# Starting My CNC Journey for PM-25MV Mill



## devils4ever (Nov 24, 2019)

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!


----------



## matthewsx (Nov 24, 2019)

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


----------



## devils4ever (Nov 24, 2019)

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?


----------



## JimDawson (Nov 24, 2019)

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.


----------



## markba633csi (Nov 24, 2019)

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


----------



## matthewsx (Nov 24, 2019)

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?



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


----------



## devils4ever (Nov 25, 2019)

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?


----------



## matthewsx (Nov 25, 2019)

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?



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

john


----------



## bakrch (Nov 25, 2019)

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.


----------



## devils4ever (Nov 26, 2019)

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?


----------



## bakrch (Nov 26, 2019)

devils4ever said:


> 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?



I should leave this to somebody who actually uses that particular program, but generally, you can:

1. do a partial "open" chain of the feature.  
2. You can sketch lines that can then be selected later as a machining boundary (which you should be able to keep the tool inside, centered on, or outside of).  "Avoidance", "Air" and "Containment" are other names I've seen for features to help control a toolpath like this.


----------



## Boswell (Nov 26, 2019)

and a final last resort option is to edit the resultant G-Code to remove the parts you don't want.  Most likely there is a way to tell your CAM software what features you want to mill.


----------



## devils4ever (Nov 27, 2019)

So, I'm going through the same design in Fusion 360 and I'm having a similar issue with the CAM part. I can't get the software to only mill out the cutout. What should I be using? 2D Adaptive Clearing? 2d Contour? Or, some 3D method?


----------



## bakrch (Nov 27, 2019)

Most likely 2D adaptive clearing (I would need to see the part/feature to give better direction), but again you need to sketch some lines and use the said sketch lines as a machining boundary to limit where it will cut.


----------



## devils4ever (Nov 27, 2019)




----------



## bakrch (Nov 27, 2019)

Here is an example.

The 2D adaptive path for this particular part wants to do all of this when left to its own devices.







So I drew a rectangle to limit it. (note the two smaller rectangles up top, more on that later).






Selecting the rectangle as a chain under the "stock contours" section will get you a yellow line that looks like this. The blue area shows what will be cut.






The ensuing toolpath calculation. I forget why I did this, probably had clamps in the way or something.






Back to the two small squares from the above picture. I used those in a 3D parallel toolpath to restrict machining area for these the fillet radii (was being lazy and didn't want to do the extra setup to mill them the conventional way).


----------



## bakrch (Nov 27, 2019)

devils4ever said:


> View attachment 306674



I would definitely use 2D adaptive for that. Another thing that springs to mind, that may or may not matter in this case ... but is a MUST know for Fusion.

When you select the contour you would like machined, click on it ... then click on the same line again to open up the custom dialog box. For some reason, screenshots are not capturing it for me so here is a link that explains it pretty well. Anyone just learning Fusion 360 has little to no chance in figuring this out on their own, and it would be a struggle to use the software without it.









						QUICK TIP: CAM Contour Selection - Fusion 360 Blog
					

The Selection Manager is a powerful tool for anyone using CAM in Fusion 360. Watch this QUICK TIP to learn how to dial in your contour selections.



					www.autodesk.com


----------



## devils4ever (Nov 28, 2019)

Okay, I'm getting closer. But, I'm getting an error about "empty toolpath" after doing this selection.

As you can see, I have made the proper selections and chose Open.



The correct area is highlighted, but I still get this error about empty toolpath.


----------



## bakrch (Nov 28, 2019)

Try either offsetting your bottom height, or reselect the contour on the bottom of the part.  Right now it looks like X and Y area is sorted, but it has no Z depth information.

The empty toolpath warning is very unhelpful, so generally I go in and change 1 thing at a time until something generates, then tweak it to my liking from there.


----------



## devils4ever (Dec 1, 2019)

I got past the empty tool path error.

I'm still trying to decide which way to go: Fusion 360 or FreeCAD. They both are not easy to learn. I do like the idea of having the CAD/CAM software on my LinuxCNC PC. 

FreeCAD has its issues too. I don't know how to only select certain areas to contour. It may not be possible.

I've been reading that Fusion 360 seems to be moving toward charging for hobbyist. If that's the case, the decision is easy.

I have my LinuxCNC PC up and running now with the ASRock Mini ITX DDR3 1066 Q1900B-ITX MB, 240 GB SSD, and 16 GB DDR3 RAM. My jitter numbers are good under 16,000.


----------



## TomS (Dec 1, 2019)

devils4ever said:


> I got past the empty tool path error.
> 
> I'm still trying to decide which way to go: Fusion 360 or FreeCAD. They both are not easy to learn. I do like the idea of having the CAD/CAM software on my LinuxCNC PC.
> 
> ...



I am a hobbyist and use Fusion 360.  A few weeks ago I renewed my non-commercial user's license with nothing more than a few clicks of the mouse.  Never say never but I am a believer that Fusion will remain free for us hobbyists.  If you still have reservations you can save your files in several different formats that FreeCad can open, which is what I do.  I'll keep using it until they start charging, then I will evaluate whether it makes sense to pay up or move on.


----------



## devils4ever (Dec 2, 2019)

After playing with both Fusion 360 and FreeCAD for quite a bit, I've decided to go with Fusion 360. I don't think FreeCAD is quite there yet. It still needs a bit more polishing. It may be me, but things are a little harder to do and a little cruder in FreeCAD.

The only downside to Fusion is I can't run it on my LinuxCNC platform and the potential cost in the future. 

I hope I don't regret this...


----------



## devils4ever (Feb 18, 2020)

I'm starting to get a little worried about *Fusion 360*. I keep getting messages regarding subscriptions, pricing and such. I have a feeling they heading towards removing the free option for hobbyists.

So, I'm thinking of revisiting *FreeCAD*. My biggest concern was the CAM part of the software. But, it seems there are workarounds.


----------

