Just out of curiosity, what's the primary difficulty with printing nylon? With PETG my issue has largely been that it will produce a little glob that drags across the print surface during the start of the print. If I can get a clean first layer, the part will almost always come out pretty good. I may try switching to a new nozzle to see if that helps, but I find it frustrating how often PETG seems to need nozzle changes.

Ironically I had PETG dialed in almost perfectly until I realized I had the wrong thermristor setting. I was even getting great bridging with it..

 

Physics. Nylon has a very narrow window where it is liquid but doesn't boil, you have to keep the pressure just right in the nozzle or it will boil, which a lot of people confuse for not being dry enough. Even bone dry nylon will pop and sizzle and turn your print into foam if you get it too hot, don't use enough pressure, print too slow, etc. Nylon is best printed with 100% infill, and at the same speed for infill and outlines. Supports can be difficult to remove because the material is not brittle. It's just a very touchy material to print for all the same reasons that once you get it dialed in, its amazing. Taulman 910 is by far the best I have played with it sticks readily to an 80 degree bed with a coating of glue stick. It will warp if you don't smash the first layer into the bed tho.

 

@Elmo Clarity - I've printed these all off and think i understand how they all fit together, but would it be possible to get photos of your drag chain and mounts? Want to confirm what parts I believe should go where and see if possible there is a missing piece that attaches to the hotend carriage.

Thanks!

 

It looks like I missed the Y axis support base so including it here.


This is the Y Axis Support. Attached to all of the supports is either a toplink or bottomlink part.


This is on the XY Gantry. It is the Y Axis Support base on the bottom. The top is the lower part of the X Axis Support.


Front view of the X Axis Support


And the top of the carriage with the X Axis Support base part.


I am working on a new extruder so this doesn't look like Carl's direct extruder. And that glob of white stuff on top of the support base is hot glue from testing a part.

 

Thanks for this. I really appreciate it, should be able to finish this thing up finally this weekend!

 

Post pictures so we can all see how it turns out.

 

Will do.

 

Okay. Trying to get this monster finished so I can move on to my next printer project (maybe that is why it is fighting me so much. Doesn't want me to leave it). Printed these 25mm cubes for testing. I am using the same gcode file. Just hit print a second time to print the second one. So I don't think this problem is caused by the gcode. So where should I start looking to find the problem?

 

Early morning guesses...

Skipping steps?

Check driver voltage.
Check driver temp.
Check motor temp.
Check belts for correct and equal tension.
Check movement for smoothness.
What firmware and version?
Acceleration too high?
Check steps per mm in firmware.

 

Well. No change with 0 infill and no top or bottom. Running at slower speed really exaggerated the slant. Stopped after about 20 lays and it was leaning over more than 45 degrees. I have a feeling that I may have damaged my controller. I am using a Duet 0.8.5 and one of the drivers went bad. It caused the motor to make a loud clicking sound and skipped a lot of steps. When I mapped it over to the extra driver, the clicking went away and the printing became more consistent. Unfortunately, not in a good way. I got a new Duet ordered and going to try a Printrboard I have here I was using earlier.

 

Has anyone purchased a belt-tensions gauge for getting 'consistent' xy tensions on the c-bot? I used to use one for my belt-drive motorcycle (Yamaha Warrior), which is obviously far more heavy-duty than what can be used on the c-bot. But I'd like to do a few things:

• Make sure both belts are tensioned exactly the same.
• Do some experiments changing the tension and see what effect that has on backlash, print quality, etc.

I've been searching around Amazon, but if someone actually has one they'd recommend I'd like to hear about it

 

Actually, this is a problem I am having.

Endstops are not being triggered as far as I can tell. Besides, when the printer is not doing a home operation, it ignores the status of the endstops. (Duet 0.8.5 - RepRap Firmware)

 

Ack, I just deleted my post thinking you'd solved it (above).

Sucks you have to order a new board: That's exactly the reason I went RADDS... just in case one of those drivers goes bad, I can just swap in a new one. My Makerbot Replicator1 had one go bad the first year I had it, so have been paranoid ever since. What's interesting though is the big brains on the forums seemed pretty positive about the built-in drivers, based on the thermal dissipation qualities of being mounted directly the pcb. Guess that doesn't help you now though

 

This is always a possibility with built-in drivers. Fortunately, I have a hot-air rework station and should be able to replace the bad chip. I know this is not always a possibility for others. And I'm not sure how the driver would have gotten damaged. It was probably just one of those micro black holes I have floating around my work area that keeps causing things to stop working.

 

Question on the extruder spring.. I really don't want to shell out $10 + shipping to get a special spring. Would this work instead? I'm going for the direct drive option, if it makes a difference..
10PCS Spring For Ultimaker Makerbot 3D Printer Extruder Heated Bed New Best

If not, would it make sense to just buy a pre-made extruder kit? Sorry if this is a dumb question, it's just that the extruder assembly is the only part so far that isn't immediately obvious how it goes together just by looking at it.

 

Hi all,

Been building avidly for last month so time to share my build:

PM

PM

PM

- E3D is tricky. if you dont leave the fan on post completing the print, the filament swells and then jams. Also need to change the extrusion width. have not worked out teh logic yet, still on trial and error. unfortunately the default slic3r settings dont account for a 0.8mm nozzle, which then rips the print off the plate. Got it printing now, but a significant gap between oozes still.

- A piano wire wrapped into the wires between printhead and base works well to stop them drooping

- How do you hide all the surplus wire - am i suppose to cut them all to exact length?

- wish there was an easier way of controlling fans. seems like they keep turning off if you use the port?

- Local 2040 ALU works fine for all the build except the rails.

- How excellent Alibaba is.

- I put the threads diagonally opposite as seems that this would force the least amount of rocking. That went well, but seems we really need a way of keeping the threads aligned. If I put some GT2 belt between then then that would align, but am worried any tension would kill the stepper bearings? maybe a chain link that doesn't need tension.

- Installed some stepper motor silencers but they couldn't manage the sideways tension and angled the stepper motors on the XY axis. so removed them. working fine on Z axis but to be honest motors are quiet anyway.

- I put a clear perspex floor on the bottom and electrics underneath. looks good but worried transformer may get too hot.

Thanks for a great forum. I dont understand all the github jumbo, just hope you keep it simple so is accessible to many.

Cheers

 

@percyb :

- E3D is tricky. if you dont leave the fan on post completing the print, the filament swells and then jams.
The fan should stay on post-print: the firmware should leave the fan on until the extruder hits some temp, I think mine is 50c.

- A piano wire wrapped into the wires between printhead and base works well to stop them drooping
Huh?

- How do you hide all the surplus wire - am i suppose to cut them all to exact length?
Yep: I spent two days cutting and soldering.... And then did it again when I swapped mainboards. :S

- wish there was an easier way of controlling fans. seems like they keep turning off if you use the port?
What do you mean 'port'? Again, this may be a firmware issue? Or how the gcode is being created? All three of my fans (extruder, pla, case) all behave as expected, so something sounds amiss on your end?

Good looking build!

 

How much play should the XY bar have? I have the frame mostly assembled, but had some difficulty getting the bar tight enough to be completely rigid while still letting it move freely. A few of the spacers printed a bit sloppy and I'm wondering if that's the issue.. I guess maybe I should have went with aluminum spacers..

 

Thank you for the hard work Carl! I've been dreaming about building a corexy machine for a year. Recently i was able to begin ordering parts! My extrusion arrived this week and while triple checking my cut list I discovered an error in the C-bot Cut Calculator that was added to the Build page. That calculator does not list the "bed front cross piece" (shortest piece of extrusion found in the BOM_Rework.xls calculator). In my case this is a 240mm piece that can be easily added to the cut list on another section of extrusion. In addition the C-Bot Calculator includes the optional "Z-Platform: Bed Support Offset" which is not listed in the BOM_Rework.xls file.

 

@Elmo Clarity
Have you tried swapping the motor connections? If the tilt reverses it might be a bad motor. I'd say it might be a bad motor driver, but you already tried another driver, correct?

 

I will update this to support all three build options. The offset bed support is listed and the reason it was posted like this was due to me and someone else needing that piece. I will update the calculator to support all three options (rear, offset, and front/back)

EDIT: The calculator has been re-posted with the ability to choose which option you want for z-axis lead screws.

 

Hey @Carl Feniak @AK Eric or others. How much "play" do you have in your Z-axis wheel mounts? Mine seem to have way more than I would like (enough to tilt the bed up and down by hand pretty easily). The wheels don't seem to fully engage the v-slot. Just about ready to start printing test pieces so I am not even sure if it is a problem yet but just curious.

 

My experience... There is zero play in mine. I had to adjust the spacing a bit to get the wheels in the proper place to sit in the valley. Before that I had play and they wouldn't engaged like you have. YMMV