Geometrical algorithms for automated design of side actions in injection moulding of complex parts

Multi-Piece molds, which consist of more than two mold pieces, are capable of producing very complex parts—parts that cannot be produced by the traditional molds. The tooling cost is also low for multi-piece molds, which makes it an ideal candidate for pre-production prototyping and bridge tooling. However, designing multi-piece molds is a time-consuming task. This paper describes geometric algorithms for automated design of multi-piece molds. A Multi-Piece Mold Design Algorithm (MPMDA) has been developed to automate several important mold-design steps: finding parting directions, locating parting lines, creating parting surfaces, and constructing mold pieces. MPMDA constructs mold pieces based on global accessibility analysis results of the part and therefore guarantees the disassembly of the mold pieces. A software system has also been developed and successfully tested on several complex industrial parts.

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Metal Injection Moulding of Titanium Medical Components

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.704.155 ◽

2016 ◽

Vol 704 ◽

pp. 155-160 ◽

Cited By ~ 2

Author(s):

Vera Friederici ◽

Thomas Hartwig

Keyword(s):

Surface Roughness ◽

Surface Quality ◽

Injection Moulding ◽

Optimal Parameters ◽

Serial Production ◽

Metal Injection Moulding ◽

Titanium Surfaces ◽

Cleaning Cycle ◽

Enhanced Surface ◽

Complex Parts

The metal injection moulding technique is already established for serial production of complex parts, mostly from various stainless steels. However, for other materials, especially for titanium parts there is still the need for superior purity and enhanced surface quality. Facing the challenge of obtaining suitable medical titanium MIM parts, advances have been made at Fraunhofer IFAM over the last few years.One strategy to overcome the high risk of carbon up-take was to adjust the sintering program. Very low Argon flow rates, 50 mbar pressure and two hours dwell time at 1350°C were found to be optimal parameters. A cleaning cycle prior to the actual sintering at 1450°C under hydrogen was also found to enhance the results.Another strategy involved the choice of binder components. Stearic acid, which is often used to improve wettability of binder to powder particle, and high polymer content affect the oxygen content of the titanium parts. Low amounts of both are beneficial for high purity parts.Other investigations were performed concerning the surface quality. It was found that the surface roughness of the mould has an effect on the surface roughness of the sintered parts. Although sintered titanium surfaces as such exhibit quite rough surfaces of about 2-3 µm (Ra value) the influence of the surface finish of the mould was detectable. Using very fine powders of only 15 µm mean particle size and a polished mould a very low surface roughness of less than 1.2 µm on the sintered part was obtainable.

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A Step Towards Automated Design of Side Actions in Injection Molding of Complex Parts

Geometric Modeling and Processing - GMP 2006 - Lecture Notes in Computer Science ◽

10.1007/11802914_35 ◽

2006 ◽

pp. 500-513 ◽

Cited By ~ 3

Author(s):

Ashis Gopal Banerjee ◽

Satyandra K. Gupta

Keyword(s):

Injection Molding ◽

Automated Design ◽

Complex Parts

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Fluid-Assisted Injection Moulding Simulation: Virtual Prototyping for Complex Parts

Innovation in Engineering Computational Technology - Computational Science, Engineering & Technology Series ◽

10.4203/csets.15.14 ◽

2009 ◽

pp. 287-308 ◽

Cited By ~ 1

Author(s):

J. Sienz ◽

J.F.T. Pittman ◽

A. Polynkin

Keyword(s):

Injection Moulding ◽

Virtual Prototyping ◽

Complex Parts

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New injection moulding process for functional and complex parts

Metal Powder Report ◽

10.1016/s0026-0657(99)93586-5 ◽

1999 ◽

Vol 54 (7-8) ◽

pp. 37

Keyword(s):

Injection Moulding ◽

Moulding Process ◽

Injection Moulding Process ◽

Complex Parts

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Powder Injection Moulding (PIM) of Mesophase Carbon with Water-Based Binders

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.45.711 ◽

2006 ◽

Vol 45 ◽

pp. 711-713 ◽

Cited By ~ 2

Author(s):

Michael Gruhl ◽

B. Derfuss ◽

Christian Rottmair ◽

Andreas Volek ◽

Robert F. Singer

Keyword(s):

Mechanical Properties ◽

Injection Moulding ◽

Gelling Agent ◽

Powder Injection ◽

High Porosity ◽

Heating Rates ◽

Powder Injection Moulding ◽

Water Based ◽

High Heating ◽

Complex Parts

Since there are no net-shape techniques for complex parts made of mesophase carbon available yet, this work focuses on a powder injection moulding (PIM) approach. The single biggest problem to overcome here is the overlap of debindering and pyrolysis/sintering of mesocarbon when using conventional binders, causing high porosity and cracks. Water-based binders with agar as gelling agent can avoid this problem effectively by removing the binder in an optimized drying step. The subsequent sintering can then be carried out at high heating rates, leading to better densification and good mechanical properties. Furthermore, the dependency of the rheological properties of the water-based feedstock on its water content is investigated.

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