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I am an art rubber stamp maker, using a vulcanizer to make art rubber stamps from molds that are usually created with a magnesium plate.

The normal process is to send artwork off to an engraving firm to acid etch the magnesium plate (11 pt depth is desired) and that metal plate is then used with uncured matrix boards (a bakelight type material) that is "cured" in the vulcanizer that is then used over and over to make as many images of the rubber stamps as one would want. The vulcanizer heats up to 300 to 320 °F, and one usually uses 2000 to 2500 p.s.i. of pressure for 10 to 15 minutes to cure a mold. Once the mold is cured, it is impervious to the heat used in the vulcanizer, and the heat is used to cure the unvulcanized rubber (again, 300 or so degrees, 2000 psi, or so, for 8 to 10 minutes.

In reading up about the melting points of PLA and ABS, the 200 °C equates to around 460 °F, so there doesn't seem like the heat of the vulcanizer will be an issue, and the pressure isn't applied all at once, one usually allows the uncured matrix board to heat up before the high pressure is obtained, I'm just curious if any other stamp makers have had success with this method and/or have any suggestions about STL files for this type of printing, if there needs to be 2 or 3 degree shoulder angle added to the file configuration, or any other suggestions.

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    $\begingroup$ Having done this form of rubber stamp creation in high school, so many decades ago, I like to see that it's still around. Consider to use a hobby-grade CNC machine for your metal masters rather than a 3D printer. I expect you could use aluminum for the block rather than magnesium, although the wear factor would be higher. If 3D printing is still the focus, also research nylon SLS printing. Nylon melting point is 200°C but I don't know if it has a glass transition temperature. $\endgroup$ – fred_dot_u Aug 25 '17 at 9:49
  • $\begingroup$ A hobby grade CNC is still pretty damn expensive, my son has a new 3D printer, so the experiment here is to see if a plastic master can be made, if it will in fact work in the vulcanizer, and if so, then look into purchasing a machine for my own uses. Whether it is PLA, ABS, Nylon, or a PLA/metal hybrid, whatever works best would be of interest. I just read a little on glass transition, I'm not sure it would be an issue for what I'm trying to do. My use of the master shouldn't have any movement, other then vertical; maybe an issue. $\endgroup$ – B.Lyon Aug 27 '17 at 2:49
  • $\begingroup$ @B.Lyon: Only if around $200 is "pretty damn expensive". It's roughly the same price as you can get a good 3D printer for these days. Granted that's a lot more than "using something you already have", but it's nowhere near the inaccessibly-expensive this stuff used to be. $\endgroup$ – R.. GitHub STOP HELPING ICE Jul 22 '19 at 20:13
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This would likely not work. ABS has a glass transition temperature of 105 °C. It doesn't have a melting point because it's amorphous. Rather, as you heat the part up, it gradually transitions from a solid to a viscous liquid, but there is no "hard" transition from solid to molten at one particular temperature.

The glass transition temperature, at 105 °C, is significantly lower than the 200 °C "melting point" of ABS you quoted. At 160 °C, while ABS would not be molten sufficiently for 3D printing, it definitely becomes flexible and would deform easily.

I do not think it would hold its shape very well over the long period of time it has to spend in your vulcanizing machine, under high pressure and well above its glass transition temperature.

The surface of 3D printed objects also usually has a somewhat rough finish. If you wanted to make satisfactory stamps, you would probably need to spend a long time manually finishing the 3D printed master before making a mold from it.

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  • $\begingroup$ I wasn't sure which material would be best use, so apparently the ABS is out; possibly using PLA might work, or if the temperature is still iffy, maybe a metal/PLA hybrid would do the trick. I'm not too worried about the possibly "rough" finish of the 3D object, since what I am wanting to do is to make a 3D relief object from a 2D artwork image. The only part that is important is for the top surface of the 3D item to be smooth (that would be the artwork image part) which would then be used to make the mold. Buffing out the sidewalls could be done with a Dremel, if needed. Thanks. $\endgroup$ – B.Lyon Aug 27 '17 at 2:22
  • $\begingroup$ The glass transition temperature of PLA is even lower than that of ABS. It's around 65C. PLA can melt and deform if it's left in a car on a hot day. I think that to get this to work, you'll need to use an exotic material such as PEEK (which is very expensive, and challenging to print with). $\endgroup$ – Tom van der Zanden Aug 28 '17 at 9:16
  • $\begingroup$ I'm pretty sure I understand the concern about the glass transition temps; I'm just not sure that it would be an issue, let me explain. The machine, a vulcanizer (mine, at least) looks similar to a bench top wood planer. The top plate (platten) is fixed, the bottom one sits on a heat sealed hydraulic jack that moves straight up and down. Both platens are heated up to around 315 to 320F. An uncured board is heated for a bit before the pressure is applied, then everything is held in place for 12 to 15 minutes. If I get one board out of a 3D print, everything is good. Thanks. $\endgroup$ – B.Lyon Aug 29 '17 at 6:49
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PEI filament has glass transition temperature higher than or close to 200 C. It is difficult to print with as it is printed about 350 C and requires heated chamber reaching to 90 C.

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  • $\begingroup$ Could you add something about how PEI is a suitable material for this application? $\endgroup$ – Trish Jul 22 '19 at 12:56
  • $\begingroup$ Upgrading to a printer that can print PEI is going to cost an order of magnitude more than a cheap CNC mill... $\endgroup$ – R.. GitHub STOP HELPING ICE Jul 22 '19 at 20:15
  • $\begingroup$ @Trish Well, he is basically looking for a plastic that can handle 160C. What more can I add? $\endgroup$ – Cem Kalyoncu Jul 23 '19 at 14:51
  • $\begingroup$ @R..: Sure it will be costly (not ten times as much though), but a cheap CNC mill probably will not be able to carve delicate (probably) patterns on a stamp. It is not difficult to convert a 3D printer to a cheap CNC mill, but results for routers < 1mm is less than stellar. Also running costs of CNC mill is quite higher than a 3D printer. $\endgroup$ – Cem Kalyoncu Jul 23 '19 at 14:55
  • $\begingroup$ @CemKalyoncu The only thing you are right about in regards to CNC is, that converting a printer to a CNC is not a good idea. For a tenth of the cost of a decent PEI-able printer (which start at about 3000 $), you can get quite decent micro-CNC mills that have sub-0.1mm accuracy - if they are extremely inacurate. Most will manage to get down to half or a third of that. $\endgroup$ – Trish Jul 24 '19 at 4:50
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I don't know if I understood your question properly. You using the mold to create a rubber stamp and then you use that to stamp over stuff? If so, you simply can use 3D printing to create the stamp, if not, my answer is rubbish.

You can use a flex material to create the stamp itself and then use some hard material to create the handle. Also, you can create a mold around the stamp and use resin to fill it and/or create a resin mold and then use that mold to create the stamps by filling the "holes" with more resin.

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  • $\begingroup$ The mold is used to create the same image multiple times; the product I am selling is the rubber stamp image itself, for consumers to use for their own creative uses. $\endgroup$ – B.Lyon Aug 27 '17 at 2:08
  • $\begingroup$ Ok, sorry! I misunderstood the question. $\endgroup$ – Luis Diaz Aug 28 '17 at 6:10

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