Ultra Sonic Welding Case Study

1. Case Study
Raviteja Gangisetty

2. Case Background Information
 The Enclosures to be developed Primarily for Indian Market & overseas market.
 Enclosures consists of different plastic parts, which needs to be joined with the help of Ultrasonic welding process. To Achieve this,
there is a need to select appropriate resin, design mechanical architect & layout, develop & amp and detail.
 Multiple components especially plastic injection moulded &amp and sheet metal. To archive final assembly, these multiple
components needs to be joined for quick assembly. Hardware design need to be aligned with enclosure design & layout.
Compliance is major concern in Enclosures which need to be addressed during design.

3. Case Questions:
what would be design consideration to join two plastic enclosure parts with Ultrasonic welding
process?
 A particular part’s joint design depends upon factors such as type of plastic, part geometry and the requirements of the weld.
There are basic requirements in joint design for Plastic Enclosures:
• A uniform contact area
• A small initial contact area
• A means of alignment
• Near Field vs. Far Field Welding,
• Parallel Contact
Ultrasonic welding Part Design Considerations:
• Sharp Corners, Holes or Voids, Appendages and Diaphragming.
• Welding frequencies
• Materials considerations
• Joint design impact
• tooling and fixtures
• Welding parameters

4. Major concerns need to deal while designing casted enclosures?
Major concerns while designing casted enclosures:
• Maintain Uniform wall thickness
• Parting Lines for Cast Components and Products.
• Avoid under cuts (Internal & External)
• Ribs, External Corners & Metal Savers
• Provide Drafts and Fillets for smooth metal flow.
• Provision of inserts & slider movement

5. What are different design criteria that effects resin selection process & how would you deal
with it?
Material Considerations in Ultrasonic Welding:
 To Joining two thermoplastic parts (dissimilar Plastic ), it is necessary that the materials be chemically compatible. Otherwise, even
though both materials may melt together, there will be no molecular bond.
 A good example would be trying to weld polyethylene to polypropylene. Both semi-crystalline materials have a similar appearance
and many common physical properties. However, they are not chemically compatible, and are unable to be welded to each other.
 In addition, the two materials must have similar melt index numbers and similar melt temperatures. Several factors may affect the
weldability of the parts:
• Flame Retardants,
• Chemical Compatibility
• Mold Index
• Regrind,
• Hygroscopicity,
• Mould Release Agents,
• Lubricants, .
• Plasticizers,
• Fillers,
• Colorants and Resin Grade

6. what are different options to assemble above mention parts?
 The integrity of an ultrasonically staked assembly depends upon the geometric relationship between the stud and horn cavity, and
the ultrasonic parameters used when forming the stud.
 Proper stake design produces optimum stud strength and appearance with minimum flash.
• Staking
• Insertion
• Swaging and Forming
• Bonding and Slitting
• Alignment holes or Slots for easy locating of counter parts
• Provide Snaps or Dowel pins.
• Jigs and Fixtures.

7. What are different tempering possibilities & how to address during design phase?
 Tempering is to releases the stress in the plastic. Tempering or annealing, is heating up the plastic carefully in an oven and cooling
it down very slowly. Once the material is cool, most of the extrusion stress will be relieved.
 Drilling deep holes, uneven thickness reduction and screw thread cutting are the machining operations producing internal
stresses, which should be reduced by annealing.
• Reduction of internal stresses caused by extrusion or machining.
• Crystallization enhancement for strength and chemical resistance.
• Increase dimensional stability over a wide temperature range.
To over come the tempering possibilities during design phase follow below techniques:
• Batch annealing.
• Conveyorized Forced Hot Air Annealing (CFHA)..
• Infrared annealing (IR).

8. Thank Q