How to test bonds » Wire Pull » Appendices » force calculations

Appendix i. Force calculations

a. Wire length L

If the geometry of the sample and the wire length are known the resultant angles and forces on the bonds during wire pull can be determined. If the wire length L is unknown, it can be calculated from the loop height.

Calculate the wire length from the loop height
Calculate the wire length from the loop height

The general equation is as follows:

General equation wire length from loop height

If there is no height difference between the first and second bond and the pulltest is performed mid span, the equation can be simplified to:

Equation wire length from loop height when h2=0 and the pull is mid span

b. Position d1 from first bond angle θ

If you want to pull with a specific angle θ at the first bond, calculate the test position along the wire according to the following formula.

Equation position along wire at specific angle

c. Position d1 from second bond angle θ

Wire pull distance calculated from the second bondWire pull distance calculated from the second bond

You can use the same equation to calculate d1 for the second bond by making h2 negative. Φ then becomes θ and d1 is measured from the second bond.

Equation position along wire at specific angle

d. Angle at second bond Φ

The angle at the second bond Φ is derived from this expression.

Equation angle second bond wire pull

e. Pull at equal angles

If you want to pull with equal angles (θ=Φ), the following formulas apply.

Wire pull force calculation overviewWire pull force calculation overview

Wire pull at equal angles

Wire pull at equal angles, solve for d1

The forces t, p and s then are as follows.

Wire pull force equation t1

Wire pull force equation p1

Wire pull force equation p2

Wire pull force equation s1 and s2

Wire pull force equation t2

How to test bonds?

Wire Pull:

www.wirepull.how

Thin wire gold pull test
Thin wire gold pull test
  1. Introduction
  2. What is wire pull?
  3. What kind of wires can be tested?
  4. Objectives
  5. Tool design
  6. Tool quality
    1. Material and damage
    2. Hook concentricity
  7. Alignment
    1. Quick manual testing of thin wire
    2. Auto hook
    3. DVS 2811
    4. Triangulation
    5. Automation and wire detect
  8. Loop height measurement
  9. Work holder and clamping
  10. Variants on wire pull
    1. Vector pull
    2. SMD gull wing leads
  11. Test method settings
    1. Test definition
    2. Statistical Process Control (SPC)
    3. Data analysis
    4. Data export
  12. Failure modes
    1. Gold wire
    2. Aluminium wire
  13. Appendices
    1. Force calculations
    2. MIL-STD-883 2011.9 destructive
    3. MIL-STD-883 2023.7 non-destructive
    4. MIL-STD-883 2023.7 Appendix A

Cold Bump Pull:

www.coldbumppull.how

Click here if you wish to learn everything there is to know about Cold Bump Pull (CBP). The extensive how-to on CBP consists of 13 paragraphs and 7 pages.

Tweezer Pull:

www.tweezerpull.how

Click here if you wish to learn everything there is to know about Tweezer Pull. The extensive how-to on Tweezer Pull consists of 9 paragraphs and 6 pages.


Test types

How to test bonds?

Wire Pull:

www.wirepull.how

Thin wire gold pull test
Thin wire gold pull test
  1. Introduction
  2. What is wire pull?
  3. What kind of wires can be tested?
  4. Objectives
  5. Tool design
  6. Tool quality
    1. Material and damage
    2. Hook concentricity
  7. Alignment
    1. Quick manual testing of thin wire
    2. Auto hook
    3. DVS 2811
    4. Triangulation
    5. Automation and wire detect
  8. Loop height measurement
  9. Work holder and clamping
  10. Variants on wire pull
    1. Vector pull
    2. SMD gull wing leads
  11. Test method settings
    1. Test definition
    2. Statistical Process Control (SPC)
    3. Data analysis
    4. Data export
  12. Failure modes
    1. Gold wire
    2. Aluminium wire
  13. Appendices
    1. Force calculations
    2. MIL-STD-883 2011.9 destructive
    3. MIL-STD-883 2023.7 non-destructive
    4. MIL-STD-883 2023.7 Appendix A

Cold Bump Pull:

www.coldbumppull.how

Click here if you wish to learn everything there is to know about Cold Bump Pull (CBP). The extensive how-to on CBP consists of 13 paragraphs and 7 pages.

Tweezer Pull:

www.tweezerpull.how

Click here if you wish to learn everything there is to know about Tweezer Pull. The extensive how-to on Tweezer Pull consists of 9 paragraphs and 6 pages.


Test types


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