Brazing, heating and machining 3D printed items

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Fender
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Re: Brazing, heating and machining 3D printed items

Post by Fender »

Actually, a turnkey solution is available, from Shapeways. For example, here is “drawhead” design, which most people would call a “link and pin” coupler. This design was uploaded to the Shapeways site, and could be ordered in one of several materials. Here are the cost estimates from Shapeways:
5056BCDD-04F3-4DC4-8CF6-F9B0BB4A80B0.jpeg
Obviously, the bronze version is the most expensive. I believe it is, in fact, a lost-wax casting. The steel (bronze-infused) is much less, but still expensive. The plastic version is the cheapest, and could be used to make your own investment casting. Or, to be used as a pattern for a conventional sand casting with a pair of cores.
Dan Watson
Chattanooga, TN
apm
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Re: Brazing, heating and machining 3D printed items

Post by apm »

Anyone here care to venture a guess if one took the plastic part that Dan Watson posted what a foundry would charge to investment cast assuming they could work it like any other wax part? Dan how many cubic inches is that part $532 makes me wonder if it's really investment cast unless that thing is huge
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Fender
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Re: Brazing, heating and machining 3D printed items

Post by Fender »

A friend of mine was getting some custom valves made at Shapeways, made from bronze. Now, they are much smaller than this drawhead, and therefore much less expensive. But also, he needed a bunch of them, so the design sent to Shapeways replicated the valve multiple times, each of which was linked to the others by a bridging connector. Using this strategy will reduce the unit cost, since you are only ordering one “part” from Shapeways.
Last edited by Fender on Sat Jul 24, 2021 7:27 pm, edited 1 time in total.
Dan Watson
Chattanooga, TN
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Fender
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Re: Brazing, heating and machining 3D printed items

Post by Fender »

APM, the drawhead is about 21 cm**3 in volume.
Dan Watson
Chattanooga, TN
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Fender
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Re: Brazing, heating and machining 3D printed items

Post by Fender »

If were to order a part made from the bronze-infused steel that required tapping, I would consider making a bushing with the internal thread from bronze or steel in the lathe. Then drill an oversize hole in the part, and silver-solder the bushing into the hole.
Dan Watson
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Dick_Morris
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Re: Brazing, heating and machining 3D printed items

Post by Dick_Morris »

I'm don't know what types of plastics Shapeways offers, but regular resin does poorly in investment casting. It doesn't burn out cleanly and leaves ash behind. I've had good luck with PLA using a filament printer, but the prints aren't at the same level of detail as a resin printer.

One option would be to get your own resin 3D printer for $200-$300 and a liter of Siraya Tech castable resin for $75 and print your own. There is a learning curve, but the technology and knowledge base has advanced and it's a lot less steep than it was when I started a couple of years ago. I'm not sure what the price would be for the investment castings done or how easy it is to find someone to do them.

My Elegoo Mars 2 Professional is a $300 printer and prints can be as large as 5.08in(L)*3.15in(W)*6.30in(H) or 129mm(L)*80mm(W)*160mm(H).

Another option if several castings are needed is to make a rubber mold from the print and then use wax for the investment casting.
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