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I'm a partner in a plastics manufacturing facility (injection molding, thermoforming). 3D printing has been big for us. No, we don't make money directly from i

I'm a partner in a plastics manufacturing facility (injection molding, thermoforming). 3D printing has been big for us. No, we don't make money directly from it, or not very much. And it's extremely expensive per unit. But it allows us to design a part for injection molding, and then iterate it many times until we are happy with the functionality of it. Once we commit to an injection mold, it might be $15k or $30k to get it made, and it'll take 6 months. But we know that the fit will be nearly perfect by the time those first shots come out. Then we can roll with making thousands or hundreds of thousands of parts per day at the efficiency of scale. The way that 3D printing is used by hobbyists looks fairly different than the way it's used in industry. In industry, we're mostly still using traditional design-for-manufacturing principles for the prototype: for example, we're designing it so that it could be injection molded and ejected properly from a mold, even though the 3D print doesn't need that. That's because our intent is to merely confirm what we see in Solidworks in the real world, and to show a customer an idea in their hands in the shape and form it'd actually be produced at scale. I'm not compelled by the idea that 3D printing is going to make a big difference by allowing very small runs of parts (except for prototyping in the manner above). That's because like everything, there is a power law when it comes to parts. Nearly all the revenue comes from medium and higher volume products. Sure, it's useful in niche applications, and for things like jigs, but as much as people love to talk about the power of long tails, it rarely is as good a fit to the real world as the power law. But the idea that 3D printing is making a big difference in improving the design and innovation with those medium to higher volume products made with conventional manufacturing methods is absolutely true.

hinkley 4y ago
Why does it take so long to make molds? Has prototyping reduced the number of molds you have made? Has that decreased the wait time, or are more people making molds and so the wait time is now increased instead?
- analog31 4y ago
  I've worked in the plastics industry. A lot depends on the kind of mold of course. A mold can be somewhat complex when all is said and done, and made from a combination of parts that have to be ordered, or materials that are difficult to work such as hardened steel. Producing multiple pieces that fit together correctly and aesthetically can be an art. Whether the mold actually works in your machine without problems depends on the quality of the mold maker. And it could boil down to the fact that mold making is a mature industry with a lot of established supply chain and lead time expectations, and nobody is trying to rock that boat. Of course you don't want to spend all of that time to get a mold that you can't use because you screwed up on your end and forgot to add a needed feature. The world has not moved away from the benefit of a physical object that you can hold in your hand and see that it's actually right. And the 3d printed prototype can also let you check other things while the mold is being made, such as the fit of things like circuit boards, buttons, and connectors.
- mediaman 4y ago
  Molds are surprisingly complicated. They weigh 1,000 pounds or more; some molds we have weigh 10,000 pounds. They're made of high grade tooling steel that must be annealed to the right hardness and ductility. At each injection, they are subject to pressures of 25,000 pounds per square inch, and this happens every ten seconds 24/7 for the duration of the run (which can be weeks or months). Over time, plastic cuts into the steel, like water on rock in a canyon. So it takes lots of milling time, because tool steel can't be cut fast, like wood or aluminum. The molds also have to be machined to high tolerances. Take vents as an example. Vents allow the ambient air inside a mold to escape as plastic fills, but they must not allow the plastic to escape out the mold on the same route, so they must be machined to a tolerance of around 3 tenths of a thousandth of an inch. That in turn requires high precision CNC machining over fairly large spans, and with many subassemblies to make sure the two halves fit together just right. Some kinds of molds can be completed faster. Usually smaller parts, or parts where a base size of a mold has already been completed and you are just using inserts. Or if the mold is not expected to last very long, it can be made out of weaker material, which also cuts faster. I think there are some interesting software opportunities to improve mold build lead times. I suspect some of the design of the molds could be more procedural and automated than they are. That would help cut down the engineering time. And some people are exploring 3D printed molds, which is a cool idea, but currently they are very weak and not useful for production because nobody yet has figured out a way to 3D print high grade tool steel. 3D printing has actually likely increased the number of mold designs we're doing, because it makes it easier to innovate and iterate, and easier for a customer to feel comfortable with a design and move forward with it. It reduces customer utility and engineering risk, and so cuts the total cost of product development.
stavros 4y ago
> I'm not compelled by the idea that 3D printing is going to make a big difference by allowing very small runs of parts On the contrary, that future has been here for years. I print a ton of stuff for me (I'm printing one now!), they aren't prototypes (as in, I won't eventually make them "from something else"), they are the final part. 3D printing has enabled me to have custom parts, to my exact specifications, in record time, for pennies. It's amazing. Of course it's not going to make a difference to your revenue, the entire point is that, with a 3D printer, I don't have to come to you at all.
- mediaman 4y ago
  Don't get me wrong - I love 3D printing! I use it myself to make enclosures for electronics projects, or to replace parts that have broken on my old sailboat, which happens often. Notably, I don't turn to my business to injection mold these parts, because it makes no sense to make a mold for one part! Without 3D printing, I'd probably have someone mill custom parts, which is a lot more expensive. But I'm a realist. Look at the total poundage of all resin sales to the 3D print market. It would be generous to call it a rounding error in comparison to conventional resin sales. People like you or me are not the norm. The market for conventionally produced high volume parts is enormous compared to hobbyists 3D printing stuff at home. That's because most people consume the same small set of products repeatedly, and they care about cost, and some of my machines produce at a rate of ten parts per second with part weights 90% less than what's feasible with 3D printing. It's just the way markets work: most volume is accounted for in a small percentage of products, and engineers will always be able to get much more efficiency out of a specialized machine designed for a small number of high volume items than a general purpose machine that can produce anything.
  - stavros 4y ago
    Of course, no argument there. But the fact that printing presses produce most of the world's printed paper doesn't mean inkjet isn't useful. I guess it depends on how "plug and play" printers can become, right now they are pretty fiddly. Still, I think their growth is pretty healthy, even if not every home has one.

hinkley 4y ago

Why does it take so long to make molds? Has prototyping reduced the number of molds you have made? Has that decreased the wait time, or are more people making molds and so the wait time is now increased instead?

analog31 4y ago
I've worked in the plastics industry. A lot depends on the kind of mold of course. A mold can be somewhat complex when all is said and done, and made from a combination of parts that have to be ordered, or materials that are difficult to work such as hardened steel. Producing multiple pieces that fit together correctly and aesthetically can be an art. Whether the mold actually works in your machine without problems depends on the quality of the mold maker. And it could boil down to the fact that mold making is a mature industry with a lot of established supply chain and lead time expectations, and nobody is trying to rock that boat. Of course you don't want to spend all of that time to get a mold that you can't use because you screwed up on your end and forgot to add a needed feature. The world has not moved away from the benefit of a physical object that you can hold in your hand and see that it's actually right. And the 3d printed prototype can also let you check other things while the mold is being made, such as the fit of things like circuit boards, buttons, and connectors.
mediaman 4y ago
Molds are surprisingly complicated. They weigh 1,000 pounds or more; some molds we have weigh 10,000 pounds. They're made of high grade tooling steel that must be annealed to the right hardness and ductility. At each injection, they are subject to pressures of 25,000 pounds per square inch, and this happens every ten seconds 24/7 for the duration of the run (which can be weeks or months). Over time, plastic cuts into the steel, like water on rock in a canyon. So it takes lots of milling time, because tool steel can't be cut fast, like wood or aluminum. The molds also have to be machined to high tolerances. Take vents as an example. Vents allow the ambient air inside a mold to escape as plastic fills, but they must not allow the plastic to escape out the mold on the same route, so they must be machined to a tolerance of around 3 tenths of a thousandth of an inch. That in turn requires high precision CNC machining over fairly large spans, and with many subassemblies to make sure the two halves fit together just right. Some kinds of molds can be completed faster. Usually smaller parts, or parts where a base size of a mold has already been completed and you are just using inserts. Or if the mold is not expected to last very long, it can be made out of weaker material, which also cuts faster. I think there are some interesting software opportunities to improve mold build lead times. I suspect some of the design of the molds could be more procedural and automated than they are. That would help cut down the engineering time. And some people are exploring 3D printed molds, which is a cool idea, but currently they are very weak and not useful for production because nobody yet has figured out a way to 3D print high grade tool steel. 3D printing has actually likely increased the number of mold designs we're doing, because it makes it easier to innovate and iterate, and easier for a customer to feel comfortable with a design and move forward with it. It reduces customer utility and engineering risk, and so cuts the total cost of product development.

stavros 4y ago

> I'm not compelled by the idea that 3D printing is going to make a big difference by allowing very small runs of parts On the contrary, that future has been here for years. I print a ton of stuff for me (I'm printing one now!), they aren't prototypes (as in, I won't eventually make them "from something else"), they are the final part. 3D printing has enabled me to have custom parts, to my exact specifications, in record time, for pennies. It's amazing. Of course it's not going to make a difference to your revenue, the entire point is that, with a 3D printer, I don't have to come to you at all.

mediaman 4y ago
Don't get me wrong - I love 3D printing! I use it myself to make enclosures for electronics projects, or to replace parts that have broken on my old sailboat, which happens often. Notably, I don't turn to my business to injection mold these parts, because it makes no sense to make a mold for one part! Without 3D printing, I'd probably have someone mill custom parts, which is a lot more expensive. But I'm a realist. Look at the total poundage of all resin sales to the 3D print market. It would be generous to call it a rounding error in comparison to conventional resin sales. People like you or me are not the norm. The market for conventionally produced high volume parts is enormous compared to hobbyists 3D printing stuff at home. That's because most people consume the same small set of products repeatedly, and they care about cost, and some of my machines produce at a rate of ten parts per second with part weights 90% less than what's feasible with 3D printing. It's just the way markets work: most volume is accounted for in a small percentage of products, and engineers will always be able to get much more efficiency out of a specialized machine designed for a small number of high volume items than a general purpose machine that can produce anything.
- stavros 4y ago
  Of course, no argument there. But the fact that printing presses produce most of the world's printed paper doesn't mean inkjet isn't useful. I guess it depends on how "plug and play" printers can become, right now they are pretty fiddly. Still, I think their growth is pretty healthy, even if not every home has one.