Metal milling: basic question

[drape]

Hello CNC Zone,

I'm pretty much a newbie with milling metal. We have a small Techno Router at our school and I'd like to know how folks would advise to hold metal down. I've been advised to use double stick tape on the back of a sheet of aluminum or steel and just attach that to an MDF sacrificial layer. We're a little concerned that since the router is in a clear plexi box that all the mdf dust will gum up the works in the router. But maybe that's not a problem

Is double stick tape and MDF the way to go for milling metal? should we try some kind of clamping method?

Thanks for your help

[Unabiker]

Here's a link to how I hold my stuff down. I go into it in detail about 3/4 of the way down the page:
Home Brewed vibratory finisher

[drape]

Thanks,

The bikes are great.

If we were to go with an MDF and double stick tape method (easy, few fumes) how could we remove the double stick tape without flame? Some kind of soap?

Thanks.

[Unabiker]

The easiest way to remove parts held with double stick would probably be to wedge a chisel under a corner of the part and gently pry them up. Clean up the remaining goo with mineral spirits, or Goo-gone if fumes are an issue.

[drape]

ok got it. two last questions. really.

1) Which kind of double stick tape is the one to get? what brand and where to get it.

2) We're only going to be milling 18"x24" sheets as a maximum size. how much tape do we need on the sheet? cover the whole thing? several small pieces?

[ImanCarrot]

Carpet tape is good, I leave a gap the same width as the tape width between each "stripe" of tape.

WD40 is good for making it unstick. Use a wedge and gentle but steady pressure to separate the bits. Acetone is no good- just smears the sticky stuff all over your component as does Methanol.

Oh, if you're using coolant make sure it dun attack your sticky stuff otherwise body armour may be adviseable as your part lauches itself at 3000 RPM inevetably towards your delicate bits!

Personaly I'd double tape it to just an aluminium sacrificial plate and clamp this to the machine using standard clamps... not too sure how sticky tape would adhere to MDF. Also... coolant would make MDF swell up surely?

[mxtras]

Also... coolant would make MDF swell up surely?

As does WD-40!

Scott

[Unabiker]

Something else to consider when using WD40 to help loosen up double stick; MDF will absorb WD40, which in turn will make it much less sticky then next time you go to stick anything down.
For an 18"x24" piece, I would blow 6 to 8 holes in the material in scrap areas, run some drywall screws through said holes in to the MDF, and machine away. Use some tabs to keep the parts connected to the scrap to keep things from flying around.