Universal Coil winding Machine

A good amount of the coils are multi-wind- not sure about the correct terminology, anyways these typically are in tuner circuits for RF, and I have not yet attempted to try winding one yet. Today that changed.

Typically I wind my coils with a division of 360* example 180* x2 or 90* 4 ect. To pull off these, which resemble a wind of yarn and create a wider coil, you will go in too steep an angle if you use the original formula so... How I did it was I set the width, and did almost one full rotation and moved the winder right, one full rotation left. Here's the snippet;

controller.rotate(350,300);

controller.rotate(360,-300); 


the minus 10 degrees creates a phase shift, and this created an exact of the originals. How wide it is, and how many 360s determine how many overlaps it has, remember we want to use 78* angle to wind, it provides the best results of grip and retaining the shape so it doesn't slip off the edge see:video. I also noted it is scraping some of the insulation, I believe this is because the width isn't set properly, or perhaps too tight spacing or too thin/narrow a bobbin (guitar slug) against the wire gauge.

Seems like folks need some help creating the basic construction of the machine. My first one was made with less than $60 worth of parts, the rest of it was junk bits I had laying around. You can see it in the picture files. A dial gauge indicator and Square will help keep things accurate. 

You want the linear rail to be absolutely as square as possible to the bobbin mount / "lathe" part. You can either use collects, chuck jaws, rings with grub screws. Now the X motor, which is the bobbin mount has to have as little runout as possible. I used pvc and pex tubing with double sided sticky tape for weathering windows to make the first layer.

For the base I started out with a pine board and aluminum L brackets, which now I am using a combination of 2020, 2040 aluminum extrusions which are either purchased on amazon or any cnc/3d printer maker store.

The motors, I started with NEMA 17, which is fine, later upgraded to NEMA 23- both were open loop as I had bad luck with closed loop types but supposedly closed loops are better.

The drivers pololu style are not the greatest, but it's what I used to begin with which later became logic level driving DM542T, they can run off a 5v signal- if you choose to use a raspberry pi, you will need to purchase TSX0108E logic level converters that are high speed, and bipolar so they can convert RPI's signals to the appropriate voltages.

100uf (V rating should be 2 to 3x the value you plan to run the motors at, I run mine at 20v, so 50v tolerance) decoupling caps is advisable, you can use an arduino CNC shield.

Not necessary but I like to do is braid/twist the GND and respective driving signal wires together to keep noise down. You can strip an old usb and use the braided coax over as a sleeve and tack it to earth ground/chassis. I would not advise using the wires within the USB as they are meant for 5VDC and low wattage. Ideally you want 26AWG braided wire to run the signals to the motors.

Loctite blue can help keep things square and prevent vibration from rattling a grub screw loose. A heat gun that can reach 550f will break the loctite if you need to disassemble for any reason.

Tension is important, if you can get the appropriate AWG magnetic tensioner, do it. Mine is for 42AWG to 37AWG, however if you cannot what I used with my starting setup was 2 felt discs, a wing nut, 2 washers for the pre-tension/wipe stage, second stage I used a simple spring and pulley through 3 pulleys to straighten and keep tension. Finally an old ice fishing pole's tip, about 8" with a threaded rod and spring that can adust how hard it will pull back up/recoil.

You want to feed the wire from the spool sitting upright so it feathers the wire off the spool instead of unrolling it on bearings otherwise you'd need to tension the spool as well adding  unnecessary complexity. Besides, it's how all the professional coil winding companies run wire off the spool. Static, and on a post.

The HMI display was chosen out of convince, it only needs 2 wires RX/TX to communicate, and 2 to power/ground which take up absolutely no pins and it still can be connected to USB as long as you define the pins in the sketch to not conflict with the USB. You could easily make a GUI to run the RX/TX info on your computer/laptop instead of an HMI if it is within your skills. 

The power source I used is an adjustable lab bench supply which allows me to adjust voltage, limit current and has overall low noise and protections an otherwise dangerous linear supply would. One could disassemble a semi newer junk monitor or TV and use the 32v and 5v taps assuming you know what you are doing.

The feed arm, I used a simple metal pivoting arm on the linear rail and a U bend of mains copper wire with the bottom smoothly polished and somewhat flattened. Other things that work are a V notch cut into metal, a window seam tool roller, or possibly a V cut bearing with a quarter sanded down. A rigid titanium needle with a ruby coated funnel also will work assuming you smooth out the channel and it doesn't strip enamel off.

This is the basics, if anyone is confused, has any questions or needs more information just let me know. All the wiring is straight-forward and the pinout is in the sketch. The more solid you can make the machine with less pitch, roll, yaw slack/runout. The better your coils will turn out.

So, I have a BEHA gas lamp tester that uses a simple flyback feedback style to generate roughly 12kv to test gas lamps. It has nothing wrong with it but for science I am going to strip it down and other coils to learn how to recreate them.

First I need to find out the type of wire used. It was potted but I managed to strip the epoxy with a heat gun due to the coil being impregned with paraffin prior potting which allowed it to peel off without much damage.

1. OD of wire is 0.07mm
2. Lit it on fire to strip the cotton/silk and determine whether it is solid, or litz. It was solid, 0.05mm so roughly 41 to 40 AWG cotton, nylon or silk severed enamel coated wire.

3. Next I observe the top of the coil, it has a bike spoke pattern which tells me it is an even number of bends as per the coil winding pdf listed in the files I have included.

4. Now this is where it gets hairy, 15 spokes raised from center to edge, 15 sunk from center to edge, 30... to check if my math is correct I take the wire dia 0.07mm x 30 = 2.1mm now to check the height of the coil against the math. It measured 4.17mm so my assumptions were incorrect. 0.07mm x 60 = 4.2mm is the correct math, however it does not resemble 60 turns for a coil. It looks more like a 1,000 turn because I have wound similar ones, so what is missing?

5. The thing here is, to make ONE full layer which is the height of the wire dia x 2, it needs to go around 360 more than ONE revolution. The circumference of the bobbin, width of coil, n total bends, phasing/spacing and wire diameter determines the total amount of 360* revolutions that are required to create one full layer, and the amount of times it did this will be 1 times the total height of the coil in this case it was 60, and assume it took 40 revolutions to create 1 full layer so 60 divided by half (because it overlaps it created 2x the wire dia as a single layer) now we are left with 30x40=1,200 turns.

That seems a lot more accurate to create 12,000 volts. (2x9v batteries = 18v, subtract losses, say 70% efficiency which is 12.6v assuming fresh batteries. 12.6v x 1,000 turns... BOOM 12,000 volts. Math is your friend.

6. So, how do we get that total 360* revolutions number to know exactly what to input into the turn amount? First we find C, for circumference. This is the OD of the coil bobbin. Let's say its 16mm So where C is circumference, we put 16. Example C*3.14= is 16*3.14=50.24mm total surface circumference.

With that number, now we need the coils width, and the wire diameter/spacing. I have one that's 3.25mm wide now we divide that against the wire diameter. Say the wire dia is 0.07mm... 3.25 divide 0.07mm equals 46.42 total revolutions to create one full layer that is wire diameter * 2 (due to overlap)

So, lets back up a bit to the coil in question I am trying to recreate.6.37mm wide divided by 0.07mm OD of wire =91 now 91*30=2,730 total turns. Whups, probably more like 20kv anyways it is not as wide as my 1k coils on a 16mm bobbin, however it is not a "pi" wind, its either progressive, or retrogressive and it un-evenly moves a little to the left or right gradually building layers interlocking them increasing the width all while retaining the high Q low, Capitance quality. I have mostly been focusing on "pi" style anyways. That's y'alls lesson for today, again if anyone thinks they can help with coding to flesh out the features let me know.

Just recently modified the wire spool to have a smoothed down PC fan grill as a guide to keep the wire off the rim of the spool since its old and rough, kept snagging.

Still looking for someone to help convert formulas to code, flesh out the rest of the winding and upload it to githib as a multi-winder. I need some type of non-blocking dynamatic speed shift to adjust a single speed of the feeder to retain the original angle as the circumference grows.

Also looking for a mechanist to recreate the feed head, and create a few extra simple parts.

As the coding stands it's bare bones that's been manually adjusted. DM542T drivers toggles are:

1. on
2. on
3. on 
4. off
5. on
6. on
7. on
8. on
Tensioner is set with 9.7 on the magnetic dial, and 10 on the rebound. Wire is 37 AWG basic enameled however nylon severed enamel should be used, or nylon severed litz wire.

A few videos are uploaded to my YT channel, which basically consists of video recordings of the winder in action, as well as me unwinding a coil. https://www.youtube.com/channel/UCAB5vRHQBghMYF7Q-pgQcrQ