Research Papers

Influence of Injection and Cavity Pressure on the Demoulding Force in Micro-Injection Moulding

[+] Author and Article Information
C. A. Griffiths

School of Mechanical, Aerospace
and Civil Engineering,
The University of Manchester,
Manchester M13 9PL, UK

S. S. Dimov

School of Mechanical Engineering,
The University of Birmingham,
Birmingham B15 2TT, UK

S. G. Scholz

Institute for Applied Computer Science,
Karlsruhe Institute of Technology,
Karlsruhe 76344, Germany

G. Tosello

Department of Mechanical Engineering,
Technical University of Denmark,
2800 Kgs. Lyngby, Denmark

A. Rees

College of Engineering,
Swansea University,
Swansea SA2 8PP, UK

Contributed by the Manufacturing Engineering Division of ASME for publication in the JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING. Manuscript received May 13, 2011; final manuscript received February 26, 2014; published online April 11, 2014. Assoc. Editor: Allen Y. Yi.

J. Manuf. Sci. Eng 136(3), 031014 (Apr 11, 2014) (10 pages) Paper No: MANU-11-1170; doi: 10.1115/1.4026983 History: Received May 13, 2011; Revised February 26, 2014

The paper reports an experimental study that investigates part demoulding behavior in micro-injection moulding with a focus on the effects of pressure and temperature on the demoulding forces. In particular, the demoulding performance of a representative microfluidics part was studied as a function of four process parameters, melt temperature, mould temperature, holding pressure, and injection speed, employing the design of experiment approach. In addition, the results obtained using different combinations of process parameters were analyzed to identify the best processing conditions in regards to demoulding behavior of microparts when utilizing a COC polymer to mould them.

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Fig. 1

PC part demoulding defect

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Fig. 2

μ-IM injection and cavity pressure curves, including characteristic numbers

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Fig. 3

Curve of demoulding force over time

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Fig. 4

(a) Microfluidic part (b) mould insert

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Fig. 5

Microchannel features

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Fig. 6

Cavity (Pc) and injection (Pi) measurement positions

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Fig. 7

Normal distribution of P results

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Fig. 8

Histogram of Pwork and Femax experimental results (the plotted points represent the average values of the 10 trails at each setting while the error bars represent the 1σ standard deviation)

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Fig. 9

Histogram of Pmax and Femax experimental results (the plotted points represent the average values of the 10 trails at each setting while the error bars represent the 1σ standard deviation)

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Fig. 10

Main effects' plot of Femax (error bars represent the average 1σ standard deviation of the considered effects; Femax σ ranges from 0.6 to 1.4 N)

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Fig. 11

Main effects' plot of Pmax (error bars represent the average 1σ)

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Fig. 12

Main effects' plot of Pwork (error bars represent the average 1σ)

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Fig. 13

The effects of Vi, Ph, and Tm interactions on Pmax




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