In order to prevent cracking, an approach to heat treatment level of aluminum materials was required also. The heat treatment level is T5 (it subjected to artificial aging hardening after cooling from high temperature processing). Takeyama, who is want to eliminate cause of cracking immediately, is find some valuable information on Internet and books carefully and starts to think that the material processing of O level (the material was annealed to get a soft state) is the best one .

However, Komatsu Kogyo at the time did not have any information (know-how) about O-level. Based on the literature, O level material was made in a heat treatment furnace for trial, and the best material was searched together with the trial of material shape.

Takeyama who works on heat treatment and looks at it. Naito who looks strict but gentle inside. With 20 years of career gap, the cold forging technique has been surely delivered.

As the heat treatment level changes, mechanical properties and surface hardness of part will also change. Nishimura, who is in charge of sales, took charge to get understanding from the customer. He explains the content, if it passed the endurance test, then it should be no problem and the development went forward.

As an aside, the adjuster chain, which is an exterior part, it is not only has to meet requirement about mechanical properties but also will be evaluated from the design. The design approval was strict only for the adjuster chain, which is the best-selling model at customer site, but this high hurdle has somehow exceeded.