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Injection mold size limit?


This topic contains 4 replies, has 5 voices, and was last updated by  Edward 2 years ago.

Rob Jameson complete

Injection mold size limit?

08/04/2017 at 00:30

Hi Everyone!

I’m interested in making the injection moulder and making a part that is larger than I’m seeing in Daves videos. I’m wondering if people have tried to make larger plastic parts with this? How big were they? What were results?

My part is approx 8 inches by 8 inches by 5 inches. Do you think that size will work??

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07/05/2018 at 19:39

Has anyone thought of making a double injection for larger molds? i.e. 2 barrels pushing plastic into the mold?

05/05/2017 at 12:05

With the standard blueprints you can inject 180cm^3 of plastic at once, so you can make a cube of 6x6x5cm.

You can use a bigger or longer barrel and then you increase the volume of the injection machine.

i hope this anwsers your question.

(radius^2 * pi * heigth of the barrel)
(13mm^2 * 3.1415 * 350mm = 185.000 mm^3) (but the top part is difficult to melt at once so to be save 180cm^3)

02/05/2017 at 16:11

Building on the previous answer, you could make the part using the injection moulder. The limiting factor in the size you can create comes down to the ability of being able to distribute the plastic before it cools back it’s rigid phase i.e., no longer flows.

By increasing the speed and temperature the plastic is being injected will aid with being able to introduce the plastic into the mould before it drops out of its transition/glass phase. With a larger mould, the resulting change in pressure from introducing a larger volume of plastic will impede both the quality of the part and the effoet required to inject the mould. Assuming a solid shape of the above mentioned dimensions, you’ll be best to have an atmospheric vent coming out somewhere in the mould if you wanted to fill it with plastic.

Another option which will allow yout to complete it slower would be to preheat the mould, or at least insulate it such that there isn’t such a sudden loss of heat.

Please post some photos when you’re done. Cheers!

10/04/2017 at 19:19

That question is too open to answer straight.
It has all to do with the design – i.e. can you get the liquid plastic to flow where it needs to go before it cools and sets.
As long a you have enough plastic in the patron and the power to get it out, a solid cube can always be made. A “hollow” cube with thin walls however will be a completely different story.

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