Why are industrial injection molders so big compared to hobby ones?

[BucketOfFish]

I was looking up plastic injection molders for a project, and I noticed that while benchtop injection molders can be very small, industrial ones weigh several tons and take up an entire room! What accounts for this difference in size? Is it simply the capability to apply more pressure, or is it perhaps the heating element? What is it in an industrial injection molding machine that makes it so big?

 

[tygerdawg]

"the capability to apply more pressure"

Yup, that's pretty much it.

Rule of thumb I learned for sizing molding machines: 5 tons of clamp force for every 1 square inch of projected area of the mold. Do the arithmetic to see how big a machine must be (in tons of clamp force) to mold something the size of a Dell laptop case. Or the hood of an automobile.

If one wants to mold something that large, then they also will probably require the capability of squirting a lot of plastic into that big mold cavity. That adds to the physical size because of the needed size of the injection screw.

 

[Bandit127]

There are also economic pressures on people (businesses) that make a living from injection moulding.

This tends to drive multiple cavity tooling and reduced cycle times.

Your bench top machine may be able to cope with a bottle cap. I wonder how long it would take to make one?

I was reading about the world record for caps yesterday. A 1.9s cycle time with a 96 cavity tool. This ran on a machine with 420 tonnes of clamp force.