3M double-sided tape



sorry, but I can't imagine how you would negotiate all the problems machining with tape to hold your part;
What problems would those be? Have you ever tried it? Maybe you need to stretch your imagination a bit...
Certainly it's not for production runs of a lot of parts, the time involved in taping and untaping would be too long. But for prototypes or short runs of certain kinds of parts, it can be the only reasonable alternative to long fixturing times.
I have machined all kinds of parts with tape over the years, aluminum, plastics, wood... I agree a good baseplate is important, I used solid acrylic bases for machining aluminum and acrylic parts, REN for most other things. It's important that you squeeze down the parts to get max adhesion, I have some t-slot clamps that work well. Another thing to do (if you can) is to drill holes and put pins in the base that absorb the side force on the part while machining. The tape then just has to resist the vertical pull-up forces. When you're done, blow off the extra liquid and then douse the part with alcohol. Wait a few minutes and start prying it up with a short bladed putty knife...
--moi
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David Janes, the Pro/E guru. Fancy seeing you here at AMC.<BR>&gt;<BR>&gt; I got stuck with setting up a model shop, otherwise you probably wouldn't see me around AMC. I was there a while ago asking about a post processor for a Bridgeport XV-710 with a Fanuc 0i-MC controller (with less success).<BR>&gt;<BR>&gt; I've started using something called Mitee-Grip, which is a heat<BR>&gt; activated adhesive film. You heat your part when you're done to pull<BR>&gt; it off. I've even used it in limited production of parts with low<BR>&gt; surface area without too much problem.<BR>&gt;<BR>&gt; I heard of this stuff a long time ago, never tried it so thanks for the reminder.http://www.miteebite.com/products/mitee_grip_e.html <BR>&gt; This says heat on an electric hot plate or griddle. How do you heat yours? The safety committee would probably be less concerned with a heat gun than a hot plate.<BR>&gt;<BR>&gt; I also like super glue. It is strong and stiff, but when you get under<BR>&gt; it with a chisel if pops off clean. I use a piece of high density REN<BR>&gt; (5169) that is bolted to the table and given a skim cut. The glue<BR>&gt; usually sticks to it better than the metal or plastic part, so the<BR>&gt; part usually pops off clean. Then I just face it again for the next<BR>&gt; part. I've milled everything from PVC to stainless steel this way.<BR>&gt;<BR>&gt; Gluing to REN sounds like a good idea. When I tried it a couple months ago, I glued an aluminum block to an aluminum plate. It was a bitch to get off and left most of the glue on the part. The piece I made was a "brick", but for thin bottomed parts, I anticipated bending problems. Maybe the REN base plate would take care of that. I just got the REN for exactly that purpose so I'll have to test a variety of adhesion methods.<BR>&gt;<BR>&gt; David Janes<BR><BR>sorry, but I can't imagine how you would negotiate all the problems<BR>machining with tape to hold your part;</BLOCKQUOTE> <DIV>This is about numbers and investigation. And, yes, there are drawbacks, limitations, complications &amp; accomodations. But, first off, lets deal with the most common misconception regarding workholding with tape~it couldn't possibly be strong enough. Again, let me emphasize, it's about the numbers, and these numbers come down to material removal forces&nbsp;vs holding power. Large cutters, deep cuts, heavy chip loads require maximum holding power; small cutters with shallow depth of cut and low chip load could be hand held (done all the time in sanding, grinding,&nbsp;buffing and polishing).</DIV> <DIV>&nbsp;</DIV> <DIV>So, lets get some numbers on the table. Let's say, you're holding down a 12 inch square part with three one inch strips of tape. And, let's say the tape has a pull off strength of 30 psi which is 30x36=1080 lbs. Now, you are looking for a cutter which, if slammed against the side of this plate (not rotating/cutting), would dislodge the plate before breaking. What diameter cutter would that be? Carbide? HSS? Your choice. Then double it for your roughing cutter, running at a reasonable cutting rate and you'll never have a problem of unanticipated part separation. The only time I've ever had bad results is when trying to cut tall, skinny parts, patterned on a large plate when I cut through to the tape. Generally, if I'd&nbsp;set tools to the tape and stayed .002 above, I had no problem. And, recognizing the holding limitations on tall, skinny parts, you make accommodations, you reduce cutting forces by lessening cutter size, depth of cut and chip load.</DIV> <DIV>&nbsp;</DIV> <DIV>David Janes</DIV></BODY></HTML>
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On Jan 10, 5:51pm, snipped-for-privacy@gmail.com wrote:

Oh yeah man. Tape is great compared to just using a vacuum. And we machined hundreds of thousands of pounds of plastic last year using nothing but vacuum to hold it down. No edge pins or anything. And that's *feeding* at 1,800 IPM... Its all about the surface area, the height of the part, and avoiding cuts that lift the part.
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snip
Setting up a model shop, hell, I wish I was saddled with such a "bummer" project. I've never used an Oi-MC, but I've had good luck with an O-M C just using a default Pro/E post, #12 I think...


This says heat on an electric hot plate or griddle. How do you heat yours? The safety committee would probably be less concerned with a heat gun than a hot plate."
I clean both parts, roll out some of the sheet and sandwich it between my material and the REN, I then heat the material with a propane torch (moving quickly) until the adhesive melts (under 200F) then I set a weight on it until it cools. Your safety committee probably wouldn't like that too much...
The ability to remove something thin without bending it is nice. Down sides are the goop is too thick for extremely tight thickness control in Z, the bond strength isn't that high, and it can leave a residue that needs to be removed (don't try to remove it in a tumbler, mucks up the media).


When using an aluminum sacrificial table surface I clean the part with a coolant damp towel, and I clean the fixture with acetone. The glue stays on the fixture, the part usually stays clean. When using REN, I skim it dry and blow it off with air. Again, the glue favors the fresh REN.
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got stuck with setting up a model shop, otherwise you probably wouldn't see me around AMC. I was there a while ago asking about a post processor for a Bridgeport XV-710 with a Fanuc 0i-MC controller (with less success). "<BR><BR><BR>Setting up a model shop, hell, I wish I was saddled with such a<BR>"bummer" project.</DIV> <DIV>&nbsp;</DIV></BLOCKQUOTE> <DIV>Sounds good, doesn't it. Dream job, really.... if you have management support. If you're not fighting them constantly,&nbsp;every time they doubt your competence, every grand that's spent, with no plan, no vision, no budget. The CNC arrived on the loading dock, Jan '07,&nbsp;in time to get accounting another line item of capital expenditure for '07. But, it was almost 6 mos before management decided where to put it and to "make ready". That's just the tip of the iceberg. "The rest of the story" would take volumes that a better man would have quit over. And I've basically given up a design career for this horse manure. Yeah, it's been loads of fun. Hey, it's in Sunny San Diego... I'll send them your Resume (maybe make a couple grand for a referral). My boss keeps saying they're going to hire somebody to do the job. Yeah, sure, once I get them to the place where they can hire a cheap, button pushing zombie. No, forget sending the Resume, you're WAY overqualified.</DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV>&nbsp;</DIV> <DIV>&nbsp;I've never used an Oi-MC, but I've had good luck<BR>with an O-M C just using a default Pro/E post, #12 I think...<BR><BR></DIV></BLOCKQUOTE> <DIV>I am about to revisit the post processor question. I'll take a look at the output of #12. I know what code I'm looking for. Ideally, I'd be making my own with G-post. Any experience with this? Pointers?</DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV><BR><BR><BR>&gt;"I heard of this stuff a long time ago, never tried it so thanks for the reminder.<BR>This says heat on an electric hot plate or griddle. How do you heat<BR>yours? The safety committee would probably be less concerned with a<BR>heat gun than a hot plate."<BR><BR>I clean both parts, roll out some of the sheet and sandwich it between<BR>my material and the REN, I then heat the material with a propane torch<BR>(moving quickly) until the adhesive melts (under 200F) then I set a<BR>weight on it until it cools. Your safety committee probably wouldn't<BR>like that too much...</DIV> <DIV>&nbsp;</DIV></BLOCKQUOTE> <DIV>I used to do the sandwiching but also applied Kant-Twist clamp. This was especially useful with tape. You could see the effect through Lexan. I think I'm gonna try a Milwaukee heat gun on the Mitee-Grip: no explosion hazard, no cylinders to go empty, better temp control. Although, yeah, I really do like fire! And the little pop it makes when you light it.</DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV><BR><BR>The ability to remove something thin without bending it is nice. Down<BR>sides are the goop is too thick for extremely tight thickness control<BR>in Z, the bond strength isn't that high, and it can leave a residue<BR>that needs to be removed (don't try to remove it in a tumbler, mucks<BR>up the media).<BR><BR></DIV></BLOCKQUOTE> <DIV>But Z depths are probably good enough for prototypes. And&nbsp;they are machine accurate from one depth to another on the same operation.</DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV><BR><BR>&gt;"I glued an aluminum block to an aluminum plate. It was a bitch to get off and left most of the glue on the part"<BR><BR>When using an aluminum sacrificial table surface I clean the part with<BR>a coolant damp towel, and I clean the fixture with acetone. The glue<BR>stays on the fixture, the part usually stays clean. When using REN, I<BR>skim it dry and blow it off with air. Again, the glue favors the fresh<BR>REN.</DIV></BLOCKQUOTE> <DIV>This is all good stuff.</DIV> <DIV>&nbsp;</DIV> <DIV>Muchas gracias, Seor!</DIV> <DIV>&nbsp;</DIV> <DIV>David Janes</DIV></BODY></HTML>
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<DIV>I've used tape before to hold stock to a fixturing plate, so I know this method works for holding raw stock. What I don't know is any of the technical specs. These were based on holding plate to plate, aluminum plate base holding a variety of materials, mostly aluminum, but also ABS, Delrin, REN, Polycarbonate, and the like, no steel, so no exotic alloys. I did all this with strips of 1" wide double sided tape, sometimes full coverage, sometimes half. What I have no idea of is which, of the hundreds of such tapes 3M sells, would be adequate for my purposes. Also, coolant's involved, esp for aluminum. Anyone use such a tape? I'm on a number hunt. ENGINEERING! IT'S ALL ABOUT THE NUMBERS. It's our daily bread, the bed we lie on, the air we breathe, the car we drive in, the food we eat, the house we live in, the products we buy.</DIV> <DIV>&nbsp;</DIV> <DIV>David Janes</DIV></BLOCKQUOTE> <DIV>Thanks to all who participated including those skeptical of workholding with tape/glue/wax/etc. Your help and encouragement are invaluable.</DIV> <DIV>&nbsp;</DIV> <DIV>Muchas gracias, Compaeros!</DIV> <DIV>David Janes</DIV></BODY></HTML>
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