posted 10-27-2002 11:33 AM
This posting was done anonymously, the poster is known to FSD administration and will be provided to all interested parties as approbate. I am an engineer in South America and Im working in a woven bags factory in Quality Control. We have a problem with a determinate PP material. 1. We need in black material use Anti UV in the melt. Normally whe dont use it. 2. The feed screew was damaged in the feed zone and this PP Material have a size and a form which increase our actual input in 30%. The problem is if we dont use Anti Uv we have a bad tape, its have very bad appereance (it not plane). This is the operations condition with others material Screw: 100 RPM Temperatures : 190 - 220 ºC Output : 185 m/min (140 kg/h) OPeration Conditions with PP Material with Anti UV Screw: 100 RPM Temperatures : 190 - 220 ºC Output : 250 m/min ( 185 kg/h) We need some information about what is tha best sizel, form of the PP to increase the otuput of the machine. How the uniformity can increase or decrease the extrusion process Why the tape have this degradation what happen in the freed screw that we need to use Anti UV Thanks a lot
posted 11-03-2002 05:45 AM
The best PP "size" to use is at it's highest flowable bul density - namely pelletized. I cannot fathom any relationship in using a UV additive to a damaged feed section, unless: A.) You believe in Vodoo. B.) The Purchashing Manager (or others) is being taken out to lunch by the UV supplier. C.) A combination of both A. & B.
What you have NOT disclsoed is the level of UV used, the form of the PP your using, and the actual extrusion conditions for the PP form you are running.
Without these, then it is sort of like witchcraft.
posted 11-03-2002 10:52 PM
As your output increases when you add the U/V additive (and hold all processing parameters the same), it appears the U/V additive is promoting the passage of material in the feed zone.
Can you tell us a bit more about the damage in the feed zone? Perhaps if you experiment with different temp settings in this zone, you may find a setting that gives the same output without dosing in the U/V. Have a look at this link http://www.blkclawson.com/content/8techtips/techset.htm
What supplier/grade of PP are you using?
Steve Hodgson
[This message has been edited by Steve H (edited 11-03-2002).]
posted 10-27-2002 11:33 AM
