Starting My CNC Journey for PM-25MV Mill

devils4ever

devils4ever

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All,

I bought a PM-25MV mill about a month ago hoping to convert it to CNC. You can see my thread regarding this purchase here: Possible Purchase of PM-25MV. I figure I should move this discussion here since it's no longer about purchasing and moving the mill, but about CNC conversion.

I plan on using Fusion 360 for CAD/CAM which I'm finding is not easy to learn. The 3D aspects are new to me as are the CAM part. I'm sure I'll have questions on this topic. I'm assuming Fusion 360 questions are okay to post in this forum? I also plan on using LinuxCNC (LCNC) for the control software. I'm very familiar with Linux so this shouldn't be an issue. Of course, the CNC part of it is new.

I have a few options for the PC that will run LCNC. I have access to a used PC from work. Specifically, it's Lenovo ThinkCentre M92p with 240 GB SSD and 16 GB of DDR3 memory. I installed LinuxCNC 2.7.14 on it and ran the latency test and got around 23,000. From what I've read, this is decent and usable. However, the issue is there is no parallel port, only Ethernet. Rather than buy a Mesa card with more complexity I decided to buy a new motherboard (ASRock Mini ITX DDR3 1066 Q1900B-ITX) and use the SSD and memory from the Lenovo PC. This motherboard has a parallel port built in.

For the rest of the parts, I plan on using:
DM860T motor driver with a NEMA34 1000 oz-in stepper motor for the Z axis
DM542T motor driver with a NEMA23 400 oz-in stepper motor for the X axis and Y axis
ST-V2 Breakout Board

For the last bit with the ballscrews and mounting hardware, I haven't fully decided yet on which way to go. I can either buy a kit from various sources (ProCutCNC, arizonavideo, etc.) with all the parts or I can buy each separately and mill the mounting hardware. I'm looking for advice on this aspect.

All comments/advice is welcome! Thanks!
 
Cool,

I’m using the ST-V2 board with LinuxCNC now and it seems to work fine. I would definitely at least try making your own stepper mounts since you have the mill, that way you could splurge on better ball screws.

since you’re a Linux guy why not put the effort into learning FreeCad? It won’t be any harder than Fusion and I’m pretty sure it can do everything that AutoCad does without the closed license. Also, I just want someone else on here using the same setup I have ;)

Cheers,

1ohn
 
I can try to make the mounts, but I'm a newbie and figure I'll mess them up. Plus, I don't know where to get the bearings and such. I'm thinking a kit would be a lot easier, but a lot more expensive.

I tried FreeCAD briefly and didn't like it. It seemed hard to learn. However, I must say that Fusion 360 isn't easy to learn either. I am struggling a bit with this as well. I'm pretty good with DraftSight, but it's only 2D and they are starting to charge for it in January. I might go back and try FreeCAD again.

Does FreeCAD do the CAM part as well? Or, just CAD?
 
Here is a really good place to start, and it's absolutely free. https://academy.titansofcnc.com/ Will take you from zero to making parts in a few days, really helped me with Fusion 360.
 
I think you would have fun making your own stepper mounts and would gain valuable insight and experience with cutting tools and so forth which will carry over into your CNC. Also, having Linux experience is a plus
I say go for it
Mark
 
devils4ever said:
I can try to make the mounts, but I'm a newbie and figure I'll mess them up. Plus, I don't know where to get the bearings and such. I'm thinking a kit would be a lot easier, but a lot more expensive.

I tried FreeCAD briefly and didn't like it. It seemed hard to learn. However, I must say that Fusion 360 isn't easy to learn either. I am struggling a bit with this as well. I'm pretty good with DraftSight, but it's only 2D and they are starting to charge for it in January. I might go back and try FreeCAD again.

Does FreeCAD do the CAM part as well? Or, just CAD?
Click to expand...

You would still stick with LinuxCNC for machine control. Just like with Fusion there are multiple different ways to generate the g-code files, I'm still learning so probably not much help with that.

The way I see it, unless you can actually write your own software like @JimDawson there's a lot to be said for going open source. Sure, Fusion is "free" for hobby use and AutoCad has been around since forever so they're not likely to change their terms anytime soon. It's just for me I'd rather not boot my machine into Windows 10 any more than I have to. I've gotten to where the only thing I run on Windows is QuickBooks since that's what my bookkeeper and accountant use. It's not a religious thing for me, I've just used Linux long enough to see the benefits of the open source model.

I'll bet that once you get proficient with one, using the other is going to be much easier, 3D design is a challenge to get one's head around regardless of the tools. The biggest difference I can see is FreeCad has a large user/developer base and is constantly being updated while AutoCad has the "stability" of only one developer and updates are only done by them based on what they think users want.

Either one will get your parts designed and code ready for the controller, just get going with it and see what works best for you.


Cheers,


1ohn
 
I think the bearings are the biggest question mark for me. What type/size/etc do I get? Do I just mill a circular pocket for them to reside in? Are they pressed in?
 
devils4ever said:
I think the bearings are the biggest question mark for me. What type/size/etc do I get? Do I just mill a circular pocket for them to reside in? Are they pressed in?
Click to expand...

For the ballscrews? Lots of times they will come with it.

john
 
Maybe I am weird, but I thought Fusion 360 was super easy to learn. I had years of Mastercam experience before starting, so having those parallels to draw from was quite helpful.

I learned it back when Lars Christensen's youtube channel was new and active, and before the software layout was updated. I imagine his tutorials would be difficult to follow after recent changes to the general terminology.

If you get stuck with anything, feel free to ask. I notice that plenty of folks on here really know how to use it.
 
I've been playing with FreeCAD and think I'm getting used to the CAD part (Part Design workbench). Now, I'm trying to get the Path workbench running. I think I found a limitation. I have a 12" X 6" X 0.188" piece of Plexiglass (Acrylic) that needs 12 holes drilled into it of two sizes. I got that working.

It also has a 0.750" deep by 2.930" cutout in it. I want to use a 1/4" endmill so I get a 1/8" radius on the internal corners. FreeCAD won't let me mill out just that area. It wants to go around the entire perimeter even though the piece is cut to final size. Obviously, I can't do that since I need to clamp this down on the mill table. I just want that cutout milled. I read a little and it seems this feature was removed a few revisions back. So, other than hand editing the G code output, what can I do?
 
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