Making a variety of containers, and producing high-precision molds requires "craftsmanship"

Izumi Seiki Co., Ltd.

6-6-46 Takihama, Niihama, Ehime 792-0893

TEL (0897) 32-6232 FAX (0897) 32-6535

Certified products and technology
IML mold (in-mold label), SHI valve gate system

Izumi Seiki, as the plastic mold manufacturing division of Sumitomo Heavy Industries Ltd., was established in 1987 as a joint venture of Sumitomo Heavy Industries, Plastic Machinery Division and the Sanko Machinery Industry (Niihama City).

The core business is the design and manufacture of molds used in the manufacturing technology of plastic products called injection molding. We mainly produce food-related products such as yogurt or pudding containers or plastic bottles as well as medical-related products, such as syringes or petri dishes.

We can also handle molds used for "in-mold labeling", the injection molding technique where the container molding and label attachment are done at the same time, and "SHI pulp gate system" where resin can be injected into the mold without unnecessary raw materials. We also manufacture molds that provide added-value such as multi-color or opaque labels and cost reduction

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In injection molding, a plastic product is made by pouring plastic resin into the gap of the mold. We mold very thin products with wall thickness of only 0.4mm to 0.5mm, meaning that high accuracy is required in the mold. "It is difficult to ensure concentricity." in particular. Put simply, concentricity is an indicator of whether the product is uniformly processed around the central axis. In recent years the shape of food containers has become complicated, we test repeatedly by, for example, changing the direction of positioning to continue to increase the accuracy, and finally we finish the mold by "polishing" by craftsmen. Depending on the product there can be visual and texture requirements such as highly transparent container surfaces, and rough surfaces. Such texture is dependent on the processing conditions of the mold surface. The company explains the reason to stick to manual work, "making subtle size adjustment and texture cannot be done by machine.".

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Since food manufacturers require unique containers for their food, the container design changes for each product. Therefore, "It is rare for us to manufacture the same mold twice, we make a new mold every time" he says. The company has experience with making difficult molds such as an eighteen-sided shape with a pattern and a texture like pottery. Facing these ever-changing requests, the "importance of determining what the challenge is for the new work", and repeated trial and error towards solving the problems, have been factors in increasing the level of mold design know-how and processing technology.

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The policy of the company is to continue to promote the automation of the production process in the future. We want to build a system by 2016, but the final polishing process step that "cannot be done by a machine" will utilize "craftsmanship” as we have always done. Also the company plans to build a network of partner companies to enable outsourcing of processes such as the machining of the mold parts in busy periods. The company also plans to arrange a system to evaluate and guide partner companies.

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