Snap-fit joints in plastics.pptsunny-plastic.com/upload/201703/17/201703171402454555.pdf · •...
Transcript of Snap-fit joints in plastics.pptsunny-plastic.com/upload/201703/17/201703171402454555.pdf · •...
Snap-Fit Joints
in Plastics
Lanxess HK
Semi-Crystalline Product
Asia Pacific
• Introduction to Snap-Fit Joints in Plastics
• Snap-Fit Joint Types
• Design Factors for Snap-Fit Joint
• FEM Demonstration
Content
Introduction to Snap-Fit Joints
in Plastics
• Bonding
• Welding
• Mechanical Joining
Plastic Joining Techniques
• Rivets
• Screws
• Inserts
• Molded Threads
• Press Fits
• Snap Fits
• Simple
• Economical
• Rapid
• Separable / Inseparable
Snap-Fit Joint Benefits
More demanding
tolerances
Constant strength
Requires undercut
Relaxation /
Creep-failure
Snap Fit
vs.
Press Fit
Pullout
Force
Insertion
Force> @
Pullout
ForceInsertion
Force
No Additional
Parts Needed
Requires Fastener
Components
Vibration Resistant
Less Energy
Required
May Loosen
Under Vibration
Requires Tightening
Operation
Snap Fit
vs.
Screws
Hermetic Seal
Difficult
Hermetic Seal
Easy
Dissimilar Materials
Integrally Molded
Compatible Materials
Special Welding
Equipment
Snap Fit
vs.
Welding
Snap-Fit Joint Type
• Cantilever
• Annular
• Torsional
Snap-Fit Joint Types
Cantilever Snap Joint
Annular Snap Joint
Annular Snap Joint (cont.)
Torsional Snap Joint
U-Shaped Snap Joint
Discontinuous Annular Snap Joint
Snap Member
Hollow Cylinder Snap Joint
Before During After
BumpsSnap Member
Bumps
Distortion Snap Joint
Plan View Section View
Cantilever Variation Snap Joint
Snap In
Snap On
Snap Assembly Methods
Snap In
No Undercut Method
Typical Applications