PRS Alpha issues

[denmanmarine]

Hi All,

I have tried to search for an answer to this one but no joy so far.

After a few days of fairly hiccup free cutting with only the odd software related glitch I have had an interesting afternoon.

I had tool pathed up a simple file for 6mm plywood that included a drill path, a half depth rebate and a through cut - all using 3 different cutters.

I now have a checklist I run through before I cut so I don't miss anything so with all boxes ticked I got started on the drill path but instead of drilling, the machine ramped down to full depth and took off trying to cut the ply as opposed to drilling. This continued until I hit the spacebar as the bit(2.5mm) snapped off. Personally I felt a lot of pride for that little drill bit cutting so far in the ply (around 5") before giving up but it all was obviously not right.

I went back into V-carve and double checked the toolpaths - all ok. I went and checked the shopbot file - all ok. Turned the machine and computer off, re-stared, zeroed all and the drill path cut as it should, and the rebate cut as it should as well.

I was feeling pretty confident by that stage but after changing to a 1/4" spiral downcut, I was zeroing the Z axis and on the first drop to the plate it seemed a little quicker than normal and hit hard enough to leave a small dent in the plate but it rose up slowly and re-touched slowly as per normal and I got the message that it was zeroed and to put the plate away.,

When I re-commenced the file again, the spindle moved slightly then plunged straight down very quickly and the only thing stopping it going further was the collet nut which ended up buried in the ply by a few mm. The spacebar did not stop the machine and I had to use the e-stop button to actually stop the router.

After I turned everything off/on again and checked the files AGAIN, the piece cut as it was meant to.

I am still running 3.8.8 but now I see that there is a new version. The guys at shopbot suggested to revert to an earlier version a few weeks ago when I had a few buggy issues but I have persisted to see if I can find out if it is something I am doing rather than the software.

Has anyone else had an issue similar to this and if so what was it caused from?

Andrew

[adrianm]

When you re-started after the original issue how did you reset the Z before running the Z-Zero routine?

If you've lost position it doesn't know where it is and the Z moves are all relative moves from where it thinks it is.

After an issue where I'm not confident of the Z being in the ballpark I always move it manually to within a few mils of where zero is and set it manually before moving back and running the z-zero routine.

It should have reset itself after you ran the routine though which is confusing me (not hard I know!) a bit.

Not sure what caused the original issue. The only time I had something like that was when I had the z zero position the wrong way around from what I had designed and the bit plunged right through the material on it's way to the starting point.

I changed my Post Processor so it doesn't go down at the same time as it moves to the starting position and added a warning box to remind me to double check the Z.

I expect Brady will be along with the correct answer before long. :)

[denmanmarine]

Hi Aidan,

Thanks for the reply.

After the initial issue I restarted the machine and re-set all axis. The Z was re-zeroed with the plate once the new bit was in and each subsequent tool change was re-zeroed with the plate.

The only thing I could possibly think of was when in the MTC mode it asks if you want to use the interface to raise the Z to change the bit that I use the interface to move the spindle close to home so I can actually reach the bit but I have done this without issue many times.

Andrew