CNC Sewing machine question

The frame to hold the material is pretty large. When the CNC program is in the sewing mode, it will be moving at a very slow rate, and should not break the needle, as the fabric has some stretch to it. When making larger moves, as between letters, the "spindle" should be stopped with a timed pause command to allow the needle to go fully up before moving. I think this will really solve the problem.

Jon

Good suggestion on the Rugbot. I downloaded his .hal and .ini files. He is using hypot and a DMM servo. I am not familiar with either of these things... so I will do some research. From what I read, the hypot makes the speed of the "spindle" correlate with the speed of the x and y.

I will study this a bit more... hopefully I don't need to get a servo. With a servo I'm sure I could program everything so that the x and y only move when the needle pulley is between 160 and 360 degrees.

Jon,

I understand what you mean. The reason I was trying to time everything so that it doesn't move while the needle is down is to avoid bending it into the hook on the underside. The slot on the spinning hook is pretty narrow that the needle goes into. I think it could tolerate more bending in the x than the y.

It is a good suggestion though. I will try it and see what happens. Worse case scenario, I have to replace the hook.

Thanks,
Rick

I've no experience with cnc sewing machines but plenty with conventional ones. I can say that you'll need to make sure the bed isn't moving when the needle is down. Best scenario it will just give you rubbish results because the stitches will be in the wrong place, worst case you'll get constant broken needles.
You should have the best part of 180 degrees of spindle movement to do the bed moves. Perhaps a little less for reliable results. I suspect you'll need really high speed and torque on your x/y to get good results.

You've seen this guys video yeah?

I agree SPH. Right now my strategy is to have the needle stepper running constantly, but have the x/y moves take place when the needle position is between 160 and 360 degrees. The needle is down between 0 and 160 degrees.

The piece I am missing is:
- how do I measure the stepper position while it is in spindle mode?