Video - Injection Compression Molding Process...

I visited a customer the other day, and was turned onto the Compression-Injection molding process. This was a first for me... I've had a little exposure to injection molds and mold factories, but am by no means an expert.

So per their suggestion, I hit up YouTube, and found this video on the process. Although you don't get to see too much action on the molding side, I was seriously impressed by all the automation involved in the whole process. Especially the speed at which the whole line is running.

Anyway, I just thought I'd share the video, as I'm sure a few of you all might enjoy it like I did.

Thank you for posting it.

But I don't understand quite what is going on, I see an injection molded plastic
butter container.

Assume injection mold, then some vacuum forming going on while still hot ?
I'm not seeing the "compression" part on the video.

I designed an electrical box, and it was "compression molded", polyester resin with high glass content,
much different process.

The way he described it, the plastic is injected before the mold fully closes, and then is "compressed" as the mold closes fully, and what I assume cures the material. There's a shot somewhere about half-way of an indicator mounted between the mold halves. Watch the indicator, and it's pretty easy to see then.

This part too - just like any other food container I assume - uses an "overlay" for the label as well. It took me a couple views to, make sense of all that was going on but the vacuum tooling is loading the label into the "A" side of the mold, while the other vacuum tool is removing the finished part from the "B" side of the mold. (Maybe I have my A/B side mixed up, but you get the idea.)

What I didn't fully realize when I was fondling their parts, was that there was no way you could simply "eject" a part that thin, without the ejector pins going right through it. Now after seeing the video, the vacuum tooling helped get the part out of the mold, by assisting the ejectors.

The more I dissect everything that's going on, the neater it becomes, but maybe I'm a nerd. Anyway, I think it's neat to see what it takes to make a simple-looking food container.

Food containers are not a curable plastic, they set from cooling down, i do see how compression moulding lets you run a colder mould though with out getting material flow issues in such thin sections hence a faster cycle time.

I think that the wall is too thin to mold. so they start injection, then finish closing the mold. A similar process is done to make an internal part of Alkaline batteries. Too thin to inject, so they inject, then squeeze to get a .005 wall.
I was impressed by the IML (in mold labeling).

Davis In SC said:

I think that the wall is too thin to mold. so they start injection, then finish closing the mold. A similar process is done to make an internal part of Alkaline batteries. Too thin to inject, so they inject, then squeeze to get a .005 wall.
I was impressed by the IML (in mold labeling).

Click to expand...

I always wondered how they did that. Simple now after seeing it, but had me scratching my head the first couple containers I tried to remove the labels from. ha ha

Davis In SC said:

I think that the wall is too thin to mold. so they start injection, then finish closing the mold. A similar process is done to make an internal part of Alkaline batteries. Too thin to inject, so they inject, then squeeze to get a .005 wall.
I was impressed by the IML (in mold labeling).

Click to expand...

When I first saw the part, I asked him if it was thermo-formed, it was that thin. In handling the part, the walls can't be any thicker than .010".

The in-mold-labeling has always impressed me. When I was starting out, I was delivering tools to different molding factories, and they were always willing to let a young pup ask questions, and show me how they did things. I distinctly remember some interior trim parts for the then-new F-150, which would have been around 2006. They were molding wood-grain and carbon-fiber "labels" onto the parts, and I was so impressed that they could do that - I still am...

The next time you get in your car, look for any interior parts that look painted, or have any design on them. With the rarest exceptions of luxury cars costing 6-figures, they're all in-mold finishes. Too cool...

So it is similar to how 2-liter bottles are made, only using 1 mold though.

Neet-O

They injection mold a test tube with the top threads normal, then secondary blow mold the test
tube to be the thin bottle section.

Seems such a so simple consumer part. I wonder the cost of such a machine.
Bob

CarbideBob said:

Seems such a so simple consumer part. I wonder the cost of such a machine.
Bob

Click to expand...

It's an odd business for sure.

There's allot of it around here, although I don't get into it much.

I was in a mold polishing shop, and the owner was explaining this to me:
He went out to repair polish a 96 cavity mold, that made the little threaded boss and
cap for orange juice containers (1 quart cardboard box type, fitting is on side of angled top)
That mold has unscrew and all kinds of other fancy mechanism to make these in one shot.

He went on to explain how the owner of the local plastic shop took a large risk in having a 96 cavity
mold make (largest to date) for these, to lower the cost.

In doing so, the cost per piece went down, so now you see these re-sealable fittings on smaller
(and cheaper selling price) items like pint containers of creamer.

So his sales volume went up.

They are now bankrupt (and closed down) because of non-paying customers (where have we seen this before) and competition.

Did someone say 96 cavity mold? Gee, what could possible go wrong?

PLASTISUD - 96 Cavity mold for 29/25 Cap with slides - YouTube