Knit Line Techniques

Dispense Techniques for Cure-in-Place and Form-in-Place Gasketing

In cure-in-place (CIPG) and form-in-place (FIPG) gasketing applications, the gasket creates a seal used to protect critical components from air, dust, and moisture intrusion, prevent leaking and dampen vibration. Achieving a good knit line can help to eliminate voids and ensure bead fusion to deliver a reliable seal.
 

Knit Line Dispense Techniques

Determining the appropriate knit line dispensing technique is an important consideration in dispense system programming and setup. Several knit line techniques include the overlap, parallel pass, butt joint, and sloping overlap.
 

Overlap

Overlap Knit Line Technique

Sloping Overlap

Sloping  Knit Line Technique

Parallel Pass

Parallel Pass Knit Line Technique

Butt Joint

Butt Joint Sloping Knit Line Technique

 

 

Automation Techniques

Programming of the robotic dispensing system can also play a critical role in achieving bead path application requirements. Depending on part complexity and axis, adjustments to the automation motion can help optimize the dispensing process. Several automation motion techniques include the rake motion, traditional motion, reverse rake, and reverse rake and brake motion.

Traditional Motion

Traditional Automation Technique

 

 

Rake Motion

Rake Automation Technique

 

 

Reverse Rake Motion

Reverse Rake Automation Technique

 

 

Reverse Rake and Break Motion

Reverse Rake and Break Automation Technique

 

 

Summary

In CIPG and FIPG, knit line dispense techniques and automation motion techniques play a critical role in proper bead dispense and achieving the desired knit line. In addition, here are some other important considerations:

  • Rheological properties of the material
  • Material viscosity
  • Temperature
  • Bead profile and functionality
  • Dispense valve sealing technology
  • Dispense parameters
  • Equipment fixturing
  • Substrate design and complexity

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