| next newest topic | next oldest topic |
| Author | Topic: Die Blankets |
|
RBaratt Senior Member Posts: 5 |
posted October 29, 2004 12:23 PM
   
Has anyone experimented with the use of die blankets on their extrusion lines? My company is looking into them hoping to reduce energy costs. Any thoughts,... positive or negative, would be greatly appreciated. Thanks. Rick IP: Logged |
|
Tom C Moderator Posts: 399 |
posted October 29, 2004 01:19 PM
I have found die insulation helpful in evening out the temperature of the die head in areas that were poorly heated. Energy savings will be low as much of the die heat comes from the polymer itself. Tom C IP: Logged |
|
RBaratt Senior Member Posts: 5 |
posted October 29, 2004 01:31 PM
Thanks Tom, We have estimated the cost savings to be $4000/year/line. We have installed the blanket on one line and several die zone temperatures are overshooting their setpoint by 20 degrees or more. I thought I may need to adjust barrel temp profile to reduce melt temp before entering the adapter and die zones. IP: Logged |
|
Tom C Moderator Posts: 399 |
posted October 29, 2004 04:00 PM
Depending on your process barrel temperatures can have little effect on the melt temperature. Consider this; you may lower the temperatures of you barrel enough to lower the melt temperature, but increase the load on the motor enough to more than offset the energy savings on the die. The best solution is a screw design which processes the melt efficiently enough to keep the melt temperature down while providing the required output. Savings from screw design like that can be $5-20,000 per year in electricity. Tom C IP: Logged |
|
RBaratt Senior Member Posts: 5 |
posted November 01, 2004 08:52 AM
Tom, thanks again...for very helpful information. I appreciate all your responses to forum questions and I have been looking at past posts to find any information that may help me to better understand and perform my work. I am a degreed plastics engineer with more experience in injection molding than extrusion. I am not the expert I would like to be in the extrusion process,... and I am having trouble finding helpful information on extrusion. Tom, in your opinion are there a few particularly good publications that would help a process engineer with good practical information? Especially information on how to improve productivity and reduce costs. Like all companies these days, management is looking at me to find ways to reduce their costs. IP: Logged |
|
louis33 Senior Member Posts: 88 |
posted November 01, 2004 09:36 AM
Rick First thing to do to control costs would be to get a good system to collect the data needed to identify areas for improvement; such as process yield, start-up scrap, line speed restrictions (down stream handling limits)and post extrusion problems (quality) to name a few. You can do that using a simple database or spreadsheet. Identifying problems at that level will yield the biggest back for the buck. After that, you can pursue optimum screw designs for the specific materials being processed and automation. As Tom has often said, screw design is important! And automation? Well it seems to be the best way to compete in this world economy. I am curious, since you came from an injection molding background, do you find it interesting as I do, that there is little thought given to screw design in molding versus extrusion? Louis IP: Logged |
|
Tom C Moderator Posts: 399 |
posted November 01, 2004 12:18 PM
Rick, Don't get me started on cost control! Really, it is a huge issue that goes way beyond the extruder, as Louis pointed to. For many extruders the largest cost is in the resin, so a great focus is put there. Unfortunaly this is a problems for process engineers who have to deal with the latest flavor of resin to hit the extruder. Often someone saves a penny a pound, only to throw away 20% of the resin on process problems. Try to find the key elements in your business that influnce cost and competitiveness. If you half scrap by running 10% slower, what is the net? Or does sales go crazy becasue of late orders? Or would one big extruder be more cost efficient? Or would 10 smaller extruders deal with the variety of products better? The questions that test the status-quo go on and on. To me that analysis is fascinating. Good Luck Tom C IP: Logged |
|
RBaratt Senior Member Posts: 5 |
posted November 01, 2004 03:46 PM
Thanks Louis, The injection molding facility I worked for began using standard screws based on the material suppliers suggestion. We molded mostly LCP's and I found a screw manufacturer who claimed to have design, for both the screw and check ring, specifically for LCP. This eliminated our recovery time and short shot issues. IP: Logged |
All times are ET (US) | next newest topic | next oldest topic |
  |
|
Contact Us | Feed Screw Designs
Powered by Infopop www.infopop.com © 2000
Ultimate Bulletin Board 5.45a
