[cartman635]

I have MeshCAM and CutViewer and could use a lot of help generating the tool paths. I can only generate tool paths for one face of my chosen model, and only for 2 cutters. So, I am trying to figure out how I can rotate my model to generate another tool path, and how to generate a tool path with more than 2 cutters. I would also like to know about roughing and finishing. I also haven't figured out how the mill will know there should be a tool change.

Help on viewing the tool paths in CutViewer would be great, too.

I just started looking at MeshCAM and I am trying to make an AR15 lower for myself. Any help would be greatly appreciated.

[robgrz]

Right now you'd have to generate another toolpath if you need to define a different set of tools or define a different region. Then you'd just run the toolpaths back to back in your machine. (This will be changing in future versions)

For an AR-15 lower, I think you'd be better off to rotate the object in your CAD program and position it to a place where you can easily zero from a known feature that you've already machined. I don't recall seeing anyone machine an AR-15 lower using a 4th axis.

You do have the option to rotate the model in MeshCAM but you may not have the ability to place the zero in the exact location you need if it wasn't one of the stock corners.

-Robert

[feederic]

I'm actually interested in doing the same thing once my mill is actually built, and was wondering the same things (newb).

How exactly do you define more than two tools? The rougher and finisher?

[robgrz]

Just run through the process again and save another gcode file. For some of the complicated jobs I do I have a roughing and finishing pass that do the bulk of the job. Then I have another file that I run where I use a 1mm tool and the Define Region command to machine a few tiny details as a separate toolpath.

-Robert

[cartman635]

That makes sense.

How do I determine what end mills to use for roughing and finishing? I think I want a shorter one for less deflection, but don't I also want a wider one to cut more out? How do I choose those limits?

Also, how do I drill out holes in MeshCAM? There will be many that I need to drill out.

[robgrz]

MeshCAM does not support drilling nativity so you'd have to get the coordinates from your CAD system and do that manually.

You definitely want the shortest tool possible. I'd recommend that you grab a demo of G-Wizard from CNCCookbook.com . That will show you the deflection for a given endmill and help you pick feedrates for the material you are using.

With regards to endmill diameter, you'll want to use the largest diameter that will fit in the areas you need to machine and leave you with an acceptable corner fillet.

-Robert

[cartman635]

I figured out how to orient the models in MeshCAM and Solidworks and have some additional questions. If I generate and use a toolpath for say the left side of the AR15 lower, how can I only cut half way down the billet so I can flip the part and mill the right side with another set of toolpaths?

Also, once I have milled the left and right sides, how do I indicate to the top and bottom since they will now have been partially cut on the previous operations? After I have run through one set of tool paths, I want to go again using the same model in MeshCAM until I get to my finishing cuts, but if I go through again how do I get my mill to cut a now partially completed piece of metal? Can’t I only use predefined stock?

Plus, some of the curved portions of the lower are coming out rough and choppy. Are there guidlines I can use to smooth out some of the curved areas?

[robgrz]

You can use the CAM->Set Max Depth command to only go thru half of the part

I would finish both sides before flipping. Then you'd need to find your zero from some known feature. Off of the top of my head, I'm not sure where the best place would be on an AR-15.

If you only want to machine a section of the part, roughing the magwell for instance, then you can use the Define Machine Region command to constrain the toolpaths to only that area without reroughing and finishing the whole part from a different side.

The roughness is probably caused by the type/size of the cutter compared to the stepover/stepdown used for finishing. If you can show your results and the settings then I can make some recommendations.

-Robert

[feederic]

I would finish both sides before flipping.

Just curious, you mean mill the left and right sides before milling the top and bottom correct?

[robgrz]

Sorry- I was thinking about it laying in the vise- not the top or bottom of the finished product.

I think I'd do the left and right (as you're holding it in a shooting position) before the top(where the sights go) or the bottom (where the mag goes in).

-Robert

[feederic]

I hope you guys don't mind me tagging along in this thread

Since roughness in curved areas was mentioned, I am having similar issues with the back tangs of a 1911 frame. I've only really been playing around with the SW, and am using the predefined stock endmilll and ballnose endmill in MeshCAM.

[robgrz]

If you can share photos and settings then I'm sure that we can get you on track. Until then, I have a post on my site that outlines a bit about the stepover values:

How to Choose a Stepover - GRZ Software Blog

If you send me the cad file then I can show exactly how I'd approach it. I have Solidworks so that's no problem.

-Robert

[feederic]

If you can share photos and settings then I'm sure that we can get you on track. Until then, I have a post on my site that outlines a bit about the stepover values:

How to Choose a Stepover - GRZ Software Blog

If you send me the cad file then I can show exactly how I'd approach it. I have Solidworks so that's no problem.

-Robert

Well its hard to pass up an offer like that! Where should I email you? I can take some screenshots and post them tonight or tomorrow.

[robgrz]

[email protected]

-Robert

[feederic]

Sent you the email. Hopefully I can figure out how to use this sw and get things cleaned up.

Thanks Rob!

[robgrz]

I got the file- sorry for the delay in getting to it. If you can, would you mind sending a photo or screenshot of the roughness that you're getting so I can be sure to address the correct problem?

-Robert

[feederic]

Absolutely! I will try and get it out by tomorrow night at the latest.

[feederic]

Rob,

I attached the Cut Viewer output, and zoomed in on the area I am having difficulties with.

Thanks for the help.

[robgrz]

Here you go...

STI Frame Tang - GRZSoftware's library

-Robert

[feederic]

Here you go...

STI Frame Tang - GRZSoftware's library

-Robert

Awesome!! Thanks Rob! That is a HUGE improvement over what I was doing. CutViewer made it clear what the pencil cleanup performs. This video made the waterfall features crystal clear.