Worlds first DIY injection molded Playmobil sword with 3D printed mold – proof of concept

Over the last couple of weeks I have been toying around with the Form 1+ and my manual injection molding machine (IASCO 66M). This is because from the very beginning of my project/blog I wanted to find out if with my limited manufacturing knowledge and my shoe string budget I would ever be able to bring injection molded weapons for Playmobil figures to life.

On my journey I have

– visited local injection molders (their offer was 15.000 Euro for a 6 cavity mold)

– had talks with specialized companies at Euromold (they first pushed back on my request due to the nature of weapon production and finally their 4 cavity mold offer was around 7.500 Euro)

– requested quotes from Protomold (their quote for the 2 cavity mold was 3.700 Euro)

All of this was unsatisfactory because the initial payments that needed to be made were a lot bigger than my tiny budget and the costs per unit only came down to 1 Euro per part if I ordered 1.000 units in one production run. Not quite what I had dreamed of.

But my experiments with a couple of 3D printers over time brought me closer to the final goal of having injection molded products in my hands (and time was on my side as well as time drove down the costs of prosumer printers heavily). When Stratasys showed their first Digital ABS which was able to produce plastic spoons in a professional injection molding machine I knew my time would come.

With all the knowledge gathered and all frustrations I have had during my project today I can announce that I have accomplished the first major milestone in my project.

I have managed to INJECTION MOLD a Playmobil-sized sword with a simple 3D printed mold from my Form 1+!!

Woooohooooo!!

Potentially the worlds first sword/product of its kind 🙂

The credit for the sword belongs to the people behind Modibot by the way. I only scaled it down for my purposes.

SLA 3d printed mold from prosumer printer with Polypropylen

SLA 3d printed mold from prosumer printer with Polypropylen

With this I have proven that anyone with time, willingness and some frustration intake can go from the idea to an semi-professional product without the involvement of exorbitantly high costs. From my point of view manufacturing of a product can now be similar to CTP (computer-to-plate) magazine publishing.

To understand and manage the injection process it took me 4 tries – each one producing better results

No1 left - too low temperature and pressure No 2 left - good temperature, too low pressure No 3 left - good temperature and pressure, too low clamp force 4. left - near perfect conditions

No1 left – too low temperature and pressure
No 2 left – good temperature, too low pressure
No 3 left – good temperature and pressure, too low clamping force
No 4 left – near perfect conditions for temperature, pressure, clamping force

Only the injected material Polypropylen is not sturdy enough and a lot more flexible than ABS. But on the other hand PP is easy to inject at temperatures of around 550 degrees Fahrenheit (290 Celsius).

Final sword - sprue cut off and flesh trimmed

Final sword – sprue cut off and flesh trimmed

Now I need to find a way to get ABS pellets and how to increase the heat in my injection machine. As I said the first major milestone is reached!!! My journey continues (and I have some surprises for new weapons for you… 🙂 )

Polypropylen is a lot more flexible than ABS plastic

Polypropylen is a lot more flexible than ABS plastic

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3 responses to “Worlds first DIY injection molded Playmobil sword with 3D printed mold – proof of concept

  1. Hi there,
    I saw your post in formlabs forum, and I was actually thinking along the same line. I wanted to try myself, but haven’t got the chance to do it. Just very curious, did you try more injection attempts? I am wondering how many shots you can use the resin mold before it breaks. Also, have you ever tried other materials? ABS can be injected at a relatively low temperature (< 60 Celsius). I am like you, don't have any background in manufacturing but just like to see what's the limit of this 3D printing.

    p.s. which desktop injection molding machine did u use? I will probably get the same one. Thanks!

    Best,
    Werner

    • Hi,
      thanks for your comment.
      Currently I have done 9 shots with the same 3d printed resin mold and the cavity of the mold is still very detailed and good (as long as you take a separation spray to prevent the hot plastic to stick to the resin). Only on the outside of the mold where the hot injection nozzle touches the resin I have burns and cracks but this is due to the high temperature of 230 Celsius (450 Fahrenheit).
      Please don´t be mislead with ABS – this is a plastic that needs a temperature of 220–250 °C to be ideal for injection mold and have the needed material flow. If you have lower temperatures you need much higher pressures to get the ABS through all tiny channels and into the complete cavity. This will damage the cavity very quickly. But so far I have not tried ABS.
      Please be aware that ABS at 220–250 °C is emitting some toxic fumes and you would like to wear an appropriate mask to protect yourself. Please think about Face shield, glove and long shirt as well because if you blow up the resin mold you can get severe burns of your skin.

      By the way the injection molding machine is a IASCO 66 M (bought it used and cheaply on Ebay) – you can probably order it here https://www.labvolt.com/solutions/8_technology_education/17-40503-00_iasco_66m_manual_injection_machine
      If you google Makezine and injection molding machine you can find a DIY instruction to build one.
      But you can also buy machines from Galomb Inc or Techkits.

      Let me know if you have any other question.

      Best
      Bernd

  2. Cool! I am setting up my thing to try one. What is the critical thickness? (from the injected space to edge of the mold, so that the mold is strong enough and not crack) Is there a rule of thumb to follow?

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