Web Thickness - Plastic processing forums for extrusion information and advice and for other feed screw applications.

Ask the experts! These processors and consultants have been there and done that. Post your enigma now!

UBBFriend: Email This Page to Someone!

Plastic processing forums for extrusion information and advice and for other feed screw applications.

Extrusion, Single Screw

Web Thickness

profile | register | preferences | faq | search

next newest topic | next oldest topic

Author	Topic: Web Thickness
hsachi Member Posts: 3 From:Summerville, SC, USA Registered: Mar 2005	posted May 28, 2005 11:55 PM While we extrude PP film of 2.5 mil thickness, we are getting 1.15 to 1.5 mil thickness for 15 secs and goes away for couple of days and it come backs. Can anyone suggest me a point to start trouble shoot the line? Note: We do add fluff into the line at the throat. ------------------ Sachi IP: Logged
Tom C Moderator Posts: 573 From:Brodheadsville, PA USA Registered: Jun 2001	posted May 29, 2005 05:33 PM Sachi, If the fluff slows down the solid feed in the extruder for anything over 15 seconds, your extruder will be starved and the condition you describe will result. I don't think anyone has perfected trim re-feed systems to the point where the extruder is unaffected by the trim scrap. Typically this would require a gear pump with screw pressure control in order to get any kind of precision extrusion. Try to determine the best economics for your process; Stay with the current situation Sell the fluff Have someone pelletize the fluff for you Invest in equipment to properly deal with the fluff, like a gear pump or pelletization system. ------------------ Best Regards, Tom Cunningham Extrusion Technical Services www.ExtrusionTechnicalServices.com IP: Logged
hsachi Member Posts: 3 From:Summerville, SC, USA Registered: Mar 2005	posted June 03, 2005 02:34 PM Thanks Tom, I found out that the day problem occured line was running with out fluff. Is there any other possible causes? ------------------ Sachi IP: Logged
Tom C Moderator Posts: 573 From:Brodheadsville, PA USA Registered: Jun 2001	posted June 03, 2005 04:53 PM Sachi, Let us work out way down the list of likely candidates. Are your barrel zone temperatures under control? Do you have a water cooled feed throat? Can you record the motor RPMs and power draw to rule out motor problems? Do you use screw cooling? Do you use a grooved feed throat? What is the diameter of your extruder? What is the typical output rate? What type of refill system are you using? Is there any possibility of bridging in the feed throat? ------------------ Best Regards, Tom Cunningham Extrusion Technical Services www.ExtrusionTechnicalServices.com IP: Logged
michman Member Posts: 2 From: Registered: Aug 2005	posted August 16, 2005 04:40 PM You should invest in a material batch blending system to feed this material in a blend of virgin pellets and fluff. quote: Originally posted by Tom C: Sachi, If the fluff slows down the solid feed in the extruder for anything over 15 seconds, your extruder will be starved and the condition you describe will result. I don't think anyone has perfected trim re-feed systems to the point where the extruder is unaffected by the trim scrap. Typically this would require a gear pump with screw pressure control in order to get any kind of precision extrusion. Try to determine the best economics for your process; Stay with the current situation Sell the fluff Have someone pelletize the fluff for you Invest in equipment to properly deal with the fluff, like a gear pump or pelletization system. IP: Logged

All times are ET (US)	next newest topic \| next oldest topic
Administrative Options: Close Topic \| Archive/Move \| Delete Topic
	Hop to:

Contact Us | Feed Screw Designs

Powered by Infopop www.infopop.com © 2000
Ultimate Bulletin Board 5.45a

�

�