Upgrading MPCNC Version 1 to C-525 version

That was a good idea. I added that and my chamfers. Should be ready to print it now.

After wire tying the motor wires to the C-Z-Lower part, it felt like I needed a wire tie connection on the C-Z-Motor mount, but probably did not. Since the motor mount did not have that many differences than the lower mount, I modified that also. I will not bother putting these designs on thingiverse unless someone really needs them since it is using the old wiring design. I meant to put the wire tie on the motor mount on the other side, but forgot I was printing it upside down. It worked out just as well on that side. Also thought I should have changed the rotation of the infill so the top/bottom layers went at more of an angle across the part. I am using 55% gyroid infill, so that angle probably does not affect the strength of the part. With that gyroid infill, seems like any angle would work just as well. The #6 nut traps were a little loose with my prints, so I made them a little smaller diameter. I attached 2 photos & a screen shot of the motor mount modification. After the tropical depression Florence leaves Western NC I will test a cut this week.

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After adjusting my MPCNC to get ready to cut again, I was finding that the 3 bearings are not all touching the EMT. I copied the C-XY.stl & the C-XYZ_T8.stl file into Draftsight & regenerated the 3d geometry in openscad so I can adjust the bearing offsets. It only took a couple of hours for each part. When looking at the geometry in 2D, I see the parts have a 22.55mm offset between the center of the 3/4" EMT & the center of bearings. With the real dimensions of my pipes (23.4mm), that gives me a 0.15mm overlap. After thinking about why all the bearings were not engaging, it occurs to me that the additional flex that the esun PLA+ plastic I am using is why it is not holding as well. This PLA+ does have less flex than the PETG that I use. I really like using the PLA+ as it prints better than PLA & not as brittle as PLA & not as stringy or flexible as PETG. Anyway I am thinking of printing one of the C-XYZ_T8.stl parts with either a 22.5mm or 22.45mm offset to see if this works better for my situation. Not sure I want to print those large C-XY.stl files again, but the C-XYZ_T8.stl files would be fairly simple to reprint & change out. Anyone have thoughts on this?

One thing I also found with the C-Z-Lower.stl & C-Z-Motor.stl file was the diameter for the cutout for the 3/4" EMT was 23.9mm and was too loose to hold the pipes after tightening all the way down on the screws. I changed it to 23.5mm & works for me now.

Oh man, don’t hate me…I have a new version sitting on my desk right now. It is only a minor revision, meaning no new tricks just refinements of the current center including the Z mounts. Jeez I hope just the three of us are following along on this thread. I think I have the the XY, XYZ, and Spacers done. Just need to do the Z clamps and maybe tweak the Tool holder a bit.

So maybe hold off a few days?

I saw your thread on that design update and was wondering how close you were to updating it, so I will see what your changes look like before printing. Thanks for the heads up.

I too was just getting ready to print the big parts in the center section… should I wait?

Yes, but no promises on a time line.

I decided to go ahead & do a test print of half of the C-XYZ_T8.stl with 0.1mm tighter clearance just to see if it fits the EMT better. I am printing this at 150mm/s with the klipper firmware. It is half done & is looking quite good. Take a look at the 2 minute video I did of it printing. Most speeds are at 150mm/s except 1st layer set to 50mm/s, solid infill at 100mm/s, bridges at 60mm/s and top solid fill at 30mm/s. Infill is 55% gyroid.

Why does your printer have a telephone attached to it? :slight_smile:

No telephone there. Maybe there is a wire that looks like a telephone wire?

Sounds like a rotary dialing phone…shhhhh I’m not that old I swear.

I remember what a rotary dial phone sounded like & I don’t remember it sounding like that. I thought this sounded like a toy machine gun.

Yeah, it reminds me of these those long cords that your kitchen phone would have so you could sit in the living room when you were on the phone. Before we got a cordless.

I started reprinting the Burly parts today. Here are my print stats for this XYZ part. This part feels pretty strong, so I will continue printing the other parts. I will probably keep my modified 525 Motor & Lower mount since I added my wire connections to them & looks like they should work with this design.

50% gyroid infill at 100mm/sec

4 perimeters

0 - 5.95 at .3mm layer
5.95 - 14.35 at .2mm layer
14.35 - 21.95 at .3mm layer

2.48oz
4:57:35

 

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I have been side tracked on some other printing projects for Halloween, but should be able to get all the center section parts printed next week. Since I had already reverse engineered the C-525 center parts for my own purpose, I redid the burly parts also (sorry Ryan, but I promise not release these changes unless you want them). Ryan, one comment you will like on the reverse engineering is that your adding of more resolution to the curves does make it more difficult to modify. I did make one change to the XYZ part that may help give my bolts more support with the PLA+. Actually I have decided to print these in PETG now, but should still help. I added nut traps for the inside nuts on the XYZ part. I initially only added half a nut trap as seen in the printed part photo, but it did not hold the nuts completely while tightening them. The openscad screen shot shows the other half of the nut traps added.

 

hi geodave. can you pls briefly explain how do you make such chamfers in openscad?

I use a variety of ways depending on the chamfer needed. With this design, I probably used all my methods. The simplest method is a 4 side cylinder rotated the correct way. For the rounded corners, I used rotate_extrude with circle set to 4 sides. For the inside chamfers of this, I used hull() of the 2 linear_extrudes, .1mm high & the z translation set to the correct heights of each. I use Draftsight Pro to generate the 2d geometry I need for the linear extrudes.

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I see. It’s a lot of work. I know hull() and minkowsky() and use them (sometime as own module rcube() - rounded cube).
But I thought may be you know some library that makes it more easy.
I like openscad, but chamfers and fillets in it are really painful.

You are right, I know of no simple solution for chamfers. I never use minkowsky() since it is sooo slooow. I do wish hull() would work on concave surfaces and not just straight & convex, think that is the right term for that.

That XYZ part is pretty much the only one I highly recommend to print in PLA not PETG. It holds the key to most of the rigidity.

I would love to add nut traps to everything but it is very high on the hate mail I get so I am trying to not use them. If we all just used the same hardware this build could be simple!