Die Swell

[AgeOfEmpire]

Hi,

Could you give some information that How can I measure die swell diameter without using laser sensor.? Could you advise
an apparatus for this aim?

Thanks a lot

 

[plastx]

The laser is the best way. You can cut extrudite as it exits the die and then measure the diameter but there will be should error as the polymer will cool and change dimensionally. The polymer must also have enough melt strength as it exits the die for this to be approximated.

Compare the diameter of the die orifice with the extrudite diameter.

 

[AgeOfEmpire]

Hi plastx,

Firstly ,thank you very much .I have interested in this area resently.According to the your reply,I think that you are experienced on this area.If you give permission,I want to ask a question.
I will calculate viscosity and other parameters of polymers without using a software.So my job is very difficult,I think.I will mount a pressure thansducer above the die to measure pressure drop inside die.And then I will use bagley correction.But orifice die also can be used for this.What is the better method to measure the pressure drop in capillary ?

 

[plastx]

My experience has been using a rheometer that had the software that calculated the Bagley correction. There is a way of manually calculating but I don't have the formulas. They might be available on the web somewhere. The calculations rely on a "zero-height" die which would then have no pressure drop in theory. Thus having a very short die and a longer die (same orifice diameter), run the same rheometer conditions (speed, temp, timing) and compare the results.