1. Classification of solidification processes

2. Principle of the process
Structure/Configuration
Process modeling
Defects/quality control
Design For Manufacturing (DFM)
Process variation

3. Shaping Processes For Plastics - Extrusion
1. Introduction
Screen pack

4. Shaping Processes For Plastics - Extrusion
1. Introduction
Extrusion is a compression process in which the material is forced to flow through a die orifice to provide a long, continuous product whose cross-sectional shape is determined by the shape of the orifice

5. Shaping Processes For Plastics - Extrusion
2. Analysis of Flow Rate

6. Shaping Processes For Plastics - Extrusion
Find the flow rate with respect to various parameters in the system. These parameters include: parameters of the screw, the clearance between the screw and the inner surface of the barrel.

7. The goal of the engineering analysis:
The flow rate or production rate
The pressure of the extrudate or product

8. die Extruder The general idea to meet the goal: A
The result of the equilibrium in pressure between the extruder and die
Flow rate at the end of the extruder without the presence of the die.
Flow rate at the beginning of the die with the presence of the die.
die A
Extruder

9. w Screw surface v d Drag flow Barrel
Flow rate of the extruder (not including the die) d w v
Screw surface
Drag flow
Barrel

10. d w v dc A
(1)

12. Back pressure flow

13. Back pressure flow
(2)

14. Net forward flow Qx
(3)
Linear relation between the net flow rate and head pressure.
Assumption: viscosity is constant.
The structure: extruder only not including die.

15. Shaping Processes For Plastics - Extrusion
The design parameters: those that define the geometry
of the screw and barrel.
Independent operating parameter
The operating parameter: those that can be changed
during the process to affect the output flow
Variable: characterize the production
Dependent operation parameter

16. Shaping Processes For Plastics - Extrusion
Maximum head pressure to cause no flow
Maximum pressure and maximum net flow rate

17. Extruder characteristic Qmax
Shaping Processes For Plastics - Extrusion
Extruder characteristic Q
Qmax
pmax p

18. The result of the equilibrium in pressure between the extruder and die
Flow rate at the end of the extruder without the presence of the die.
Flow rate at the beginning of the die with the presence of the die.
Extrude characteristic
die A
Extruder

19. die Shaping Processes For Plastics - Extrusion
Determination of the operating point
Actual Pressure and Flow rate out of the die
Die characteristic
die

20. Shaping Processes For Plastics - Extrusion
Determination of the operating point Qx
Die characteristic
Qmax
Operating point
Extruder characteristic
pmax p

21. Example:
Given: - diameter D=120 mm
- length =3.0 m
- channel depth =8.0 mm
- pitch = 95 mm
- viscosity = 75 pas
- head pressure = 4.0 Mpa
Find: the rotational speed of the screw required to achieve a volumetric flow rate of 90 cm3/s

22. Solution to be filled in the classroom

23. Summary: Process has input and output.
Input of the material: quantity and quality of the material.
Output of the material: quantity and quality the material.
Device or manufacturing machine operates on the material  input and output relation of the material
Input to the device: torque on and rotation of the screw bar.
Output from the device: axial force on and rotation on the screw bar.
Head pressure on the material.
Forward flow, back flow, net flow.
Operating point  actual flow rate and actual (head) pressure

24. General manufacturing system theory

25. Shaping Processes For Plastics - Extrusion
Discussion
A manufacturing process is to change the material to meet some requirement on the material.
Requirements: quality, quantity, time, cost, and sustainability.
Quantity with respect to time is called production rate.
The whole manufacturing system at the equipment level can be viewed as consisting of devices and materials.

26. Shaping Processes For Plastics - Extrusion
Discussion
Both the device and material are under the manipulation from the external system that supplies energy or power and material.
There are several parameters in the manufacturing system: device parameter, process parameter, product parameter.

27. Shaping Processes For Plastics - Extrusion
Discussion
Device parameter/system parameter/design parameter: a category of parameters that describe the device, e.g., diameter of the extruder, length of the extruder, etc.
Independent process parameter/operating parameter: a category of parameters that describe the action on the material, e.g., rotational speed of the screw bar, heat energy supply, etc.
Product parameter/process variable/dependent process parameter: a category of parameters that describe or characterize the product, which is the output of a manufacturing system, e.g., the flow rate, etc.
Product parameter or process variable or dependent process parameter depend on both device parameter and process parameter.

28. Shaping Processes For Plastics - Extrusion
Discussion
Manufacturing system design and control:
Device design: to determine the device parameter.
Process design: to determine the process configuration and parameter.
Product modification: design for manufacturing.
Device control.
Process control.
Product quality, quantity, cost, time, and sustainability

29. Integrated Manufacturing Technology
Design of products
Design of manufacturing processes
Design of manufacturing systems or devices
They should be integrated to improve the manufacturing practice. Manufacturing practice is measured by:
Performance (quality, quantity, delivery time, cost), and sustainability (stability, green, resilience)