Thread: Plastic injection moulding?

What kind of bobbins? for a ferrite tranny or a conventional E-I unit?.

Laminated steel cores. Actually for permanent magnet alternators, but look to be the same as E-I transformer type.
I've just ordered some bigger ones, thinking to cut them down to size, but proper ones would be better.
The core size I want is 18 x 11mm.

Jordan

Last time I looked at the price of doing an injection moulding setup...well, the finished parts were cheap (not even a cent each) but the setup costs were huge ($20k plus).

I know there are some hobbyist injection moulders, and have seen designs for some bog simple, manually-operated machines. The most difficult part I think would be making the steel moulds, luckily right up our alley.
Or, maybe 3D printing?

Jordan

Hercus used to make an injection moulding machine, there was one at Hiedelburg tafe which I don't think ever got used.
It wasn't that big, looked kind of like a drill press but was bolted to the wall.
I remember using one in secondary school to make file handles.
I vaguely remember seeing a Hercus one on ebay a while ago which sold for bugger all because I don't think people knew what it was.
Cheers,
Greg.

There are Gingery plans for making up an injection moulding device using a drill press for the injection pressure. Only small parts but may be big enough.

[ame=http://www.amazon.com/Build-Plastic-Injection-Molding-Attachment/dp/1878087312/ref=sr_1_1?ie=UTF8&qid=1346819478&sr=8-1&keywords=gingery+injection]Amazon.com: Build a Plastic Injection Molding Attachment for a Drill Press (9781878087317): Vincent R. Gingery: Books[/ame]

Michael

Originally Posted by nadroj

Laminated steel cores. Actually for permanent magnet alternators, but look to be the same as E-I transformer type.
I've just ordered some bigger ones, thinking to cut them down to size, but proper ones would be better.
The core size I want is 18 x 11mm.

Jordan

I took a look at a Neosid catalogue http://www.elnamagnetics.com/wp-cont...MG/catalog.pdf
They have E42/20 bobbins on page 41 (59-120-66) that are 11.7 x 19.4mm x 19.6 tall core size. If it's the right size, you could remove any air gap between the bobbin and your core steel with a few strips of lamination and then glue in place to prevent vibration. You need to minimise any air gap in the core with transformer steel as much as possible.