Enter the diameter of the extrusion die, the product outer diameter, the core diameter, and the outside diameter of the tip into the Draw Down Ratio Calculator. The calculator will evaluate and display the Draw Down Ratio.
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Draw Down Ratio Formula
The following formula is used to calculate the Draw Down Ratio (area-based for annular flow).
DDR = (DD^2 - DT^2) / (PD^2 - CD^2)
- Where DDR is the Draw Down Ratio (unitless)
- DD is the diameter of the extrusion die
- PD is the product outer diameter
- DT is the outside diameter of the tip
- CD is the core diameter (for example, the product inner diameter or the diameter of the wire/conductor being coated)
How to Calculate Draw Down Ratio?
The following example problems outline how to calculate Draw Down Ratio.
Example Problem #1
- First, determine the diameter of the extrusion die.
- The diameter of the extrusion die is calculated to be: 5.
- Next, determine the product outer diameter.
- The product outer diameter is measured to be: 2.
- Next, determine the outside diameter of the tip.
- The outside diameter of the tip is found to be: 3.
- Next, determine the core diameter.
- This is measured to be: 1.
- Finally, calculate the Draw Down Ratio using the formula above:
DDR = (DD2 - DT2) / (PD2 - CD2)
The values given above are inserted into the equation below and the solution is calculated:
DDR = (52 - 32) / (22 - 12) = (25 - 9) / (4 - 1) = 16/3 = 5.33
Example Problem #2
The variables required for this problem are provided below:
diameter of the extrusion die = 10
product outer diameter = 7
outside diameter of the tip = 6
core diameter = 4
Test your knowledge using the equation and check your answer with the calculator above.
DDR = (DD2 - DT2) / (PD2 - CD2) = ( )
