Aluminum mold for small HDPE prototype part

[Ingenuity]

I am new to the world of polymer prototyping and mold making, so any assistance to the following is much appreciated.

I am tasked with making a small number of HDPE components for an end-use of corrosion protection to a small steel structural component.

I have machined an aluminum mold (2 piece mold) and I have a polymer injection machine and HDPE to make the components. The part is relatively small and is an annular disc of 2" dia, 1/8" thick, with 5/8" dia central hole, as follows:

The 6061 alum mold I made is 3" diameter, and each half is 3/8" in thickness, with a machined recess of 1/16" to each half to create the 1/8" component thickness, complete with injection port, and also internal alignment holes/pins.

So my questions are:

1. Do I need to use a release agent applied to the alum mold, and if so, are there any preferred/recommended types?

2. Should I plan on pre-heating the mold or possibly using a mold band heater?

Thanks in advance.

 

[Demon3]

Why not buy a sheet of HDPE from e.g. C S Hyde (online and their products are on Amazon) and stamp out the rings? It would be a lot cheaper for a small number of parts.

Dr. Chris DeArmitt
President

Expert plastic materials help

http://www.phantomplastics.com

 

[Paulkuklych]

Demon3 has the right idea stamping from flat sheet. Another option is to machine the disks from a length of 2" diameter rod.

Paul Kuklych

http://www.improve-your-injection-molding.com

 

[Pud]

The answer to your questions are both no, but the advice given above will be worth heeding...

Can't quite see why both tool halves are machined? A toolmaker would have put a 1/8 deep impression in the moving half and kept the fixed half flat. Alignment becomes much less critical then. (This also ensures part stays on the moving half when tool opens).

Personally, I would get them water jet cut rather than stamping as it will give better edges, and will not require any tooling. Machining sounds promising, but I have no experience of how HDPE machines.

H

www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.

 

[Demon3]

Here they offer to cut small runs of custom shapes from HDPE sheet for you.

http://www.cshyde.com/die-cutting-services.html

Chris

Dr. Chris DeArmitt
President

Expert plastic materials help

http://www.phantomplastics.com