Transient viscoelastic heating characteristics of polyethene under high frequency hammering during ultrasonic...

Area of Science:

• Polymer Science
• Materials Engineering
• Manufacturing Technology

Background:

• Ultrasonic plasticizing micro-injection molding offers advantages like low energy consumption and reduced waste for micro-nano part fabrication.
• The precise mechanisms and transient viscoelastic heating phenomena under ultrasonic high-frequency hammering remain incompletely understood.

Purpose of the Study:

• To investigate the transient viscoelastic thermal effect and microscopic polymer behavior under ultrasonic processing.
• To elucidate the relationship between ultrasonic process parameters and polymer heat generation.

Main Methods:

• A combination of experimental approaches and molecular dynamics (MD) simulations was employed.
• A simplified heat generation model was developed, and high-speed infrared thermal imaging was used for temperature data acquisition.
• Single-factor experiments examined heat generation with varying plasticizing pressure, ultrasonic amplitude, and ultrasonic frequency.

Main Results:

• Ultrasonic process parameters significantly influence the forms of polymer heat generation.
• Three primary heat generation patterns were identified: dominant at the sonotrode head, dominant at the plunger end, and simultaneous at both ends.

Conclusions:

• The study clarifies the transient viscoelastic thermal effects in ultrasonic plasticizing micro-injection molding.
• Understanding these heat generation patterns is essential for optimizing process parameters and improving the manufacturing of micro-nano polymer parts.