Carbide Post Processor not honoring Fusion 360 CAM orientation setup.

[Anonymous]

Hi Everyone... I got a problem...

I have a piece that I'm trying to machiene on my ShapOko 3 using Carbide Motion v2. My Initial problem was that the machiene was not behaving like the simulation in fusion 360. I posted a discussion on the Carbide 3D forums (can be seen here) Through some of the responses that I have recieved on that forum post I can only come to the conclusion that Fusion is not honoring the origins that I am setting up in my CAM opperations and is instead defaulting to using the model origin when writing the G-code. I am using the Carbide3D.cps post processor but have also used the Generic Mach 3 and gotten the same result. Please Help Me! I'm at the end of my rope!

[HughesTooling]

I just ran a back plot and the code matches Fusion. One thing it might be is it's calling the G54 offset, have you got that set as your datum, I'm just wondering if you've setup on G53 and the code is using a different offset.

A couple more observasions, in you setup you haven't selectet the model and with the post you're using you should set an offset. If you set the offset to 1 you can make it the default so you don't need to set it every time.

[Anonymous]

Hi Mark! Thanks so much for your reply. I don't think I setup G53... to be honest I'm not sure what G53 is or does. I did take your other suggestions though. I selected the body under model in the setup and entered a 1 for WCS Offset. Still can't understand why in the code the first sets of movements are in Z+ instead of Z- when I'm setting Z0 in the setup to be the top of the stock? I don't really understand the raw code very well but after having others look at it in my other forum post It seems like whatever is generating the code is not paying attention to my origin setup in CAM. 

[HughesTooling]

The line with G28 tells the control to use machine coordinates so it should go to the Z home position not the part Z0.0. Do you have limit switches, without switches you don't have a home position.

Here's some info on G53 54 ect. Mach3 G codes.

I think what you should be doing is homing your machine this sets your G53 then change to G54 and set you part datum. If your machine doesn't support G28 you would use G53 then Z0 to go to the machine home.

[Anonymous]

It is my understanding that the Shapeoko 3 does not come with limit or home switches (those can be installed separatly). So... I don't have these. Is there some kind of "work around"? I'm not really comfortable messing with the raw g-code. I just don't understand why, If I'm defining the X0, Y0, and Z0 in the Fusion 360 CAM Setup and then Zeroing out my machiene at the same point on the physical stock, isn't this all the information needed to make this part? 

[HughesTooling · Accepted solution]

The post can be modified to move to an absolute Z position instead of G28 Z0.0. The only problem is if you have along cutter and a tall job and and the hard coded Z height is to high you'll run out of travel, not good if you don't have limit switches!

If you go to the CAM Posts forum you can request a modified post. You might even find one on here if you do a search this question comes up quite often. Here's the link to the posts forum. Link