cnc quilter

[4lowie]

Hi all,
I've just started on the wife's cnc quilter. I've built a couple of cnc routers so I thought this would be easy.... Ran it for the first time today (without machine for now) and I have a couple of questions.... If we have a constant stitch speed how do we make sure the x-y speeds are constant? Mach 3 seams to slow down quite a lot on the turns even though I have CV ticked, this would mean very close stitches on the turns and then they'd open up as it accelerated on the straighter bits..

Secondly are there any good current threads on these quilt machine builds?

Cheers Dave

[Jmhx2]

I set up a Handi quilter for my mother recently, being into CNC I really scoped out their design approach. They use two encoders on the x and y, it's feedback is fed into a stitch regulator. The faster/slower the machine moves the faster/slower the stitch. What are you using to control stitch speed?

[wwendorf]

Hey there,

I have been using robotic quilting machines since about 2001. If you do not have encoders on each axis, and want to keep a consistent speed, you need to do it by adding in Tangential control . Mach3 has a feature that supports this, but basically, mach3 does the math when you move different axis and keeps the speed consistent no matter what angle you are moving at. The nice thing is that with Tangential control, the only thing you have to worry about is setting the sewing machine at a specific speed and let the speed of the stepper motors control your stitch length as they will always be moving at the same speed in any given direction.

However, if you are coming into a tight corner on a pattern, you have to keep your overall speed slower or the steppers will "skip" steps.

Hope this helps!

Wade

[4lowie]

Thanks guys

I've improved things quite a bit by maxing out the acceleration and changing the cv setting to .000001 this is what I found on the mach 3 forum...

Can you please tell me more about the tangential control.

Cheers Dave

[wwendorf]

I can't tell you much more, but if you google it, you will find a lot of information on it.

It basically gives you consistent speed not matter what angle you are moving at.

Wade

[MrFluffy]

Interesting thread, I just dug up someone elses thread on the same subject from 2013, but at least this one is only a few months old not years.
Im at the starting this myself stage soon (I'm just finishing off a linuxcnc conversion of a bridgeport mill first).
I've got to fabricate a tubular quilting frame with some parts from a commercial frame and we've bought a older nolting hobbyquilter mid arm to go on the one I'm constructing (because I liked the idea it was mechanical in nature and easy to fix/modify). The stitch regulator issue is weighing on my mind as nolting don't supply one for this model, but we have a gracie one which uses external encoders which we used with a brother shortarm machine but will need some adapting to work with the nolting but if I can get away without and using some constant speed controls, that would be even better.

Also, how do people deal with winding on between passes? since the rolls will change diameter as they get towards the end of the quilt and be dependant on how thick the batting etc is as to how large that change is, to keep a constant winding distance I presume its got to have some sort of encoder to measure the distance wound for the control to understand.

I want to use the crossxy layout and linuxcnc to control it, crossxy because it means I can mount the steppers on the frame, and only need two so I can use larger steppers and drivers to deal with the weight of the nolting, and some GT timing belt across the length of the frame (full queensize frame). But I will use mach if there's advantages it brings that emc doesnt. I just tend to use linux because I'm a unix code monkey by trade, and I know its insides well.

The other area is sensors of what the quilting machine is doing, ie is the needle down/in motion, does the control need to know that so it doesn't try to move the machine with it down and not moving (and break a needle), thread break detection (a scaled down wire edm style tube with a switch on it) etc?

I'd like to find some good threads too!

[samco]

I would think with linuxcnc you could generate a xy velocity signal in hal based on the actual speed of the axis to control the stitching. (although I think there are quite a few ways this could be done in linuxcnc..)am

[trickey]

Hi Mr Fluffy I have been away for awhile and have just came across this site, I noticed that your last note was about a year ago, I was a regular on the other quilting site, but all interest seemed to have petered out, my wife also has a Nolting fun quilter which has a genuine cruise control, but their cruise control don't come cheap, I believe that it would cost about $ 2500 + ( Australian dollars) to have one fitted, they have an encoder on each axis,and variable stitch length.
I also built the quilting frame,if i can be of any assistance to you be in touch

trickey