3D Printed Injection Molds

A team at Budapest University has successfully created a functional injection mold for prototyping by using a Stratasys 3D printer.

Prototype injection molds are expensive. They are typically machined out of steel or aluminum which is both costly and time consuming, due to the complex geometries of most molds. [Dr. Jozsef Gabor Kovacs] works in the Department of Polymer Engineering at Budapest University, which is where he came up with the innovative approach of using 3D printing to produce a prototype mold.

The mold was printed in Digital ABS PolyJet Photopolymer plastic using a Objet Connex 3D printer. The injection material used was polyacetal; which has a fairly low melting point of 175°C. By using this method they were able to go from a prototype mold to a test part in less than 24 hours. We don’t even want to think about how expensive that would be to expedite from a machine shop.

After the break you can watch the entire production process from printing to molding.


[via adafruit]

28 thoughts on “3D Printed Injection Molds

  1. This is great, as long as you have the $250,000 3D printer they used and the injection molding machine. Also the material used to print the mold is ~$1200 per 3.3 kg container.

    Yes it is a great development but do this with a reasonably priced 3d Printer and I will be really impressed.

    1. This is totally possible with cheap 3D printers and ABS – I’ve seen it done using molds printed with standard ABS on an old cupcake and a benchtop HDPE injection molder. It is certainly functional, but injection molding into low-resolution molds gives low-resolution parts, and the wear on the mold is pretty extreme. At the time, my conclusion was it’s neat that it’s possible, but not worth more work on developing it.

      1. Yeah, i will have to be skeptic here as well.

        They are using very expensive 3D printer stuff… the DigitalABS (insert copyright and trademark symbol here)… http://youtu.be/uIbyYrqtMes?t=2m48s

        they advertise injection molds in their brochure for crying out loud… how does this “hack” carry any significance.

        It could very well read “Budapest University spends a lot of money in a product, and uses it for the intended purpose”

        hack my metal shiny ass.

        Now… if you want to contact the company from the video above and get more information on that exhaust header printed with that DigitalABS(tm) that they claim works in an actual car engine… then i will respect hackaday again :)

  2. For the price of that 3D printer (well, for a couple hundred grand less) it could be done with a good CNC setup. Heck, with 24 hours lead time you could do it with a conventional machine shop that would cost less than $250K including the building.

      1. Then you know why molds are made of metal instead of plastic. Production prototyping is not like EE prototyping. Your work is worthless if it does not use the exact same materials.

        This is neat but would cost more in the long run through failures, iterative processes, and rework loss which is why a university is doing it instead of a major manufacturer.

        1. I concur.
          Generally mold and die design is not a iterative process. We usually design the tooling based solely on the part drawing, and are expected to get it right the first time. With the dies I used to design, just about the only tweaking that had to be done was on the bends where my caluclated values didn’t jive with the reality of the materials we were working.

          My mold experience is fairly limited, I only worked on 4 molds, which were definately NOT prototype molds, updating the tooling for parts of the M-16A4, back in the 90’s. Injection molded plastic parts, which were then used for investment casting in steel. Hammer,trigger,peephole site. Gettting the shrinkage right twice was tricky. Colt didn’t desight the tooling, the military didn’t desigh the tooling, we did, same as all the other subcontractors.

          1. ^design
            forgive my typos, don’t quite know how I was hitting “H” instead of ‘N”

            I wonder what keeps turning off spell-check in firefox.? some script here?

    1. Agree, this sounds like the beginning of something. Of course the 3D printer they’d used puts it *way* beyond the financial reach of your average maker, but the concept could have a ripple effect.

      My feeling is that even if the precision is not so hot, there is room for low cost benchtop injection mold machines for makers which are able to crank out multiple of something in short-order. This is where the game-change will occur because no longer is it taking 23 hours for me to print each item, nor do I have the hassle of urethane and molds and such. Instead, I do one print, a mold, and then I can crank out 10 or 20 or 50 of something that makes it financially viable to sell. Sure, it’s not full-scale production quantities – not even small scale – but it’s a chance to seed a market with something that will hold up better than printed plastics and which will enable me to generate the income necessary for proper tooling and production quantities after the concept has been aired a bit.

      Let’s not forget how wide the chasm between production and prototype and imagine a chance to insert a “middle of the road” solution in there that adds one more step to make the leap a little more manageable.

    1. Define mass production. With the amount of effort it looked like it took them to de-mold, you might get 12 pieces an hour. And then when does that mold fail or cease to produce usable parts due to wear?

  3. Surely the point is to sidestep manufacturing processes like injection moulding? That’s the big step forward.
    Incidentally most of the cost benefit analysis above is plain wrong as it doesn’t take into account the long term payback. How much would the 70th mold cost? Still the full cost of the machine? Pull the other one. Though working in current mold manufacturing would seem to be a bias.

    Still want a 3d printer. Still haven’t found an optics application that will justify it!

  4. Serious question… what’s stopping someone from 3d printing an object, making a 2 part mold if it, then inject hot plastic into the concrete mold? How well does concrete stand up compared to steel in injection molding process?

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