Hi folks, I've had issues with the sizes of holes in my 3d-printed parts. I've found it necessary to use a .25mm x-y hole compensation (which widens all hole diameters by .5mm). Without this I need to drill out every hole which works but is a bit tedious and also creates lots of dust that is liable to get into bearings.
The x-y hole compensation works well, except for the J2 motor support, whose hole for the J2 motor is not technically a 'hole' because it is not actually closed (it is split, presumably so i can be expanded slightly). Luckily, there is another setting for this called x-y contour compensation.
On the other hand, I have to turn off x-y hole compensation for the J2 spacer (otherwise the hole is too wide) which is meant to go around the exact same piece as the J2 motor support. So I feel it can't be a systematic issue with my print settings.
I'm wondering if anyone else has experienced this? Does it make sense to adjust the source STEP files?
When printing the structural components I have by default drilled all fastener holes prior to tapping just to make sure the size was correct and the tapped holes were clean. I did find I had more issues on my older low budget ender printer. With this printer in many cases I needed to adjust hole sizes. I had fewer issues on my anycubic and recently I picked up a bambu labs printer and have had no issue with hole sizes on this printer. Im curious, what printer do you have?
I also have a bambu labs, p1s! I'm printing in PLA (I think in the instructions you mentioned you've used ABS). I'm using the 0.2mm strength @BBL X1C preset, with a few tweaks (x-y hole compensation, elephant foot compensation, 60% sparse infill, rectilinear sparse infill, 5 wall loops, tree supports.
I'm considering building a few arms, hence trying to get them to come out at the right size straight from the printer.
Potentially silly question, but the STL files say they were last modified in ~2022, does that sound right? At a bit of a loss as to what could be the issue otherwise.
@peter-choy A majority of the parts have not changed in quite some time. There are a few of them that should be more recent such as the J6 housing and J2 motor mount.
The J6 housing has a diameter of 32mm (measuring in bamu labs slicer), whereas my j6 motor has diameter 35mm. I can see the file was last updated on 18th Dec 2022. I feel this must be stale / an error? Would you be able to check the latest STL / STEP files that you have locally?
In absence of another solution I can either compensate the hole by 3mm, or scale up by ~10%. Though I will need to check if either of these impact downstream connections.
The J6 gripper mount STL also seems old, it's clearly different from the pictures in the manual, and the shaft diameter doesn't match the j6 motor!
For posterity:
I found the correct STL files for J6 Housing and J6 gripper mount. They are under the top level directory 'AR4-MK3 3D Print Files'. I was confused because most of the important parts (including an incorrect / old J6 Housing and J6 gripper mount) are located under 'AR4-MK3 3D Print FIles > AR4 Structural Components' (which is where most of the important 3D printed parts are).
I'm continuing to use x-y hole compensation to get the correct sizing for most holes in the build. I also use x-y contour compensation as whenever two perpendicular holes meet, it is not considerd a 'hole' by the slicer but instead considered a contour.
Sorry about that, I'll get the folder structure fixed and the obsolete print files removed.
