Hi All

Here may be the answer to all those wanting to build any sort of CNC sewing machine!

The program path needs to be reversible because the thread often breaks when stitching requiring the machine to be backed up to before the break, then rethreaded. and finally restarted, overlapping the end of the first run in the trade called "back tacking" and the restart.

The controller needs to reverse, and this one can! I am sure the 35000 program segments will be more than enough to do this sewing paths are very simple. It needs to be a simple push button function with the path reversal shown on the Display screen.

Thanks to the post below this may be the solution.

I stumbled across the You tube Channel "Applied Science".
https://www.youtube.com/watch?v=rpHYBz7ToII
The post describes Building an EDM Drill.... quite interesting, however I do not wish to build one.
However the builder just happened to mention that the CNC controller he used was able to feed in reverse back up the program buffer as well as forward. I nearly fell of my chair!

So I emailed the KFLOP company and promptly got the following response.

Quote
Yes our KFLOP Controller has the ability to perform hardware feed rate override (FRO) including negative feedrates.  See here.  KFLOP has a motion buffer that can contain up to 35,000 coordinated motion segments.  This is typically many seconds of motion depending on the complexity of the path and speeds.  So it is possible to reverse this amount of motion.  When using Feed Hold in our KMotionCNC program two buttons (Forward/Reverse) are enabled which are coded to command the Feedrate to +0.2 and -0.2.  See this video. the important bit is towards the end.

https://www.youtube.com/watch?v=uPQfGeydsDM

As far as I know Mach can not do this? Can anyone confirm?

End Quote

Regards
John