Ideal DIY Pickup Winder Features?

[Robert Technology]

I am new to pickup winding but am looking for a fun project to take on with an extra PLC (programmable logic controller) and HMI that I have laying around.

I'm hoping to get some insight into what features the ideal pickup winder would have. Is there anything that would be useful outside of things like:

• Rotation direction (CW Vs. CCW)
• Total rotation count
• Speed up/Slow Down at startup/stop
• Lateral movement for programmable scatter and coil distribution

That's basically what I have seen on commercial and DIY units online and seems easy enough to accomplish with a programmable unit. Anyone have any other advice that I may not find from basic research? I'm going to order some pickup parts from Mojotone to figure out the best way to mount to the motor shaft, but it seems like a PLC, an HMI for control/dispaly and a motor should get me most of the way there.

Thanks!

[jack briggs]

All the above

[kayakerca]

You may want to include:
- Traverse start position option to be either left side or right side (top or bottom) of the bobbin.
- Bobbin height/traverse distance (distance between the inside top and inside bottom of the bobbin).
- Lateral movement distance parameter to accurately align the wind start position setup (in predefined increments [e.g. .0028/.028/.125/.125/Bobbin height itself]).

[Robert Technology]

You may want to include:
- Traverse start position option to be either left side or right side (top or bottom) of the bobbin.
- Bobbin height/traverse distance (distance between the inside top and inside bottom of the bobbin).
- Lateral movement distance parameter to accurately align the wind start position setup (in predefined increments [e.g. .0028/.028/.125/.125/Bobbin height itself]).

This is good stuff that I wouldn't have thought of! Thanks!

[kayakerca]

This is good stuff that I wouldn't have thought of! Thanks!

Anytime. Spent a few months on that same road a number of years back. The result was well worth the few bumps in the road during the journey.

[ken]

If you use automatic traverse wire feed (selffeeding) instead of always having to sit in front of it...

A 'broken wire detector' and automatic 'bobbin full shutoff' is always a good thing if you decide to let the winder run by itself. Then it can run in the background as you do other things. It's almost like having another helper for free

What PLC and boards are you planning to use?

Following this one...

Ken

[David King]

You might want to read through the old thread that Elepro started when he began designing his automated winder's architecture. His was all about repeatability vs randomization in the tpl. He used stepper motors for both the spindle and the wire feed traverse so that he could completely sync up the two. Basically a PIC to a 60 char display that went through a series of "conversational" questions to determine the desired variables and constraints. It has a very simple interface. A number of us got the PIC and PCB and then organized a group purchase of BOM kits from Mouser. I still have mine assembled and ready to run but no time to design the perfect hardware compliment I'd envisaged.

[Robert Technology]

Very interesting! I'll have to check out the Elepro thread on this topic to see what other people have done in the past. I don't have any experience with pickup winding so I appreciate all of the details you are sharing.

I definitely like the idea of some sort of automation related to a "broken wire detector" and that shouldn't be too hard to add in. I'm planning on using cheap servo motors for the positioning automation, and possibly for the drive of the winding as well.

For the actual automation I'll be using a "cheap" Koyo Click PLC from Automation Direct. It's what most of my students typically use for our PLC class so I'm hoping to get something similar to them. I've used the Allen-Bradley MicroLogix 1100 in the past, but that unit is being phased-out of production, so it's time for me to switch to what the bulk of my students will be using. Control and setup will be accomplished through a C-More HMI (probably just the cheapest touch-screen unit that Automation Direct offers).

I'm not entirely proficient with text-based coding but will share what I end up with in case someone wants to translate it to a language that can be used with a PIC, otherwise I'll take that on this Summer to finally get the hang of some C Language!

[salvarsan]

I've thought about this a lot lately since I'm building a hobbyist CNC engraver for milling circuit boards so this may be long. Please read through it first, THEN tell me I'm full of shit.

I want a CNC pickup lathe that has assorted adjustments and event detections like

• bobbin traverse limits,
• traverse speed and steps,
• static wire tension,
• wire breakage,
• maximum winding speed,
• variable winding speed.

A host computer application would provide the smarts for winding density and patterns.

This level of control means that, in addition to the essential turns per layer spec, you could experiment with complicated coil patterns like such as segmented winds or yarn ball weaves, the ultimate scatter wind.

I've found a lot of CNC resources that are available to us . . . if we decide ahead of time that. . .

the pickup winding lathe is to be controlled by G-codes.

The G-code specification is a standard for controlling machine tools by computer and is formally called RS-274.

TL,DR Version:
Use as much off-the-shelf, free, open source stuff as possible and tweak it into submission.


Machine firmware:
GRBL (pronounced "gerbil" because it's bigger and more capable than a mouse) firmware can handle direct machine control. It is free, open source, and runs on an Arduino UNO, a pleasantly inexpensive hardware bit with a congenial (for C/C++ language) development environment. A ready-to-use controller board ranges $30-$50 and has more than enough functionality to handle a pickup lathe's motion, traverse limits, and safety switches. GRBL has been broadly adapted to engravers, mills, lathes, XY plotters, and laser cutters. 3D printer controllers have NOT.

Host computer software:
A stripped and tweaked CNC lathe application that generates G-codes can run on the host computer. There are many open source ones out there and the maintainers can often be coaxed into helping, especially if you throw small $5-$20 contributions at them.

Hardware:
The hardware is the difficult part.
The custom parts are the adjustable bobbin limit switches, wire tension detecter, spindle faceplate, and others I can't think of at the moment.

The traverse mechanism could be hand-crufted. Or purchased as a "Z-axis linear actuator/slide table" with only 50mm travel -- short stroke since most pickup bobbins are ~3/4" (19mm) or less.
Amazon wants $60 shipped and the Chinese firm Banggood sells them for $50 with about a 1 month worst case delivery time.

A few small accuracy enhancements like a helical shaft coupler (AKA flexible coupler) and on-motor servo control add another $35 to the cost, more if you're in a hurry and order from Amazon. The closed loop SERVO42 is a relatively recent development that offers excellent position accuracy.

The spindle motor need be no faster than 1200rpm and could run under PCM speed control (inexpensive) but some manner of rotation position would need to be built in.

CALCULATIONS
For argument's sake, assume that an average finished pickup coil is 60 winds per layer, 60 layers of #42 single build wire = 0.0028" diameter. The stepper motor + lead screw are 200 steps/rev + 2mm pitch or 0.01mm step (0.0004").
The GRBL controller delivers 33,000 steps/second at maximum.

Assume a 0.25" high PAF bobbin, very underwound at 60 winds/layer and 60 layers -- easy numbers but unrealistic.

A .25" traversal needs 625 steps -- so we have enough accuracy at ~10 single steps/wind.

If the spindle motor is typically run at 600rpm = 10 rev/sec, 6250 steps/second are easily within GRBL controller capabilities although I'm not sure about the stepper motor (which may be only 2000 steps/second so multiply the final results by 6250/2000 ~= 3).

Each layer takes ~6.25 seconds or maybe ~19 seconds.

60 layers takes 375 seconds or 6 min 15 sec (or maybe 19 minutes), a reasonable estimation, and time enough to make coffee.

This is not intended to be a perfect prediction, only a ballpark estimate.

-hizself

[smisco]

Use of an absolute encoder on the wire traverse axis-----the ability to store and recall several "work coordinates" based on setups for different bobbins----And the ability to apply offsets to the work coordinates

[LtKojak]

http://www.ukcnc.net/index.php/produ...i-coil-winder/

This CNC one is excellent for prototyping, and more than good enough for low-volume production, although a little bit pricey as first investment, it'll pay itself up in the 1st year alone of a typical "boutique" winder revenue that allows to support himself.