Steps

[Cartierusm]

I've done searches and still can't grasp the overall picture. If any can help I'd appreciate it. I don't need 10 pages of details just a little description of what I need to accomplish a normal cnc task. A little info first, I have a 48" x 48" CNC router table I built from scratch. I'm using Mach 3 and have BobCAD/CAM and Solidworks. I've setup Mach 3 using the basics, calibration my motors etc... What I don't understand is let say we are making a square 3" x 3" and I place a piece of 4" x 4" piece of 1" maple on the table near the center of the table (not in any particular place). Now do I used CAD or CAM? I can't seem to figure out the difference. SO let's say I draw a square 3" x 3" in BobCAD what program do I use to answer the following questions: do I have to tell the program that I'm using a piece of wood 4" X 4", how do I tell the CNC machine where the piece is located, how do I tell it how many passes to take (especially if want to take small passes), how do I calculate where the cutter hits the piece of wood, how do I tell it which direction to cut and then move the cutter so it doesn't hit anything on it's way back to making a deeper cut on the same piece.

I have a ton of more questions I just don't understand where to tell the machine to do all this stuff. If anyone can answer some of these or tell me where I can read a tutorial on the progression from drawing to machine setup. Thanks, I've been reading the manuals that came with my programs but they are a bit confusing without knowing where some of the steps come in.

[High Seas]

For what its worth I'll take a stab at the questions - Let me say I've been away from the machining for a year - so my answer will be PROCESS oriented - not to close DETAIL. I needed to figure this out for myself too - so I can understand your confusion. All that said, try this on:

DESIGN THE PART:
Use your CAD program and design the part. You'll want to have an output that can be converted into some type of Machine File.

For example you could use iges, stl, or whatever and convert into machine code with an appropriate conversion program Don't know what you have on hand ... I'd probably take the Solidworks as an stl file for the next step.

CONVERT TO MACHINE LANGUAGE:
You now take the second BIG step. To make the part you have designed ready to be machined - but hang on - its not always simple....

Personally, I like a small program STLWORK. It lets me take an stl file and generate machine code. please note I am Not associated or affiliated with the company- I just like it. There are a variety of options and opinions - try and find something you like. What you want to end up with is a file that contains the G-Code for the machine to run on.

Depending on what program you use - you may be able to specify the safe heights for rapid moves, set up so you don't cut "air" , roughing and finishing passes. May even include slabbing as an option as well.

This is when Tool Changes and things like that and other machine pauses are written into your code to make the job a bit easier.

{NOTE You BOBCAM might do all this for you if it is well integrated with your BOBCAD -- not familiar with the products - sorry but the process is the same - you want to generate G-Code}

MACHINING THE PART:
NOW -- you are nearly there. Less coding and more placing and setting up the machine. First open the nc file in MACH ( or whatever you GCode is in (txt, etc). You might like to do a trial run/simulation before the next steps.

With Mach2, - suppose 3 is the same - you'd place and secure the stock on the milling surface.

Now, manually move (jog) the router and bit to the location you want to identify as zero, x. y, z. Tell the computer that is where it is! (Use the Mach controls to set this new reference zero position.)

Don ear protection and safety glasses then, turn the router on.
Stand - back and let the chips fly! Well, ya gotta press GO

NOTE - I would suggest starting with a 1 inch block of foam rather than the maple to "proof" your setup and design before turning the maple into chips for the bbq! Use a vacuum (shopvac) to catch the foam bits and wear a mask! Stand near the STOP BUTTON and be Vigilant!

CHECK THE PRODUCT:
Remember speed and feed for materials is different - an advantage to using foam - you can fly thru the material and see the product in prototype before investing nice materials.

Hope that lays out a process for you - I'd be happy to have some of the experts add some revisions. I don't wanna screw up in a couple of weeks when I fire the machine back up.

Jim

[Cartierusm]

Thank you that was a good start. I read through more of the Mach 3 manual and it seems I'm slowly getting there.

When designing a part right now all I need is one side routered out, should that just be a profile of a straight line in a CAD program?

[ger21]

Most of what you're asking needs to be done in BobCAD. The only thing you need to do is set your axis' to 0 in Mach3. the 0,0,0 in Mach3 should correspond to where you drew the part in BobCAD.

[Cartierusm]

So let's say I draw a square in BobCAD, then I set the tool path, size bit I'm using, break away coordinates(where the tool move when it's not cutting so it doesn't hit anything), ipm speed, how many passes and how deep of cuts in each pass....all that in BobCad.

Then I mount a piece of material on my table and move the cutter to the exact spot I want to start cutting, so slightly touching the workpiece Z=0, and the virtual corner I want to start cutting Y=0 X=0, and then zero out the DRO in Mach 3 and then run the program?

[DareBee]

You have it figured out now

[Cartierusm]

Thanks guys. Now I have to figure out BobCAD. I'm very technical and used to be an IT guy and did graphic design for many years and so far BobCAD doesn't seem to be a very well designed program, but maybe all CAD programs are this way.

I basically was fooling around and drew a single line representing the one side I need milled and was looking for a place to input all those variables I talked about in previous posts and couldn't find any?