understanding of the configuration file of Marlin, not Repetier, I found this video #18: Calibration extremely useful. If you feel like changing the firmware completely, this may come in handy.

With respect to the Slicer's profile settings... I am not sure about that at all.
The reason that you have no RAMPS board is that, on your MKS board, the RAMPS and the Arduino are merged into one. Any new controller would work, as they all run the same firmware. There are many to choose from. As you are just experimenting (and reverse engineering) at this stage, I personally would buy a cheap Chinese Arduino Mega 2560 (€6) and RAMPS (€4) board on eBay, for a total of only €10 (if you buy them separately - don't get a combination "deal" as they are generally more expensive - although compare the prices first, you may find a bargain), to test your settings. Once you are happy with those settings, then you can spend more money on a better board, should you feel that you need it.

Footnotes
1 If you have to get around the licensing, then it sounds like you could/should recompile the firmware, or use some other firmware, i.e. Marlin. However, wait to see what other people suggest.
2 There really isn't much risk in uploading new firmware. The only risk, which I guess Mark is referring to, is that you may/will not have the correct firmware settings for your make of printer, and therefore the printer may not work correctly, until you get the firmware settings correct. So, in that respect, it is a good idea to buy a secondary Arduino Mega and RAMPS1.4 board to play with, for just $10 (Chinese clones work just fine). But, as you say that your board already has bad settings, and you do not wish to pay for more licensing, then you haven't much to lose by uploading new firmware to it, except the warranty. So, if I were in your position, and I did not want to pay the licensing, I would set aside the supplied controller (for possible future use/reference), and use a Arduino Mega 2560/RAMPS 1.4 combination to control the printer. That said, if your printer is still under warranty, can't you ask the manufacturer to supply you a new controller with the correct settings?
3 There is no way of extracting the code from an Arduino and then modifying it. You need the original source code files. See Is there any way to download a sketch from an Arduino? OK, you can obtain the machine code, but unless you are an expert, or guru, modifying it is impossible.
4 The installation order, of the Arduino IDE and Repetier, will not matter. You probably need to rebuild the firmware, I would guess, but I am not 100% sure. It might be a good idea to contact the vendor to see what they recommend, before overwriting their code (assuming that the control board came pre-programmed)
5 I found this video #18: Calibration extremely useful, for configuring Marlin, and understanding the firmware settings in the Configuration.h file.
6 You may find this link useful for your "tweaks": Repetier-Firmware configuration tool for version 0.92.9 version

Actually I just need to change a few parameters in the firmware since after an unexpected reboot, the calibration got all screwed up. But when I tried to do that using the repetier host, the log constantly shows the name of my printer's manufacturer and I'm unable to execute anything. Is there any workaround to it?

@OjasviSrivastava - Can you post the log file contents, or a relevent excerpt, in your question? Also, clarify in your question that you are using Repetier Host and state exactly what happens, and what you are doing, or trying to do. The more information you provide, then the more accurately someone will be able to address the issue that you are experiencing.

I've added a screenshot. I've never really done this before so let me know if you need any more details. Is it important to install Arduino IDE before repetier host? I did it in the other order.

@OjasviSrivastava - No the installation order will not matter. You probably need to rebuild the firmware, I would guess, but I am not 100% sure. It might be a good idea to contact the vendor to see what they recommend, before overwriting their code (assuming that the control board came pre-programmed). WRT the log, instead of a screen shot, it would be better to copy and past the actual text from the log (if possible), as, thereafter, it is easier to copy, or search (whereas the text in a screenshot is neither copiable nor searchable), or provide both the text and screenshot.

well the vendor is asking me to renew the contract which will cost me a lot. He'll provide me any support only after I do that. If I could only tweak the relevant parameters (delta radius, rod length etc) without rebuilding the entire firmware that'd be great. PS: I've pasted the log in the question. Hope that helps

@OjasviSrivastava - If you have to get around the licensing, then it sounds like you could/should recompile the firmware, or use some other firmware, i.e. Marlin. However, wait to see what other people suggest. Can you edit your question to state the actual brand/make/model of the printer? BTW, I found this video #18: Calibration extremely useful, for configuring Marlin.

so there isn't any way to edit the current configuration.h file? I'll wait for some time for an answer to this. Alternately, is there any way to view the file so that i can use most of the values and change only the relevant ones while compiling a new firmware? Also, is Marlin better than Repetier?

@OjasviSrivastava be aware that there is some risk burning custom firmware.  I know of one person that tried this and was unable to print for quite some time.  If you cannot tolerate the down time, I recommend that you consider either buying a second controller card (they are often VERY cheap on ebay if your printer is using a generic RAMPS/Melzi board) or get an external programmer (that connects to the ISP connector) so that you can first make a copy the firmware/fuse settings so you can restore your printer controller to its current state if things do not go well.

@markshancock can you please elaborate the two methods you've stated here? I have zero idea about all this. Any tutorial link would be helpful too. So you're saying that a firmware can only be copied to another controller card/ external programmer? I was wondering if there is any way to extract the firmware from the current board as a workable file that I can tweak in Arduino IDE. So far I've only been able to extract EEPROM value using Repetier host. But for all I know, those values are incorrect as my printer is likely reading those values following the unfortunate reboot

@OjasviSrivastava - Sorry, I meant to reply last night. There is no way of extracting the code from an Arduino and then modifying it. You need the original source code files. See Is there any way to download a sketch from an Arduino?. OK, you can obtain the machine code, but unless you are an expert, or guru, modifying it is impossible.

@OjasviSrivastava - There really isn't much risk in uploading new firmware. The only risk, which I guess Mark is referring to, is that you may/will not have the correct firmware settings for your make of printer, and therefore the printer may not work correctly, until you get the firmware settings correct. So, in that respect, it is a good idea to buy a secondary Arduino Mega and RAMPS1.4 board to play with, for just $10 (Chinese clones work just fine). But, as you say that your board already has bad settings, then you haven't much to lose by uploading new firmware to it, except the warranty.

@OjasviSrivastava This article explains how to use an AVR programmer to backup your existing firmware so (in theory) you can always get back to your original code.  As Greenonline mentioned, this is a binary backup and is not intended to be modified.  Trying to reverse-engineer modifiable code from the binary code on the Arduino is not realistic.

@OjasviSrivastava - As comments may be deleted at any time, I have moved the pertinent information, from those comments, into my answer, as footnotes, so that the information is not lost. Please see my updated answer.

@markshancock - As comments (especially extended discussions, such as this) may be deleted at any time, it might be wise to post the information, contained in your comments, into an answer - so that the information is not lost. Also, it would centralise the information, and save others having to trawl through a lot of comments  :-)

@Greenonline I've edited the question with a picture of my printer's control board. Please let me know how to proceed. My printer is not under warranty otherwise the vendor would've taken care of everything.


text:
Cura grey large grey area, almost nothing fits…
I can't seem to understand the margins that Cura uses or how to fix them for my machine. Look at this:

I can't seem to tweak the stuff under machine settings to anything that does this better:

Maybe a bit of dup of Cura not allowing full print area to used, but I think my case is a lot worse and can't be explained by skirts.

As Carl points out in his answer, could you post your brim/raft/skirt settings?

You are using Cura 2.5, you should mention it in your question... I see that you have posted this query on Cura 2.3 - Not using full print area as well... so presumably you have made brim/raft/skirt all visible and set to zero?

I had mistakenly left the setting "one at a time" in print sequence. This meaning the printhead needs a lot of room since it will go back and forth in z.
Cura allocates this extra space even if there's only one object.

Don't modify your question inside an answer.  Either edit the question or delete it and post a new question.

@CarlWitthoft is quite right. The answer to your question seems to be that you had "one at a time" selected. It is good that you found a solution to your problem, and that part should remain, in this answer. However, your additional points seem to be another question. It would seem to be best to cut those additional points from this answer, and then paste and post them in another question, whilst linking back to this question, as reference. Otherwise, people will not be able to address, and answer, your new queries.

Removed my opinions. Thanks for pointing it out. I guess there's that human need to explain why I didn't think about it :) But it doesn't belong here of course.

That looks like you've got the "brim" set to a very wide value.  I know you said it's not explained by skirts --which, as Greenonline pointed out, is not the same as a brim--, but you didn't post that setting. At the same time, make sure you don't have a 'raft' set up.
One other possibility is that your source file actually contains a very large first layer.  Try looking at the STL file in Meshlab or Meshmixer to see what's actually there.

+1, but technically speaking, a skirt isn't exactly the same as a brim... see What are main differences between rafts, skirts and brims?

@Greenonline thanks - I wasn't actually aware that Cura supported skirts; just brims.

No brims, skirts or rafts.

authors: אביבית וזאנה


text:
Monitoring X, Y, Z position of extruder in real time
I have a wooden first generation Replicator with dual extruders and I'm trying to get an X, Y, Z position from the printer to the computer in real time. Is that even possible?
The firmware used by the replicator is version 5.5 I believe, and I've been doing tests with ReplicatorG but I'm not married to that software.
Please let me know if you need any extra info before being able to comment on this...

I personally use a Dremel and the Dremel 3D software. Using that software I am able to see what the layer pattern will be like but I am not able to see the printing on the software in real time. Could you give me more information about your software and your printing setup. I personally don't know why you would want have you pc tell you what is happening when you can just look at the machine itself. But looking at your question from the surface I would say there is not way. The x,y,z coordinates wont show in real time on your PC if you printing via SD card like i do.

The firmware used by the replicator is version 5.5 I believe, and I've been doing tests with ReplicatorG but I'm not married to that software. From Ecnerwal's comment it sounds like Repetier might have more functionality?

There is an open source MTConnect adapter/agent written in Python for MakerBot Replicator that includes axis position. To my knowledge it was only developed for and tested on a Replicator 2, though.
https://github.com/mtconnect/makerbot_agent

oh dang, thank you! this looks rad! I think the 2 had additional data logging mechanisms (the makerbot desktop software seems to offer some sorts of monitoring functions but only on the 2?) but I will dig into it.

I'm not sure you would actually need the MTConnect adapter/agent for anything, but it was developed by some random users not MakerBot. So there must be some way to get axis position natively in order to write this adapter/agent in the first place.

right - I dont think the hardware existed the 1st gen reps, so no native position monitoring as far as I understand things

Late to the conversation, but applying the MTConnect Adapter/Agent linked above to a Replicator Dual mostly provided Extruder (both) and Heat Bed temps (I believe commanded and actual), some of the standard state values (Execution State, Activity, etc.), and the program running.

Depending on your methods, you can easily (evidently) get (or compute) "where the printhead is commanded to be" in more-or-less real time, as evidenced by the "progress display" in Repetier Host software (based off the G-Code it's sending to the printer) - though I have found it advisable to stick with the temperature display while printing as I've had the host bog down on processing the display at least once, which then made the print go slow.
As for "is it even possible" - sure, how much would you like to spend? Add encoders to each axis that are read by the computer, or by something (probably not your printer processor for "least impact on the printing" and "most real-time") that reads them and talks to the computer. The more precise you need, the more expensive it gets. Of course that also starts to probe 'what you mean by "real time" ?' as there are applications where the time spent reading the encoder and sending/receiving the data would be considered "not real-time" by the time the computer had the data, but for the average person with a printer built partly from wood, it's likely "real-time enough."

thanks Ecnerwal. I'm going to explore some software routes before getting to buying encoders, but I agree with you that if I really wanted to monitor xyz position in real time (an update rate of 1/10th a second is probably fine) that would be the way to go. I'll definitely look into Repetier - the tracking doesn't have to be perfectly accurate. This is for a (music) composition project, so I have a fair amount of freedom deciding what is needed / accurate enough but its hard to know in advance.


text:
How to fix bad extrusion on my printer
Around 30% into a large print I had to cancel as the layers of the print were not full layers and looked very stringy. Here's a couple pictures of what it looked like.

I have a feeling that it may be because of my retraction settings either being too high or too fast as this section it was printing had to use a lot of retraction. My retraction settings are 40mm/s for 4.5mm. I was printing at a pretty slow speed (around 55mm/s), and I'm sure confused on why it's not extruding properly at certain times. If anyone has any idea on what is happening and how to fix it it will be gladly appreciated!
I have an Anycubic Delta linear printer with a Bowden extruder, I use white 1.75 mm PLA at 200C, .4mm nozzle

Maybe try reducing your printing speed to 30 mm/s. Are your settings appropriate for the filament diameter? What is the diameter of the filament that you are using? Nozzle size?

What material type, temperature settings, etc?

This looks like missing extrusion due lack of filament feed. The feeding gear needs more traction. Retraction I recommend 80mm/s for 2.0mm

It appears that at a certain point, you're running into issues with the extrusion being a bit too viscous / melted causing it to over-deposit or string (fail to retract completely). It also looks like this issue gradually gets worse as you go. This really feels like nozzle over-heating to me.

My troubleshooting steps would go like this:

Make sure my cooling it set correctly and fan is working properly. The nozzle doesn't adjust its temp for changes in extrusion speed. At times the printer has to rely on the cooling to get the extrusion leaving the nozzle to an ideal deposition temp, which is far lower than the temperate of the nozzle.
Check my tool paths to make sure I'm not starting to return to the same X/Y position too immediately when I reach certain layers, not allowing the previous layer to fully solidify. Consider tweaking the slicer or printing at a lower temperate.
Check if there's a lot of variance in print speeds for different tasks (shell, infill, etc). It can be hard for some printers to maintain the right temp for the extrusion about to be deposited if the speed changes too rapidly. If your printer has been heating extrusion rapidly for quick movements and then the speed slows way down, it can struggle to keep the subsequent slow filament from getting overcooked, as it can't instantly cool the nozzle even with proper cooling. Bring the various extrusion speeds closer together.

Your point #1 sounds incorrect. The temperature of the nozzle doesn't generally get changed with changing extrusion speed, and the general advice for cooling fans is to avoid hitting the nozzle with the flow, as it's intended to cool the extruded filament only.

What you said is correct. And admittedly the way I wrote that is a bit misleading... the cooling primarily affects the temperature of the extrusion, not the metal of the nozzle. However, the nozzle is always far hotter than the melting point of the PLA. So if the PLA spends more or less time in the nozzle without effective cooling just outside the nozzle, it will still be past its ideal deposition temp.

Try using 20 mm/s and 3.9 mm for your retraction and that should help. Also, what is your fan speed at?

Are you able to offer a bit more explanation on why 20mm/s and 3.9mm would make an improvement? How did you come up with these magic numbers? Also, please note, that to request clarification from the author ("what is your fan speed at?"), you should leave a comment on the original question rather than posting an answer.

I got the numbers from my personal experience and that is just what worked best for me after trying a whole  bunch of different retraction settings

It seems your printing temperature is too high. If there's a tiny space between the nozzle and the Teflon tube, high printing temperature will lead to a partial clog. And this will lead to under extrusion. Try lowering printing temperatures and printing speed. And also check whether there's a gap between the Teflon tube and the nozzle.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Complete list of fasteners for the Sintron Kossel
TL;DR
I need a complete list of fasteners (bolts, nuts and washers) for the Sintron Kossel.

Has anyone bought this kit, and knows the answer, or knows where this is documented?
A complete list would be great, but in particular, I need the dimensions (M2.5/3/4/5? and length) and quantity of the bolts (and nuts) which:

fasten the PCB mounted mechanical switches to the PLA rectangular end stop spacers/holders, and;
fasten the PCB mounted mechanical switches and the PLA rectangular end stop spacers/holders to the extruded 2020 aluminium.

I have:

Searched the web, but to no avail;
Read the product page, which states only "screws and nuts provided";
Contacted Sintron, but not had an answer;
Obtained the Sintron build manual but there is no list contained therein, nor contains details about the fasteners relating to the endstops, and;
Obtained the Blomker manual, from which the Sintron manual is copied, but that also has no list (as well as not being relevant with respect to the endstops).

Note that I am only interested in the fasteners specifically for the Sintron Kossel and not the Kossel in general. The Sintron uses the PCB mounted mechanical switches (with four holes), and not the simple barebones mechanical switches (with two holes), and uses 2020 aluminium1, not 1515 OpenBeam:

Why? Because I purchased only the 3D printed parts from Sintron, and I am sourcing the rest of the parts cheaply, either locally or from Chinese suppliers on eBay.

1 In my particular case, there is an additional complication. The profile of the non-standard/non-"European" 2020 extrusion that I am using, does not take T-Nuts, only M5 hexagonal nuts (it is unbelievably difficult to find the standard 2020 extrusion in Bangkok). Combine that with the fact that the Sintron kit uses only M3 nuts and not M5 (I only discovered this after purchasing the printed parts kit (see the email from Sintron, in my answer below) - not through lack of research, but because there is no available list of fasteners), then I have the problem of finding a nut to use (see Fat hexagonal M3 nuts, with outer diameter greater than 6 mm).
Here is a photo

The Sintron build manual clearly states what fastener is used for each location.  Every picture has the size and length on it.

For the endstops you're just going to have to measure what you have for parts and buy as needed.  I'm not even sure how they use all 4 holes as it looks like 2 of them may block the connection.

Also, many wire cutters/crimpers have bolt cutters built-in near the hinge that are more than capable of cutting M3 screws - http://a.co/dew90MR so you could just buy the longest length you can find that are fully threaded and cover everything below.

@tjb1 - Unfortunately, the SIntron build manual does not state it clearly for the endstops. Blocking the connection - yes, it is a pretty crappy printed kit, to be honest, FolgerTech is superior, although I only paid $20 for the PLA parts and $20 for the 2020 aluminium... Cutting bolts to length. with wire cutters, tends to damage the thread of bolt. A Dremel will do though, I suppose, but I would prefer, in order to keep costs to a minimum, to order the correct length of bolts, as the longer bolts cost more... Not by much I know, but I'm building these for people on extremely tight budgets.

@tjb1 - Hmmm, yes, upon reflection, the manual does clearly state that M3 bolts are used for the frame assembly. If only I had read the manual before buying the 2020 that only accepts M5 hex nuts, I would not be in such a pickle, I must admit.. :-) I might have to use this set of 2020 extrusions with another part set, that does use M5, and get a new set of lengths of "European"/Standard 2020 cut for use with the Sintron kit.

Have you tried to buy your extrusion from Misumi?  I'm not sure if they ship to the UK but they do have a European site and it is fairly cheap from them cut to whatever size you want.

@tjb1 - I am in Bangkok. I looked at Misumi about a month ago, but aluminium in Thailand is about 30-50% the price of US/Europe... although that would explain why you don't always get quite the right specification... :-)

You may want to simply make square "nuts" to suit your extrusion with flat stock, a saw, a drill, and an M3 tap. That's what I'd do, anyway, if I couldn't find ones to purchase.

@Ecnerwal - Good idea, that would be a great answer to my question on SE.Engineering: Fat hexagonal M3 nuts, with outer diameter greater than 6 mm

After examining the guide (Kossel mini instrution by sintron technology_v2) and the printed parts kit, I came up with an 99.9% complete parts list. The lists relating to the effector and autoprobe mount maybe slightly incorrect:
##Parts List

###Listed by Printer part/section:

####Fasteners

#####BOTTOM VERTEX (QUANTITY = 3)

For each:
10 x M3 x 8 mm
10 x M3 nut (T-nut)

#####TOP VERTEX (QUANTITY = 3)

For each:
5 x M3 x 8 mm
5 x M3 nut (T-nut)

1 x M3 x 35 mm
1 x M3 nut
1 x M3 washer

#####IDLERS (QUANTITY = 3)

For each:
1x M3 x 25 mm
4x M3 Washers
1 x M3 Nut
2x F623ZZ

#####MOTORS (QUANTITY = 3)

For each:
2 x grub
4 x M3 x 8 mm
1 x 16T/20T GT2 pulley

#####EFFECTOR

6 x M3 nyloc nuts
6 x M3 x 25 mm

4 (5?) x M3 x 16 mm <<==, or
2 (3?) x M3 x 16 mm <<==
2 x M3 x 20 mm <<== For the auto probe, if mounting the autoprobe directly on to a collar, above the hotend, and not on to the flange on the Sintron PLA collar

4 (5?) x M3 nuts <<==

2 x M3 x 8 mm <<== fan mounted to Sintron PLA collar
2 x M3 nuts <<==

1 x PC4-M6

Note: Some additional bolts are required for the mounting of the hotend. It is unclear what these are. See link.

#####VERTICAL CARRIAGES (QUANTITY = 3)

For each:
2 x M3 x 20 mm

#####ROLLER CARRIAGES (QUANTITY = 3)

For each:
2 x M3 x 10 mm
1 x M3 x 25 mm
3 x M3 nuts
3 x M6 x 25 mm
3 x M6 nut
2 x M6 washer (optional)

#####ENDSTOPS (QUANTITY = 3)

For each:
1 x M3 x 8 mm <<==
1 x M3 nut (T-nut)
3 x M3 x 8 mm <<==
3 x M3 nut

#####SPOOL

6 x 625-2RS Bearing (or 625zz)
5 x M5 x 20 mm
1 x M5 x 25 mm
6 x M5 nut
6 x M5 washer
(or 7 x M5 washer – there is a discrepancy between the kit (7) and the manual (6))
3 x M3 x 8 mm ?
3 x M3 nut (T-nut)

#####EXTRUDER

1 x M3 x 40 mm
1 x M3 x 8 mm
1 x M3 x ?? mm <<==
2 x M3 nut (T-nut)

1 x PC4-01

#####AUTOPROBE

Note: This is optional

2 x M2.5 x 12 mm
1 x M2.5 x 12 mm
2 x M3 x 8 mm <<==  If mounting the autoprobe on to the flange of the Sintron PLA collar (if mounting directly on to a collar, above the hotend, then these are not required, and 2 x M3 x 20 mm replace 2 x M3 x 16 mm on the effector)
2 x M3 nuts <<==  If mounting the autoprobe on to the flange of the Sintron PLA collar (if mounting directly on to a collar, above the hotend, then these are not required)

Safety Pin 2.5 mm
Spring 23.5mm

Terminal Block
1.5mm Allen key

Note: Some additional bolts are required for the mounting of the autoprobe, as well as the hotend. It is unclear what these are.

#####GLASS BED

3 x M3 x 8 mm ?
1 x M3 x 20 mm
4 x M3 nut (T-nut)

#####RAMPS

Note: This is optional, as mounting on the top will interfere with the spool

2 x M3 x 35 mm
2 x M3 nuts
2 x M3 nuts (T-nut)

###Total Parts:

####Fasteners

#####BOLTS

Size, Length, Quantity
M3, 25, (1×3)+(6)+(1×3) = 3+6+3 = 12
M3, 8, (10×3)+(5×3)+(4×3)+(4x3)+(3)+(1)+(2)+(3) = 30+15+12+12+3+1+2+3 = 78
M3, 16, 5
M3, 20, (2×3)+(1)+(2) = 6+1+2 = 9
M3, 10, (2×3) = 6
M3, 35, 3
M3, 40, 1
M6, 25, (3×3) = 9
M5, 20, 5
M5, 25, 1
M2.5, 12, 3

#####GRUB SCREWS

Size, Quantity
?, (2×3) = 6

#####NUTS

Size, Quantity
M5, 6
M6, (3×3) = 9
—
EITHER

M3, (10×3)+(5×3)+(1x3)+(1×3)+(5+2)+(3×3)+(1×3)+(3×3)+(3)+(2)+(2)+(4) = 30+15+3+7+9+3+9+3+2+2+4 = 90

OR

M3, (1×3) + (1×3) + (5+2) + (3×3) + (3×3) + (2) = 3+7+9+9+2 = 33
and
M3 T-slot nut, (10×3) + (5×3) + (1×3) + (3) + (2) + (4) = 30+15+3+3+2+4 = 57
—

#####NYLOC NUTS

Size, Quantity
M3, 6

#####WASHERS

Size, Quantity
M3, (1x3)+(4×3) = 15
M6, (2×3) = 6
M5, 6 (or 7)

####Bearings

Size, Quantity
F623zz, 6
625-2RS, 6
OR
625zz, 6

####Printed Parts

TBD

####Structural

3 x 2020 x  750/600 mm
9 x 2020 x 360/240 mm

####Electronics

1 x Arduino Mega 2560
1 x RAMPS 1.4
5 x Stepper drivers
3 x PCB mounted mechanical switch
3 x Stepper motors
1 x Extruder stepper

####Belts

3 x 16T/20T GT2 Pulley
GT2 belt (5 meters)

####Other Parts

Safety Pin 2.5 mm
Spring 23.5mm
Terminal Block
1.5mm Allen key
9 x Delrin wheels
9 x 696zz bearings

1 x PC4-M6
1 x PC4-01

###Uncertainties

The fasteners required for the following parts is, as yet, unclear

Effector/Hotend mount
Autoprobe mount
Additional Extruder holder screwpoint

###Assumptions

Hotbed frame mounts (assumed to be M3 x 8 mm)
Spool frame mounts (assumed to be M3 x 8 mm)
Endstops (four M3 x 8 mm are used, not just one)

See also Kossel - Sintron parts list.

I have a partial answer from the suppliers:

Hi
Good Day !
thanks for your contact.
we use M3 bolts + T-nuts .
i suppose the problem is , you don't have T-nuts , right ?
T-nuts is used for 2020 extrusion.
with warm regards.
james

I replied for a clarification of the length required:

Many thanks for the reply.
I have two types of 2020 extrusion, with differing profiles: one that
  takes T-Nuts, and; one that takes regular hexagonal M5 nuts.
For the T-nut extrusion I have both M3 and M5 T-nuts.
However, the second type of 2020 extrusion takes regular M5 nuts.
  Regular M3 nuts will not stay in place, unless I can find some M3 nuts
  with a larger outer diameter, greater than 7 mm.
With respect to the M3 bolts, what are the lengths required? Are two
  lengths used? One length to secure the endstop switch and holder to
  the 2020 extrusion, and then another length to secure the remaining
  three holes? Looking at the diagram in your build guide, it seems as
  if only one bolt is used to secure the endstop switch and holder to
  the frame, is that correct? Are any other bolts used to secure the PCB
  mounted switch the the endstop holders.
I thank you in advance.
Best regards

I followed this up with a second email

Hi again James,
Following on from my previous reply.
Firstly, I have found that flanged M3 nuts will work perfectly, in the
  extrusion that will not accept T-Nuts.
Secondly, what I really am looking for is a list of the lengths (and
  dimensions) of the bolts used throughout the Sintron build. In
  particular the endstop bolts. Rather than having to iteratively deduce
  each bolt, a list of the bolts used would be very handy.
I thank you again in advance for your kind consideration.
Best regards,

I received a second reply from Sintron

Hello Friend.
for endstop . it's M3*8mm .
i am collecting the list of them for you soon.
thanks.
james

As a friend of mine said "sounds like a lot of data; but no useful information".  I added some info on the t-nuts and screws to my answer above that may help.  This is another solution that might work.

@markshancock - The particular 2020 aluminium extrusion, which I am using, will not accept regular T-Nuts, although I am not sure about the slim half T-Nuts. See Fat hexagonal M3 nuts, with outer diameter greater than 6 mm. Flanged hex M3 nuts seems to be the way to go.

@markshancock - I love the idea of 2830 pieces of fasteners... :-)  Unfortunately, upon further thought, flanged hex M3 nuts aren't a solution, after all. They would have no purchase on the sides of the slot and would spin hopelessly upon being tightened. Seems like I will have to get standard extrusion, that will accept T-nuts, and use the non-European extrusion for a different set of printed parts that use M5 nuts.

I am really surprised you are having so much challenge with the t-nuts fitting the extrusion.  The extrusion you have must have an non-standard profile.  If you buy more 2020 from eBay, I recommend you buy the t-nuts as part of the set.

Here is the offering on eBay where I got the profile.  I dislike linking eBay offerings since they are temporary.  I'm including it separately so I can deleted it later if the link goes dead.

@markshancock - I bought the 2020 in Bangkok, 6 meters for $20. See Fat hexagonal M3 nuts, with outer diameter greater than 6 mm for a photo

I found two lists for the Kossel mini (the documents you referenced are for a mini, so that is what I am assuming you got).  One as a Google Doc and one as an order sheet
Both seem to list all the fasteners.
Here is a Sintron mini carriage assembly and it lists the hardware included
I found an ebay listing for the Sintron 2020 Rails.  The recommended screws are M3x20mm and here is the infor on the required t-nuts.
Happy building.

Note: I don't have a Kossel; so, no guarantee the lists are complete.  Anyway, it is a kit; so the parts you need is a bit "flexible".  I built a Tronxy X3 kit and the parts supplied were mostly complete; but, several build steps called out parts that weren't in the kit.  I am glad I have a pretty good selection of screws and nuts in my shop.

Many many thanks, but unfortunately, they are not for the Sintron kossel. I have seen those links (see my (confused) blog Kossel 3D Printer. However, the Sintron Kossel, whilst having many common features with other Kossels, is a bit of a particular/peculiar beast. W.R.T. the  endstop holders, the Sintron uses the PCB mounted types (with four holes), and not the simple barebones mechanical switches (with two holes) that the TriDPrinting/Google docs uses. I'll update my question to be clearer.

@Greenonline   Well that is complicated.  I'll see what I can find and add it to my answer.

For the M3 t-nuts, could you use this printed solution.
You are just attaching a PCB; so, it you wouldn't need that much strength.
Another excuse to use your 3D printer. ;)

That is a good tip, but I need them, principally (along with other reasons), for attaching the extrusions to the vertices, so they need to be strong and in metal really...

But, why can't you use M5 for the other locations? (Note: Use of "But,"  is a homage to your English Post

All of the holes in the Sintron printed parts are M3. I considered reaming the holes to make them M5, but i don't want to lower the integrity of the parts, i.e. weaken them, nor have (slightly) misaligned screw holes, etc.

Did you buy them or print them your self?  I could see not wanting to redrill the holes in a printed part (as it you could cut into the infill); but, certainly they couldn't be that difficult to change the design to use M5.  I can't imagine the margins around the holes would be thin enough to compromise the part.  They can't be carrying that much load.

I ordered them from eBay. BTW, this is a good answer, but it answers the wrong question. That is to say that it doesn't provide a Parts List for the Sintron, which is what I am looking for here, but it does provide a solution to the big fat nut that I'm looking for on SE.Engineering. So, you should post this answer as an answer, or have it migrated, to my question on SE.Engineering: [Fat hexagonal M3 nuts, with outer diameter greater than 6 mm](Fat hexagonal M3 nuts, with outer diameter greater than 6 mm)

@Greenonline, I will add the comment to you engineering post; but, IMHO, it is providing you with a different option for one of the parts to use (so, an alternate parts list).

Unfortunately, I've just realised that this, as it stands, won't work, in my particular case (with the strangely profiled 2020), as it won't accept T-nuts, real, printed, or otherwise. However, I could use the same idea/principle to print some pseudo T-nuts that would fit the profile.

Best to make it your own anyway.  Maybe customize it to you hole pattern.  That is one of the benefits I love about 3D printing, you can make what you want rather than having to use with they make.

Another option would be to purchase some 4mm x 5mm bar stock and tap your own holes.  All you would need is a drill press and an M3 Tap.  That would be as strong or stronger than someone else's t-nut.

Now that would be a great answer to Fat hexagonal M3 nuts, with outer diameter greater than 6 mm


text:
Dual extruder setup in Marlin
I have a Tevo Tarantula with a MKS Base 1.5 board and dual extruders.  I am running Marlin RC8 Tevo Community build for the dual extruder, large bed and SN04 sensor.
All temperature sensors work and give accurate reading but E1 when activated runs at 100% until the overtemps kicks in and shuts down the system.  Like I said, it reads proper temperatures through the thermistor it just won’t stop at the set temperature.  I checked the MOSFET and there is no obvious scorching or bad solder joints on the MKS board.  This leads me to believe it is a mix-up in firmware but, being a bit of a newbie on this, I am still getting familiar with G-code and Marlin.
I have confirmed the correct board is being referenced in firmware from boards.h but looking at configuration.h I just get confused.  What I am thinking is somehow/somewhere E1 might be referenced as a fan that is just off or on.  Anybody have ideas?

Is this build what you are using?

I am not sure what the hardware config is for the Tevo Tarantula
Make sure your configuration.h file is setup for your hardware.
The extruder defines are describe in Conditional_LCD.h
It looks like the configuration.h file on GitHub is configured for a single extruder.
For example, if you have 2 hotends; but, "HOTENDS=2" is not set then the I/O will not be configured for the 2nd hotend.  I just looked at the code and if HOTENDS == 1 then the MOSFET_D_PIN will be used to control FAN1 (which sounds very similar to what you are describing that you are seeing).
  #if HOTENDS == 1
    #define FAN1_PIN     MOSFET_D_PIN
  #else
    #define HEATER_1_PIN MOSFET_D_PIN
  #endif

If the tarantula uses a single hotend, don't define SINGLENOZZLE but define SWITCHING_EXTRUDER and (i think) EXTRUDERS=2.  Then the code will expect the single hotend to be connected to D10.

Thank you for the direction to go. The setup is dual and I "thought" I had checked that.

"Dual" can mean several things.  Do you have two separate extruders (hotends), a (single) mixing extruder, or a (single) standard extruder with a dual filament feeder?  Marlin has to be configured for the specific type.

I had a similar problem, my documentation was wrong and the heater & thermistor were wired in backwards. Maybe recheck your wiring and even try reversing the temp sensor on your board.

Do you mean that you swapped the heater and thermistor connections, or do you mean that the thermistor was connected to the right therminals - but backwards? Thermistors and heaters are generally not polarized, and can be connected either way around. They're just simple resistors.

So, following on from Mark's answer, in line 298 of Conditional_LCD.h, you would need to change:
#define HOTENDS       1

to
#define HOTENDS       2


text:
What tweaks do slicers use to get rafts to stick?
I've always had trouble getting prints to stick directly on my bed, but had great reliability when use rafts. This didn't present a problem when I was using PLA, but I recently got a roll of PETG and it is very hard to remove rafts, so I am once again trying to figure out whats wrong.
I am printing the same file (currently a simple square for testing) with the same settings, except I am turning rafts on/off. When rafts are on, my print sticks perfectly. When rafts are off, my print doesn't stick at all - not even the skirt (which sticks fine on the raft print). With rafts on, I can watch my printer lay down a nice line for the skirt / first layer. With rafts off, I watched plastic ooze out of the nozzle and ride along with the print head, not sticking to the plate at all.
I have a stock Monoprice Maker Select v2 with the PEI surface it shipped with. I haven't tried any bed additions/changes to get better adhesion, since I know rafts stick fine with what I have. I figure there must be some settings I can change to make my first layer stick too. I am using Simplify3D & have tried a few basic tweaks, but I am largely stabbing in the dark.
What are the specific characteristics of a first layer raft, in comparison to a first layer of my print, that might make it stick better?

San you include a photo/image of the part so w get an idea of what you are trying to print.  A photo of the part where it connects to the bed would be especially helpful.

@markshancock I was trying to print a 3d benchy before, and have switched to a 20x20mm square (5mm tall) on the theory that it would be a particularly easy shape. I can try to take a photo later.

The 3dBency should adhere fine without a raft.  Even with that, I often use a skirt to help.  Also, it is common to use a material to help adhere to the table.  Glue Stick is probably the most common for that.  Another issue can be bed temperature.  Some materials will curl and peel away from the bed if they cool to quickly.

Sounds like you're not priming the nozzle properly at the start of the print. I found some initial g-code which extrudes 10mm at the corner of the bed - will try and find it again for you...

Have you ever cleaned your bed with something to remove fingerprints, fat and dust?

You could experiment with the 'cleaning' part of the startup gcode shown here
G1 X100 Y0 F4000 ; move half way along the front edge
G1 Z1 ; move nozzle close to bed
M109 S200 ; heat nozzle to 200 degC and wait until reached
G4 P10000 ; wait 10 seconds for nozzle length to stabilize
G1 E10 ; extrude 10 mm of filament
G1 z15 F12000 E5 ; move 15 mm up, fast, while extruding 5mm
G92 E0 ; reset extruder

I'm not completely persuaded that it helps a lot, but the idea is to fill the extruder (with some pressure from the bed at a 1mm gap) right before starting the skirt. Typically, I still find the first line of skirt may be quite blobby, but a 2nd line of skirt seems much better. Obviously you need the bed alignment right too. A raft seems to have enough 'extra' extrusion to mask these issues a little bit.
Later reflection suggests that these introductory G-code snippets (I've now started using the PRUSA one of a line along the edge of the bed) risk problems  with flexible filament, so it might be best to err on the side of conservative for the extrude volume rather than assume that more is better here.
You can find other similar solutions in this question: Writing G-code : swiping at start of print

Interesting. I wonder if adding an extra couple lines of skirt will do the trick.

@MrGlass that gave me the best bang-for-buck.

The default gcode coming out of Cura 2.5 (MacOS) performs this kind of pre-extrusion.

@CarlWitthoft - Disagree. It's machine dependant, and they seem to typically extrude 3-5mm in free space. https://github.com/Ultimaker/Cura/search?p=2&q=machine_start_gcode&type=&utf8=%E2%9C%93

had to check it wasn't just old settings overriding a new default...

When I started work on mine, the bed leveling and radius (Delta-only issue) were horrid, and my erstwhile assistant was fond of using a LOT of glue stick, which sort-of made things work, though in many cases with no first layer extrusion.
As I sorted things out, I found an apparent bug (Repetier Host (Mac) and Marlin 1.1.0-RC8 firmware - not sure which side the apparent bug is on, really, but I'd guess Repetier) where setting the first layer by percent lead to no extrusion, and setting an actual width/height it extruded. I also got the bed level and radius sorted so the first layer settings actually applied to most of the print area, rather than being wrong for most of it.
Finally, we sorted out some temperature issues (wrong thermistor type setting) and then found a fairly large discrepancy between the heater block and the nozzle (screwed into it) temperature. I now lay down the first layer (PLA) at a purported 240°C, based on a number of trials at different temperatures (which might change with a different batch of filament, I guess) and the rest at a purported 215°C. I set the first layer width to double the height so it's really laying down some plastic. An excessively LOW first layer height also causes problems (as there's very little plastic coming out if the layer is very low, even if you set the width wide.)
My bed is not heated and is plain glass, but I now get reasonable sticking with a very thin layer of gluestick (I put a dab on and rub it around with a little bit of water - it's barely visible.) With a coated heated bed that sticks to rafts, I think you'll just need to work on your first layer settings (including a level bed) and should not need to worry about glue at all.

Good point on bugs - lots of this code is probably correct only in places where it is easily measured, with off corner-case side effects.

While using rafts with PLA is a good idea due to warping, PETG is a material that requires very little build plate adhesion.
When I printed with PLA, I would normally use a two layer raft with a 0.3 mm air gap. With PETG, however, I only need a skirt. I recommend calibrating your extruder height so that when you slide a piece of paper underneath, you feel a gentle tug. While 0.2 mm is enough for printing PLA with rafts, 0.1-0.15 mm has worked well for me in terms of distance from the extruder nozzle to the heat bed.
Also, would you mind sharing your extruder and heat bed temperatures? Ive found that although PETG will melt at the same temperature as PLA, it tends to drag behind the extruder nozzle if the temperature is below ~240°C.
One final note: Even though most PETG distributors specify that a heated build plate is not required, a heated bed helps my prints stick better. I run a 60°C heat bed which seems to make my prints smoother in the end.

Thanks. I know I should be able to print PETG without rafts, which is why I asked this question :) Hopefully we can solve my problem.
I have calibrated my nozzle height as you suggested. As for temperature. I have been running at 245c for the nozzle and 60c for my bed. I did a quick test at 250c but had the same issues.
Still, though, my rafts stick, so I feel like I have the height/temps right (or good enough). I should be able to replicate whatever conditions make the rafts stick using first layer settings (I believe).

Ok, what kind of material do you have on your heat bed? My prints stick with some blue painters tape and nothing else, no glue, no nothing. If you would like, I can share my Cura profile with you so that you can try my settings on your printer. Something else that comes to mind is the environment around your PETG- is it humid or dry? PETG filament is especially susceptible to humidity which may affect the ability of your prints to stick.

My bed is PEI (comes stock on the monoprice printer), sorta a knockoff buildtak. Only time I've had to use painters tape was when my heated bed broke.
Its in a basement that might be humid, but if that was the main factor rafts wouldn't stick either.