What is the compression ratio in extruder?
The compression ratio is the ratio between two depths, the feed channel depth and the metering channel depth (compression ratio = feed channel depth / metering channel depth).
What are the advantages of twin screw extruder?
The main advantages of twin-screw over single-screw extruders are: Pumping efficiency is better and less dependent on the flow properties of the material. Mixing is more efficient. Heat exchange rate from barrel surface to the material is faster and more uniform.
How do you find the compression ratio of a screw?
55 second clip suggested3:23L/D Ratio & Compression Ratio of Extrusion – YouTubeYouTubeStart of suggested clipEnd of suggested clipIt is the ratio of length of the screw by diameter of the screw. So length of the screw divided byMoreIt is the ratio of length of the screw by diameter of the screw. So length of the screw divided by diameter of the screw.
Why is twin screw extrusion starve fed?
Twin screw extruders are generally starve fed and for these machines mixing and melting actions are improved. These have led to the concept of starve feeding for single screw extruders. In starve fed extruders, the polymer is metered into the machine with a feeder.
What is twin screw extrusion?
A twin screw extruder is a machine consisting of two intermeshing, co-rotating screws mounted on splined shafts in a closed barrel. The screws are tight and self-wiping, which eliminates stagnant zones over the entire length of the process section. This results in high efficiency and perfect self-cleaning.
What is Torque in twin screw extruder?
Torque=total torque for both screw shafts, denoted in Newton-meters (N-m), kW=motor rating on the HSEI twin-screw extruder.
How much clearance do you need between screw and barrel?
|These are the Recommended Maximum Wear Clearances between screw and barrel for best output performance|
|Screw Size||New Part Clearance||Max Wear Clearance|
What is compression ratio in plastic processing?
The ratio of the feed zone channel depth to the meter zone channel depth, referred to as “compression ratio” , typically ranges from 1.5:1 to 4.5:1 for most thermoplastic materials.
What is screw L D ratio?
The L/D ratio is the ratio of the flighted length of the screw to its outside diameter. The ratio calculation is calculated by dividing the flighted length of the screw by its nominal diameter.
What is the significance of LD ratio?
So an aircraft with a high L/D ratio can carry a large payload, for a long time, over a long distance. For glider aircraft with no engines, a high L/D ratio again produces a long range aircraft by reducing the steady state glide angle at which the glider descends.
Why does a twin screw extruder mix better than a single screw extruder?
Twin screw extruder has remarkable mixing capability, because of the intermeshing screws and the broad diversity of specialized screw designs that allow the extent of mixing to be precisely adjusted leading to control the degree of mixing. Plasticizing capacity of twin screw extruder is better and faster.
How does a single screw extruder work?
Single screw extrusion uses one screw within a cylindrical barrel to continuously push plastic through a constant profile die (Figure 12.7). Production rate is typically measured in mass per hour (lb/hour or kg/hour) and is controlled by the screw speed of the machine.