Hi,
I need to mill 2 Polymer80 lowers (I know that most folks do not like these). I have access to a CNC machine and was wondering if anyone here has milled one of these lowers on a CNC machine? If so, is there a certain program or settings that are needed to properly complete them?
Thanks!

Yes.  All CNC milling centers are numerically controlled and require programming for tool selection, tool path, feed rates, etc.

Thanks for the info. If I read correctly during my search on the internet, the code is stored in a G-Code file? Is that something that I can write by adding how many inches (or whatever unit of measurement is used by the CNC machine) to a file created in notepad? Or do I have to use 2D or 3D drawings in some program like Autocad to create the file? Sorry if these sound like really stupid questions, I just have never dealt with CNC machines before and am trying to learn as much as possible from folks who are more knowledgeable than myself on the subject. If this is too big a project, I will simply complete them with a mill.

If you're asking these questions it's too big of a project...

Programming for CNC work is a learned skill that people spend thousands of hours perfecting.

That's what I figured but wanted to use the advantage of the machine if possible. LOL!

I did one at home with my little baby CNC.  First step was to model out the trigger pocket in 3D.  Then convert the model into a file that my CAM software uses. Then output the CAM software for g-code that the CNC software uses. That step is where you need specific machine info (feed rates, depth of cut, origin point, cutter type, path overlap).  Mount up the 80% lower.  Watch it run for a while and you're done.  This was my first project on the CNC. I did a trial run on a laminated block of oak to make sure it was going to do what I thought it was going to do.  



There's a boo boo toward the front of the pocket from where I had some technical difficulties (I paused the cutting and made a trip to town...the computer went into hibernation and the CNC software locked up. oops!)









CHRIS





 
 

Are you using Mach3? What CadCam are you running?

Yes.  Mach 3 for the CNC.  It's an older version that was licensed to my work.  I ended up buying the whole setup for a couple hundred dollars but the CPU is on its last leg, I think.  That hibernation thing locked it up pretty bad.  Had to do a full reboot to recover.



I'm using MeshCam for the CAM software.  It is pretty easy to use.  I have zero experience with g-code or machining paths and was able to figure it out.  Another member of the site was using it to make his custom knife handles and I gave it a shot.  Glad I did.



CHRIS

I'll have to look into Mesh Cam, did you have to do any tool changes in the middle of the program? This has me confused on Mach3 since i don't have a TTS style tool holder i have to re zero every tool at every change. But i haven't figured out how to do it in the middle of a program? Are you familiar with this?

I'm using HSM Express, it's a plugin to Inventor. Very easy to use

I haven't done a tool change yet.  The tutorial that I watched showed how. There's supposed to be a setting in Mach3 that will stop the program for the change.  When that happens, go back to origin and lift the z-axis.  Install your tool and reset z-axis zero only.  Then you continue with your program. They make it sound pretty easy! lol.



I cheated and used one EM for my cutting and put up with the longer cut time.



CHRIS

Ha ha i know what you mean about them making it sound easy. lol I cheat by making a separate program for each cutter. lol I need to figure out the correct way to do it so i can save time.

Another Cam program that is a great Value is CamBam!
I have been using this since I started CNC Milling.
You can used it to Draft your Design...to generate your Tool-Path and finally generate your G-Code...
Check out their site, there are some nice getting started videos and tutorials ...
CamBam Site


Good Luck

Ca_Longshot

P.S. Use a CAM program cut down on the "hundreds" of hour of writing code "By Hand"

You young-ens are so spoiled. I have machined  two 80% lowers and two lowers totally from scratch with a milling machine with numerical readout no CNC.