File conversion

[zachmartin1806]

Hey everybody I have a student work on a project as part of his MIT admissions, part of his project involves the use of our old tabletop CNC. Sad thing is we don't have the software to convert the file from an .ipt to a gcode file. If anybody could help him by converting the file it would be greatly appreciated. Thanks in advance.

[ablatner]

It doesn't really work like that. There's no direct file conversion. You need a CAM program like Mastercam. It doesn't just take the part file and make g-code. It needs a lot of user input to tell it the tool path, which tools to use, etc. There's plenty that depends on the mill and tools you'll be using. I would recommend asking another local team or machine shop that to make it for you.

Someone can correct me if I'm off about something.

[aldaeron]

The programming is not hard at all as Andrew said. There are many programs (MasterCAM, SolidCAM, VisualMILL, etc). Two clarifications

First, when you are in Inventor save or export the file as a STEP file (I use SolidWorks so I am not sure what menu it is in - my guess is that 'Save As ...' will allow you to choose STEP). This is a neutral format that any CAM program can read. Some CAM programs do read .IPT but there is no guarantee. STEP is a format everyone uses. Try to avoid IGS/IGES.

Second, you need to know what post-processor your CNC uses so you can tell the CAM program what type of codes to export. Different systems use different codes to represent the same thing. In the maker space I use there are lots of older random machines, each with its own set of codes. If you try to run Bridgeport G Codes on a LinuxCNC conversion the program will not work and the controller will beep at you a lot.

Good luck!

-matto-

[DampRobot]

I have to put a plug in here for hand G-Coding. (It's how they did it in the good old days!) If you don't want to buy/learn a CAM package, and the part isn't too complex, you really can hand program the mill.

Each mill is different, but here's the gist of it: each program starts out with a series of commands (part of a header) that get the mill ready to cut. Sets the zero, which mode the mill is in, etc. Then, before each cutting sequence, you tell the tool to spin at a certain rate, such as S1500 (in RPM) and the direction (CW or CCW) with the correct M command. The feed rate (usually in inches per minute) is then set with the F command, F2.5 for example. On some mills, you need to set the tool zero using a H command (H01, for example would import the Z-zero for the first tool).

After the setting up, it's just a matter of controlling the toolpath with G00 and G01 commands. G00 followed by an x, y, or z coordinate (or a combination of the three) moves the mill to that location at the maximum mill speed. G01 moves the tool in a straight line from the last coordinate to the one given in a straight line at the feed rate. G02 and G03 are used for cutting in circles, but its a little to late for me to get into that...

Heres some psuedo-G-code for drilling a hole and returning to the origin:

G00 X0.5 Y2.375 Z3.0
G00 Z0.5
G01 Z-0.75
G01 Z.5
G00 Z3.
G00 X0. Y0.

You get the idea.

This is just an extremely quick primer on G-code, if you want to do it for real, search around for your mill model and the exact G and M codes it uses. Or, you know, you can always just get a CAM program and learn to use it.

[zachmartin1806]

I understand and know how to manually write g code but the part has an internal gear which isn't exactly the most fun thing in the world to do

[TedG]

Not sure if this applies, but what about exporting to a DXF file, will that work?
We use inventor and when we need a complex part cut out with a CNC, we export the 2D profile to a DXF file and our "sponsor" machine shop cuts it out on their CNC.

Maybe your situation is different?

[aldaeron]

If you know your post processor and can send me a STEP I am happy to send you a programmed file (assuming I have the post processor or it is easy to locate).

-matto-