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Hi all,
time for a small contribution
Not being able for personal reasons to MD for now 3 years, I decided to try setting up my own coil winder and do some coils for my IB detector .
I got the idea from one of Gary´s first designs (I think it was Gary), but wanted more quality, i.e. no loose windings, since the beginning.
The construction should be a vertical setup, the wire feeder should be backed up with a wire tension regulator, to avoid that the spool unwinds wild and messes up the spooled wire. A turn counter may be added later, maybe.
Vertical setup was easy. As a tension regulator I fixed 3 small plastic rolls on a separate board. The wire may be deviated via one, two or all three small wheels to keep a correct wire tension and avoid a chaotic unwinding spool.
I will not post pictures from the whole coil winder, the more important part was the jig or mold to manufacture the coils.
The mold for the coil to be wound should meet several criteria:
- simple, easy to assemble and disassemble (foolproof), time factor not being crucial as I don´t plan an industrial production, at least not yet;
- allow an easy extraction of the coil produced without damages, very important;
- allow the fixation of the coil with resin already within the mold, ideal;
- allow clean work, meaning no sticky fingers;
- adaptable to different wire gauges, additionally;
- reusable, hopefully;
- low cost, if possible (this criterion was not matched, counting all the try outs).
However, the coils themselves, just cost a few meter wire and 5 to 10 gramms of epoxy resin.
To be honest, it took me several months to come to the final design of the mold, getting an idea, rejecting it as foreseeable difficulties were appearing, looking for different material and so on.
I finally opted for a sandwich mold: 2 outer parts holding the coil in shape, one inner part having the form, diameter and thickness of the coil to be wound.
The three parts shall be hold together with screws all around, one central hole being for the axis of rotation.
Plywood should do it.
But I decided to use laser cut acrylic glass, having in mind that it will be easyer to get the epoxied coil off a smooth surface than from a rugged wood surface (although silicone grease or any grease can simplify this, it might mix with the epoxy resin and influence cure time and quality of later epoxy)
Anyway, not using any grease to avoid the resin staying glued onto the mold remained a challenge.
By pure chance I found a kind of very thin plastic band (0.08 to 0.1 mm thickness), it might be Tyvek, or something similar, sold in small rolls and used to seal metal water pipe connections (plumbing - craftsmen used or still use hemp fibres.)
I wound this plastic band around the edges of the 3 mold parts, meaning the surfaces which will be in contact with the epoxy. The restraint thickness, good elasticity and toughness of this plastic band made it non critic in the sandwiching procedure.
Once the plastic band fits and sticks onto the mold parts, these get assembled, fixed with screws and put onto the coil winder.
Then the gap is filled with epoxy resin from a syringe and the wire turned onto the mold into the resin. The resin cures and holds the wire in place after +/-30 minutes. (30 minutes curing time should be enough)
After the resin cured completely after +/ 12 hours, the screws of the mold can be taken off. Then the first side of the mold is loosened by pressing a fingernail into the plastic band between the epoxied coil and mold. The second side of the mold is taken of the same way. The remaining plastic band can now be teared of, most ofthe time, the coil comes with it from the center mold part, if not, a bit pressure from the side causes the coil slide off.
Time used for one D coil: 15-30 minutes to fix plastic onto mold edges and assemble mold with screws, 2 minutes to prepare coil winder and assemly, 5 minutes to prepare the resin, 5-10 minutes to apply resin to mold, 15-20 minutes to wind coil until resin starts to cure. 12 hours minimum for resin to harden out.
Next step will be: balancing DD coils
time for a small contribution
Not being able for personal reasons to MD for now 3 years, I decided to try setting up my own coil winder and do some coils for my IB detector .
I got the idea from one of Gary´s first designs (I think it was Gary), but wanted more quality, i.e. no loose windings, since the beginning.
The construction should be a vertical setup, the wire feeder should be backed up with a wire tension regulator, to avoid that the spool unwinds wild and messes up the spooled wire. A turn counter may be added later, maybe.
Vertical setup was easy. As a tension regulator I fixed 3 small plastic rolls on a separate board. The wire may be deviated via one, two or all three small wheels to keep a correct wire tension and avoid a chaotic unwinding spool.
I will not post pictures from the whole coil winder, the more important part was the jig or mold to manufacture the coils.
The mold for the coil to be wound should meet several criteria:
- simple, easy to assemble and disassemble (foolproof), time factor not being crucial as I don´t plan an industrial production, at least not yet;
- allow an easy extraction of the coil produced without damages, very important;
- allow the fixation of the coil with resin already within the mold, ideal;
- allow clean work, meaning no sticky fingers;
- adaptable to different wire gauges, additionally;
- reusable, hopefully;
- low cost, if possible (this criterion was not matched, counting all the try outs).
However, the coils themselves, just cost a few meter wire and 5 to 10 gramms of epoxy resin.
To be honest, it took me several months to come to the final design of the mold, getting an idea, rejecting it as foreseeable difficulties were appearing, looking for different material and so on.
I finally opted for a sandwich mold: 2 outer parts holding the coil in shape, one inner part having the form, diameter and thickness of the coil to be wound.
The three parts shall be hold together with screws all around, one central hole being for the axis of rotation.
Plywood should do it.
But I decided to use laser cut acrylic glass, having in mind that it will be easyer to get the epoxied coil off a smooth surface than from a rugged wood surface (although silicone grease or any grease can simplify this, it might mix with the epoxy resin and influence cure time and quality of later epoxy)
Anyway, not using any grease to avoid the resin staying glued onto the mold remained a challenge.
By pure chance I found a kind of very thin plastic band (0.08 to 0.1 mm thickness), it might be Tyvek, or something similar, sold in small rolls and used to seal metal water pipe connections (plumbing - craftsmen used or still use hemp fibres.)
I wound this plastic band around the edges of the 3 mold parts, meaning the surfaces which will be in contact with the epoxy. The restraint thickness, good elasticity and toughness of this plastic band made it non critic in the sandwiching procedure.
Once the plastic band fits and sticks onto the mold parts, these get assembled, fixed with screws and put onto the coil winder.
Then the gap is filled with epoxy resin from a syringe and the wire turned onto the mold into the resin. The resin cures and holds the wire in place after +/-30 minutes. (30 minutes curing time should be enough)
After the resin cured completely after +/ 12 hours, the screws of the mold can be taken off. Then the first side of the mold is loosened by pressing a fingernail into the plastic band between the epoxied coil and mold. The second side of the mold is taken of the same way. The remaining plastic band can now be teared of, most ofthe time, the coil comes with it from the center mold part, if not, a bit pressure from the side causes the coil slide off.
Time used for one D coil: 15-30 minutes to fix plastic onto mold edges and assemble mold with screws, 2 minutes to prepare coil winder and assemly, 5 minutes to prepare the resin, 5-10 minutes to apply resin to mold, 15-20 minutes to wind coil until resin starts to cure. 12 hours minimum for resin to harden out.
Next step will be: balancing DD coils
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