Coil winders Ideas

[Woodenspoke]

I collected a batch of parts for the last version I concocted, then real life intruded on my fun again.

I'll get back to it as soon as possible. Right now the mechanics are a bobbin holder on the end of a stepper motor, a stepper driving a leadscrew to move the tension/guide assembly left/right on a ball-bearing drawer slide, and a roller/brake tensioner on the moving part of the slide.

I was surprised - I got an accrued drawer slide, and the straightness (which matters not a farthing for this!) was under 0.001" in four inches. Play was zero, indicating a residual preload on the balls as received. Just remarkably good.

Man this thread seems very familiar. I think most everyone is over designing your whole CNC winder thing. Even the linear movement is over built for what you need to do with it. Figure if you are around .015 accurate your fine. If you were cutting out parts you want to see numbers closer to .001. A screw is the way to go and they are cheap, you don't need ball screws for this kind of work. They make connectors for attaching the screw to a stepper shaft. These are also inexpensive. You just need to stop the traverse device from rotating and that can be done with simple materials.

You are also going to need a controller run by a computer. That is the only way you will have flexibility over different pickup designs. Right now an older computer is better suited for the task.

The biggest issue is programing. What I have and have seen is for cutting out parts, you follow a line and generate code for following that line. here you are just rotating in a CW or CCW direction a certain number of turns and then Moving a linear shaft CW and CCW in a set pattern of your choosing.

When steppers stop they stop you do not need to worry about additional movement. You want 1500 turns it stops at 1500 turns and no more.

Maybe someone has a program to generate these two motions and give you the code to feed to the computer program which runs the stepper controller. Otherwise you will need to learn to read code. If anyone has something that will do this for you I'm all ears.

I will post a message on the CNC zone and see what feedback I get.

[R.G.]

Man this thread seems very familiar. I think most everyone is over designing your whole CNC winder thing. Even the linear movement is over built for what you need to do with it. Figure if you are around .015 accurate your fine. If you were cutting out parts you want to see numbers closer to .001.

Wooden, you're doing a "Ready, Fire, Aim" again. You gotta actually read the posts.
(1) I said, and I quote "I got an accrued drawer slide, and the straightness (which matters not a farthing for this!) was under 0.001". Obviously the straightness of the linear motionmatters not a farthing. I literally wrote down that it was unneeded accuracy.
(2) You gotta do the math. The precision (not accuracy, they're different) of the side to side motion does matter. A pickup winder is putting down wire with a typical diameter of 0.002" to 0.003". If what you're trying to do is place turns even closely to where you want them, yeah you really do need precision of something less than half a wire diameter. If you read the previous posts about having a CNC winder replicate some arbitrary pattern, yes, that kind of precision is needed for the traverse. It's not needed for the bobbin rotation. For that, an accuracy of 200 steps per rotation is quite enough.

A screw is the way to go and they are cheap, you don't need ball screws for this kind of work.

Who said anything about ballscrews? My leadscrew is a 6" length of 1/4"-20 all thread.

They make connectors for attaching the screw to a stepper shaft. These are also inexpensive. You just need to stop the traverse device from rotating and that can be done with simple materials.

Yeah. The coupler I've used is a short length of 1/4" ID auto fuel hose and stainless clamps. They're pretty much cheaper than the purpose made couplers and add damping and misalignment tolerance as well. Who said anything about expensive couplers?

You are also going to need a controller run by a computer. That is the only way you will have flexibility over different pickup designs. Right now an older computer is better suited for the task.

Well actually, I have that covered. I have an assortment of older computers that are otherwise worthless. I have an old laptop that was targetted for this particular task. I spent over three decades working for a major computer company, so the computers are the easy part.

The biggest issue is programing. What I have and have seen is for cutting out parts, you follow a line and generate code for following that line. here you are just rotating in a CW or CCW direction a certain number of turns and then Moving a linear shaft CW and CCW in a set pattern of your choosing.

Line followers have obvious problems in a coil winder where the "line" length needs to be at least the length of the repeating pattern. For reproducing a custom pattern, that might be the length of the entire wind conceivably. That's certainly what one should shoot for. Using a stored pattern in a computer is much easier once you get past the need to describe the pattern to the computer.

Beyond that, A generic motion control program can handle the motions. There are low cost programs to do just that.

When steppers stop they stop you do not need to worry about additional movement. You want 1500 turns it stops at 1500 turns and no more.

It's not exactly that simple. Steppers do start and stop where you say as long as you have taken into account the motor and load inertia and are not asking it to produce accelerations or decelerations exceeding the torque which the motor can produce, or the maximum step speed. Exceed those and the motor will lose steps. If you are only counting steps, not looking at an external position encoder, you lose some positioning accuracy.

Maybe someone has a program to generate these two motions and give you the code to feed to the computer program which runs the stepper controller.

Yep, someone does. It's very common in the DIY CNC community, of which, there is one.

Otherwise you will need to learn to read code. If anyone has something that will do this for you I'm all ears.

Look up "Mach" on google.

In addition, many of the participants here have spent years if not decades working on computers and programming. The computer part may well be the simplest of it. I know it is for me.

I will post a message on the CNC zone and see what feedback I get.

That's been done by one of the forum participants here. Do a search on CNCzone for "coil winder" before you post.

[erikbojerik]

RG, did you ever get around to putting this one together?

[Woodenspoke]

Yes and no. Bought all the parts then turned some PVC for the disks. The turning part did not come out right. PVC is just too soft. Ran the setup using some clamps to hold everything down and it worked. I have to make a decision on a new material for the disks. The counter and reed switch works fine as does the motor except at low speed the tork is also low and pressure will stop the drive

I have not gotten back to this project because I am selling my house and moving (have a buyer), so many things have been put on hold over the past 5 months. Getting to the point of packing my shop now. UGH.

[Drools]

I just found this thread, although it is an older one it has some great info on the relationship between bobbin speed (RPM) and traverse speed (PPS – passes per second). I was looking around for a lookup table that I could load into the memory of an Atmega48 or Arduino. I'm not sure a stepper has to be used for the bobbin motor, just so long as we can determine the RPM of the bobbin just about any hobby motor could be used. I think a simple small nema17 stepper motor could be used for the traverse function. I think it greatly simplifies things with just one stepper driver. Unfortunately gear-head motors are more expensive and probably not available to the average tinkerer but they would be ideal for a bobbin motor. I have one salvaged from an old piece of equipment. I think it and a nema17 along with my Arduino will do for starters and moving up I would dedicate an Atmega48 as I have a few of them.