QUESTIONS I. What are the differences between adiabatic heating and thermal heat
ID: 2087518 • Letter: Q
Question
QUESTIONS I. What are the differences between adiabatic heating and thermal heating as appl extruders and why are both important? 2. Discuss why the compression zone of a nylon-type screw is so much shorter than the 3. Discuss the temperature profile shapes normally used for nylon and polyethyl 4. Describe a spider die. What adjustments are typical and how are they made compression zone in a polyethylene-type screw. purpose screw. Which is higher in actual value? What are the slopes of each? 5. Discuss three operational steps that can be taken to reduce the thickness of an ex truded part. 6. Explain the effect of molecular weight distribution on extrusion. 7. Discuss the relationship between the melt temperature and the location of the frost line in blown film manufacturing. 8. Discuss why melt pumps are rarely used with twin-screw extruders. 9. During the operation of an extruder in making thin-walled tubing, several defects have been encountered that appear to be small globules of resin. Investigation of these glob- ules reveals that they will soften but not melt when heated. Explain what these glob- ules might be and suggest two possible remedies for eliminating them. 10. Ecpiain why outside-diameter dimensional control is easier than inside 11, why do the cross-sectional shapes of the die orifice and the final (cooled) extruded part 12. Assume you are working for a custom extrusion company that uses many dies, -diameter di- mensional control for extruded pipe. sometimes differ? resins, and many colors. To keep costs down, your company generally buys naturalExplanation / Answer
1. Generally both thermal heating and adiabatic heating are involved in extruders for extrusion.
The term thermal heating indicates that the heat is provided to the extruder by supplying heat by external means. For example induction heating or electrical heating of barrel of the extruder.
Whereas the adiabatic heating refers to the heat that is provided to the extruder by means of mechanical energy i.e, the grinding or sliding action of screw on the resins inside the extruder.
They both are important because, the heat energy provided by the both processes combined to melt the work piece or bring the work piece into the plastic state. So, both of them play their role in completing the extrusion process.