CNC Help please

[studysession]

I have never CNC'ed before and trying to figre somethings out.

Need help on this:
Lets say I want to mill out a motor plate. I do a drawing in either AutoCAD or SolidWorks and export to DXF. I put a 3mm cutting bit in the mill and now every edge will be 1.5mm less than what I want it to be. I need to learn how to compensate for the diameter of the tool I am using to cut with.

If anyone knows how to do this and give me directions with either SolidWorks or AutoCAD - that would be most appreciated! Thanks!

My milling machine
http://studysession.com/h7/WorkBench.JPG

Bought it from:
http://www.simplycnc.com/

And CNC software used:
http://www.artofcnc.ca

[buscht]

You have 3 ways that this can be done.

1. In AUtocad, offset your part geometry by 1.5mm, trim and extend your lines to make sure they end properly, delete the original geometry and program using the offset line.

2. Use additional programming software that takes care of this offsetting for you.
www.sheetcam.com will work. It adjusts the tool path by 1/2 of your cutter diameter

3. Take advantage of the cutter compensation feature in Mach2. This is best used in conjunction with 2. (Not Sheetcam, but some programming software with write a program that utilizes cutter comp) Otherwise you have to add this code manually and this can be quite complicated.

[Rekd]

Solidworks and ACad are only design packages. You'll need to be able to convert that to run NC code. This is done with a CAM program. Many CAM programs also have CAD in them, so you can design in them as well as create machine code.

Some controllers can import DXF files and you can machine from them. You can manage the offset amount thru the tool table on the controller. Enter either the dia or rad of the tool, depending on how the controller reads it, (my HAAS' can do either).

If you get a CAM package, you can specify the tool dia and it will automatically calculate the amount to shift.

[studysession]

Thanks for the replies - 2 things:
1> Do you know where to set the parts geometry is AutoCAD?

2> Is there a decent FREE CAM package that will do this and is easy to use.

I am completely new to this. So a lot of them terms and everything used is new to me. Thanks for the help!!

Attached is a jpg of what I am trying as my first part. It took a while but i finally got the stepper motors set in the Mach2 program where when i draw a part with a pencil it comes out perfect now. It took me a long while to figure out draw the part with all the correct measurements and now I have this. Once I figure this tool/cutter thing out, I will be ready and try and CNC my first part. Up until now I have been just doing the mill by hand until I figured this out.

Thanks again for the help!

[buscht]

1> Do you know where to set the parts geometry is AutoCAD?

? I don't know what you mean by set, but to offset the geometry, simply type offset in the command line and then type in the offset distance, then pick your entities

2> Is there a decent FREE CAM package that will do this and is easy to use

Ha HA HA. Just kidding, right now SHeetcam is available free in Beta, its about as easy as it gets, but I wouldn't call it easy for a beginner

[replicapro]

I just looked at the simplycnc site and they converted an x3 sieg. Im in the middle of converting mine and I went to look at what they did for the z axis and it looks like they put the stepper on the drill press handle instead of the z axis lead screw. Is this something I should consider?

[studysession]

Here is pic of the X1 Sieg I bought from simplycnc.com

As for me knowing anything about AutoCAD. I am a complete noob. I am having hard time understand of what you are saying to do in AutoCAD. I have the AutoCAD for Dummies book, but it is not easy to find in there or in the help files.

Thanks!!

[studysession]

Here it is - My first 100% CNC'ed part done by me!!!!!!!!

Thanks for all the help. I used the OFFSET command in AutoCAD to compensate for the radias of the tool. I did have one mess up - that was the center hole that the diff sticks through. I had to dremel it a bit for it to work. For my first time CAD'ing and CNC'ing I think it was a good job.

I did my own motor plate instead of using the modified TMaxx one. I will be CNC'ing my own steering servo holder soon.

I now need to figure out how I will moun the batteries to be secured.

Next I will make my own steering servo holder. Still not sure how I will mount the batteries. I emailed a friend and seeing what advice he has. Tell me what you think of it so far.

In a couple of weeks I am getting a Chili Pepper motor sent to me for the buggy from http://www.brushless-motor.com/

kh

[studysession]

Is anodizing hard to do? I would love to make my motor plate purple to match the rest of the ali on my car.