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 Extrusion, Twin Screw
 plate out deposits on thermocouples
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josephweeks Member Posts: 2 |
posted May 04, 2005 04:20 PM
  
I need a way to accurately measure the melt temp of the plastic at the end of the barrel. Before they had used a temperature probe but had problems with metal deposits forming on the upstream side of the probe and burning. Anyone know where you might get a flush to the barrel mounted probe? Possibly an IR probe. IP: Logged |
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Tom C Moderator Posts: 515 |
posted May 04, 2005 08:31 PM
Joe, A couple of options: 1) A manual or motorized insertion probe which are reliable, but fragile and may still have the same burning problem. 2) An IR proble mounted in the barrel. I have not been too happy with the results I've had in the past. I'm not sure of all the technical issues that caused the problems. 3) An Ultrasonic probe which measure temperature by sending utltrasonic waves through the melt. This is completely non-contact and has been tested on PET. Let me know if you are interested, as I have more information. Not cheap. 4) An IR gun measuring the melt as it leaves the die. Performed correctly I find this to be a very reliable method. Again there are a lot of details to deal with here, so please contact me if you are further interested. This is an interesting area of extrusion which has no direct and complete answer. ------------------
Tom Cunningham
Extrusion Technical Services www.ExtrusionTechnicalServices.com IP: Logged |
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josephweeks Member Posts: 2 |
posted May 09, 2005 04:44 PM
I am interested in the ultrasonic method. Who makes it? Is there a website? Also why were you dissatisfied with the IR probe. IP: Logged |
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Tom C Moderator Posts: 515 |
posted May 10, 2005 11:51 AM
Joe, Regarding the IR melt probe, I just did not get accurate and consistent readings. My guess is that I could not keep the sensor window consistently clean, and that with some materials the radiation from the metal from the die opposite the probe influenced the reading. This was probably 20 years ago that I tried it. In the mean time I have not heard anyone promoting these mounted IR probes. I'm very happy with my IR gun results, but it is a very specialized unit, not one of those $100 jobs from the hardware store. I will attempt to contact you directly regarding the Ultrasonic unit. ------------------
Tom Cunningham
Extrusion Technical Services www.ExtrusionTechnicalServices.com IP: Logged |
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Tom C Moderator Posts: 515 |
posted May 16, 2005 12:27 PM
Joe, Sorry, can't figure out how to contact you. Please send an email with your contact information. tomcun@ptd.net ------------------
Tom Cunningham
Extrusion Technical Services www.ExtrusionTechnicalServices.com IP: Logged |
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