Thin metal work holding. Super glue to the rescue...

I always dreaded milling thin metal. without a good way to fixture. It's floppy and results in horrible surface finish etc. Then I read about using superglue and a sacrificial plate. I never would have guessed it would have worked so well and without much effort. I used a scrap piece of 1/2" 6061 as the fixture plate. The piece I machined was 1/4" thick stock machined to .185" thick. I sanded both sides with 400 grit sand paper, cleaned with acetone, applied glue, and pressed in the vise for ~ 5 minutes. I ran a 2.5" face mill .02" deep at 50 IPM and stood far away from the mill in case things went bad :-). The bond was very solid and no issues at all. To release the part I used a heat gun on the face of the machined part for a few minutes that ran under cold water. The thermal contraction of the thinner material made a "pop" sound and a tap of a hammer on the back side of the fixture plate released the work piece. I can see doing a larger number of parts in a single sheet using this method without the cost/complexity of a vacuum fixture.

Attachment 256914

https://www.youtube.com/watch?v=Mbrl...ature=youtu.be

Thanks for the vid!!! Part looks great!

Very nice. I may have to try this...been double sided tape from HF for Carbon Fiber machining and acrylic.


I have a great new idea for vacuum fixture I cant wait to show when completed, but this is great idea and will need to try.

-Jason

Slick!
On another forum I follow some small engine builder projects and one person uses epoxy and a wood board back plate then media blast parts clean.
This process sounds like it would be cleaner and faster, thanks for sharing!
md

I tried the Devcon epoxy recently based on perhaps the same example, and it didn't stick to the mill scale on my HRS backing material. When I screwed the 304SS stock to the fixture the work got very hot on the thin sections (I use air blast as coolant). Aluminum would be much better for conducting heat from very thin sections I believe.

pretty cool. I have seen this used for milling knife inserts. to "dress" the fixture between parts they would just run a fly cutter across at 0 and take off all the glue that way

Anybody tried the low melting point polymer that Tormach sells for fixturing odd-sized parts?

Mike

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Originally Posted by MichaelHenry

Anybody tried the low melting point polymer that Tormach sells for fixturing odd-sized parts?

Mike

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Im pretty sure its just 'polymorph plastic' - you can pick it up on ebay or most electronics stores (jaycar in aus). Not sure it would work well as a glue though, getting Z tolerance would be a pita, as its more like taffy than water when heated. I have heard though that hot glue (same as you use in hot glue guns) can work well...

I use a lot of double sided tape and have had very good results.

I just learned about Crystalbond 609, a thermal plastic used for fixturing PCBs that looks like a good candidate. A friend of mine did a video where he used it to fix a penny to an aluminum rod and shaved it down on the lathe. Releases with heat and can be re-used.

Thanks for that KVOM. I have recently had the need to thin down a circuit board on my surface grinder and it did a great job with double sided tape, but it came apart when I tried removing it. Looks like Crystalbond makes several types of adhesive that are perfect.

Are you using standard cyanoacrylate or is a specific superglue?