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Mach 3 Beginner's Questions
« on: August 19, 2015, 11:20:25 AM »
Hi guys.

The company for which I work has just bought a fairly basic run-of-the-mill 3-Axis Chinese CNC Router/Engraving machine.

I've got the demo version of Mach3 up and running and connected to the router. I can control the Axes using the arrow keys. Everything appears to be all fine and dandy, it's just I'm having mixed results when trying to mill the demo files. I'm hoping the answers to the following questions will be able to help:

1) For any given GCODE file, before pressing GO, how do I know where to place the bit? Do I position it to the centre of my working area or the bottom left hand corner? What in the design dictates this?
2) When setting the home position, how far up and down the Z Axis should the bit be? Should I start with it just touching my wood/plastic or raise the Z Axis to the top of its limit?
3) Say, for instance, I have a working area of 15cm x 15cm and I load one of the demo files, e.g. the roadrunner gcode file. If this is much smaller than my working area and I increase the X and Y scale to make it fit, how come when I start the milling process speeds are much, much reduced and the whole process would take hours.
4) Very often when trying to mill a demo file, Mach3 just stops after a few random lines. I am using a desktop PC with a dedicated Parallel port and not a laptop with USB connector before anyone asks.

If someone could give me just a quick overview of their initial working instructions I'd very much appreciate it as I feel like the above simple questions have not been covered in the many hundreds of pages of manuals and youtube videos I've watched.

Thanks in advance.

Offline RICH

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Re: Mach 3 Beginner's Questions
« Reply #1 on: August 20, 2015, 08:27:39 AM »
A#4 - You are using a Demo so Mach has a limit on the number of lines that can be run. I would think that your company would get
a licensed version of Mach if the are going to use it.

All the other questions.
First I suggest you get the CNC Programming Handbook by Peter Smid as it will provide you with a solid understanding of using a CNC
Machine. Read the first 100 pages or so as that will shorten your learning curve. You can learn a lot by watching the Mach videos.

For your thinking............
Look at the first few lines of the Gcode for a program and you will probably see the initial machine moves to see where the program
starts, ie; could be an edge, the center of a hole, etc . The part programing must start somewhere!

Generaly speaking,
When you just start Mach it does not know where Machine coordinate 0,0,0 is until the machine is Referenced / Homed etc., so once that is known by the controller, it also needs to know where the part is, and when the part location is defined the controller can now coordinate the moves necessary to do the machining. It knows where it is and it knows where it is going and can implement the gcode.

There is more to setting up a job, and again, the need to understand the basics  is very important. Welcome to the learning curve.
Should be someone at your company that can share their knowledge with you.


Offline olf20

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Re: Mach 3 Beginner's Questions
« Reply #2 on: August 20, 2015, 07:41:02 PM »
You are going thru what a million or so of us have gone thru. I'm not even
close to understanding all the abilities of Mach3 but I can get stuff done.
Start with something simple.
If you are going to be drawing with software then I personally like Vectric
VcarvePro / Aspire.
You can use the software for free to try it out. By drawing a simple box
and posting Gcode to Mach3 you will understand the process much better.
I also purchase the book that Rich spoke of. It's worth it!!
olf20 / Bob
Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998