Water Kills - Injection Molding Moisture
five questions
Moisture, moisture, moisture.
Think about how you store, prepare and mold plastic resin.
If moisture is present during molding.
You are going to have splay marks on you apart.
The good news . . .
Splay is distinctive.
And it’s easy to spot.
Here’s how I manage moisture in injection molding.
Feel free to steal some of these suggestions.
First step . . .
Figure out where the moisture is coming from.
What are the possibilities?
Ask these five questions.
And follow the answers.
ONE . . . . is your cooling controller leaky?
The controller is outside the machine.
Off to the side and around the back.
Often forgotten in the RCA process.
It’s where I look first because it’s easy and any nasties will be obvious.
Take a walk around to the back of the machine.
Move some tubing around.
Put hands on the controller, the tubing and all connections.
What do you notice?
Is the tubing old or too long?
If things are messy, then you need to fix the mess first.
TWO . . . . did you Check the connections on the tool?
How do the connections look?
Maybe they are old and damaged.
Is the fitting a bit messy?
Any drips?
Use your fingers to test and feel.
Remember . . .
If it looks like crap.
It’s probably crap.
THREE . . . . was the material dried properly?
This is the key moisture managing procedure.
Pay attention to this.
Make sure this part of the puzzle is in place.
It may save your parts if bad moisture protection processes exist elsewhere.
Ok, you have a dryer and you are drying the material.
One question . . .
How do you KNOWWWW that the material is dry?
Make sure you have moisture measurement equipment and a solid SOP.
Worst case, this will reveal if you have a moisture issue.
Best case, it’s a vital component of your IPQC process.
FOUR . . . . is there condensation forming on the tool surface?
You tool is sweating.
NOOOOO. It’s not working too hard.
Hot tool steel + humidity = condensation (sweaty tool).
You can use your fingers a dark paper napkin to investigate.
What do you fix this?
Check that your cooling is doing what it’s supposed to do.
Is your cooling . . . . cooling?
Is the molding shop too humid.
Believe me, you will know.
Your t-shirt will tell you.
Get some humidity control equipment if other fixes don’t work.
FIVE . . . . what are the material storage conditions like?
Are material bags protected from the elements?
Take a trip to the warehouse.
Any chickens?
Any mushrooms growing?
Ha ha. I hope things are not “that” bad.
Is the storage area obviously wet?
Yes, material drying before molding will fix most issues.
But a terrible storage setup will translate into wet part issues.
Moisture is sneaky
Be careful out there
Moisture is a sneaky killer in injection molding.
Follow these recommendations.
And watch your moisture issues disappear.
Good luck.