This is my first working delta build [1]. I learned a ton, but it is by no means a perfectly precise build, despite my best efforts. However, it does work, so I'll take it as a win.

The T3P3 kits are no longer available, so I sourced all of the parts independently, and upgraded parts where and when I thought appropriate. So this build has:

• A Duet 2 WiFi with 4.3" PanelDue
• Haydn Huntley's magball arms
• An Orbiter 2.0 extruder
• A 24V heated bed
• An E3D Revo Micro hotend

[1] My first actual build was based on Johann's original design with 1515 extrusions. I met him several years ago and he gave me a box of loose parts, most of which came from an incomplete OpenBeam kit. I eventually completed the build (that being my first substantial electronics project), but my first 4-5 layers came out very poorly. Despite replacing nearly every component in the build, I never did figure out what was causing the problem and eventually abandoned the build and started over.

@aerouta I use a 3510 fan for the print fan and a 2510 fan for the hotend fan. I was able to make a 40mm fan work for the print fan, but the clearance was too close for comfort. I find 35mm works nicely. I also replaced the 5V stock Revo fan with a 25mm 24v fan. 25mm was the smallest size I could find that operated on 24v.

Hotend Fan

Print Fan

The models are parametric, so they can be made to fit other fan sizes. I'm happy to share them if anybody is interested.

• 25mm Hotend Fan STL
• 35mm Print Fan STL

I put some more work into my build and managed to get rid of the twist. My prints are coming out very nicely now. Thank you everyone for the help.

I believe my issues came from two major areas:

1. I mentioned earlier that my bed had some tilt to it. I was aware of the tilt, but I was under the impression that the Duet controller could compensate for it. The documentation states that a level bed "isn't essential, because RepRapFirmware can compensate for [it]." Anyway, I redesigned my bed mounting parts and gave the bed a lot more support.

2. I am using FSRs, but I had not done a great job of calibrating them. This meant that in some cases the nozzle had to depress the bed a lot to generate a reading. When I redesigned the bed mounts, I also used the opportunity to calibrate the FSRs and to make sure that their ambient resistance was in a range where they would be sensitive enough to detect approximately 500g of mass.

I still have some other settings to dial in now, but at least I can move on from worrying about the straightness of my prints. Thanks again!

@dc42 What is considered an acceptable amount of deviation?

@dc42 Thank you! G32 reports a deviation of 0.066mm. I am using a v2 Smart Effector.

This is my first working delta build [1]. I learned a ton, but it is by no means a perfectly precise build, despite my best efforts. However, it does work, so I'll take it as a win.

The T3P3 kits are no longer available, so I sourced all of the parts independently, and upgraded parts where and when I thought appropriate. So this build has:

• A Duet 2 WiFi with 4.3" PanelDue
• Haydn Huntley's magball arms
• An Orbiter 2.0 extruder
• A 24V heated bed
• An E3D Revo Micro hotend

[1] My first actual build was based on Johann's original design with 1515 extrusions. I met him several years ago and he gave me a box of loose parts, most of which came from an incomplete OpenBeam kit. I eventually completed the build (that being my first substantial electronics project), but my first 4-5 layers came out very poorly. Despite replacing nearly every component in the build, I never did figure out what was causing the problem and eventually abandoned the build and started over.

I'm starting a new delta build and I'm curious about how to best determine the position of my idlers. In his "Precision Kossel build" blog post, dc42 suggests adjusting nylock nuts to keep the idler pulley in place. Does the exact position of the idler matter? If so, how can I determine where on the screw the idler should sit?

On a tangent, I've noticed some threads where folks have recommended the use of shoulder bolts. These bolts are unthreaded, so what is the preferred way to position idlers on shoulder bolts? Should I print some spacers? And if so, how can I determine the length of the spacers so that the idler is correctly positioned?

@aerouta I use a 3510 fan for the print fan and a 2510 fan for the hotend fan. I was able to make a 40mm fan work for the print fan, but the clearance was too close for comfort. I find 35mm works nicely. I also replaced the 5V stock Revo fan with a 25mm 24v fan. 25mm was the smallest size I could find that operated on 24v.

Hotend Fan

Print Fan

The models are parametric, so they can be made to fit other fan sizes. I'm happy to share them if anybody is interested.

• 25mm Hotend Fan STL
• 35mm Print Fan STL

Thanks @giostark.

Frame alignment: When I disassembled the printer and began reassembling it, I checked for alignment on the top and bottom frames. I also tightened them down with belt clamps. I think they are in good shape.

Rod length: I'm beginning to suspect my rods more and more. Currently the measuring tools I have can only give me accuracy to within +/- 0.2 mm, so I don't think I can detect errors to the degree stated in the post you linked.

I did not get them from China, but when I inspected them more closely I found one that had a loose ball joint and another one that had the ball joint glued in at a slight angle. When I repaired them, I measured them all to be the same to within that 0.2 mm margin, but I'm guessing that perhaps that is too wide of a margin for accuracy.

BLTouch: I'm not using a BLTouch.

Bed: This was previously an issue, but I've since fixed the bed mounting and the glass is very secure and level on the frame now.

I think the next thing I'm going to try is a new set of arms. It seems like the preassembled rods on AliExpress are about the same as the cost of materials, so I'm going to give them a shot as well as making some new ones of my own. I'll update the thread once they arrive (which will not likely be any time soon given lead times from China these days).

@dc42 Thank you. I also replaced and tightened down the pulleys. They seem firm and in the right positions.

Just to close out this thread... since this is not a Duet-related issue I've moved the thread to the deltabot forums on Google Groups: https://groups.google.com/forum/#!msg/deltabot/MKpY_hvHnLE/vij7Q4LOAwAJ.

Thanks again for all of the suggestions here.

I was a bit premature in declaring victory. I continue to have issues with layer shifting and autocalibration. At this point I've tried almost everything except replacing the steppers. I've taken everything apart, measured parts to ensure they are sized accurately, and replaced the timing belts, pulleys, and idlers. Still, no improvement to the layer shifting.

What's really confusing me is why the autocalibration gives me such wild results between runs. Here is the output from the last few invocations of G32:

Diagonals 215.000:215.000:215.000, delta radius 105.620, homed height 236.757, bed radius 70.0, X 1.482°, Y 0.880°, Z 0.000°
Diagonals 215.000:215.000:215.000, delta radius 110.722, homed height 237.256, bed radius 70.0, X -14.987°, Y -7.550°, Z 0.000°
Diagonals 215.000:215.000:215.000, delta radius 106.415, homed height 236.746, bed radius 70.0, X 1.289°, Y 0.492°, Z 0.000°
Diagonals 215.000:215.000:215.000, delta radius 105.221, homed height 236.595, bed radius 70.0, X -1.524°, Y -0.171°, Z 0.000°
Diagonals 215.000:215.000:215.000, delta radius 106.281, homed height 236.804, bed radius 70.0, X 1.278°, Y 0.430°, Z 0.000°
Diagonals 215.000:215.000:215.000, delta radius 106.814, homed height 236.817, bed radius 70.0, X 0.138°, Y 1.348°, Z 0.000°
Diagonals 215.000:215.000:215.000, delta radius 106.660, homed height 236.546, bed radius 70.0, X 0.512°, Y -0.868°, Z 0.000°

This is just a sample from today. There are times when the control board detects nearly 0 degree offsets, but most of the time it's something like 0.5 degrees. The second one you see is a bit crazy though -- it thinks my build has a nearly -15 degree angle! This is my first ever build, so I may not have done a great job, but I can assure you that nothing about my build is this inaccurate. I have also watched every moving part very closely, but my eye is unable to detect any sort of wobbling or movement.

@dc42 You mentioned two things that I thought might be the culprit: my belts and the diagonal arms. I tested the arms and they are all the same size (measured as best as I could with my tools). I also wondered if I had abused my belts, so I replaced them in case there was any stretch or wear.

Any other suggestions? Could it be my linear rails? Or might the motors have some issues?