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3-D printed injection moulds may soon become a reality. They're already here for small parts and short production runs. With metal 3-D printers now a reality, as sizes increase, I can see a 3-D metal-printed mould capable of producing a full-detail kit within the next decade, or even less at the rate things are progressing.

Charlie Larkin

https://formlabs.com/blog/3d-printing-for-injection-molding/?utm_source=direct&utm_medium=email&utm_campaign=contentnewsletter-12-20&mkt_tok=eyJpIjoiWTJOaFpUWmhNREZsTXpsbCIsInQiOiJCOUVsZFdDa1JYeENPTU5Pd1pIWElcLzlNa2g2WkE4STZjUHFCUVZtcGdRVUNwOWZ1VnBjR0x4eWhoU2VMU3B6MG1CS0tcL1BnTWVheit3R0NNdU9oQm82cGR6VTN2aUVGNWp0Vll1QkNmTnRqcDZZY2JxRGVtSUNNMVVtYW8rTTRXckVTaHJ4dHpqM2dkOUEyeGoyUm9sUT09In0%3D

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3 hours ago, 1930fordpickup said:

Short runs of a 1000 makes this an interesting option for some subjects. I wonder what kind of tolerance they can hold.  A station wagon mold of a 70's car or other low production models would be good for this. 

The plastic moulds...tolerances may be relative, but for probably 200-300 kits, given the shapes, etc. they'll be dealing with, they're still a good deal. A full-detail kit mould would only run about $3,000 to print in high-strength plastic, and maybe another couple hundred for a machinist to clean up. Even if you had to make 3-5 copies of the moulds, you'd still be cutting mould cost by at least half for the machining alone (not counting other development costs, and even they could be reduced substantially, as I think curbside kits, or kits with low parts count would be best.

The moulds made from A2 steel should do okay. 3-D A2 steel, from what I'm told, has all the strength and working characteristics of conventional steel except it can't be welded. It can be tapped, threaded, drilled, machined, polished and painted. The major issue with the steel right now is (1) the prices of the printers are still pretty high, and (2) they can't print stuff that's all that big yet.

Charlie Larkin

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On 1/19/2021 at 6:40 PM, charlie8575 said:

The plastic moulds...tolerances may be relative, but for probably 200-300 kits, given the shapes, etc. they'll be dealing with, they're still a good deal. A full-detail kit mould would only run about $3,000 to print in high-strength plastic, and maybe another couple hundred for a machinist to clean up. Even if you had to make 3-5 copies of the moulds, you'd still be cutting mould cost by at least half for the machining alone (not counting other development costs, and even they could be reduced substantially, as I think curbside kits, or kits with low parts count would be best.

The moulds made from A2 steel should do okay. 3-D A2 steel, from what I'm told, has all the strength and working characteristics of conventional steel except it can't be welded. It can be tapped, threaded, drilled, machined, polished and painted. The major issue with the steel right now is (1) the prices of the printers are still pretty high, and (2) they can't print stuff that's all that big yet.

Charlie Larkin

Charlie I have no idea what the cost of the printed molds would be. But Machinist cost to clean them up will be a lot more than a few hundred dollars. Just as you  said still cheaper than cutting steel molds for short run subjects. The bodies alone for use on existing chassis would be great  Cabs for Semi's 

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2 minutes ago, 1930fordpickup said:

Charlie I have no idea what the cost of the printed molds would be. But Machinist cost to clean them up will be a lot more than a few hundred dollars. Just as you  said still cheaper than cutting steel molds for short run subjects. The bodies alone for use on existing chassis would be great  Cabs for Semi's 

With conventional machining, you're correct.

3-D metal prints fairly smooth, so the the only thing you need to do is what would amount to the final polish, and maybe a small amount of clean-up/adjustment. Not sure, but around here, machinists charge around $40-50/hour, or more if it's a specialty shop.

Charlie Larkin

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15 hours ago, Brian Austin said:

What's the advantage of printing molds vs. just printing out the parts?

I would think speed (quantity) and quality.
 

Even very good printed parts still have visible layers. A final polish on a printed mold would clean that for injection.

Injection molding is fast enough to do at a production rate for the size and quantity of parts/sprues needed for an entire kit. 
 

Correct me if I’m wrong. 

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Yes and no. It is a visible layer on a smooth surface. If you were to take a fingernail and scrape over it, you would not feel anything but smoothness. If this was printed with a more transparent resin, you would see lots of layers. The printer prints in layers. Take a look at the trunk deck and fenders which have a much greater slant then the cowling. Do you see layers? Just because you can see a layer doesn't mean the surface isn't smooth. A person would have to be into 3d printing and actually do it and understand it to know how it works.

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