Thick plating technology realizes mirror precision for molds
Through its lens mold manufacture and mass production operations, Nittoh has succeeded in manufacturing high precision mirror-finish inserts meeting all the requirements of design and manufacture.
Heat treated stainless steel is the material normally used for optical inserts, but this material alone is not sufficient to provide the necessary high precision mirror finish or aspherical surface accuracy. For this reason, Nittoh usually applies an electroless Ni-P plated surface of 100µm or thicker that we machine to a mirror finish with the required shape accuracy. Application of thick and accurate electroless Ni-P plating requires very advanced technologies, so the few platers in Japan who could do the work had a monopoly. We therefore set about researching and improving our own technologies in order to reduce development times for customers, and as a result developed the technology for forming electroless thick pitless plating. Nittoh has established a system of high quality thick plating that other companies cannot beat.
| No. | Evaluation Criteria | Results |
|---|---|---|
| 1 | Chemical composition | Nickel (89 to 91%), Phosphorus (9 to 11%) |
| 2 | Hardness | HV 535 (non heat treated) HV 561 (200°C heat treated) HV 800 (300°C heat treated) HV 900 (400°C heat treated) |
| 3 | Adhesion | No peeling when machining plated parts |
| 4 | Thickness uniformity | Good throwing power, with accuracy of up to ±10% of required thickness |
| 5 | Wear resistance | Good |
| 6 | Specific gravity * | 7.9 (plated) 7.8 (recrystalline after heat treated at 400°C or higher) |
| 7 | Melt temperature | 896°C |
| 8 | Electrical resistance | 36µΩ (plated) |
| 9 | Coefficient of thermal expansion * | 13ÁE0-6cm/cm/°C |
| 10 | Thermal conductivity * | 0.00105 to 0.0135 cal/cm/sec°C |
| E！E/td> | Magnetism | Nil (plated), but becomes magnetic after heat treated at 300°C or higher |
| E！E/td> | Structure | Completely non-crystalline when plated, but crystalline and showing segregation effect after heat treated at 300°C or higher |
* Data provided by plating solution manufacturer
4529 Konami, Suwa City, Nagano Prefecture 392-0131 Japan