The influence of flow and thermal properties on injection pressure and cooling time prediction

In order to further investigate the influence of mold temperature in rapid heat cycle molding on shrinkage of plastic past, a self-developed vehicle-used blue-tooth front shell high-gloss mold and an auxiliary device for controlling the mold temperature were employed in experiments. And the effect of the other parameters on shrinkage of part with fixed or changed mold temperature conditions was also studied. Results reveal that the shrinkage of RHCM part is reduced obviously compared with a conventional one, decreasing as quasi-linear with mold temperature increased gradually. At same mold temperature conditions, packing pressure, followed by packing time, is the most significant parameter on shrinkage of part, while cooling time has almost no impact on it. Melt temperature and injection pressure effecting on shrinkage of part exists a critical value, near the thermal deformation temperature of plastic. When mold temperature is set below this temperature, injection pressure has more significant than melt temperature, but it is the opposite. With being elevated gradually of mold temperature, shrinkage of part shows a slight decrease trend under same melt temperature and injecting pressure. While it fluctuates as a “V” shape with a narrow range under same packing pressure, packing time and cooling time presumed conditions, and reaches the minimum near the thermal deformation temperature of plastic.

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PENGARUH INJECTION TIME DAN BACKPRESSURE TERHADAP CACAT PENYUSUTAN PADA PRODUK KEMASAN TOPLES DENGAN INJECTION MOLDING MENGGUNAKAN MATERIAL POLISTYRENE

Jurnal Teknik Mesin ◽

10.22441/jtm.v4i3.1269 ◽

2017 ◽

Vol 4 (3) ◽

pp. 15

Author(s):

U. Wahyudi

Keyword(s):

Quality Control ◽

Injection Molding ◽

Injection Pressure ◽

Cooling Time ◽

Injection Time ◽

Injection Speed

Produk kemasan kue atau toples adalah produk rumah tangga yang sangat dibutuhkan untuk menaruh berbagai macam-macam kue kering, Produk plastik ini terdiri dari badan dan tutup, kedua komponen ini pada saat dirakit memerlukan kepresisian yang lumayan bagus oleh karena material yang digunakan plastik, maka faktor penentuan penyusutan(shrinkage) memegang peranan sangat penting pada saat dicetak dengan mesin injection molding yang menggunakan material polistyrene. Pada saat produksi pernah terjadi kegagalan produk fitting terlalu kencang dan ada juga fitting yang kendor antara tutup dengan badan akibatnya produk tidak lolos produksi oleh quality control. Didalam tugas akhir ini penulis melakukan langkah-langkah bagaimana teknik menganalisa cacat penyusutan (shrinkage) material plastik terutama di khususkan material polystyrene dimulai dari proses injection molding lalu diambil sampel produk dengan tingkat pengujian yang berbeda lewat settingan parameter. Dengan waktu injeksi dan backpressure yang berbeda-beda akan menghasilkan ukuran produk dan nilai shrinkage yang berbeda pula. Nilai temperatur leleh yang baik digunakan untuk material polistyrene dengan ketebalan produk kemasan toples 0,75 mm, diameter produk 140,94 mm dan tinggi 58,29 mm. berkisar antara 2400C – 3100C. Cacat penyusutan pada material polystyrene pasti ada walaupun tidak sebesar pada material lain seperti PP dan LDPE dan bisa diminimalkan dengan setting parameter proses yang bagus. Nilai shrinkage yang baik dan ideal dan sesuai standar terjadi pada settingan backpressure 30 kgf/cm² dengan waktu injeksi yaitu 2 detik. Dengan parameter yang konstan, mulai dari injection speed 120 cm/s, 65 cm/s. Injection pressure 1400 kgf/cm² dan pack pressure 1200 kgf/cm², pack time 0,5 sec, Shot size 55 mm, kemudian cooling time 2 detik dengan temperatur mold 600 C.

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Optimisation of Processing Condition Using Taguchi Method on Warpage for HDPE-Clay Composite

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.660.28 ◽

2014 ◽

Vol 660 ◽

pp. 28-32 ◽

Cited By ~ 1

Author(s):

Mohd Halim Irwan Ibrahim ◽

M.H.A. Manaff ◽

M.H. Othman ◽

N. Mustafa ◽

S.R. Masrol ◽

...

Keyword(s):

Taguchi Method ◽

Signal To Noise Ratio ◽

Processing Condition ◽

Injection Pressure ◽

Cooling Time ◽

Screening Tests ◽

Ratio Analysis ◽

Signal To Noise ◽

Melt Temperature ◽

Injection Speed

Injection molding is one of the most important processes in manufacturing nowadays. Thus, attention must be give towards the optimization of the product defects. Parameters have been chosen by screening tests to improve the process quality. The main purpose of this study is to optimize the processing condition using Taguchi Method on shrinkage for HDPE-Clay specimen. The experiment starts by preparing the mixture between HDPE and clay. Then, screening test is conducted to obtain the parameters. The parameters are melt temperature, injection speed, injection pressure and cooling time. By using the array orthogonal L9 (34), signal to noise ratio and ANOVA were conducted. Based on the S / N ratio analysis, best combination can be produced for warpage (melt temperature: 190°C, injection speed: 40%, injection pressure: 30% and cooling time: 3 seconds). While for ANOVA, melt temperature is most significant with 60.28% for warpage.

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Shrinkage and Warpage in the Permanent Shape of Sape-Memory Polyurethane Parts

Materiale Plastice ◽

10.37358/mp.21.4.5536 ◽

2022 ◽

Vol 58 (4) ◽

pp. 102-113

Author(s):

Sukran Katmer ◽

Cetin Karatas

Keyword(s):

Shape Memory ◽

Injection Moulding ◽

Flow Direction ◽

Injection Pressure ◽

Cooling Time ◽

Mould Temperature ◽

Melt Temperature ◽

Packing Pressure ◽

Permanent Shape ◽

Packing Time

The shape memory effect, as the most important ability of shape memory polymers, is a working property and provides the design ability to shape memory polymer features. Shrinkage and warpage are important parameters to control the dimensional accuracy of permanent and temporary shapes of an injection moulded shape memory polyurethane (SMPU) part. In this study, the effects of injection moulding parameters on the shrinkage and warpage of the permanent shape of moulded SMPU parts were experimentally investigated. The parameters of injection pressure, melt temperature, mould temperature, packing pressure, packing time, and cooling time, were chosen as the injection moulding control factors. Taguchi�s L27 orthogonal array design table was used with six injection moulding parameters and their three levels. The results showed that the part has different shrinkage ratios in three main directions, namely, the flow direction, perpendicular to the flow direction, and the direction through the thickness. The results of the analysis of variance showed that the cooling time is the most influential parameter on both the shrinkage (except in thickness) and warpage. The shrinkage in the flow direction as well as in perpendicular to the flow direction decreased with increasing the cooling time. Warpage also decreased with increasing the cooling time. Injection pressure and melt temperature were found to be effective on shrinkage in thickness. Effects of mould temperature, packing pressure, and packing time were found to be limited. A statistically significant relationship has been noticed among shrinkage, warpage, and residual stresses during the study.

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