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Plastic Injection Molding - Post Mold Labeling

Avogel

Registered Visitor
#1
Post mold our part is still warm. During the next 24hrs (the cooling cycle), the part will shrink.
Does anyone know of a label product that will will either shrink with the plastic, or allow for that shrinkage and not pucker or wrinkle?
Currently we have to double handle our product after 24hrs to apply the label.
My goal is to find a label that will allow application right of the mold.
We use a number of different size labels.
Our product is returnable packaging, with kit trays, shipping containers. Mostly for automotive.
 

ScottK

Not out of the crisis
Staff member
Super Moderator
#2
Re: Plastic Injection- Post mold Labeling

Post mold our part is still warm. During the next 24hrs (the cooling cycle), the part will shrink.
Does anyone know of a label product that will will either shrink with the plastic, or allow for that shrinkage and not pucker or wrinkle?
Currently we have to double handle our product after 24hrs to apply the label.
My goal is to find a label that will allow application right of the mold.
We use a number of different size labels.
Our product is returnable packaging, with kit trays, shipping containers. Mostly for automotive.
Google "in-mold labeling" or "in-mould labeling"
This was used just in blow molding when I was in the industry about 15 years ago, but it looks like it's expanded into injection molding.
 

kuyakut

Involved In Discussions
#3
Post mold our part is still warm. During the next 24hrs (the cooling cycle), the part will shrink.
Does anyone know of a label product that will will either shrink with the plastic, or allow for that shrinkage and not pucker or wrinkle?
Currently we have to double handle our product after 24hrs to apply the label.
My goal is to find a label that will allow application right of the mold.
We use a number of different size labels.
Our product is returnable packaging, with kit trays, shipping containers. Mostly for automotive.
If you want it labeled during molding process , try the in-mold labeling.
For most of automotive plastic parts that dont go for painting they use in-mold labeling.
 

Ronen E

Problem Solver
Staff member
Super Moderator
#4
Hi,

In-mold labeling is an option, but it will require some investment in the equipment.

Looking at the process as it is:
Shrinkage due to cooling doesn't take 24 hours. It shouldn't take more than 15 minutes, unless the wall thickness is excessive (bad part design) or the ambient temp. is very high. Shrinkage over extended periods usually relates to post-molding crystallization of the polymer matrix - what sort of resin you use? In some cases (POM) it can continue shrinking for months, with an exponential decay rate. The best way to minimize this effect is to create favourable crystallization conditions in the mold. Usually this means a higher mold temperature (see resin manufacturer's recommendations) and longer cycle time, so there's a trade off. What usually happens is molders try to cut cost by using cooler molds to shorten cycle times, and end up having all sorts of dimensional stability / warpage issues.

Cheers,
Ronen.
 
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