Casting Technology

Iron Casting

We realize highly reliable manufacture, made possible by our product-specific production systems and streamlined operations.

Capable of forming iron in any desired shape, casting – as the technology vital to the manufacture of parts and components mainly for automobiles and construction machinery – has supported the development of major Japanese industries. As times change, ever higher performance is expected of cast iron parts and components in terms of light weight, compactness, functionality and eco-friendliness. In order to meet these customer needs, Koyama has established its own advanced production system while continually enhancing its technological strength. The results are our proud cast iron products with world-leading performance capabilities.

Examples of Manufacturing Processes

Molding of master mold and core

We have melting facilities such as electric furnaces and cupolas, out of which we choose and use the most suitable one according to material properties and required cost performance. We discharge the optimal molten metal after analyzing and adjusting its 48 different components using a CE meter and an emission spectrophotometer.

Molding of the master mold and core
This is the process to make the master mold by pouring molten metal into the desired product shape, and to mold the core which will become a hollow cavity that forms the interior of the cast product. This process requires the highest possible precision and strength. Our originally developed contactless core has realized the casting of parts and components with extremely complex shapes.

Pouring of molten metal
Our highly efficient and energy-saving automated facilities enable us to pour molten metal into the mold – safely, accurately and efficiently. We can supply cast products of the highest possible dimensional accuracy thanks to the use of state-of-the-art casting machines.

Pouring of molten metal

Cooling, flask removal, and shot blasting (sand shake-out)
After a certain period of cooling time suitable for the hardness of the product, the product is separated from the sand mold (flask removal) and the sand is removed from the product by striking iron particles against it through shot-blasting.

Deburring and finishing
Our in-house-developed “Barinder” has functions of a high-precision NC machine tool. It enables the finishing precision – and at a low cost – as required by the customer.

Heat treatment
Heat treatment is given to relieve stress inside the cast product and to adjust hardness. At Koyama, heat treatment of excellent combustion efficiency is possible thanks to the adoption of a waste heat recovery burner.

Washing process
We use a water-blaster nozzle and a robot nozzle to remove sand adhered to the product’s interior surface.


In addition to process-by-process quality inspection, we also conduct pre-shipment inspections based on the strictest standards, which include shape measuring as well as non-destructive inspections using an endoscope and X-ray.

Light Metal (Aluminum) Casting

High-precision, complex, lightweight and high-strength parts and components … We meet all these industrial needs with our own original aluminum casting technology.

unlimited thanks especially to the metal being weight lighter thaniron. Koyama succeeded in developing a breakthrough core-forming technology, which resulted in ever more complex and functional aluminum cast products. Koyama’s inimitably superb technological strength coupled with its outstanding product capabilities keep the company as the industry leader of its field. Koyama also deserves a special mention for the development of its proprietary water-cooling technology for special molds, which effectively densifies product structures. These advantages together allow us to continually take up the challenge of as yet unknown possibilities and encourage us to plan, develop and manufacture cast parts and components that meet diverse industrial needs.

Pouring of molten metal

This process uses gas to melt an aluminum alloy that has specific properties as required by customers for their products.。

Forming of gravity mold and core
Produced in this process are a mold (that allows molten aluminum alloy to be poured using gravity) and a core that forms the cavity inside the product. We produce both gravity molds and cores within our own factory, the results being parts and components that meet diverse needs of the customer such as products of complex shapes, high functionality or thin walls.

Pouring of molten metal
We use highly efficient, energy-saving automatic pouring equipment to pour molten metal into the mold – safely, accurately and efficiently.


Deburring for finishing
Using our proprietary high-precision Barinder with NC machining functions, we realize the perfect level of finishing precision as required by the customer – at low costs.

Heat treatment
Our fully automated heat treatment process efficiently eliminates even the slightest distortion and adjusts hardness.

Our strength lies in us delivering the product after providing the cast product with machining and assembling it into a complete part or component.

3D measurement

3D measurement
Whether it is a small part or a large component, we conduct three-dimensional measurement of product shapes as part of our quality inspection to guarantee quality in the ultrahigh-precision order that perfectly meets the needs of the customer.

Final inspection
Our strictest quality inspections include, in addition to process-by-process inspections, endoscopic and non-destructive inspections such as using X-rays prior to final shipment.