I'm thinking I'm going to start printing all the upgrade parts for my machine...and am leaning towards ditching hicwic and moving to the stock mount...I may try and make an adapter that attaches to the stock mount and accepts hicwic so I can re-use my laser and pen and dragknife mounts....but for the router I'm not really happy with wicwic and want something stronger.
Onshape is terrible for quickly modifying existing STL's. There's VERY little it can do with a mesh import (and STL's are a type of mesh):
https://cad.onshape.com/help/Content/mesh.htm
Once a mesh is imported into an Onshape Part Studio, you can:
Create a three point plane using mesh points
Measure the surface area, and distances to and from mesh points
Obtain mass properties for solid meshes
Project mesh points in a sketch (via the Use tool)
Create Mate connectors at mesh points
Reference a mesh point for ‘Up to vertex’ operations (as in Extrude)
Which is pretty limited. Basically you can use the mesh points for various things and you can do calculations on the mesh but that's about it. As far as I can tell you can't actually modify the mesh in any way. You can't resize it, you can't add to it, you can't remove from it....
So for quick little changes Onshape isn't great.
What I've been doing is recreating the part in OnShape using the mesh as a reference. I want to do a video on this. If you look at that cutter project and look at some of the 525LaserMount2 part studio you can probably get an idea for how I do it. The process for that one was basically:
Create a new plane using the 3 point method and picking 3 points off the bottom of the mount portion of the laser mount.
Create a new sketch and use the "use/project" tool to pick points off the mesh that define it's outline. Then use lines, arcs and circles to recreate the outline (This is Sketch 1):
Extrude that sketch. In this case I did a blind extrusion because I was trying to match the height of the needle cutter, if I was trying to recreate the original STL I'd do a "Up to Vertex" instead and pick a point off the top surface of the original mesh.
Next I created a sketch on the face where the mounting holes go and drew in the mounting holes. I didn't reference the mesh for these though, I measured the C-ToolMount part from the original MPCNC design (which you can see in another PartStudio) to measure it I had to create a sketch based off three points on the face with the holes, then picked 3 random points from each hole and used the 3 point circle to re-create them. Then I was able to click on them and in the lower right it showed me their dimensions, and I could select the bottom of the face and the center of the lowest circle to get the height off the bottom - and the centers of any two holes to get the distances between them.
So back in 525LaserMount2 I used those measurements to create mounting holes in Sketch 2 and Sketch 3 which I then removed from the mount with extrudes 2 and 3.
Next I added 2 .8mm chamfers to the top and bottom to match Ryan's original design.
That gave me a mount the height of the cutter drawn natively in Onshape. It sounds like a lot but it really only took me about 5 minutes or so.
The next part is where I'm not sure if I'm doing things right...I haven't really read the docs or done the tutorials on this kind of stuff - just sort of played around to figure it out....but...
I went back to my "cutter' PartStudio and used the derived tool to bring over the part I created in 525LaserMount2. I then used the transform tool to turn it 180 and move it into position. This is the part I'm pretty sure could be done better as I just eyeballed it - and I'm sure there's got to be a way to do that more accurately. I think adding mate connectors would make it possible but I haven't fully come to terms with mate connectors yet
With the mount basically in position I then extruded the two faces next to the holes to add more support to the cutter. Then did another little extrude to fix a small gap between the mount and the big square connection in the center of the cutter.
Then I added a few fillets on those new extrusions to smooth things out.
And finally made new sketches off the faces of the mount with the holes, did a "use/project" to get the original holes in the sketches, and draw slightly larger circles around them which I then extruded as a remove from the mount to make the cut outs to allow easier access to the mount holes.
One thing I'm not happy about is that I lost the fillet on the back of the cutter - OnShape is choking on adding it back now. Really I need to go in and cleanup the feature history since I didn't draw this in an optimal manner. I should also ditch all the fillets and redo them based on the final design.
Again, this all sounds a lot more complex and time consuming than it was. I had less than 30 minutes total into adding this mount onto this cutter...and I'm still figuring out some of these tools (like the derived thing.)
The way I'd rather do this is how I did the hicwic mount....(which you can see if you go to the "Manage Versions" button in the upper right and look at the "new-mount" version of this project. There I just drew it in as part of the initial sketch that I extruded for the main body of the cutter. But I'm not sure if there's a way to "import" a sketch (like Sketch1 from 525LaserMount2) into a different sketch in a different part studio. There probably is but it was late and I was tired and didn't want to deal with figuring out how
This design is really crazy overkill. The cutter doesn't NEED 6 mounting holes. And the attachments between the mount and the cutter are way more substantial than they need to be. And when I finally have my new style MPCNC parts to upgrade my machine and am ready to swap over....instead of just adding cutouts to access the mount holes I'll probably redesign the "shoulder" area of the cutter so it's narrower at the back and doesn't get in the way in the first place. I'm also worried it's probably almost impossible to install a motor on this unless you're good at building ships in bottles...so I'd probably open up the back more to give easier access to the motor mounts...though I guess you could just install the bolts from the back and put the nuts on the front so it's not that big of a deal...I just don't like seeing nuts on the front like that
Oh, and I didn't recreate the fillets around the mount holes like Ryan has in his design...I just forgot them last night since it was getting late.
As for other materials. I love PETG - remember I printed my entire MPCNC in it! And I really want to love Nylon...but Nylon does NOT love me
I'll have it printing fine doing test pieces...then go to print something "real" in it and suddenly it will be underextruding like crazy again. I've tried higher temps, lower temps - no difference. I still suspect the issue is the idler on my extruder...since tightening it up solved the problem at one point. But now the problem comes and goes and tightening it further doesn't help. So I've shelved my nylon until I can build up this geared extruder and give it a try to see if it works any better for me.