My custom Cartesian

wilriker

Reports indicate that the original stealchChop mode (as implemented in the TMC2130) is no good for 3d printers because it doesn't work well for high speed moves. The newer stealthChop2 (implemented in the TMC2208/TMC2124, TMC5130 and a few other driver chips) is supposed to be better. But I'm not convinced, because I have seen my Ormerod printer (powered by a Duet 2 Maestro with TMC2224 drivers) skip steps when in stealthChop2 mode, whereas it doesn't in spreadyCycle mode with the same acceleration, jerk and max speed settings.

I heard that for stealthChop(2) to be of any use at all you definitely need at least 24V and better even more (as the TMC chips can handle more). But I also heard that stealthChop was never meant for such a purpose, so I can confirm this.

As your printer is a Cartesian with 1.8deg motors, if you increase the driver voltage to 24V, then changing the motors to low-inductance types may not give you much more speed. And vice versa.

I know. Ironically I am currently slicing in Cura with "only" 75mm/s and travel moves set to 120mm/s (capped at 110mm/s by printers max configured speed) and I don't even intend to increase this speed - changing these parts is purely out of me being able to do some more upgrades that are equally overkill as putting a Duet Wifi on an Anet A8. But that's who/how I am.

wilriker

@obeliks I did not have the time to take some nice shots yesterday (as I planned) and probably will be away for the weekend as well. So sadly you have to wait until next week for images.
I also just checked my phone but strangely there is not a single image of the full printer since changing to the aluminium frame.

wilriker

Funny aside: when trying to post this description in a single post the forum told me I need to keep it shorter because I exceeded the maximum of 10,000 characters.

wilriker

Change: Added "Additional Sensors" to the printer section.

OBELIKS

I tried your settings and my steppers seem to work with 500mA. But I could make them skip with one finger. So I will leave them at 900mA as I had before (I am 90% sure they have 1680mA max).
The rest did not make much difference, only extruder motor got louder.

Also while I was playing with currents, I went to max recommended (80%) and successfully melted the gear on my printed Drakon extruder (homemade Titan extruder) Steppers were at 80°C It took some time to assemble the old extruder and print new gear, but all is well again.

wilriker

@obeliks If you still have the "old" 1.68A steppers (as it appears to be) reducing them to 500mA is bound to fail.

Phaedrux

@wilriker said in My custom Cartesian:

A self-contained hobby so to speak.

This is very accurate. It certainly seems that way sometimes, but I think the most satisfying thing to do with 3D printing is design a model to fix a problem, no matter how small.

Thanks for the write up, I can't wait to see what you've done with the A8. I suspect it will be very well done.

wilriker

@phaedrux Thanks! I added one image of the printer in the second post just now. I will add more images probably on Monday in a new post below with comments to each image. Have to process the images first, though.

Not everything is done to my expectations on the printer, yet. For example, I am still at a rewiring stage that will go on for another while. But I will go into a little more in detail about all these things together with the other images. Just did not want to let you wait any longer.

wilriker

Images!

Here they come.

Still the original Anet A8 MK8 Extruder and Hotend. At the top you can see the end of the Reverse Bowden and at the bottom/front is my alternative part cooling duct. What you cannot see in this image is that I have a silicone sock on the heater block which really helps a lot with maintaining temp and protecting the fan duct from melting.

Just a view of the full printer from another angle. To the left you can see the case for the Duet and in the rear the filament spool inside a plastic bag.

And here we have it - slightly misfocused - my case for the Duet based on @deckingman's version. I slightly changed dimensions and made space for a 92mm fan (I think Ian's is made for a 60mm fan) that I still had laying around. Rewiring is still work in progress and as these images were taken on Saturday it already looks different today.

Cable management. I have these printed cable ducts (originally only clips but scaled to 50mm in Z) to keep my cables where they are supposed to be. The speaker cables are 2x2x2.5mm² for power from PSU -> Duet.
The other wires visible are from two steppers (Y and right Z) and will probably replaced in the near future by 4x0.5mm² in its own PVC insulation (this one is lost in translation, no clue how this is technically correct). I want to basically have all kinds of connections separated from each other to prevent shortings between different voltages for e.g. motor, heater, fan, sensors, etc.
Heavily out of focus in the front is the DHT22 for ambient temperature and humidity.

My simple filament run-out switch and the frame-fixed part of my Reverse Bowden. I don't like about the switch where it currently sits at because it means I still have about 30-40cm of filament to go before it really runs out at the extruder but I have yet to design another solution closer to the extruder - maybe with the change to my Titan+V6.

The machine needs to be silent so beQuiet! 92mm fan to cool the board on the backside. Currently this is wired in parallel with the PSU fan (same model) and triggered if the heated bed is above 25°C. As these fans are barely audible I can take it that this sometimes is the wrong trigger.

Filament spool on (hard to see) ball bearing roller together with 100g of desiccant (with color indicator). Also visible in the bag is the second DHT22 sensor. I would prefer a dry-box but I have only very limited space so for now it has to be like that.

Sadly the part that I wanted to show here primarily is out of focus: Y-belt-tensioner. This was already part of the PK8 frame set and works very well. Also a shot of my poorly self-cut mirror tile (it is only 216mm in Y instead of the desired 220mm - but it was only my second cut of glass ever ).

Z-motors are decoupled with silicone dampers but I am not too happy with these. They do reduce vibrations a lot but noise reduction is only minor. Will replace them in the future by those classic Nema 17 dampers.

Lead-screw nut. Replaced the original brass one with one made from POM. I cannot say if this is really more silent but at least it has a much better frequency that I recognize less as noisy. Also in this image the X-belt-tensioner.

X motor with grounding and the "movement indicator" I used when I was working on stand-still noise reduction that at that time also included reduction in movement-noise for which it required a better visible indication for micro-steps. Also you can see that the rather cheap GT2 belts leave black powder behind.

My upgrade Omron micro-switch for most precise repeatable Z homing. As I use no Z-Probe I need a reliable way to determine Z=0 between prints - and in the end these are still very cheap even though being a brand-model.

A little more details on the heated bed. From bottom to top:

Igus RJ4JP-01-08 in printed adjustable holders so they can be compressed (as they are supposed to be) on 8mm smooth rods. But even like that they are just not working 100% as I expect them to.
3mm aluminium holder for heated bed
Sheet of cardboard to hold the insulation layer - taped with Kapton tape
SilkaWool 13mm insulation wool
PCB heater with 3mm aluminium heat spreader
3mm Ikea mirror tile cut to (approx.) the size of the aluminium plate

Replacing the Igus bearings by more suited Igus bearings (RJZM-01-08 - or if I cannot get these working RJZM-02-08 in SC8UU aluminium blocks) is probably next after finishing wiring work. Also I think about replacing the glass plate by something like GeckoTek to reduce weight.

Cable strain relief for the heated bed. The holder on the left is fixed to the holder of the heated bed.

PSU with fused power-plug. This is no longer the current state as shortly after taking the images I finished the rework of this part where the power box sits in its on case. This will be screwed to the frame above the PSU later.

And this will be the lid for the Duet's case. Printed in translucent red PETG with infill explicitly chosen to look good (as their is no structural enforcement required for this part). This will be probably go on the case tonight.

T3P3Tony

Thanks for the update! This will be a good collection of upgrades for anyone looking to improve the stock prusa like printers.

mrehorstdmd

I had some no-name Chinese GT2 belts in my printer and had it all apart recently and found that they, too, left black dust on the machine near the motor/drive pulley. I also found the black powder caked in the grooves in the pulley, easily removed with a toothbrush. I wonder if that sort of thing is going to cause some degradation in print quality after a couple years of use if you don't periodically clean off the pulleys.

I have replaced the belts with Gates GT2 that have nylon facing on the teeth and no longer see any black (or other color) powder around the motor or in the drive pulley grooves.

JoergS5

@mrehorstdmd please tell me what type the Gates GT2 is: do you mean a Poly Chain GT2, which is available as 8 MGT and 14MGT? The teeth are 8 and 14 mm apart, which confuses me a lot.

And Gates PowerGrip: I can only find PowerGrip GT3 2MGT, 3MGT and 5MGT.

Only GT3 2MGT has a 2 mm teeth distance, Do you use those?

And if it is GT3 2MGT, can you use the normal GT2 pulleys?

It's all very confusing.

whosrdaddy

@joergs5 : I think he uses LL2MR09 (9 mm belt), 6mm version is LL2MR06

JoergS5

@whosrdaddy said in My custom Cartesian:

LL2MR06

Thank you for the information.

My eb.. does not find it ;-(
This will become hard to buy for me.

mrehorstdmd

@joergs5 said in My custom Cartesian:

@mrehorstdmd please tell me what type the Gates GT2 is: do you mean a Poly Chain GT2, which is available as 8 MGT and 14MGT? The teeth are 8 and 14 mm apart, which confuses me a lot.

As someone else posted, I am using LL2MR09 belts. I do not see any difference in print quality between the no-name belts and the Gates belts, but rubber dust doesn't give me a lot of confidence in the long-term viability of the no-name belts.

JoergS5

@mrehorstdmd Thank you to clearify. 09 has the disadvantage for me to replace everything. But for higher tension it may be woth it.

wilriker

@mrehorstdmd said in My custom Cartesian:

I do not see any difference in print quality between the no-name belts and the Gates belts, but rubber dust doesn't give me a lot of confidence in the long-term viability of the no-name belts.

At the time of purchasing these belts I did not have any clue of what I was doing. By now I know that whenever I have to replace a belt I will also switch to a genuine Gates one. Even if it is just to get rid of the dust.

@JoergS5 When I switch to Gates belts, I will purchase these. From all I know these really seem to be genuine Gates although coming from Hong Kong.

JoergS5

@wilriker I am sure this puffy rice tastes very good

Thanks for the hint.

OBELIKS

@wilriker Well soon I will be able to tell you if those Wantai 42BYGHM810 are any good. I checked and ruled out everything but steppers, so I ordered these.

wilriker

@obeliks I have to admit I miss a little bit of reference of what problem you are trying to solve.

I thought about these motors now for a while. My largest uncertainty is the difference in motor length compared to what I currently have. Since I use dampers on the motors these additional 8mm could be a problem for at least Y axis as my holder for the heated bed has a rather small cut-out for the motor.

But then again, motors are probably not going to be the very next thing to exchange, so lots of more time to think about it.