Injection Molding: Material Change with EasyPurge Purging Compound

Injection Molding Material Change: POM BLACK  → PA CLEAR

Goal: Black Specks Removal

Summary: 

Machine: 400T 

Material: POM Black to PA Clear

Easypurge Purging compound consumed: 6 Sachets (120 Grs)

Time: 15 Minutes

Industry: Automotive

Factory Location: Germany

Scope: Spindle

Injection Molding Material Change: Findings

POM  has a lower melting point, 180°C (356°F) than the PA, therefore the material degraded when the temperature was increased in the screw in order to reach the melting point of the Polyamide to 280 °C (536 °F).

Degraded POM causes contamination in the spindle generating black specks during production.   

Solution:

Bridge material: HDPE

First, The barrel was emptied before the purging process.

At the working temperature of POM, virgin HDPE was used as bridge material to remove the majority of Black POM.

HDPE was used along with the sachets of Easypurge purging compound (without opening) added directly into spindle entrance.

The next step was using more HDPE virgin material to remove the rest of the BLACK POM and black specks.

The machine heat was increased up to the polyamide working temperature.

The following step was purging using polyamide with Easypurge purging compound sachet.

Finally, PA was used to remove the rest of the purging material in order to start production.

Final Results:

 

Purging Compound Consumed

Total Purging Time

 

 EasyPurge Purging Compound 

6 sachets (120Grs)

15 Minutes

 

Comment by the Process manager:

“We have had 5 batches rejections during this year due to the presence of black specks this year. We’re happy to see that we have found the correct process and product for this common material change for us”.

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