Customer Support With DIY Plywood


#21

(Previous version removed, see later posts.)

Okay, this is a working configuration file for Marlin 1.1.8. This should work with either the MKS GEN-L v1.0 that shipped with the printer, (though I haven’t loaded it on that board yet) or with the MKS GEN v1.4.

It is configured for a heated bed. that should be easy enough to turn off if you just want to use the printer as it came. It is configured for 3 point leveling the same as the factory firmware was, so this should work with the stock build plate. It also works with the one that I made which holds the 275mmX220mm Hictop heated build platform, of course. All other hardware configuration is the same.

I may change this file again, but at present I think that it works acceptably well. I still need to tune the driving current on my A4988 stepper drivers. My extruder is under-extruding and the motor is stalling still, and I may want to adjust some of the travel rates after I tune the drivers. Steps/mm are all tuned to match the firmware that shipped with the printer, so that should be all good, bed geometry matches.

There are some differences with how the LCD controller works, I think that the rotation direction in the menus is reversed. I got a compile error when I tried to fix this, but I also think that the other direction makes more sense.


#22

Oops. I zipped this up without saving the last few changes, so there’s still no saving settings, or a couple of other tweaks, though this should still work. I’ll have to re-do this later when I get home, and will update tomorrow.


#23

Configuration.zip (21.7 KB)
Okay, this is the version that I managed a successful ~4hr print with last night.

Some potential issues, it does seem like there’s a little bit of under extrusion, however the settings do allow you to fine tune the steps/mm. I would guess that it needs a 1.5-2% increase. I’m going to do a re-calibration. I remember that the default firmware (Same steps/mm) seemed to be a couple of percentage points low for the extruder before, but it wasn’t the biggest issue, and I never did correct it, since without a heated bed, I never got a successful print large enough to be really bothered by it. Oh, and I had estimated the offset between the Z probe and the hotend as 15mm I think. It’s probably more than that, I wasn’t actually looking at the printer at the time that I did that. I took that into account for the probing points, so if you want to change it for more accuracy, it shouldn’t break anything.

I can’t really guarantee the acceleration settings. My Y axis belts are a little loose right now, and I’m getting some ringing on sharp corners. that was there before, but it seems like it might be a touch worse.

Of course this configuration assumes that you’re using a 100k thermistor for bed temperature settings. This still seems to be the most common configuration, and probably won’t adversely affect people wanting to add a heated bed.

Other than that, this Configuration.h file ought to upload to the GEN-L board that the DIY kit came with (Or a replacement GEN v1.4 board, as I have here) and allow you to add a heated bed.

Additional hardware needed for heated bed:

  1. Heated bed (duh)
  2. replacement build platform. The acrylic build platform that came with the DIY kit probably shouldn’t be heated to the kinds of temperatures that a heated platform is likely to see. I made mine from thin MDF and some rare earth magnets with printed bumpers for the leveling points.
  3. Add-on external MOSFET. (If you are running a 12V heated bed like me, or you want to keep using the stock power supply with the barrel jack connector.
  4. Larger Power supply of appropriate voltage for your heated bed. A 24V/15A power supply should be adequate to do everything, but if you try to power a 24V heated bed from the power supply that came with the kit, you’re going to have trouble. If you use a computer ATX power supply (12V heated bed), I would strongly recommend that you use a relay to jumper the power on pin when you turn on the main power switch.

#24

I updated the .zip file on the main thread. I’m very confident in this version, as I used it for a couple of successful prints over the past couple of days. I’ve got it installed on Marlin 1.1.8 on my GEN v1.4 board, should install just fine to the GEN_L v1.0 board, too. includes all of the functions that I’ve used on the printer to date, including saving settings. It is possible to allow the hot end to get hot enough to damage itself now, but using “common sense” settings and not trying to print polycarbonate (280 deg C) should be safe enough. ABS at 240 deg C should be perfectly acceptable. PETg at 260 deg should be possible, but might result in damage to the PEEK plastic in the nozzle. I forsee myself changing the hotend out in future and going to an all-metal one.

Here’s hoping that this helps you make use of your kit! All in all, I think that once I get those Y axis belts tightened, this is going to end up as a very nice printer.


#25

While this seems to work, I had a little problem. The PEEK plastic mount for the hotend melted a little on me. Just enough that the head moved a little out of alignment,and the extruder jammed. I had not tried to run anything hotter than 240 deg C, which was the most that I was able to get to before. of course it may have got a bit hotter now (which it will) without the printer immediately shutting down with a thermal error. Or else the temperature sensor isn’t a 100k thermistor, which is what I configured it as. The printer overall seems to function as I would expect, so I think that I have the sensor setting correct, but there is the possibility that I have it configured wrong, and that I was actually extruding at much higher temperatures, but I don’t think so. The extrusions were behaving well for my test prints, and layer adhesion and bridging behaved very much as expected for the target temperature of 240 deg C. (This woiuld occasionally trigger the printer to shut down before, as it would reach the shut down temperature of 250 deg C.) The upshot here is that if you use this firmware, it may be configured for the wrong temperature sensor, and if it isn’t, be careful not to melt your hot end throat.

Anyway, I have most of the hot end taken apart, though I cannot get the thermistor out of the casing, it’s in there too tight. I also can’t get the hot end off of the PEEK tube. It sits at a slight angle to the tube now. I might be able to separate it, but not with the other stuff stuck together. I have ordered a replacement throat (https://www.amazon.ca/gp/product/B07D6W3B8Y/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1) from Amazon. I won’t be able to use the same heat block with it, though. It also looks like it needs a PTFE tube. I might try with brass or something instead.

I am looking at options to rebuild, possibly with an all metal hot end, so that I can print in higher temperature materials like nylon. Doing so will necessitate changing out the Z probe and part cooling fan. At that point, it probably won’t resemble the standard kit enough to use the same firmware configuration anymore.


#26

Well, because I have to change hardware, at this point I’m going to stop further development on this configuration. Please note, that this version does not have the hot end thermistor correctly configured. I do not know which the correct one is, but it most certainly is not the one that I selected. Since it no longer seems possible to get this information from the manufacturer, I would suggest that some trial and error is needed. Alternately, if you choose arbitrarily lower extrusion temperatures (I’d suggest capping between 190-200 deg C indicated) in your slicer configuration, you’ll probably be safe. This ought to give you an adequate safety margin.

Most users will need to edit this configuration anyway to remove the configuration for a heated build platform (Though you could use it this way, just connect a thermistor to the control board, and leave the bed temperature at zero when you generate your gcode.)

If anyone cares:

My future plans for this printer are to change out the hot end with something more durable, with a higher temperature range sensor, and change the Z probe system out to enable mesh leveling, which will make the firmware no longer able to deal with the stock printer, pretty much at all.