Undercut Free Parting Direction Determination for Injection Molded Parts Using Surface Based Accessibility Analysis

Particularly for rapid tooling applications, delivering prototype parts with turn-around times of less than two weeks requires fast, proven mold design methods. We present a region-based approach to automated mold design that is suitable for simple two-piece molds (consisting of core and cavity), as well as molds with many additional moving sections. In our region-based approach, part faces are partitioned into regions, each of which can be formed by a single mold piece. The basic elements of our approach are concave regions (generalized pockets) and convex faces since these elements are central to the identification of regions. This paper focuses on the initial steps of automated mold design, including a problem formulation, methods for identifying the basic elements from part faces, and combining them into regions. By seeking to minimize the number of mold pieces, different partitions of faces into regions are explored until the smallest number of regions is found. During this process, a linear programming problem is adopted for finding a satisfactory parting direction of a region. Algorithms are presented for the region generating and combining process. Our approach is illustrated with several examples of industrial injection molded parts.

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Generation of optimal parting direction based on undercut features in injection molded parts

IIE Transactions ◽

10.1080/07408179908969895 ◽

1999 ◽

Vol 31 (10) ◽

pp. 947-955 ◽

Cited By ~ 18

Author(s):

M.W. FU ◽

J.Y.H. FUH ◽

A.Y.C. NEE

Keyword(s):

Molded Parts ◽

Parting Direction ◽

Injection Molded

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Determination of Mold Parting Direction Based on Automatic Molding Feature Recognition

Volume 2: 19th Computers and Information in Engineering Conference ◽

10.1115/detc99/cie-9119 ◽

1999 ◽

Author(s):

Zhengchao Gu ◽

Zhenyong Zhou ◽

Shuming Gao ◽

Jiaoying Shi

Keyword(s):

Feature Recognition ◽

Recognition Algorithm ◽

Injection Mold ◽

Automatic Design ◽

Molded Part ◽

Molded Parts ◽

Automatic Feature Recognition ◽

Parting Direction ◽

Injection Molded

Abstract Mold parting direction is an important factor to verify the moldability of a molded part. The determination of mold parting direction is the first step to achieve automatic design of an injection mold or a casting die. A method using automatic feature recognition is proposed in this paper to automatically determine parting direction of an injection mold. Parting direction determination of a molded part consists of three steps in our approach. First, all features of a molded part are recognized using a universal hint-based feature recognition algorithm, and all candidate and feasible parting directions of each feature are determined according to the type of the feature. Then, all candidate parting directions of the molded part are automatically generated from all recognized features candidate parting directions. The optimal parting direction is finally chosen based on certain criteria. The case studies on several industrial parts show that the proposed method is effective and efficient in determining the optimal parting direction of injection molded parts.

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A Study on the Birefringence Measurement in Injection Molded Parts Using Two Different Laser Sources and R-G-B Separation of White Light

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.187 ◽

2006 ◽

Vol 326-328 ◽

pp. 187-190

Author(s):

Jong Sun Kim ◽

Chul Jin Hwang ◽

Kyung Hwan Yoon

Keyword(s):

White Light ◽

Low Cost ◽

Main Idea ◽

Injection Molding Process ◽

Molding Process ◽

Laser Method ◽

High Productivity ◽

Molded Parts ◽

Injection Molded ◽

Plastic Parts

Recently, injection molded plastic optical products are widely used in many fields, because injection molding process has advantages of low cost and high productivity. However, there remains residual birefringence and residual stresses originated from flow history and differential cooling. The present study focused on developing a technique to measure the birefringence in transparent injection-molded optical plastic parts using two methods as follows: (i) the two colored laser method, (ii) the R-G-B separation method of white light. The main idea of both methods came from the fact that more information can be obtained from the distribution of retardation caused by different wavelengths. The comparison between two methods is demonstrated for the same sample of which retardation is up to 850 nm.

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Silane-Functionalized Sheep Wool Fibers from Dairy Industry Waste for the Development of Plasticized PLA Composites with Maleinized Linseed Oil for Injection-Molded Parts

Polymers ◽

10.3390/polym12112523 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2523

Author(s):

Franciszek Pawlak ◽

Miguel Aldas ◽

Francisco Parres ◽

Juan López-Martínez ◽

Marina Patricia Arrieta

Keyword(s):

Linseed Oil ◽

Microstructural Analysis ◽

Dairy Industry ◽

Poly Lactic Acid ◽

Industry Waste ◽

Wool Fibers ◽

Molded Parts ◽

Silane Modification ◽

Injection Molded ◽

Sheep Wool

Poly(lactic acid) (PLA) was plasticized with maleinized linseed oil (MLO) and further reinforced with sheep wool fibers recovered from the dairy industry. The wool fibers were firstly functionalized with 1 and 2.5 phr of tris(2-methoxyethoxy)(vinyl) (TVS) silane coupling agent and were further used in 1, 5, and 10 phr to reinforce the PLA/MLO matrix. Then, the composite materials were processed by extrusion, followed by injection-molding processes. The mechanical, thermal, microstructural, and surface properties were assessed. While the addition of untreated wool fibers to the plasticized PLA/MLO matrix caused a general decrease in the mechanical properties, the TVS treatment was able to slightly compensate for such mechanical losses. Additionally, a shift in cold crystallization and a decrease in the degree of crystallization were observed due to the fiber silane modification. The microstructural analysis confirmed enhanced interaction between silane-modified fibers and the polymeric matrix. The inclusion of the fiber into the PLA/MLO matrix made the obtained material more hydrophobic, while the yellowish color of the material increased with the fiber content.

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