Extrusion Issue & Troubleshooting

Time:4/9/2019 night shift

Abnormal state report on extruder

The extrusion materials burned like paste, please note the color was changed from white into sandy brown.

https://youtu.be/cfv4dmeer_k

Causal analysis 

The reason is water came into the extruder, it will be dangerous if we keeping on running. The screw and barrel should be clean up and feeding into new materials and fix the Vacuum system

Why the water will come upstream into extruder?

Normally it won’t happen because the one-way water valve with negative pressure, the dust and gas will be transferred in a single way.

But if we forgot to shut off the water pump, the water will keep on going to the vacuum tank, the one-way valve is an air valve application, there are some materials will stick on the gasket, which makes it’s not100% closed, so the gap will make the water easy entry into the tank, some times the tank  has full filled materials like the photo shows(please remember to clean up the vacuum tank and the strong magnetic every day-shift), the water will go through the pipe into the extruder.

It was a mistake operation and it will happen again if we don’t follow up the standard shut off checking out

P.S.: The strong magnetic can’t be throwing on the ground, otherwise the magnetic force will fail.

How to solve this problem?

Please check Extrusion Line Shut Off Procedure on YouTube.