Finishing sunken text in 3D prints On several occasions I've wanted lettering/numbering printed as part of a design, but with the ability to make it stand out more effectively in the printed object without having to do detailed manual finishing. Is there a good material which can catch in and fill sunken (depth 0.4 mm, width 0.6-1.0 mm) lines/strokes of alphanumeric characters without sticking to the surface (including fine layer ridges) of the print? My best result so far has been with crayon wax, but I wonder if there are more suitable materials. (Polymer clay, perhaps?)

Results with crayons:

Durability is nice (and essential for some applications), but for many uses I have in mind it's not such a big deal. For example another place I've wanted clear text is on test panels to check nut/bolt thread sizes, in which case the text is unlikely to receive harsh treatment but any heat-based curing processes might effect the dimensional accuracy negatively. So both durable and non-durable solutions are interesting to me.

I think your instinct is good.  The trick is finding the right modeling compound, with the right curing properties, that will stick to your polymer dice, and will be available in colors you like.

Amazon has some epoxy-based clays that appear to be either terra-cotta or black.  If these colors work, this may be the right choice.  Most epoxies will cling well, and it seems to have minimal shrinkage when hardening.  You could probably add some pigment and alter the color, but I doubt you could get a white, yellow, or any light color.

There are some air-drying clays, but the reviews show that these have higher shrinkage.

There are some bake-to-harden clays that harden between 250 and 300 degrees Farenheit.  If you printed with ABS or a high temperature plastic, it might work.  You would have to try it to know.  300 F is only 149 C, so maybe.  PLA wouldn't stand a chance.  If you can print polycarbonate, it might work better.

This material looks interesting: https://www.amazon.com/Polymer-Modelling-Modeling-Tutorials-Accessories/dp/B0716D1VDM?ref_=fsclp_pl_dp_6  There are lots of colors, and it can be cured in a 275 Farenheit oven, with a hot-air gun, or by boiling in water.


Anet A8 ignores extruder temperature? I don't understand what's wrong with my G-code. I have set the printing temperature to 195 °C but when I try to print, the target temperature is always 0 °C and printing never starts.

I have tried changing material preset to different PLA profiles but that didn't help at all.
G-code:
;FLAVOR:RepRap
;TIME:1736
;Filament used: 0.676205m
;Layer height: 0.1
;Generated with Cura_SteamEngine 3.4.1
T0
M190 S50
M104 S195
M109 S195
M82 ;absolute extrusion mode
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 F9000 ;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 F9000
M117 Print0ng...
M83 ;relative extrusion mode
G1 F1500 E-6.5
;LAYER_COUNT:96
;LAYER:0
M107
G0 F600 X90.425 Y93.152 Z0.3
;TYPE:SKIRT
G1 F1500 E6.5
...

In addition, the extruder and heat sensor are working. An older G-code file correctly sets 200 °C as the target temperature for the extruder.

This G-code prints just fine
;FLAVOR:RepRap
;TIME:4628
;Filament used: 1.44191m
;Layer height: 0.15
;Generated with Cura_SteamEngine 3.4.1
T0
M190 S60
M104 S200
M109 S200
M82 ;absolute extrusion mode
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 F9000 ;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 F9000
M117 Print0ng...
M83 ;relative extrusion mode
G1 F1500 E-6.5
;LAYER_COUNT:80
;LAYER:0
M107
G0 F4800 X72.96 Y99.484 Z0.3
;TYPE:SKIRT
---

Note, I have never modified the firmware or changed anything except what I can change with the frontpanel.

There is nothing wrong with the G-code, M109 S195 sets and waits for the temperature to reach the set point. There must be a different reason, other than G-code, why the temperature is not set correctly.

After updating your question by adding another G-code script, the conclusion is that there is nothing wrong with the G-code itself. The problem is that the printer cannot set the 195 °C temperature.

Could it be that the minimum temperature is 200 °C and that it doesn't set a temperature lower than the minimum value?

If you are comfortable enough to flash a new firmware (which you should always do with an Anet A8 as it has no thermal runaway protection) you could try to see if this is a firmware problem.


Where to find "Heat deflection temperature" , "Impact resistance Charpy" and "Tensile strength" for a specific brand Filament PLA? I have an MK3S 3D printer, and I use this table as a reference on how to tune my printer for a specific Filament
brand.
https://help.prusa3d.com/en/materials
I am trying to find a few missing parameters for a specific brand Filament PLA in the table.
The missing parameters are listed and shown in the image below.

Heat deflection temperature
Impact resistance Charpy
Tensile strength

Where is the best place or reference to find such missing data?

Unless the Manufacturer offers them, you have to extrapolate from other brands. Most PLAs are very close and hit within 10% of one another.


Cura is printing support on nothing? I am new on 3D printing, but I cannot understand how support structures (in Ultimaker Cura 4.4.1) can stand if they do not lay on anything, but air. Throwing everything away after 9 hours of printing is not a good experience, did I do anything wrong?

In the attached screenshots images of the sliced model and Cura settings for support structures are shown.

Demonstration of the issue

Here some pics of the real printing results at 50 %-60 % of the work done. One of the two critical supports was barely done while other one, the same encircled in the slicer model, was not. I saved the printing attaching with some glue an "L" shaped piece of cardboard.

UPDATE 11/01/2020

The tree support option greatly failed, but if anybody could suggest different settings I will be happy to try and report here an update. These are some screenshots:

I've highlighted with red pencil the horizontal pieces of structure supported by nothing. I have to say anyway that the resulting model is worth to Moebius, could be an alien spaceship it-self!!!

I have partially fixed the problem setting the support horizontal expansion to 3 instead 0 mm as suggested by a more skilled friend. Anyway, this is clearly a workaround of an intrinsic bug that appears just with Anycubic printer setting and not with other printers configuration. The drawback of using 3mm instead 0mm is that the supports become too strong and some of them completely envelop model parts.

The image of the sliced print part is not very clear but printing support on air is a feature of Ultimaker Cura. This is done when support is laid on top of your print part if you enabled Support Placement to Everywhere, which you did. The default Cura setting for Support Bottom Distance (which is a sub-setting of Support Z Distance) is the layer thickness specified in Layer Height. If you have a layer height of 0.2 mm, the Support Bottom Distance is also 0.2 mm. For the top, option Support Top Distance this is two layer heights, so 0.4 mm in this example. These options are visible in the expert mode, you can search for them in the search box, see image below.

Why should you want air in between your part and the support?

You'll soon find out when you want to remove supports, if no gap is used, the support will fuse to the print part. This is only interesting (no gap between print part and support structure) when you use a different filament for support like PVA or break-away filament; e.g. PVA dissolves in water.

Note on the updated printed part images, you seem to have a stringing issue that needs to be resolved first. Note that it tries to print support on top of inner side of the toroid. Maybe fusing the support will help you to slice better supports, or alternatively set option Support Placement to Touching Buildplate and use an experimental option called Tree Support. You can also try to change the print orientation by rotating the print. Last resort is to design the supports yourself in a 3D model software program.


Uneven layers- Ender 3 I got my ender 3 about a month ago, it was working fine. Tried a new brand, overture, this is when I started experiencing problems. First, I was clogging nozzles left and right, then I went back to hatchbox, and my layers are messed up...

I wonder if this problem is unrelated to your material or printer, and purely a matter of slicer breakage. Have you tried printing gcode files you created before the problem appeared? If you use Cura and upgraded it, you might have hit one of the bugs where it assumes by default you have 2.85 mm filament, even though your printer actually uses 1.75 mm. That will create underextrusion that has the whole printed object coming apart like an unravelling mummy. When I've seen it happen, it looks very similar to your picture.


How to avoid nozzle from hitting the model? When printing objects higher than approximately 8-10 cm, sometimes nozzle hits the printed model and knocks over it. After 7-8 hours of printing that's really annoying. I'm using Creality Ender 3 Pro with Ultimaker Cura. How can I avoid this problem?

As a note; it happens with thick, wide models without support structure too. I'm using Ender 3 Pro's stock magnetic bed.

Here are some photos of printed model.

I use Esun PLA+, the part was on baseplate without any loss of contact. It was like one layer missed its coordinates and then all corrupted.

I think it's not related with bed adhesion because for example for this model, it didn't knock over the model.

There is no roof for the model, I think it doesn't need any support structure. Here you can see the expected finished one:

It seems the problem was because of Z-axis leveling (level of the X-axis), I found out that the right side was more than 3-4 mm below the left side when the Z-axis height exceeds around 8-10 cm. Below 8-10 cm, the two sides were even. I calibrated the X-axis by turning the eccentric nuts of the wheels and tighten them. I will try printing soon with some test objects.


Ender 5: Bowden tube shifts in/out of extruder during retractions I have an Ender 5 with an aluminum extruder that was printing beautifully for a few days after building it. I received a Capricorn bowden tube and new couplings as a gift, and replaced those, and now I have stringing issues I can't solve.

I've been all over the map with settings (temps, speeds, z-hop, retraction, etc. etc.), I've swapped the tubes, the couplings, the filament, I've checked for clogs, and put clamps on the collars, but no matter what I do, the tube shifts in and out during retractions by about .25 - .5 mm. I suspect that has something to do with the stringing, as nothing else has solved it.

Any suggestions are appreciated. I haven't made adjustments to the extruder, but I don't know if that's possible or necessary. I've never had a system using the bowden, so that part of 3d printing is new to me. I'm using 3d Solutech PLA.

If it's just the pressure fitting on the brass coupler that shifts in/out, or the PTFE tube shifting slightly in/out but remaining in the coupler, that shouldn't be a problem unless it's so loose it can come out entirely. The blue clips which should have come with the printer are intended to stop this motion or at least provide enough pressure to prevent it from falling all the way out.

Regarding the small 0.25 - 0.5 mm of play, effectively it just means you lose that much length from your retractions, since part of the retraction goes into pulling the tube back into the coupler. When the retraction is reversed, the effective filament position should go back to what it was before the retraction. As long as your retraction amount is sufficient after the loss, it should not cause stringing.

You probably need to look for another cause of your stringing.


Wear resistant nozzles I recently purchased some glow-in-the-dark PLA filament (just "because"). Being new to 3D printing, I didn't realize you shouldn't run this type of filament through a standard brass nozzle and should replace it using a "wear resistant" type nozzle. This is true of carbon fiber type filament as well.

My questions are:

What types of nozzle material are considered "wear resistant" and are some materials better than others?
Can I use this type of nozzle all the time (ie: are there any downsides for regular use)?
What types of filament should you use a wear resistant nozzle with?

E3D have a blog post on the subject of hardened nozzles. The common abrasive materials are carbon fibre, wood impregnated filament (or any other particulate fill), and some pigments. The blog describes that as little as 250g of the more abrasive filaments can wreck a brass nozzle.

For wear resistance, different manufacturers will have different options. Stainless steel is a little harder than brass, and hardened steel is a big step forward. If you fancy spending more money, aluminium oxide (i.e. Ruby) is an option.

The downside is printability and cost. Specifically thermal conductivity of brass (or copper) is very good when compared to steel. However, this may not be the limiting factor for your printing unless you're running a very large machine. The various materials may also give different friction/wetting performance which can affect jams.

Depending on the printer and the type of hardened nozzle, it probably makes sense to avoid swapping between hardened and standard nozzles most of the time.

Hardened nozzles cost between 3 and 20 times what you will pay for a branded brass nozzle (and arguably a bag of no-name brass nozzles can be treated as near enough free disposables in comparison).


Bed leveling method? Is there a good method or tool to level the bed of 3D printers? I find myself making small adjustments a lot and it's mostly just trial-and-error. A normal bubble level is of limited help and trying to figure out if the head is the thickness of a sheet of paper from the bed in all corners is beyond the capability of my vision.

There are several ways.

1) Simplest is the business card/paper method.

This video shows how simple it is: Leveling the platform

You should feel the same amount of resistance between the hotend and the bed on all sides. On some 3D printers there are 3 screws holding the bed (eg. Solidoodle) and on others there are 4 screws on each edge (e.g. Prusa i3).
On some 3D printers you need to rotate a screw with a screwdriver to adjust it (e.g. Solidoodle 3) and on some you have a nut (mostly wing nut) (e.g. Solidoodle 4).

I find most people move the extruder around when adjusting the bed by controlling the motors. I think the quicker way is stopping the motors (in Repetier Host it's the "Stop Motor" button) and moving the gantry by hand.

Tutorial: 3D printing guides - Bed leveling

2) Second one is just more advanced version of the above. You use a dial indicator/ micrometer attached to your extruder and make sure the number on the dial is as close as possible on all edges.

Level the Print Bed on a RepRap / RepStrap 3D Printer with a Mitutoyo Dial Test Indicator

Micrometer op 3D printer

There are also digital versions of this tool.

You might need to print or make some other way a piece to be able to attach a micrometer to the extruder (there might be one for your 3D printer on Thingiverse already).

Now, remember I mentioned that you adjust the height of the edges of the print bed with a screw/nut? Well, since there is a lot of vibration during print those tend to get out of place and that might explain why you end up readjusting it over and over again. What I have found to solve this is to use a single drop of Loctite (cyanocrylate glue) in the middle of the nut/screw. A single drop will secure it in place but also not make it impossible to unscrew in the future.

3) Setting up auto-bed leveling on your 3D printer if it's modable enough:
3D printing guides: Setting up auto bed tramming leveling tilt compensation!.

Finally, if you can't get the bed leveled no matter what, it might be uneven. That's usually caused by warping. Both PCB beds and aluminum beds can get warped. With the former just sandwich a glass bed on top of it and it should be fine. Warped aluminum is pretty hard to flatten. In this extreme situation you might need to get a new aluminum sheet cut and drilled, preferably a mm thicker one which is less likely to warp under the same conditions. I think this happens when you either set the bed temp too high and/or the thickness of the aluminum bed is too small (bad or cheap 3D printer design).


missing small sections of layers after a retraction So I am missing small sections of a layer when it prints, after a retraction for a layer change or a move, the extruder stops moving (no it isn't clicking or anything else. Just not moving). Which is fine for a few millimeters because the pressure inside the Bowden setup keeps pushing enough filament through. However, once that isn't enough it starts to make very thin lines with beads of plastic just barely holding things together. Basically this ends up as a good 2 cm or more at times of highly under extruded lines.
This happens in the slowdown after the retraction when it is restarting.
it simply doesn't move the extruder at all.
The reason I know this is because I can see the extruder not moving, in that brief period. I know it is not the extruder clicking or anything else because I can disengage the extruder spring and push filament through manually during this time with no issues.

I am using Ideamaker currently because I like it.

I have looked at this Holes/ missing layers (after retraction) in 3d printed objects
which is somewhat similar in appearance, but not in reason.

EDIT:  So I figure it is some form of coasting that IdeaMaker has implemented for their Raise printers. I am going to try and reduce the length of the coaster attempt to convert my Bowden to a direct drive with titan extruder. I have the Titan already, but it has been giving me issues with not having enough power to push filament without ripping it to shreds. That's another thing I have to look at at some point when I have the time.

Try lowering your retraction settings further. I have had this issue before as well, but you need to experiment with your retraction settings in order to get it right. I would suggest placing 2  one cm blocks side by side and starting with a retraction of 2 mm and working your way up from there until you get the lowest stringiness with the least amount of under extrusion.


Setup for a firefighting solution inside a heated chamber that doesn't destroy the printer? Heated chambers, especially homebrew ones, might pose a fire risk if the printer inside has a really bad day and its TRP is defective or - oh horror - deactivated. We are dealing with a class A fire if it ever starts to smolder, so water is out. Many other firefighting measures - like an ABC extinguisher might destroy the printer. On a ferry, I saw signs that they had Halon firefighting in the machine room. But that stuff is near unavailable, the more fancy replacements expensive and a typical, pre made deployment system costs thousands.
Is there a way how one might set up a firefighting solution oneselves, using somewhat readily available parts?

Firefighting Agent
One Halon alternative is the rather simple and cheap gas CO2. It is neither toxic nor hard to get: "60 liter" water-carbonation bottles are readily available over the counter to create soda water and contain some 200-300 liters CO2
Alternatives are Argon and Nitrogen, but those don't come in these small canisters and dissipate more quickly, but they also need the chamber to be gas-sealed.
Because non-flammable gases act by smothering the flames, it is vital that rooms in which such a gas firefighting system is installed are not rooms in which people are usually, and in case of a workshop, it might be required to disarm the automatic trigger while the door is opened!
Deployment System
Such a soda water machine also would deliver the most crucial parts of a deployment system: the valve. To activate it, a solenoid can be used - once current flows through the solenoid, the valve is pushed open and the CO2 will shoot out into tubing or piping leading into the build chamber.
The gas canister should under no circumstances be inside the build chamber's heated compartment but somewhat close.
Release System
Now we need a way to trigger the solenoid. I propose to use at least some redundancy in construction.

Manual Mechanical Override. This can be as simple as a lever that bypasses the solenoid and activates the valve manually. Also useful for functionality tests.
Manual Electric Override. Using a 9V block battery and some sort of latching switch/button. The solenoid is directly powered from the "reserve" battery now.
Automatic via a microcontroller. Using a small programmable chip, one could use a spare thermosensor inside the chamber to detect temperatures of dangerous levels. As a direct response, it triggers the solenoid to release the gas into the chamber and continue to do so for at least long enough to fully flush the chamber, even as the temperature drops with the injected firefighting agent. It might be best to also trigger an alarm, for example, a repurposed doorbell. If one goes for such a solution, an output of the current chamber temperature could also be integrated, though I strongly discourage from integrating the fire suppression as a part of the printer board!
Automatic via a thermal switch. More simple in design, a Normally Open Thermostat Switch could be used instead of a whole microcontroller. Such a switch could use the same power source as a manual electric override switch, and indeed, be mounted parallel to the same switch. The downside of a hard-wired thermostat switch is, that it sets a hardwired maximum chamber temperature. It'd be best to choose a switch with a reset-temperature that is as far from the trigger temperature as possible to ensure that the chamber contains as little O2 as possible. The availability of switch types here dictates the voltage of the system.

What about the chamber heat control?
Once the firefighting system engages, the chamber should no longer get access to fresh air. This could possibly be made by having a different solenoid push a shutter in front of the air intakes and/or by de-powering any chamber cooling fans.
Door Safety
A magnetic switch in the door should cut power to the solenoid, ensuring that only the mechanical manual override can fire the system.


How to work with PETG? Settings, caveats, etc We've been doing some printing with PETG filament on Ender 3 Pro printer and the result were awful:

Here are settings we used:

Extruder: 240 °C
Bed: ~70 °C (± 10 °C)
Speed: 80 mm/sec

There are a few types of problems that we had:

Initially filament did not stick to the bed - those 3 items in the middle of the picture are example of this issue. This got fixed by increasing temperature of bed to 80 °C.
At some point a piece would get dis-attached from the bed and would move around together with the extruder around - two prints in the upper right corner of the picture were cancelled for this reason.
Models are very rough, like a cheaply made snowball - that tiny model in the upper left is suppose to be a cattle-bell. Could you tell?

Additional info

Filament that we used indicated

extruder temperature 230-240 °C
printing speed 40-90 mm/sec
no info about bed temperature

Question(s):

What are some optimal, tried and tested options for printing PETG? (Temperatures, speed, etc)
What are some caveats/difficulties of working with PETG to look out for? (For example, I've read that PETG likes slower speeds. Is that true?)
Is it possible that the model of 3D printer does not work well with this type of filament? (I don't have much experience printing so I can't know)

Slow down!

80 mm/s is much too fast for PETG. Try 45 or 50 mm/s instead, even for infill, supports, and other less-visible areas.


Why does my model stop printing at the same spot? I have a Monoprice Maker Select v2 printer which has a printing height of 7".

I tried to print this trophy.

The first time I printed, it stopped about 3/4 of the way (about 5.5").

I use Ultimaker Cura to move the model's z-position down, effectively splitting it in half to print the top half. But on the 2nd print, it seems to have stopped at the same point. There was a lot of extra PLA filament curled up at the end.

Did my printer just jam or am I missing a setting that allows it to print the remaining top portion?

The answer is that you have not used support structures. The printing fails as a result of missing support structures.

If you look closely to the Ace of Clubs card at the top, you will see that the lower point is being printed from out of nothing, this corner needs to be supported. When unsupported, the extruded filament flows freely and where it deposits is unknown. Usually this extruded filament sticks to the nozzle or ends up stuck at the next piece of the printed layer building up. This build-up can cause the head to hit the print and ruin the print.

To enable support in Ultimaker Cura configure your setting accordingly:

These settings are accessible when you select custom settings:

If the options aren't visible, use:

and type in the option.

Please do note that using supports does not guarantee that the print will not fail! Especially when using long slender support structures, the chance that a support structure fails increases with the amount of support structures and the length of the structure. Sometimes long slender support structures are knocked over.

Sidenote:
Your printer has more issues, if you look at the brim, it is not a continuous bed adhesion layer, it looks like it does not adhere too well, see also the bottom of your trophy.


3D printing a boat hull I am wondering if it would it be feasible (at an affordable price) to 3D print a boat hull (small dimensions, maybe something like 60x40x20 cm).

I am mostly concerned about:

durability (against salty water, UV rays, extreme temperatures
(under the sun or in a cold ocean)
strength (the material should be able to resist some chocs and maybe a little bit of pressure if a wave was to smash on it).
waterproofness

Those characteristics should last during extended periods of time in water (at least several months, maybe more, about a year or two).

Is there any easily accessible 3D printing material that would match those characteristics?

You will really need to specify your constraints better because the short answer is yes, what you describe is entirely possible, but without knowing whether you are limited to a particular budget, process, or aesthetic, it's not a particularly useful answer.

Some machines (ex. Stratasys Connex 1000) will print models up to 1m in length, so sure, you could print an entire hull with the dimensions you specify.

Pros:

Monohull construction
Excellent surface finish
Many resin options are UV and salt water resistant with decent enough durability

Cons:

Ridiculously expensive machine with decently expensive resins
It will waste plenty of support material in printing (which means added cost too)
Not really easily accessible, but some design studios will have them and will print things for you, for a cost

Other machines (ex. Ultimaker 2 Extended) will print models up to 30cm along the vertical axis. It would require some assembly in the end, but you could segment your build and get a boat hull in the end.

Pros:

Easily accessible
Fairly low cost (Maybe under \$1000 for the machine vs nearly \$1M and many filaments cost 1/10th that of polyjet resins or sintering powders)
The materials themselves can be UV resistant and salt water resistant

Cons:

Joinery and seams create passageways for water ingress, so you'd need secondary sealant
The FDM process itself isn't always watertight, so you'd need sealant anyway
Low interlayer adhesion limits the tensile strength along one axis and the shear strength in one plane, so you'd either need composite hull panels with varying print orientations (in which case, just do a composite layup instead) or a fairly careful analysis of principle hydrodynamic stresses

There's significantly more to the discussion as well, but without really understanding your design constraints, it's difficult to give any concrete advice.


Removing pla from extruder I read that the best way of removing ABS was to let the temperature at the hot end to drop to around 190deg c then a sharp pull. This worked really well. I am trying to print with PLA but no matter what temperature I drop the hot end to I get left with a length of PLA in the feeder tube. OK I can heat the hot end and poke the excess down with a wire but that is a pain. I think the technique is right but the temperature is wrong. Any help great fully appreciated.

One resource you can use is called the nylon cleaning method. It works by setting nylon filament temperatures, pushing nylon filament into the nozzle until only nylon is extruding, then cooling the hot end to a specific temperature. The page linked suggests a hard yank, but I disagree. Brutality is not a recommended action for 3D printers, in my opinion. When I use the NCM and the hot end reaches the correct cooler temperature, I use pliers and lever them against a suitable surface. The lever action is slower, yet the mechanical advantage is increased, making removal easier.

Some 3D printer users disagree with the expense of nylon, which is, on the surface, excessive. I've found that I am able to see light through the hot-end after using this method, however, so I find the expense justified by a completely clean filament path.

The above linked page also includes the modification of this method for use with the same type of filament to be cleaned, in your case PLA.

Consider that you should be able to use ABS to pull PLA from the nozzle. Heat the nozzle to the lower end of your ABS filament temperature and push or extrude until you get the ABS color. Allow the hot end to cool to the low end of PLA temperatures and reverse the extruder/pull out the filament.

If you use contrasting color filament (for example, white PLA, black ABS) you should be able to see the ABS collecting the other color as you remove it. Eventually, you would have no contrasting color, indicating that the previous filament has been removed.


Laser Engraver with Smoothie, RAMPS 1.4 or AWC708C? I have an old laser engraver that runs from Windows 98SE and DOS-6. Yup, still works fine but a pain as I regularly have to open it up and unplug and re-seat all the ribbon connectors. Fifteen of them and I tire of that fast.

I am thinking of pulling out all the electronics and installing a TB6600 stepper drivers and Arduino to run G-code. My order of desire is based on price, RAMPS, Smoothie and the AWC708C. I'd actually like to stay away from the AWC as it is closed source and I would be stuck with whatever it has.

With the existing NEMA 17 steppers I can get rapids to 400 mm/s. Will a RAMPS system drive this fast enough? It doesn't have to be that fast, but close to and certainly not below about 200 mm/sec.

I have been searching but cannot find any actual figures achieved. If not then I guess my second option is the smoothie.

Marlin supports a stepping frequency of up to 40kHz. For a pretty typical setup with 100 steps/mm, this translates to 400 mm/s - obviously, if you use higher microstepping settings or use finer pitched belts you will get a lower maximum speed.


Build plate cools during print I am using a Flashforge Creator Dual Extrusion 3D Printer with RepG (ReplicatorG), and tonight a print completely detached from the build plate.

I reset everything and watched it closely.   It is a simple abs print at 230/110 degrees.

A few seconds after start of print, I noticed that the print bed temp had dropped to 109... and kept dropping.

This is new behavior.  I haven't started to troubleshoot yet.  I am looking for suggestions on how to troubleshoot the issue.

Edit 1:

Tonight RepG would not connect to the printer.  I reseated the USB cord
  and now it does.

The test print is ABS at 230/110 from this open scad.

difference()
{
    cylinder(d = 10, h = 2);
    cylinder(d = 9,  h = 2);
}

Pᴀᴜʟsᴛᴇʀ2/Oscar
  Once the print starts the print bed begins cooling.  It is cooling before
  any filament is laid down.

Edit 2:

Examination of the gcode shows the root cause.  It does contain

M104 S230 T1 (set extruder temperature)

It does not contain a

M109 S110 (set build plate temperature)

When I manually add the M109 to the gcode file, the model prints normally, and the build plate temperature holds for the duration of the print.

The drop in temperature last week is due to the fact that I tend to preheat the printer before actually starting the print.  Since there was no M109 the bed plate cooled to ambient temperature.

There isn't a hardware issue here.   Most likely it is a Rep G configuration error of some sort.

Edit 3:

I resolved the issue by a fresh install of the latest Rep G.  I rebuilt the profiles from scratch with G Code to set the correct bed temp.  Thank you for your suggestions.

Your bed is obviously capable of heating up, so I would double check your cable for any kinks, cuts, blow-outs, or general connection issues both where your machine rests during warm-up and Z0 where your machine begins printing.

Most likely there is a poor connector or kinked/cut wire for the build plate.

If that doesn't appear to be the issue, I might also suggest checking your power supply. I've heard of other similar machines' power supplies not being quite strong enough to support two extruders AND a heated bed.


What is the lifespan of a SLA Resin Tray? As far as I know resin trays have a Teflon coat that allows prints to stick to the build plate easier than the resin tray but this Teflon coat wears over time.

I am new to the SLA scene and am currently troubleshooting a Draken Facture and trying to hone in my setting but my print keep sticking to the bottom of the resin vat.

How often should these trays be swapped out to allow for smooth printing?

It depends on tray and resin type you are using.

PDMS

If you are using PDMS (eg. sylgard 184) coating for your tray. (B9 and similar printers using this type of tray).

Life of tray PDMS coating depends mainly on:

How long you print without breathing floor.
How reactive is your resin.

You could get 2 3 prints up to 15 20 prints.

It is suitable for printing delicate pieces.

FEP

Large number of manufacturers using FEP.

Life of tray largely depends on.

Thickness of FEP
Piece sizes and movement speed during early layers.

Usually you could use same tray for couple of hundreds of prints.
Optical quality is not comparable to other alternatives but without human error factor you could get almost unlimited prints. Delicate pieces require tough resin.

Teflon

It is halfway between PDMS and FEP.

There are other tray alternatives:

Envision uses special glass you could print on average 50 prints.
Carbon 3D uses super expensive oxygen-permeable window.


Can functional hinges be built with food printer? In trying to understand 3D printers, I have watched some YouTube videos where the crafters make items with hinges. That in itself blows my mind. It is hard to grasp how something with moving parts can be printed. But specifically I am wondering if the concept can be extended to food printers to make, for example, a sugar or chocolate telescoping lollipop (sucker)?

I don't know much about food printers. But at the very least, you should be able to print similar moving parts like hinges as you would with a standard FDM printer.

When printing things like hinges with a single extruder printer, the machine will typically be configured to include support structures. This is basically very thin scaffolding that higher layers of the print can sit on.

As Tom van der Zanden pointed out, though, this highly depends on the food medium you wish to use. With plastic, the material is heated to a less than liquid point, usually allowing the material to "bridge" across gaps. If your food medium is too thin (or close to liquid) you will not be able to effectively print supports as the medium will fall between the gaps.

If you are able to effectively print the supports for overhanging features, you should be able to knock off the supports with a small knife or toothpick. If it's a moving part, sometimes "shimmying" the part will knock the supports off.


Printer randomly moves to home during printing, then resumes as normal During printing, my printer occasionally makes some mystery moves: it will very slowly move either the X or Y axis all the way to the left/front, before very slowly moving back to its original position and resuming the print as normal. I've checked my G-code files, and the moves are definitely not part of the G-code. What could be causing this?

I'm printing from an SD card on a Cartesian printer.

The issue was due to a corrupt SD-card, which was occasionally having some garbage read from it. It turns out that Marlin will try interpret a corrupt move command like G0 X1q3.54 and still read as many numbers as it can. In this example, it would be interpreted as G0 X1 rather than (as might have been intended) G0 X103.54.

This explains my symptoms perfectly:

X and Y always moved to (approximately) their home positions, but it was always only one of them (it's quite unlikely that both moves are corrupted).
Z was not affected because Z moves are much rarer in the G-code (only on layer change) and thus it was very unlikely that a Z move would be affected.
E was not affected since a request to move E to near 0 would be prevented by Marlin's long extrusion prevention.


Out-gassing of printed material when heated We know from this answer, 3d printed materials continue to outgas after printing and being cured. My question relates to this:

How much does heating the printed object after printing (or being cured) affect out-gassing?
Does the continued out-gassing degrade the stability/quality of the print?

This is not an answer to your question, but it relates to outgassing so I am sharing it here.

I have used the acetone vapor method of smoothing the surface of ABS prints.  It works really well, and the surface becomes much smoother and glassy.  I printed a large coffee mug (lets, for the moment, ignore food safety issues) and made it very smooth.

After a couple of weeks to allow the acetone to fully evaporate, I poured a nice, hot cup of tea.  Unfortunately, the acetone had not fully left the print, and the surface was immediately covered with dozens of bubbles as the acetone evaporated and pushed against the ABS.

This effect was only because of the acetone.  Another cup that had not been vapor smoothed worked perfectly and was unaffected by the hot water.

I have not seen similar outgassing from PLA, ABS, Nylon, or PETG.

If I may hazard an opinion about the substance of your question...

I don't think that outgassing is the biggest contributor to the aging of prints and their properties changing.  I suspect that (perhaps not in order) these are larger factors:

exposure to UV light.  UV light breaks polymer bonds and reduces
the strength of plastic.
absorption of water vapor, which can both expand the material which causes stress, and chemically break polymer bonds.
long-term crystallization of the material
fatigue from repeated sub-failure stress

NASA used to have resources that spoke to outgassing rates related to suitability for space applications.


Bed too close to nozzle? I've been having some bed adhesion problems that I have been trying to solve by leveling the bed. I think that it's pretty level now but when I start a print the lines seem pretty flat. Is this true? I used a feeler gauge to have a 0.2 mm gap between the bed and nozzle, but the center feels as though there's more space, despite the tape (ie I didn't feel any resistance when leveling the center) so I'm not sure if the plastic is too squished or not.

I am printing PLA with 210 °C at Nozzle and 60 °C on bed. I also used a 130% extrusion factor for the first layer on a Creality CR-10S. It did come without a black print surface but with a glass sheet and a roll of painters tape instead, so I opted for Blue-tape.

Also, I see some stringing, which seems to happen with skirts and brims (this is my first brim) and a bit of under extrusion in the center. But those are probably concerns fit for a separate question.

No, the bed does not look too close to the nozzle, it could well be that it is too far from the nozzle. However, the brim looks okay, but the method you follow is questionable.

Using a feeler gauge of 0.2 mm is larger than the recommended paper method which is in the order of half that value (0.1 mm). You compensate this larger leveling gap with an over-extrusion of 130 %. The preferred method is using a thinner feeler gauge or a sheet of paper without over-extrusion. The reasoning is that if you have a 0.2 mm to start with, adding the first layer thickness (e.g. 0.2 mm) would imply that you are already starting at a 0.4 mm gap on your first layer. You now try to push out more filament to fill that gap (resulting in not really pressing the filament to the plate).

Furthermore, your tape does not look like it is laid down next to each other, it looks as though it is laid over each other. This creates an uneven bed surface.

Finalizing, you should do whatever you do to get the filament to stick to the build plate, if it works for you, use it. If it doesn't produce viable prints, or you are not satisfied with the surface finish, change it.


Unable to Determine Proper Print Scale of STL model I am new to 3D printing and have a Monoprice MP Select Mini 3D Printer V2. I wanted to be able to 3D-print this VR Adapter from Thingiverse. Before downloading the Cura software, I tried opening the model in Print 3D, and as you can see in this picture, it appears that the model is just under 100 mm, which is well under the 120 mm limit of the MP Select Mini’s 120 mm×120 mm build plate:

However, when I downloaded Cura and input the specs for the printer (120 mm for x, y, and z dimensions), the model appears to be much larger than the 120×120×120 area. The program tells me that the model is 132.5 mm × 180.6 mm × 36.6 mm:

I need the model to fit the controller for the Oculus Quest, so I can’t just scale it down. Can anyone tell me why I am seeing this discrepancy and how I can still print this model?

The STL format does not define unit information. So there is no way of knowing, from a STL file alone, what size it should be.
However there are only a handful of units people design with. So the unit is most likely one of inches, cm or mm. So if you inverse convert between those combinations you'll likely find the real size.
Your image is somewhat inconclusive. But it seems to indicate your object is in fact larger than your bed. As it it is 18-19 pips of height and i would interpret each as 10 mm from the image. Which would indicate your model is correct.
Split and glue? Print corner to corner you should have 207 mm length that way (but not necessarily width).


Increase Z-homing probe number I'm using latest stable Marlin 1.1.9.1 with BLTouch. The BLTouch seems a bit damaged so I want to increase its accuracy with multiple measurements.
I've increased #define MULTIPLE_PROBING to 3 but it seems it applies only to mesh ABL and doesn't work with single center homing.
I want to get something like fastprobe + average for two or three slow probes.
Am I missing something? Or it is not possible?

Homing and mesh probing are 2 separate actions, by setting #define MULTIPLE_PROBING to 3, you inherently create 3 slow probing points for the mesh probing (not the homing probing), with 2 you get a fast/slow probing action.
Everything is possible, but, that means that you need to dig into the sources; not changing the configuration constants. That is not for the faint hearted.
I've seen the responses of fast and slow probing in action, usually the difference is not existent or very very small, like one or two hundredths of a millimeter, I seriously wonder if it makes sense to use more than 2 probing points.
Please note that a damaged bed may benefit more from increasing the probing array amount (from 3 x 3 to 4 x 4 / 5 x 5). The number of probing points discussed earlier only dictates the amount of probing actions in a single point; if the sensor hits the bed the probe measurement is done, if it hits again, the value should more or less be the same (give or take the accuracy of the sensor), I do not see what damage to a bed would imply more probing measurements in a single spot. The only rationale would be if the sensor itself has a large inaccuracy with an error that is not systematic, but random. My BLTouch (original) is pretty accurate and repeatable, I've had more issues with all those cheap knock-offs.


How to move Z-axis to a specificic position (Z-max) after printing? I have a Cartesian printer in a cubic format (the bed moves vertically) with Marlin 2.x
I am not finding a way to make it move to Z-max (23 cm) when finishing the printing.
The idea is to lower the bed all the way to the max, to make easy removal of the printed piece.

To move the bed down, you simply instruct the bed to do so after the print.
The best way to do that is add a G-code line to your "end G-code" script you find in your slicer you use.
Just add the line:
G1 Z230 F500

With this command you instruct the bed to lower to your maximum Z height at speed (feed rate) 500 mm per minute.


Extruder prints fine up until further down the print So I recently installed a genuine E3D V6 (direct) on my AM8 (Anet a8 with upgraded frame). I have already been able to fix most of the print quality problems. But the last one is a hard one for me.

It prints super fine up until a certain height. Then the extruder starts slipping and starts making weird noises like its clogged but I will be able to push through filament properly after cancelling the print. I thought it was heat creep but when touching the spiral heat break it is just a tad warm. I can comfortably put my finger on it and keep it there.

I also tried two different brands of filament and it seems to happen roughly at the same spot.

I tried PID tuning (the temps are literally perfect and super straight with no fluctuations), I tried cleaning the extruder gear and checked if it was worn or anything. Then I tightened everything on the extruder, making sure everything was nice and snug.

I am not exactly a newbie when it comes to fixing my own printer and troubleshooting the problems but this one I have never seen or had before.

Do you guys have any tips for me to point me in the right direction?

Running Marlin 1.1.8. I have a BLTouch on it and an AnyCubic UltraBase.

I used a different heat break with a PFTE lining inside. After that it ran smoothly.

Probably what was happening was that my filament was getting too hot and started to stick on the full metal heat break.


Build plate adhesion, PLA Am just wondering if any conclusions can be drawn from this:

Three corners are solid, but not the one in the centre of the plate.

The bed was levelled before printing (and checked afterwards also). Even though the photo may appear to show a slant or lower corner (where the print is coming off), there is not. The bed is level, relative to the extruder, at room temperature.

The temperature of the bed is about 70 °C. I get inconsistent readings (with laser thermometer) but to the finger it feels about the same everywhere.

It's a glass bed, presumably with some coating. Is it degraded? Local temperature variation? Any ideas anyone?

From here:  https://io3dprint.com/review-anycubic-i3-mega-ultrabase/

  Ultrabase Bed
  The Anycubic i3 Mega Ultrabase is the latest version in the Anycubic i3 family. As hinted in the name, the main upgrade from the previous version is the Ultrabase bed. This is a textured coating on the Borosilicate glass bed that means you don’t need to apply any glue or tape to the bed to make your prints stick to it.

  Ultrabase is similar to the popular BuildTak beds except unlike BuildTak it doesn’t wear off and the most significant benefit is that parts are exceptionally easy to remove once the bed has cooled.

  The Ultrabase surface has a Moh’s hardness of over 7. This means you can safely use metal scrapers and blades to clean it without risk of it scratching!

Perhaps it was just not cleaned sufficiently from a prior print.


What is causing these artifacts when the extruder moves in one direction? I have a Prusa i3 that I am mostly happy with. However, I am seeing these strange artifacts when the extruder moves along one axis in one direction - in particular from the back of the printer towards the front. The extruded lines look uneven and the surface is quite rough, but only in that area and only while the extruder moves in that direction.

Here is a recent print that shows this happen. The pieces were printed side by side, and both of them show this on the left hand side, while the right is okay.

I am thinking maybe the extruder tip is slanted (not perpendicular to the bed), which causes some sort of scraping while extruding? What do you think?

In case of such difference in printing in different directions you can check if;

for x and partially z axis

filament is blocked and cannot be pulled as it should
spool is blocked

for x and y axis

rods on which caret/HB is sliding are parallel
timing belt idlers are parallel and they are in a line

Shape of the nozzle or its perpendicularity should not be the case as it's hot and it wipes layer itself.

You can also check if it's not an issue of cooling fan. It can vibrate as such.

Eventually it could be an issue of cooling itself. Let's assume you have cooling fan at the back and it pushes air to the front then when caret moves from the front to the back then cooling time is longer than when the fan goes in opposite direction.


Can a dual extruder printer print with multiple filament types? I was looking at purchasing the Creality CR-X or another similar dual extruder (note, NOT dual nozzle) printer. I know it was designed to print two colors of the same filament, but is it able to print two different filaments?
I would be printing HIPS with ABS or PVA with PLA, so the two filaments would have very similar characteristics. It's ok if the printer doesn't know there's two different filaments, I can make it work by playing with the slicing settings.

Yes and No
Yes, if you have two full hotends, you can easily print with two filament types.
Yes, if you have one hotend and both filaments melt at a very similar temperature or are the same polymer, then you can use a Prusa MMU style or splicing machine.
No, if you have only one hotend and the two materials are very dissimilar in their print temperatures (PLA with 200 °C and ABS with 235 °C), then you can't use a MMU/splicing style printing. This does preclude PLA and PVA from the same nozzle: PVA needs about 230 °C according to my data.


Weird ripping and warping of ABS print I print my ABS at:

240 °C;
with a bedtemp of 80 °C;
5 % rectilinear infill;
0.25 mm layer height;
2 solid layers top and bottom;
Fan is completely disabled;
0.25 mm extrusion width;
50 mm/s perimeter print speed;
60 mm/s infill speed;
20 mm/s top solid and solid speed;
No acceleration.

When printing ABS, I place  an aluminum foil lined cardboard box over my printer to help keep the ambient temps up for less warping and stronger prints. I've never actually measured the temperature inside, but the cardboard box insulates very well.

I get this weird kind of tearing in my prints, I'm not sure if it's from too large of gaps in my infill, too fast print speeds, or not enough top layers.

Another guess is some kind of drooping because of the high ambient temps.

The tearing only occurs on large top layer surfaces.

Looking at the infill pattern visible through the tears in the top layer, it looks as if you have unreliable extrusion on the infill layers also.

The solid fill layer is lifted and torn, so it is unlikely that one or two more layers of solid fill will make the result better.  In my experience, bumps lead to taller bumps and print failure.

These diagnostic steps have helped me:

Print a 3 layer solid fill version, the top surface should be smooth and free of bumps;
Print a single layer version, it should be smooth, well attached to the print bed, of even thickness, and a good surface for the next layer.

Given your results, I am suspicious that you may have one of these problems, which I've listed in the order of likelihood:

Partially blocked nozzle
Excessive drag from the filament supply, such as a spool with crossed filament which jams itself, preventing unwrapping;
Extruder feed roller slipping (perhaps full of dust), often a side effect of 1 and 2;
G-code error dropping the temperature;
Bad heater or thermistor, perhaps intermittent short of the thermistor, causing under heating even though the "average" indicated temperature is correct.

Printing gliders is a cool application. It shows off the weight advantage extrusion 3-D printing can deliver.  Nice.


Horizontal line z-axis not printing correctly I have just started with the FlashForge Creator Pro using the FlashPrint slicer software. I have gotten some nice prints but I am having an issue with a certain print from this model of a knife.

See image below:

Everything prints fine up to where the blade starts. As you can see, there is horizontal portion of the blade that juts out and, as I predicted, when it tries to print this, there is nothing for it to adhere to so it hangs there and when the extruder moves, it just pulls the filament around with it and creates a mess.

The object file from Thingiverse is designed that way (with it standing upright) and there are pictures on the Thingiverse page of a successfully printed knife. As I am new to this, I am wracking my brain trying to figure out how to print this.

I tried to cut the design and print the handle and blade separately (laying the blade down flat on the print surface) but the blade isn't perfectly flat on the sides so it doesn't lay flat. I suppose I could also just cut the blade and lay it vertically on the print surface but it seems as though it was designed to print in full in one piece.

Any help or any pointers in the right direction would be greatly appreciated. Thanks!

You'll notice in the screen capture that there is an icon marked "supports." This is precisely the solution required. When selected, the software should construct a series of vertical pillars in the locations required to properly print the horizontal portion of the knife blade.

It's common for Thingiverse models to have a notation Supports (yes/no) to indicate that this feature should be activated. Depending on the capability of your printer, some angles may require supports that are not required on someone else's printer model. There may also be an adjustment for angle reference to cease supports or to require. My printer will handle up to a 50° from vertical without support. Beyond that, more filament is used, but the result is superior to printing without it, as you've discovered.

Note also that support is typically categorized as "from the bed only" or "everywhere." The former prevents support from being generated between vertically separated parts of the model, while the latter permits it. Some models may have, for example, a foot on the bed not requiring support, but the arm directly above the foot does. "From the bed only" means the arm would droop/fail as no support would be generated above that portion of the model.

If you are using the ReplicatorG 0400 software, referenced from the manufacturer's web site, page 11 of the manual will have additional information regarding support within the program.


Why would one choose 12 V from 24 V, from a safety standpoint? I have seen many people saying on this site and many other 3D printing websites that 24 V systems are safer, compared to 12 V systems. By safer, I am talking in terms of fires or other electrical and component failures.

Why would a 24 V system cause less danger? I would think that 12 V would be safer because it is very common (automotive) and many parts have been around for a while that use it. Although there are an increasingly amount of boards that support 24 V, many don't or need fuses or other parts that do support 24 V.

Also, many parts that I have used are rated for 12 - 24 V. A 12 V power supply can go a bit over fairly comfortably. A 24 V power supply can't without partially going over the rating.

If I had to build a printer designed with safety as a main priority, what voltage would be best?

The most important "safety" advantage when using 24V (compared to 12V) is that to get the same power, you only need half the current. A 192W heated bed would need 16A at 12V, but only 8A at 24V.

Since one of the most common safety issues is underrated screw terminals being used for the heated bed (just search for "3d printer fire"; you'll find quite a few pictures of charred plastic around screw terminals). For example, the screw terminals on RAMPs board are only rated for up to 12A. That would be okay at 24V, but well over the limit at 12V.

Since the wire gauge is dependent on current, you can also use somewhat thinner wires with a 24V system (or equivalently: wires that would melt in a 12V setup won't in a 24V setup). The power dissipated in a wire scales quadratically with current, so the same wire being used in a 24V setup would only waste a quarter of the heat of that wire in a 12V setup. There is also less strain on switching devices (such as MOSFETs or relays). The same applies here: power loss is quadratic with current.


Can a common 3D printer be used to print masks for PCBs which use SMD components? Common 3D printers (read "cheap") may be used to print masks for PCBs (printed-circuit boards) which use PTH (through-hole) components.

But can they be used to print PCBs which use SMD components? I'd like to make boards at least for Arduino-like SMD chips.

In addition to the thermal issues Tormod raised, there is a conductivity issue. Present conductive filaments are much less conductive than copper. The power loss may be enough to affect functionality. Also, the lost power goes to heat, making the thermal problems worse.

For bulk materials, "volume resistivity" is measured in "Ohm-cm", which is the resistance of a 1 cm cube of the material, measured from one entire face to the opposite entire face (see https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity).

Copper has a volume resistivity of about 1.68 microOhm-cm.

Proto-pasta conductive PLA filament claims 15 ohm-cm (http://www.proto-pasta.com/pages/conductive-pla). Functionalize F-Electic™ claims 0.75 ohm-cm (http://functionalize.com/about/functionalize-f-electric-highly-conductive-filament/).

Printing itself significantly raises resistivity. Proto-pasta claims 30 ohm-cm along X and Y, 115 along Z. More intuitively, each cm of length of a 2.5mm wide printed trace, 0.4mm thick, should add several hundred ohms with the Proto-pasta, or several tens of ohms with the F-electric. That may be enough to matter.

It's probably worth mentioning that there's a specialized PCB printer (the "Voltera") that uses (pricey) conductive ink, and can also dispense solder paste: http://www.computerworld.com/article/2885188/3d-circuit-board-printer-a-smash-hit-on-kickstarter.html


Adding a battery backup power supply So apparently the wiring in my home is... questionable. Very rarely, plugging or unplugging things will cause a power dip. This is almost always the result of turning on a fan or something, is only for a moment before coming back, but its long enough to cause my printer to reset. I want to add a backup battery supply using either the 12v cell pulled out of an old apc ups (before the suggestion of just plugging it into that... I did, somethings fried in it and it will ALSO power cycle everything connected to it every few hours) or an old car battery. Is there any reason I shouldn't use this circuit, which was originally intended for amateur radio equipment?

Also is there anything else i should be considering?

There are a couple of points to consider with this question. First, you will need to make sure the PSU is correctly adjusted to the float charge voltage of the 12V battery. SLA should be safe to float charge, but over voltage will damage it over time.

One alternative solution (since powering the heaters will limit your run time) is to detect power failure, cut the heaters immediately, and save state to EEPROM in the firmware. This is the approach taken in the latest Prusa printers, and is a bit more complex, but might turn out to be more reliable.

If the problem you are solving really is brown-outs, then a simpler solution might be to isolate the high current and control sides of the circuit. The MCU will be run from a regulated 5V or 3V3, so a large capacitor (with diode isolation) on that regulator's input would do the trick.


How can I upgrade the drivers in the Printrboard rev. D? I have a Printrboard rev. D which includes Allegro A4982 drivers. I would like to replace them, but it appears that newer TMC drivers all require several pins for proper operation.

How can I upgrade the drivers in the Printrboard rev. D?

The developers from the Klipper firmware confirmed that Klipper doesn't care about the native functions of each pin, therefore it is indeed possible to use the expansion pins for controlling (including UART) TMC stepper drivers.

At this point I cannot confirm, but maybe Marlin allows the same by updating the pin assignments in the source code.


ASA and BVOH adhesion I am printing a mechanical part for my printer.

It's a new mount for my extruders and I have been attempting to use BVOH as a support filament so that when my print is done it will cut down on the need to finish the part and possible mistakes.

My problem is I can get the BVOH to adhere to the bed with no problem and no warping of any kind, but I can't get the ASA to adhere to the BVOH supports. I run the BVOH at 220 °C and the ASA at 250 °C with my fan at 10 % and I am using a Flashforge Creator Pro printer which is mostly enclosed.

Does anyone know of a way to get the ASA to adhere to the BVOH?

Can you tell by looking at the de-adhesion what isn't sticking?

It may be that printing the ASA at higher temperature is melting the BVOH enough that it doesn't stick, being molten.  If so, then it may be possible to print the first layer of ASA at a cooler temperature, slower if necessary to still succeed at extrusion, with fans blowing.  Then, print the next layer of ASA at a higher temperature, also with fans flowing.

A test might be to print the BVOH, then a layer of ASA, and stop.  Let it cool and test the adhesion.  If it sticks under these conditions, then a better command of the temperature profile may offer a way forward.


Can 3d printers be operated at voltages above 24 volts? Going from 12V electronics to 24V produces a reduction in the overall amount of heat generated in the electronics (that are not intended to get hot). These include the motors, drivers, mosfets and pcb traces.

Why then given that 48V power supplies and electronic components cost exactly the same as their 24v counterparts, are there no 48V 3d printers?

Is there a saftey aspect to 48V that needs to be considered?

EDIT: Yes 48V fans cost a little more but it's not exorbitant. It seems odd to move from 12 to 24 to get half as much heat, when you could move from 12 to 48v and get a quarter as much heat.

I believe the main issue is the voltage regulators and capacitors on your standard print main board are not rated for 48V. You can find some CNC shields that can handle up to 36V but these are lacking 3d printer features such as heater ports and only have 4 stepper slots.


Ender 5 (Plus) - Gantry not square to frame, how to fix? How would one go about squaring the gantry relative to the frame?
Referring to the image below, distance A and distance B are not equal.
Also would this account for the reason why when I attempt to print a circle it is not perfectly circular, and when I try to print a square, it is tilted?

How would one go about squaring the gantry relative to the frame?

You first need to make sure that the cube/box frame is square. Once this is done, you need to check whether the gantry is still not perpendicular/parallel to the top frame. If not, you need to loosen the couplers at the front that control the Y movement of the printer. See if you can reposition the gantry to be square to the frame. If that doesn't work, you need to fiddle with the bolts that hold the wheels of the X-Y carriages so that the gantry will become aligned with the top of the frame.

Also would this account for the reason why when I attempt to print a circle it is not perfectly circular, and when I try to print a square, it is tilted?

Yes, a skew gantry causes skew prints, i.e. squares become parallelograms, and circles become oval. There is another solution to fix this in firmware, but, the preferred method is to mechanically fix the issue.


Is the 8mm x 20mm bearing axle for the X-axis idler (of a P3Steel) a custom part? Here is the X-axis of the P3Steel:

The X-axis idler end of a P3Steel printer, employs an 8 mm diameter rod for the axle on which a 608zz bearing is mounted for the GT2 belt. This 8 mm rod is approximately 20 - 24 mm in length, with grooves at either end, for circlips.
A photo of the assembled idler, with the rod and circlips highlighted:

My question is: Does this part need to be custom made?
The short rod didn't come with the frame kit that I purchased (nor was it listed in the parts list, or shown in the photo of the parts - so it not as if it was omitted with my order). I have searched on eBay for it, using various search terms, and I am unable to find one. As I was not trained in mechanical engineering, I am not sure if this part has a special name, or is it just called a "smooth rod, with grooved ends"? I have also done a fair amount of googling, and although I have found some people who have constructed this particular frame, no one makes mention of this axle, nor any difficulties in sourcing it.
I have contacted the supplier of the frame, Frame Prusa I3 P3Steel v4.0 +RODS, and I am awaiting a reply.
This missing part is holding up my build progress - I already have the 608zz bearing and circlips.

Additional images
This image shows the "exploded view" and the 8mm rod can be clearly seen:

Here are images of the assembled idler, showing the bearing inside -
Front view:

Side view:

This images are a little blurry, as they are screen shots taken from the video, I3 Steel CORDOBESA con extrusor/with extruder.

You could look up a Clevis pin with one groove.
You could look up a Clevis pin with a hole for a split pin.
Perhaps a Shoulder screw with a ground shank and a low profile head.
Use a plain rod with Dome caps if you will not need to remove often.
If available an internal threaded Standoff would work.
A Slotted spring pin may work if the hole dimensions are suitable.

EDIT:
You could also cut the grooves yourself pretty easily.  Cut a section of 8mm rod to length and mount it into a drill chuck so it stick out 2-3mm 1/8". Hold a hacksaw at the edge of the chuck and run the drill for a minute with gentle pressure, try hacksaw on other side or reverse direction if nothing is happening.
A hardened rod will cut better with a Dremel type cut-off disk


But ... skateboard bearings have OIL in them, and oil is ... bad? I see plans for various spool holders, either for PLA in the open, or for whatever filament in a dry box, that use 608 bearings. Elsewhere, I see warnings not to oil your filament to make it go through the extruder better, because problems going through mean something else is wrong, and it's better to fix the other thing. So, if I use the 608's, will oil leak on the filament, and is this bad?

Typically, oiling a filament would mean to use a vegetable based or non-petroleum type of lubricant, possibly even PTFE (teflon) or silicone. Those materials will not damage PLA filament.

Oiling filament is not the haphazard application of lubricant, however. One drop on the filament sponge guide will last a rather long time and should be given sufficient time to distribute itself in the sponge, helping it along by alternately squeezing and releasing the sponge.

Ball bearings of the type you've described will not have oil, unless otherwise modified by the user/owner. The bearings are packed with grease which will not leak out under normal circumstances. Running the bearings at high speed will cause the grease to thin a bit and perhaps drip or if hot enough will "sludge up." If your bearing grease turns to sludge, the bearing has already gotten hot enough to melt out of your plastic fitting.

For spool holder applications, you can clean the grease from the bearing with a suitable solvent (denatured alcohol, acetone, soap and hot water in a pinch) and expect little impact on the drag. The spools rotate at such slow speeds and under such small load that the bearings alone will work nearly forever. This recommendation is void in dusty environments.

With respect to oiling the filament, it's not a bad idea to have a sponge dust catcher that has no oil just as the filament enters the last open location. My bowden extruder system is nearly enclosed and the sponge sits at the very edge of the spool, while a direct extrusion system would have the sponge at the entry to the extruder gears.


How to find correct part cooling fans? I have a 2-pin 40 mm axial fan as part cooling fan. I don't post a link because I would like a general answer.

It runs on 12 V and when I start it at less than 40% it doesn't start. Even if I start at 100% and then I reduce the speed, at about 30% it stops.

When I read reviews online, I see people use fan speeds down to 10%, which no fan I have ever used can achieve.

How can I pick and connect a correct fan for part cooling, so that I can freely set the speed down to 10%?

If the fan you are using is not defective and if you test another fan that behaves in a similar manner, it's possible your firmware or hardware are the root cause of the problem.

The controller directs the driver to vary the power provided to the fan. It's a method called pulse wave modulation, aka PWM. Full voltage is applied to the fan one hundred percent of the time, for full speed operation.

For fifty percent performance, half of the time full voltage is sent, while half of the time no voltage is sent. The time period is rather short, but I didn't determine that aspect of this answer.

One can find a clear explanation of PWM online but one word is worth one one-thousandth of a picture:

If your fans are not performing properly, either the program embedded into the controller is buggy, or the driver module for that unit is bugging out.


Intermittent Y-shift print issue only with multiple items I have an issue with a Y-shift every few lines only when printing multiple items at once. If I print the exact same models individually, they each print fine. Notice the shift only happens a few times, about every 4 lines, and then stops happening.
I’m printing PLA on an Ender 3 Pro, slicing with Cura 4.8 (Mac).
Any ideas on how to troubleshoot?

I initially tightened the tensioner for the x-axis belt pulley, which seemed to help. Then I double-checked my installation, and realized the belt for the x-axis was on upside down (belt teeth go in, smooth side of belt out).
So I guess it’s actually more surprising it’s been working well until now...


Is Marlin capable to work with binary G-code? I want to use a binary protocol like Repetier uses.
Can Marlin work with this/such a protocol?

No. Marlin only supports ASCII G-code, and does not (currently) support binary format. According to the List of Firmware, Repetier is the only firmware that supports binary G-code. Moreover, verifying with Marlin's source code, shows that the G-code parser can only handle traditional G-code.


3D printing template material I want to print a structure that I can embed in a resin and later dissolve. I know that some fancy 3D printing systems have raft materials etc., that can be printed and later removed easily.

Can any one suggest a 3D printing material that can be dissolved in say water or another readily available solvent?

Wash-away filament used for support in PLA printing is typically PVA, which is completely water soluble and may serve your purpose. It is easily 3D printed as the primary filament and attaches well to the build plate.

Many 3D printer filament suppliers will carry this type of support material. It is important to keep it in a sealed bag with desiccant as it will absorb moisture from the air, rendering it useless for printing.

One such resource is MatterHackers which prices a half-kilogram at US$45. The link provides suitably appropriate information:

  PVA (Polyvinyl Alcohol) is a water-soluble material that is often used
  as a support material, but can also be used to print independently.
  PVA supports are useful for complex designs where removing support
  material manually is difficult or impossible, but leaving the part in
  a water bath overnight will completely dissolve this material.


What should I think about if I want to design something modular? For a while now, I have been thinking about designing things such as small bedside tables, game/dvd/bluray racks for 3d printing. I've always thought that making them modular would be a good way to go about doing this as well.

Modular design would help to create an end result that is vastly larger than the print volume of my 3d printer. I might even be able to recycle models for use in other projects. However, I'm not sure of what I need to think about if I decide to go ahead with these ideas I have floating around in my head.

I'm assuming that certain joints (dovetail, etc), tolerances for different types of plastic due to shrinkage, and print settings (% infill, in particular) would be important to have thought about and evaluated to some extent, but I'm not sure about what else I might be missing.

So my question is to anyone who has designed anything to be modularly printed. Have you really had to think carefully about the engineering side of the print? Or am I simply overthinking this? Should I just design what I want and give it reasonable infill, walls and whatnot, and just go for a trial and error approach? I'm sure there is a method to this madness, but is a concrete understanding of this type of engineering absolutely paramount when it comes to this sort of stuff?

EDIT: Although I've marked darth pixel's answer as accepted, I'm still going to follow JKEngineer's advise and check out that book as well since I feel as though proper engineering techniques alongside a good mentality towards how I would tackle the problem (as outlined in darth pixel's answer) would prove to yield better results in the long run.

All printers are designed with an idea of WYSIWYG for sure. Depending on:

printer - type/quality/settings/configuration/assembly precission
filament - type/quality/shrinkage
user skills - manual/using app proficiency
model complexity
environment conditions and so on

you can get different results.

I venture to say users know their printers (after some time and by trials and errors) so they know how to manage dimensions to compensate all above so you will get this knowledge too.

Mathematical formula can describe shrinkage of the material, all other elements are very hard to describe (mathematically) in a general way.

Of course someone can simplify it and say: more money you spend better effects you'll get. It's sometimes true ;)

So all your modular things will be better and better if you will increase (what is to be increased) in above points especially "user skills".

Is engineering paramount? It depends of whay you gonna create. If your modular things have to lock itself, have to have threads, screws and such stuff then this is engineering. Is it the most important part of the design? Not necessarily.

I would say 3D printing moved engineering to next level. I'm talking about this or this. Is it still art or engineering? :)

This is my receipt:

think > imagine > design > rethink > redesign > give it a try > get back to thinking

good luck


Limit Switch problems on RAMPS 1.4 and custom built 3D Printer running Marlin 1.1.0-rc6 So I am trying to fix a custom built 3D printer for my institute and am running into a problem I can't wrap my head around.

So the limit switches for Y-axis and Z-Axis work just fine, but the X-Axis does not.

All three switches are Makerbot (3-pin), and all three light up the LED when they get pressed. However the X-axis does not get recognized by Marlin. When I diagnose with M119 command it does not show as triggered even though the LED is on. All the other ones do.

All three switches are connected to min (X-min, Y-min, and Z-min).

Could this be a firmware problem? Or perhaps my RAMPS 1.4 has burned out the X-axis signaling? (I doubt this because the LED on the switch still turns on).

Let me know if you need any more info to diagnose the problem.

P.S. I have also replaced the X-Axis limit switch with a brand new one and the same result happens: LED turns on upon activation but it doesn't get recognized by the machine.

Considering you're having issues with the board, and the limit switches appear to be registering, but the board isn't doing anything about it, a first good step would be to update the firmware to 1.1.9 as @0scar states. If the update in the firmware doesn't do the trick, then move on to doing as he suggests with changing the Xmax/min stuff around. This just seems like a good first logical step to getting it fixed.


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

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.


Marlin: possible to set ZMin limit when ZProbing? Question: Can a "ZMin-while-probing" be set?
Meaning a minimum Z height the printer bed can move to, while Z Probing.

Purpose: For safety reasons should the probe switch not fire for some reason.

--

in Marlin Configuration.h, I see you can set the height of the Z Axis before deploying the ZProbe:

#define Z_PROBE_DEPLOY_HEIGHT 35

In the context of this question, this is effectively a "ZMax-while-probing", i.e the lowest possible the print bed will be before Z Probing commences.

I am looking for a "ZMin-while-probing" equivalent.  The reason for this is just an added safety check - I know that if the probe switch doesn't fire by Z<=25, then it is not going to, and with this particular printer configuration, that would result in the Z Probe being driven into the printer bed.

Does a setting already exist to create a sanity-check here?

You have not stated the version of Marlin you are using. I will assume we are discussing the latest Marlin 1.1 RC8.

There is no longer any Z_PROBE_DEPLOY_HEIGHT but in earlier Marlin versions it did not function as you think; it was used to signify the amount of Z travel to execute prior to Z probe deployement. This is to ensure available space for servo-mounted, sled, or other types of "stowed" probes.  This was not a limit to the Z travel, but the amount of Z travel to always execute before begining homing.  If a printer without Z_MAX_ENDSTOP is left at maximum travel position, using non-zero Z_PROBE_DEPLOY_HEIGHT could crash a bot into the Z maximum end position.

In these previous versions of Marlin, the homing height was computed by a combination of the above constant adding and subtracting to/from some others, which has since been replaced by the simpler and singular Z_HOMEING_HEIGHT (which works indpendant from the new Z_CLEARANCE_DEPLOY_PROBE):

//#define Z_HOMING_HEIGHT 4  // (in mm) Minimal z height before homing
(G28) for Z clearance above the bed, clamps, ...

#define Z_CLEARANCE_DEPLOY_PROBE   10 // Z Clearance for Deploy/Stow

The absolute value of the maximum bed positions are used in Marlin as sanity check to ensure no axis moves greater than this amount in one movement in either positive or negative direction:

#define Z_MAX_POS 200

If your probe does not function correctly, no ficticious Z_MIN_WHILE_PROBING will prevent a faulty probe from causing a head crash into the bed, so it is not implemented, allowing the Z_MAX_POS sanity check to prevent the Z axis stepper from continuing to run indefinitely during a fauly probe condition.

If your Z_MIN_WHILE_PROBING were implemented, if the printer were powered off (or Marlin crashed, etc) with the head at any Z distance greater than Z_MIN_WHILE_PROBING there would be no mechanism to begin a print on the next poweron, since Marlin will never move in the negative Z axis except during G28 probing and after probing completes successfully.  The only way to recover in this case would be for someone to continually attempt to both home the printer then power-cycle, moving the head Z_MIN_WHILE_PROBING closer to the bed each iteration. This would be an unacceptable user exerience.

Further, if Z_MIN_WHILE_PROBING were implemented, the only percieved safety measure it would add is that during probe failure, the Z stepper would crash into the bed and continue to run for only Z_MIN_WHILE_PROBING stepper rotations instead of Z_MAX_POS rotations.  Regardless, the bed would be impacted so there is hardly any additonal safety added and a stepper driver should not overheat or cause any more damage (other than what was already done to the bed) in a single Z_MAX_POS length of rotations.

For more piece of mind during homing, you may use the Z_MIN_PROBE_ENDSTOP feature with a normally-closed limit switch wired to an available pin on your control board:

// Enable Z_MIN_PROBE_ENDSTOP to use _both_ a Z Probe and a Z-min-endstop on the same machine.
// With this option the Z_MIN_PROBE_PIN will only be used for probing, never for homing.
//
//#define Z_MIN_PROBE_ENDSTOP

Then use the Z_MIN_WHILE_PROBING feature to move the head above the Z_MIN_PROBE_ENDSTOP home position to perform probing.  This will ensure that the printer will crash for only Z_PROBE_OFFSET_FROM_EXTRUDER Z stepper rotations if the probe malfunctions:

#define Z_PROBE_OFFSET_FROM_EXTRUDER 0   // Z offset: -below +above  [the nozzle]

In summary, to prevent the head from crashing into the bed, you must ensure your Z probe is functioning correctly :)


Mystery filament cleaning fluid Whilst looking to fix a different problem I had I came across this video.

It's a filament reel holder, but at 02:40 the person uses a mysterious fluid.  I haven't seen anything like this before (though had wondered).

Mystery cleaning fluid.

What practical problems would this cleaning fluid mitigate?

That's a filament cleaner/oiler combo. The black bottle is a variety of machine oil.

The effect of oilers on prints is heavily disputed in the community. The suggestion of plant oils is a very bad one as they can create residue that stays in the hotend and create clogs.


PETG grinding with direct drive extruder I've been wrestling with a filament grinding problem for a few weeks now and I'm stuck.
The problem manifests itself as starting a print alright then extrusion stops while the printer keeps moving. When I pull the filament out I see indents from the gear then a depression where it ground down the filament.
Filament used is 1.75 mm Spool3D PETG on a Hictop printer, which is a clone of a Prusa i3. I don't know the exact part number though. The extruder is direct drive, and the 28 mm heatbreak is connected to a heatsink block rather than something with fins. Nozzle is standard 0.4 mm.
My print settings are quite conservative. Speed is 20 mm/s, retraction is 20 mm/s (though it never grinds on retraction), temperature is 255 °C, which is 10 °C higher than what works in my other printers. No print cooling.
At first I thought there was a clog, but I can push the filament though by hand quite well. I also use cleaning filament frequently and it never pulls out any debris. Heatbreak and nozzle have been changed to fresh items.
Does anybody have any other ideas of things I can try, or should I just get a new extruder?

This does sound a lot like you are experiencing the effects of heat creep (How is heat creep characterized?). You should lower the temperature of the hotend and increase the printing speed and retraction speed and possibly lower the retraction length.

If this is heat creep, a new extruder will not help you until you solve the heat creep first. A new hotend that can be cooled better might be a better solution.


Can I have a glass bed with only the center heated? I have a 15x15 cm heating resistor from my current printer (printing area: 12x12 cm).

I would like to switch to a glass bed and to rework my printer to increase the printing area to 20 cm (22x22 cm glass plate).

Would it be possible to use the old heating resistor placed only in the centre? this way I would have a smaller heated bed for ABS and a bigger one for PLA.

Would the glass crack due to non uniform heating? This is because glass has a conductivity of less than 5 W/mK, therefore the hot area will stay hot and basically never really spread the heat to the surrounding area. So the frame will be cold and the center hot, causing stresses.

Related: https://engineering.stackexchange.com/questions/31842/how-much-an-unevenly-heated-glass-plate-bows

If you're using borosilicate glass (aka pyrex) then it won't crack. You can get squares of ~20x20 cheaply off aliexpress.

If you're using window glass, picture frame class etc then you might have issues with cracking, it will depend on lots of factors like the wattage of your heater and the temperature of the room.

Your biggest problem will be that the bed heats very non-uniformly, which is unlike to give good print adhesion. I'd suggest a sheet of aluminium underneath the glass if possible, it will allow much more even heating.


Under extrusion with Cura 3.1 I upgraded from Cura 2.7 to 3.1.0 and I'm getting horrible under extrusion, I'm sure this is the software because I rolled back to 2.7 and everything is working fine again.

My printing is a Robo3D R1+ using the "custom FDM printer" profile.

Is there any new setting or a setting that isn't migrated properly that causes this?

Some users have reported upgrades to Cura changing the filament size to the default 2.85 mm. If you are using 1.75 mm filament (which most printers do), you will get extreme under-extrusion.


Extruder feedrate when loading and unloading filament I have an MKS Base 1.4 board with a TFT28 touch screen and a Titan Aero setup.

When I use the load filament command from the touch screen the motor turns at a crazy speed to load filament, whereas if I plug in my laptop and use Repetier host and send a load command it turns at a normal speed.

Is there a section in the Marlin firmware that allows me to set the actual extruding speed during load and unload?

Loading and unloading filament through the LCD options is taking care of by G-code command M600. The options used when executing the M600 command define where the head goes and how much filament is extruded of which extruder. Apparently, there is a difference in calling the M600 command via the LCD menu or (un)loading filament through the Repetier application.

The Firmware-based and LCD-controlled retract options are defined in Marlin Firmware file Configuration_adv.cfg (Advanced Pause). The settings for Repetier are probably differently defined than in the advanced configuration file; you should look them up in Repetier. It could well be that separate G-codes (or scripts) are used for this. E.g. G10 is used to retract filament as set by M207 (both length and feed rate!). G-code G11 does the opposite, it unretracts the filament as specified by M208.

To answer your question, yes, you need to alter the values of the constants in Configuration_adv.h for changing the speed when using the LCD to change the filament:

// (mm/s) Unload filament feedrate. This can be pretty fast.
#define FILAMENT_CHANGE_UNLOAD_FEEDRATE     10
// (mm/s) Load filament feedrate. This can be pretty fast.
#define FILAMENT_CHANGE_FAST_LOAD_FEEDRATE   6


How to make symmetric Low-Poly objects in meshmixer? I've made low-poly objects using Reduce function in Meshmixer. My objects are symmetric and I want to keep the symmetry in the low-poly because it's more beautiful, But the software doesn't necessary keep the symmetry.
using mirror function results in losing flat faces and many problems...
Is there any specific way to make a symmetric low-poly?

The best way would be to follow a four-step workflow:

Reduce complexity.
Cut the object along the symmetry plane.
Discard one half of the object.
Mirror the cut object along the cut symmetry plane.


What G-code commands tell the printer to change nozzle on a dual extruder printer? I have been playing around with creating scripts to generate some custom G-code for a Malyan M180 and I am having trouble understand what commands to use to switch nozzles. Sometimes I can get the nozzles to switch and it doesn't recenter but sometimes it does.
I have been using:
G54
M108 T0; switch to left

and
G55
M108 T1; switch to right

Has anyone else looked into this and have any idea what commands or sequence of commands should be used to change nozzles?

No, M108 does not do that. You are looking for T#, where # is the tool position you want:

T1 ; switch to tool position 1

T3 ; switch to tool position 3

This tells the processor to send all heating, cooling and flow commands to this tool until another tool change is specified, and invokes the X/Y(/Z) offset for the new tool position.

See http://reprap.org/wiki/G-code#T:_Select_Tool


Inductive Sensor Causes Print To Stop Just added inductive sensor to my printer (MKS Gen L Board) using Marlin 1.1.9
After some tweaking it works great!
The problem is when it starts print the sensor detects the bed and stops the print because it gets triggered.

Can I tell Marlin to ignore the Z-min readings while printing?

Solved the problem, I was missing this line:

#define ENDSTOPPULLUP_ZMIN_PROBE

Apparently the sensor required a pull-up to better define the signal.


Uneven wall thickness with test cube I noticed that one edge (which is also the starting point of the print) is always bigger than the other three. Additionally, the walls do not have the same thickness as well. The wall thickness (starting from the thick edge) starts very thin and gets thicker till reaching the thick edge again. Does anyone have a clue whats the issue?

As Fernando suggests, the problem is likely with your source file.  One easy way to verify this is to slice twice, rotating the STL by 90 degrees.  If both prints produce fat/thin sides in the same dimension on the print bed, then it's a printer problem.  If the fat side rotated with the STL orientation, then the STL is at fault.


Ender 3 Random Axis Shift My printer has been doing weird things lately.  It used to print fine, but now it's like the Y or X axis after a certain percentage time.
ie on a 24 hour print: it got off at 5 hours
on a 42 print it got off at 16%

Thoughts?

The usual suspects are overheating stepper motor drivers and over-tight belts. It can also be caused by belts coming loose in their mounts.


What is the best free source for generating g-code Ok so i have built a 3d printer from old cd rom drives. Before installing the 3d pen(extruder/hotend) i used www.makercam.com to export i file containing a star. With a marker attached the machone successfully drew a star. Now i have the 3d pen but using makercam i am not having any luck. Is there a better way to generate files for my new toy?

Try using TinkerCAD!

I'm not advertising here - I have used TinkerCAD in the past for 3D printing.
TinkerCAD allows you to easily build and create simple shapes by the press of a button. (I assume this is what you mean by generation)

It is great for testing if your homebrew 3D printer works.

Link: https://www.tinkercad.com/


Makerbot Replicator (5th generation) poor print quality Current main problem is that at various points during a print, one layer doesn’t attach well to the layer below it. That is what appears to be causing the artifacts in the second picture below, but the picture may not show it clearly.
Background
I have a Makerbot Replicator 5th generation printer. This is the one that is very locked down. As far as I know it can only use the slicer it comes with, Makerbot print, but I'd be happy to be told otherwise. It only prints in PLA and @Trish gave some good advice on drying out the filament. I've also leveled the print bed. Prints have improved from where they couldn't even finish to now where they just aren't very good quality.
The issue I'm having now seems to be primarily that one build layer sometimes doesn't stick to the one below it very well. Then they peel up and the nozzle pulls them and re-melts them into a blob. I've attached two pictures. It's worse in the first one, then I lowered the first model layer fan setting from 50% to 45% and it improved and I was able to get the print in the second picture.
Any help on what settings I can change would be great. Is this because it is underextruding? I think I'm stuck with whatever setting options are available in the Makerbot.print software.

Print settings
The default print temp for this printer is 215. This is at 210 degrees, but those blobs aren't actually burned they are a mix of the previous red filament that was on the outside of the nozzle. The travel speed is 150 mm/s, First model layer print speed is 30mm/s, Raft to model shell vertical offset is 0.26mm, Raft to model vertical offset is 0.33mm (I can't tell what the different between those is), z-offset is 0 (default), Layer height is 0.14mm. In the second picture the print was attached but separated easily from the raft.
A couple more settings that might matter is the Print speed: Outlines is 20mm/s, and the Print Speed: Infill is 90mm/s
Update 3/15/19
I made several of the changes suggested including lowering the temperature, leveling the bed, adjusting the Z-offset, and lowering the infill speed. I also continued to dry the filament in a dry box with a lot of desicant that I dry periodically. The desicant seemed to make much more difference than drying the filament at 50C for a couple hours. Print quality has improved a lot, but isn't great. I'm coming to the conclusion that the filament has been damaged by poor storage. It has been left in a drawer in a humid, hot room over the past summer or more.
I'm still using a raft because prints fail completely without it and work reasonably well with one so I have no problem using a raft. Now most of my problem is blobs of filament that I think are running down the nozzle from the heater core. I may have to take some timelapse video to figure that part out. I'm also having some stringing which may be a filament quality issue and some layer shifting.

Your printer is improperly leveled with respect to the distance of the nozzle to the bed. This, and a high raft to print part distance, causes consecutive layers to not adhere well.

PLA should not need that high temperatures to print nor does it need a raft. Rafts are interesting when printing filaments that have high shrinkage. Furthermore, a 90 mm/s infill speed is pretty high, and do not use the part cooling fan for the first few layers (if you cool too much it can curl up).

You need to re-level the bed and make sure that the nozzle to build plate distance is the thickness of a sheet of A4 paper when Z = 0.