Hey guys! Here is my second MPCNC. The first one used 23mm conduit, and convinced me the platform has enough potential to invest a little more time and money into it.
This one uses 0.065 1 inch stainless steel tubes, printed in PLA+ to increase strength, and I switched from the traditional support brackets to the Totem style one found on Thingiverse. On my old MPCNC, the tiny pads for the screws kept breaking and cracking, even after printing out of PETG. The Totem mod is a great design, and you can really torque it down without fear of breaking or cracking anything. Otherwise, the rest of the machine is stock.
The final mod was, because I had them lying around, I changed the motors on the X and Y from 17’s to nema 23s by remixing the mount STL.
The build area is 4 x 3, hoping it goes well! Thanks for all your hard work Vicious!
------- DUAL ENDSTOP HOMING
I desperately want to try and get dual X and Y endstop homing working on this machine with Marlin. I have included four endstop switch bays for this purpose. They have that functionality with the Z axis, so I think its just a matter of time to make it happen with the Y and X. Ideally, the machine squares itself perfectly every time you home it. We’ll see how far I can get with it.
It’s a beast! You need to drive each motor separately to do dual endstops, right? I guess you could just slam them until they skipped steps, but that seems awful.
I printed a part from TV that helps me start the machine square. They were the collars that clip on the post as they are about 6" long. I just have the machine always hold the steppers when it’s on, and I hold against those collars when I start the machine. It also gives me a repeatable machine 0,0.
I don’t know if the totems had there rail offset changed for the 525 update they have been out a while. Have you noticed any issues, like when joining the center assembly to the rollers? It is only a tiny change so I doubt it would matter.
I have in fact gotten the MPCNC running on all 5 stepper drivers. I am using a MKS Base 1.3 board. The new Marlin RC8 has dual X and Y stepper capability, but there is a trick to getting it to work. If I recall correctly, when the dual X and Y functionality is enabled, it looks for a pinout that doesn’t exist on the board (IE, an “E2” output after E0 and E1.). I had to go in an manually remove the extruder pinouts to make room for the X and Y steppers. I’ll have to do this again, so I’ll document it if you guys think that would be useful. Thanks for the tips re: collars, I’ll look that up. Hopefully though I can get the dual endstops working though!
Vicious,
I’m not sure if they have been updated, but they have been working perfectly, with no bending or extra resistance near the totems etc, seem to be functioning as they should. The only disadvantage is that when you do that design, you are sourcing the 100mm M4 bolts for the lockdowns. Can be difficult to get.
Here are some photos of the tensioners and motors installed. Also, I switched to lead screw for faster raising and lowering times:
Nice looking setup, I really like the Lead screw for the Z-axis.
You mentioned that, " I changed the motors on the X and Y from 17’s to nema 23s by remixing the mount STL".
I have NEMA 23’s laying around also, that I would like to use on my MPCNC. How did you remix the STL, would you mind sharing your STL for NEMA 23’s.
I remix STLs all the time using Fusion360. The trick is to turn off “Track Design History” by right clicking on the top level component. But this will kill any design history you create along the way to that point so you lose the ability to modify things and undo redo abilities. So the way I’ve been doing it is to put each STL (import as mesh) into separate designs where I convert them there into BREPs by right clicking on the mesh body and BREP it into a new component. Then I insert that component into the design where I make changes to it. There will be a chain icon beside it (looks like a figure 8). You can break the chain if you want to modify the component. You should be able to snap to surfaces and lines on the BREP object and the make the necessary changes. Works like a charm.
Heres some pictures, almost ready to go! I’m working on an epic toolmount for the DWP611, with an integrated vacuum ring. I will print that last. Here are some of what is featured in the photos:
Four endstops wired up, for when I attempt to get dual endstop levelling working.
Plugs that organize the cables coming out of the tubes.
Control panel with emergency stop and MKS Base fan case
Very clean build, congrat’s.
Ho does the totem corners hold up so far? Do they limit a bit the wobble of the structure?
That is something I’m currently thinking about changing on my machine, for the reason you mentionned (the amount of force you can use to tighten them is limited).
I planned to do my own design for these, but the totem ones look similar to what I had in mind.
Thanks! The totems in my opinion are a big improvement. because they are multilayered, solid, and there are no gaps or spaces, you can basically tighten to your hearts content. I have got the bolts CRANKED down, and because I am using washers, there is no surface damage or cracking occurring on the plastic. They hold the tubes very rigidly, I cannot bend them with my hands. Also, the built in endstop mounts are a big convenience, as well as the tensioners. The cons of the totem system is that they will require more than two rolls of filament to print the kit, and the 100mm m5 bolts can be hard to source. But if you can get around that, they are great.
Be careful with the totems. Depending on what one you used, the 525 update unfortunately changed the tube offsets and I do not think those got updated. The difference isn’t huge but there is still a difference and it could force your tubes to bend making you cut things on a slight arc.
There is a parametric version that I think is right but I can not confirm because I did not make them.
Since I did the parametric remix of the totem design, I took a look at what Ryan was talking about. I measured the original design as 27.6mm offset between the X & Y EMT’s. Ryan can correct me if I am wrong, but I measure 26mm offset between the X & Y EMT’s for C525 design. That is a difference of 1.6mm between the 2 designs. If that is correct, you should be able to change only the variable on Line 33 of the totem_Remix_Rev6.scad file to:
EMT_Z_Offset = 2 - .8; //The .8 splits that 1.6mm difference between the top & bottom totem parts.
This gives me a 26mm offset when I import the corrected assembly of totem parts into Draftsight & measure them.
If the 1" stainless is a different outside diameter than the 3/4" EMT, you should be able to change the variable on line 26:
EMT_OD = 23.6; //Size for 3/4"EMT
I think you will only need to recreate the Top, Bottom & Joiner part.
To create each of these new STL parts, On line 91 of the scad file you will also need to change the variable:
Totem_Type = 1; //1 = Totem Top and Bottom Part
Save that STL file after hitting F6 (Render)
Then change that variable to:
Totem_Type = 2; //2 = Totem Joiner Part
Save that STL file after hitting F6 (Render)
