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Rebuilding a homebrew coil winder

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Rebuilding a homebrew coil winder

Post by FRANK.C » Sat Aug 02, 2014 11:01 pm

I built a coil winder some years ago, it has served me well, but the time has come for it to be rebuilt as it is showing sings of wear.
I hope to make improvements along the way. In general I will try and make it tighter and smother in operation. I have been gathering bits and pieces for it over the last few months.
Even though I have called it a rebuild it will be really a new build.

The first section I have tackled is the supply reel. I feel the supply reel is the most important part if small diameter wire is to be wound. Most supply reels that I have seen are mounted horizontally, but I like them vertical as this minimizes the effect of any imbalance in the reel or spool.

The spindle is made from 10mm rod with a M10 tread cut into most of it. On it is mounted a brake wheel and a base to hold the spool of wire. Two bearings hold it vertical and it sits on a trust bearing.
It's got two brakes one is the main brake the other keeps back tension on the wire as its being wound.
The back tension brake has a shoe which is felt lined, a spring and screw adjusts the tension.
The main brake is operated by the jockey pulley arm, its shoe is rubber lined. It operates like a wedge in that when the shoe is offered up to the brake wheel, the brake wheel grabs it and pull's the brake shoe tighter again the brake wheel.

There is a spring which adjusts the tension on the jockey pulley the main brake works effectively regardless of the setting of this spring.
I mounted the jockey wheel on a shaft with a bearing at each end. The jockey wheel arm is made from two lengths of box section brass, one fits snugly inside the other and they are drilled so the arms length can be adjusted to suit the coil being wound. The jockey arm pivots on two bearings.

As I progress with this project I will update this tread.
Frank
Attachments
b.jpg
My old winder
a.jpg
My old winder 2
spindle.jpg
Spindle
adj.jpg
Brake and jockey wheel adjustments
wheel.jpg
Jockey wheel with bearings fitted
jockey arm.jpg
Jockey arm / main brake
base.jpg
Base with bearings and pivot shafts fitted
supply reel 1.jpg
The assembled unit
supply reel 2.jpg
The assembled unit 2

 
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Re: Rebuilding a homebrew coil winder

Post by Dr Wobble » Sun Aug 03, 2014 6:42 pm

Its really interesting looking at your winder Frank, you have some clever ideas in it. I'm especially interested in your
horizontal motor driven setup. You said in my thread that a pic controls the motor; can you give any more details please.

Having briefly looked at PICs, they sound very compilcated to a someone like me who has never written code. how easy are microcontrollers to use?

Andy.

 
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Re: Rebuilding a homebrew coil winder

Post by davegsm82 » Sun Aug 03, 2014 10:47 pm

Very nice design, some ingenious ideas there.

Andy, PIC's are easy, the arduino might be worth looking at for price and simplicity, as the programming software is free and you can get going for as little as a few quid, such as this for example...

http://www.ebay.co.uk/itm/Compatible-Na ... 2c87d18dcf

That little board is all you need, then you just download the software from the Arduino website.

Dave.

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Sun Aug 03, 2014 11:58 pm

Hi Andy
The old winder that you see in the first pictures, uses a stepper motor controller and two NE555's to drive and control the stepper motor that drives the lead screw. The lead screw is M4 traded rod and is coupled directly stepper motor. The carriage that has the pulleys to guide the wire to the coil former is coupled to the lead screw with a M4 nut. another M4 traded rod has two M4 nuts which has large washers soldered to them, there is one each side of the carriage, when the carriage pushes against one of the washers the rod pushes a micro switch at one end to tell the controler to change direction.

My new setup will be very similar but with a PIC controlling it. This will enable easier setup and more precise movement of the carriage.
I am only starting on this part of the winder but have most of the code wrote for it. I am using a PIC18F4520. I have posted a photo of the progress so far.
I will be using a M6 traded lead screw which has a 1mm pitch, the stepper motor that I am using has 100 steps, so each step will move the carriage by 10um. To get the carriage to move fast enough each step needs to be 2ms this will be approximately equal to 5mm per second movement of the carriage. To drive the stepper motor at 2ms per step and with good toque it needs a supply voltage of 18v, this is far too high a voltage to use as a holding voltage, the motor would overheat very quickly. I use 5V holding voltage and the PIC switches it up to 18V immediately before the motor takes a step.
The PIC also ramps up the speed at the beginning of each movement, first step is 4ms the second is 3ms and all the rest are 2ms, this improves the starting toque.
The first line on the display is the turns counter, the next is the wire diameter in micrometer's and then the number of turns in the last full layer wound (I put it there just because there was a spare line on the display), the last line shows the direction of travel of the carriage. The wire diameter (including insulation) is imputed via up/down switches, the PIC calculates how many steps it needs to take at each turn of the coil former. The old system had to take the same number of steps each time the former turned, the PIC can vary the number of steps for each turn so that errors don't accumulate. At worse every 10 turns it is exactly where it should be, for every time it is not where it should be it is no more than 9um out. This is far better than it needs to be and the mechanical tolerances are far greater than this.

As far as PIC's go I am just a novice this is my second PIC project.
I use Great Cow BASIC and Great Cow Graphical BASIC. It took a bit of reading up and a lot of trial and error but was worth it. It's unbelievable what these PIC's can do. I am just using there basic functions in this project.

IF you would like the code that I have wrote so far just send me a PM with your email address.

Frank
Attachments
pic 1.jpg
Control board being tested

 
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Re: Rebuilding a homebrew coil winder

Post by Dr Wobble » Mon Aug 04, 2014 7:45 am

That's a nice job Frank and well thought out, re threaded bar etc. I thought about threaded bar at one point with my winder but was unable with the tools I had to make it work. I wish I had a little lathe, I could go to town. It's possible to use a drill to turn parts, but not to any accuracy.

Thanks for your offer of the code, I have some reading up to do and will look at these arduino's. As my daughter will be doing code at school, it's about time Dad got his head round it.

Keep up the good work,Andy.

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Aug 04, 2014 3:44 pm

Hi Dave
I missed your post last night. Those arduino modules look very interesting, do I take it that you can program it directly from the USB no programmer required? If so they are a very inexpensive way of getting started.

Andy
I too wish I had a lathe, I am pining after a small one for ages.
I just use traded bar and the treads I cut was done with a tap and die set purchased from LIDL.

The code isn't difficult to learn but dose take a little time, plenty of practice and loads of mistakes but it all makes for good fun.
I found Great Cow Graphical BASIC the easiest to start with, as it uses flow charts that you drag and drop to put them together, you just have to fill in the blanks as you go. This avoids a lot of typing and the risk of spelling mistakes. It also makes configuration easy.
Best of luck with the code its good fun and can be addictive.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by davegsm82 » Mon Aug 04, 2014 10:52 pm

FRANK.C wrote:Hi Dave
I missed your post last night. Those arduino modules look very interesting, do I take it that you can program it directly from the USB no programmer required? If so they are a very inexpensive way of getting started.


Hi Frank, yes that's right, the PCB contains the processor, Crystal and a USB-RS232 converter, the board gets it's power from the USB and programming is done across the link too. As well as programming, the link can be used to communicate with a 'terminal' in the arduino programming software so you can view data and send it commands.

The processor on the board (actually an ATMEL device) runs a bootloader code, then your code runs on this.

It's a VERY inexpensive way to get going, it's not 'C' which is what I'm used to, but it's very similar in the structure. I still prefer my PIC's, perhaps that's just me being stubborn!

Dave.

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Aug 04, 2014 11:37 pm

Hi Dave
That's allot for a couple of quid, you cant really go wrong at that price.
I will purchase one and have a play sometime.
Thanks for the suggestion and information I hadn't come across them before.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Fri Aug 15, 2014 8:16 pm

The take up reel (for the want of a better word) on the old winder was purchased from China. It worked well but had a couple of bad points. It had no bearings and just ran steel on steel which needed constant oiling to keep it running smoothly the gears needed oiling or greasing as well and tended when running, to spray the oil or grease allover the place.

I got around to building the take take up reel . The winding shaft is just a 10mm rod with a M10 tread cut into most of it. It has 4 gears, 2 x 24 teeth, a 60 tooth and a 80 tooth. This gives a ratio of 1 : 8.3. All the shafts are 10mm rod and run on bearings at each end. The whole lot is built into a mdf box which will prevent any spray. 5mm traded rod and 10mm tube was used to strengthened it. There is a small magnet mounted on the winding shaft it activates a reed switch which is mounted on the roof of the box. This pulse is sent to the control board for the transverse. Some
It don't look great but "it dose what it says on the tin".

Frank
Attachments
take up reel 2.jpg
take up reel 3.jpg
take up reel handle.jpg
take up reel 1.jpg

 
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Re: Rebuilding a homebrew coil winder

Post by Dr Wobble » Mon Aug 18, 2014 6:52 am

That's nice work Frank and well thought out as usual. Where did you get your gears from? Have you put lube points on the outside of the box? I use a spray on grease for little jobs like this,saves getting gunked up.

Looking forward to seeing it all working,Andy.

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Aug 18, 2014 8:47 am

Hi Andy
I got the gears from This seller on ebay. Gears of this size appear to be difficult enough to come by.
I hadn't thought of lubing it from the outside, that's a great idea and it's not to late to put some on it yet. I had just left the front panel easy to remove.
Spray grease I haven't used but sounds ideal for this job.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by Dr Wobble » Mon Aug 18, 2014 3:11 pm

You could either drill small holes in the appropriate places so you can squirt some lubricant in,or use thin tube to direct the grease/oil fixed in place inside. I think grease nipples would be OTT.

Andy.

 
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Re: Rebuilding a homebrew coil winder

Post by Brianc » Mon Aug 18, 2014 4:46 pm

This company is a very good source of spur gears, both Delrin (plastic) and steel and their range is fantastic. I was able to assemble a complete set of change gears for my AVO No. 6 winder. They had the correct DP (size) and the central hole was not too big so that I cauld machine them all to fit the winder. Fortunately, they also fit the Douglas wave winder too.

http://www.hpcgears.com/n/products/12.s ... _gears.php

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Mon Aug 18, 2014 5:52 pm

Andy
The tube method would appear to be the best way to go, they would help to stop the lube from coming out again.

Brian
That's a great company to have bookmarked, they have a good range of gears and plastic ones too which were probably better suited to this project than the ones I used.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Thu Sep 25, 2014 9:30 pm

I finally got the transverse section done. it is a simple affair.

The carriage runs on two linear bearings.

The lead screw is M6 traded rod. it sits in bearings at each end. the bearings have a internal diameter of 10mm. Two M6 nuts soldered together one of them ground down to 10mm are traded onto the lead screw to hold the lead screw in the center of the bearings.
Trust bearings at each end of the lead screw prevent any lateral movement.

To couple the carriage to the lead screw, there is an arm on one side of the carriage that points towards the lead screw. The lead nut is a 20mm long M6, it has a short arm soldered to it at 90 degrees to the lead screw, this arm has a small piece of brass soldered to it which forms a "V" shape. The arm on the carriage fits into this V and is held in place by a spring. the action of the spring also keeps the lead nut pressed against the lead screw. This arrangement works very well there is no perceivable play between the lead screw and the carriage.

A 5mm coupling connects the lead screw to the stepper motor. I taped one end with a M6 tread, so the coupling would screw onto the lead screw.

There are no position switches as the microcontroler counts the steps the motor takes to keep track of the carriage position.

Much more to do

Frank
Attachments
transverse 5.jpg
M6 nuts
transverse 4.jpg
Lead nut
transverse 3.jpg
Carriage coupling
transverse 2.jpg
transverse 1.jpg

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Tue Sep 30, 2014 8:11 pm

After coming across an old battery drill that the battery's no longer held charge, it occurred to me that it would be relatively easy to build a automatic coil winder with it.

I removed the gubbins from it. the chuck, gearbox and motor is all in one handy unit.
I mounted this in a box together with a unregulated power supply, a mosfet and it's biasing resistors to drive it with.
There is a diode and a 33nF cap across the motor to tame the spikes it produces. It is driven directly from the microcontroller with PWM.
This unit will be directly interchangeable with the hand crancked unit so I will have a choice of hand cranked or auto.

Frank
Attachments
take up reel b 1.jpg
take up reel b 2.jpg
take up reel b 3.jpg

 
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Re: Rebuilding a homebrew coil winder

Post by Refugee » Tue Sep 30, 2014 9:25 pm

I also save dead cordless drills for jobs just like this one. I was already far advanced with an ice cream maker drive by the time I came by my first dead drill battery. So that is what my coil winder will be based on.

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Wed Oct 01, 2014 8:27 pm

Hi Refugee
It just goes to show that you should not throw out anything :) . I haven't seen any ice cream maker drive's, but it sounds interesting.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by Refugee » Thu Oct 02, 2014 2:43 am

I did start a thread when I was building the drive coupling and plinth for it a couple of years ago.
The coils are wound on a vertical spindle unlike commercial units.
viewtopic.php?t=2602&p=26538#p26538
Also the turns counter got a thread too.
viewtopic.php?t=2892&p=29565#p29565

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Thu Oct 02, 2014 8:51 pm

Thanks for the links I had missed those.
That's a great winder it looks to have loads of torque and be strong enough to wind large diameter wire.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by Refugee » Fri Oct 03, 2014 1:25 am

With a 450W motor and low gearing and plenty of space around the mandril it should be able to do a 500 VA transformer easily.
I plug it into my Variac for soft starting with fine wire but with heavy stuff the built in speed control is fine.
The internal speed control sounds like an Indian taxi at very low speed and can snap fine wire.

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Tue Oct 07, 2014 8:09 pm

The control board is completed, baring something unforeseen.
Its a bit all over the place as it has evolved with the project. The control board, the LCD and key pad will sit in an enclosure on the right hand side of the Transverse. There wasn't enough room to house the power supply so it will be in an enclosure for itself to the rear of the winder.
I have added extra decoupling cap's to the control board to keep the reg's happy.

The first line of the display is the turns wound.
The second line is the Wire diameter in um.
The third line is winding speed and any errors that has occurred while winding.
The fourth line is the width of the coil being wound and the direction of travel of the carriage.

Frank
Attachments
CONTROL BOARD.jpg
Control Board
CONTROL PANEL.jpg
Control Panel

 
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Re: Rebuilding a homebrew coil winder

Post by valvekits » Tue Oct 07, 2014 8:30 pm

Hi Frank
It is looking very good.
How does it count the turns - Is it counting "real" turns or just the calibrated pulses that drive the motor?

Eddie

 
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Re: Rebuilding a homebrew coil winder

Post by FRANK.C » Tue Oct 07, 2014 8:40 pm

Hi Eddie
It is counting real turns, there is a magnet on the chuck that operates a reed switch each time the chuck turns once. The turns counter increases by one and the carriage moves by one wire diameter. Through the menu, the required amount of turns can be set, the winder will slowdown as this number is reached and stop at it.

Frank

 
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Re: Rebuilding a homebrew coil winder

Post by Brianc » Wed Oct 08, 2014 5:52 pm

I am truly impressed, Frank. I wish I could get my head around PICs and the like but dogs and tricks spring to mind.

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