Next Article in Journal
Resistance to Cleavage of Core–Shell Rubber/Epoxy Composite Foam Adhesive under Impact Wedge–Peel Condition for Automobile Structural Adhesive
Next Article in Special Issue
Comparative Studies on Two-Electrode Symmetric Supercapacitors Based on Polypyrrole:Poly(4-styrenesulfonate) with Different Molecular Weights of Poly(4-styrenesulfonate)
Previous Article in Journal
Acknowledgement to Reviewers of Polymers in 2018
Previous Article in Special Issue
Additive Manufacturing of Polypropylene: A Screening Design of Experiment Using Laser-Based Powder Bed Fusion
Open AccessArticle

The Improvement Effect and Mechanism of Longitudinal Ultrasonic Vibration on the Injection Molding Quality of a Polymeric Micro-Needle Array

State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin 300072, China
*
Author to whom correspondence should be addressed.
Polymers 2019, 11(1), 151; https://doi.org/10.3390/polym11010151
Received: 14 December 2018 / Revised: 12 January 2019 / Accepted: 13 January 2019 / Published: 17 January 2019
(This article belongs to the Special Issue Materials and Methods for New Technologies in Polymer Processing)
A polymeric micro-needle array with high quality has been fabricated using a longitudinal ultrasonic-assisted micro-injection molding (LUμIM) method. To realize the practicability and stability in actual industrial processing, this paper is aimed at studying the improvement mechanism of ultrasonic vibration on the molding quality. The melt-filling process in the micro-needle array cavity is simulated, and the improvement effect of ultrasonic vibration is discussed. The enhancement effect of ultrasonic vibration on material properties of polypropylene and polymethylmethacrylate parts are experimentally investigated. The results show that in the manufacturing of the micro-needle array part using LUμIM, the mold-filling quality is improved by the enhanced melt filling capability and pressure compensation effect, which are caused by the increased corner viscosity gradient, reduced the filling time and melt viscosity under ultrasonic vibration. Material properties of both the semi-crystalline polymer and amorphous polymer could be enhanced by the transformation of micromorphology. It is proved that for a semi-crystalline polymer, this novel method could be employed as a material properties enhancement method, and an optimal excitation voltage of ultrasonic vibration is obtained to achieve the best material properties. View Full-Text
Keywords: micro-injection molding; ultrasonic vibration; polymer material properties; polymer rheology; micro-needle array micro-injection molding; ultrasonic vibration; polymer material properties; polymer rheology; micro-needle array
Show Figures

Graphical abstract

MDPI and ACS Style

Gao, S.; Qiu, Z.; Ouyang, J. The Improvement Effect and Mechanism of Longitudinal Ultrasonic Vibration on the Injection Molding Quality of a Polymeric Micro-Needle Array. Polymers 2019, 11, 151.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop