3 ms·

I do have experience in this area and all I can say is look at the market - injection moulded parts are literally everywhere. How often do you see 3d printed pa

by 6nf 7y ago

I do have experience in this area and all I can say is look at the market - injection moulded parts are literally everywhere. How often do you see 3d printed parts in commercial products?

kragen 7y ago
I see more blow-molded parts than injection-molded parts, but there sure are a lot of injection-molded parts. And the cup I'm drinking from is made by metal-spinning, filled with a drink poured out of a deep-drawn can with a stamped top. As for 3-D printed parts, I only see them occasionally in commercial products, but remember that low-cost 3-D printing is only about ten years old — a lot of product designs, and even more product designers, date from more than ten years ago. And even ten years ago 3-D printing prices were a lot higher than today, and there was no such thing as a US$1000 SLA machine, for example, or PETG filament, or PLA filled with wood or brass. So I think we're going to see a big move toward 3-D printed parts in the next decade or so as designers wake up to the new possibilities afforded by these processes. A few years ago the crossover where injection molding was cheaper might have been 100 parts, then 1000, and now it's 10000 — and that's when you can make the part at all by injection molding, with the extra weight, imprecision, and geometrical restrictions it adds. Maybe in another few years the crossover point will move to 100,000; but I fully expect to see designers trained in the 1980s and 1990s continuing to use injection molding even where 3-D printing would be a lot cheaper. What do you think about the questions I asked, about why some injection dies take multiple back-and-forth cycles over several months to get to the production rev instead of the one week you cited, and how that can be avoided?
- 6nf 7y ago
  The parts that CAN be 3d printed will never need multiple back-and-forth cycles because 3d printed accuracy is terrible compared to the tolerances required for some complex injection moulded parts. In fact using the moulding method your surface finish is accurate literally down the molecular level. (Of course since we're talking about plastic that doesn't mean the overall shape and dimensions are that accurate but that problem is just due to the material properties, not the process) Please note that I am ONLY talking about plastic parts. Every piece of electronics has many injection moulded parts. Show me one item in your house with a 3d printed plastic part? Sorry but you're just wrong about the future of plastic 3d printing machines. There's zero chance it will ever beat a cheap injection moulding machine pumping out 1000s of parts per hour. 3d printing of metal is completely different. That could be a game changer because we do not have good methods to mass produce complex metal parts. 3d printing of plastic is pointless as soon as you need more than 100 parts or so. Also note that your 'sterility' claim is wrong. Injection moulded parts are every bit as sterile as 3d printed parts. PLA can be used for injection moulding too, no problem at all.

by 6nf 7y ago

I do have experience in this area and all I can say is look at the market - injection moulded parts are literally everywhere. How often do you see 3d printed parts in commercial products?

kragen 7y ago

I see more blow-molded parts than injection-molded parts, but there sure are a lot of injection-molded parts. And the cup I'm drinking from is made by metal-spinning, filled with a drink poured out of a deep-drawn can with a stamped top. As for 3-D printed parts, I only see them occasionally in commercial products, but remember that low-cost 3-D printing is only about ten years old — a lot of product designs, and even more product designers, date from more than ten years ago. And even ten years ago 3-D printing prices were a lot higher than today, and there was no such thing as a US$1000 SLA machine, for example, or PETG filament, or PLA filled with wood or brass. So I think we're going to see a big move toward 3-D printed parts in the next decade or so as designers wake up to the new possibilities afforded by these processes. A few years ago the crossover where injection molding was cheaper might have been 100 parts, then 1000, and now it's 10000 — and that's when you can make the part at all by injection molding, with the extra weight, imprecision, and geometrical restrictions it adds. Maybe in another few years the crossover point will move to 100,000; but I fully expect to see designers trained in the 1980s and 1990s continuing to use injection molding even where 3-D printing would be a lot cheaper. What do you think about the questions I asked, about why some injection dies take multiple back-and-forth cycles over several months to get to the production rev instead of the one week you cited, and how that can be avoided?

6nf 7y ago
The parts that CAN be 3d printed will never need multiple back-and-forth cycles because 3d printed accuracy is terrible compared to the tolerances required for some complex injection moulded parts. In fact using the moulding method your surface finish is accurate literally down the molecular level. (Of course since we're talking about plastic that doesn't mean the overall shape and dimensions are that accurate but that problem is just due to the material properties, not the process) Please note that I am ONLY talking about plastic parts. Every piece of electronics has many injection moulded parts. Show me one item in your house with a 3d printed plastic part? Sorry but you're just wrong about the future of plastic 3d printing machines. There's zero chance it will ever beat a cheap injection moulding machine pumping out 1000s of parts per hour. 3d printing of metal is completely different. That could be a game changer because we do not have good methods to mass produce complex metal parts. 3d printing of plastic is pointless as soon as you need more than 100 parts or so. Also note that your 'sterility' claim is wrong. Injection moulded parts are every bit as sterile as 3d printed parts. PLA can be used for injection moulding too, no problem at all.