F360 Post Processor returning to home with incorrect Z value

Hello this is my first post and hoping someone can help?

I've just completed building a custom CNC router that uses the excellent Openbuilds Blackbox X32. Last night, I ran my first few jobs. The first two were levelling the spoiler board and engraving a grid into it, which both went well.

For the third job, I created a simple corner clamp and although the job cut the piece perfectly, once complete the machine proceeded to return the cutter to the start location and in doing so, ran the cutter straight through the work piece. It appears the Z coordinate changed once the job completed from 0 being the top of the workpiece to 0 being top of the spoiler board which was the location of the cutter when the job completed.

I use Fusion 360 for CAD and CAM using the Openbuilds/Fusion 360 post processor. Reading posts on this forum, I was fully aware I needed to home the machine prior to starting the job so that was the first thing I did, I then set the workpiece XYZ zeros using the Touch Probe before running the job.

As mentioned, this was last night and I haven't had chance to run another job/test since but wondered if there was anything obvious that I should be aware of when I run it again?

Sorry in advance if this has been covered before, I found lots of forum articles on Z axis issues at the start of a job linked to not homing but couldn't find anything about post job issues?

 

Thanks David, I'll take a look this afternoon and let you know.

 

Hi David,

I was able to make the change you recommended and this sorted the issue straight away. Thanks again for your help.