Site: Meiko Company
732, Shimoimai
Futaba-cho, Kitakomagun
Yamanashi 407-01, Japan

Date Visited: 14 December 1995

JTEC/WTEC Attendees: L. Weiss (report author), P. Fussell, A. Lightman, R. D. Shelton

Hosts:

Yosie Ueno

Tomio Ueno

Kazuo Yoshida

Koki Hiizumi

Minao Ueno

Seiji Shimizu

HISTORICAL PERSPECTIVE

There are approximately 1,000 jewelry manufacturers, employing 8,000 people, in the Yamanashi Prefecture where Meiko is located. However, the number of skilled laborers who can manually build intricate wax jewelry patterns is declining, and companies are going overseas for cheaper labor. In response, the Industrial Research Center in the Yamanashi Prefecture began to develop a machine to automate manufacturing in 1987, with 50% of the funding from the national government and 50% from the local prefecture. The first prototype machine was completed in 1991. The Industrial Research Center then went to Meiko to finance and to manufacture a commercial machine. Meiko is a local manufacturer of measurement instrumentation (gas analyzers and pressure and temperature sensors) with 80% of its products OEMed by Fuji Electric Corporation. Meiko was selected to develop this modeler because of the company's close relationship to Fuji Electric (so it is well capitalized) and also because of its internal capability to meet development needs. Meiko developed the software, resin, and process for jewelry applications. After a 6-month beta program, Meiko incorporated the user feedback and began sales.

OVERVIEW

Meiko manufactures and markets a low-accuracy, photoresin-based rapid prototyping system optimized for making master patterns for plaster mold castings for jewelry applications. It also produces and markets a CAD system (JCAD3) focused on the needs of the jewelry industry. Meiko has sold 10 of its "laser stereolithography" machines since December 1994 at a price of ¥14.01 million (including software but not the PC). JCAD3 can be purchased separately for ¥1.5 million. Since the machine is not affordable by the hundreds of small jewelry foundries in their prefecture, the company also serves as a service bureau.

Process

The machine, which goes by the name Meiko, is a photoresin-based system using a HeCd laser delivered through a fiberoptic manipulated by XY translational stages. The recoating mechanism is a simple doctor blade device.

NEEDS, GOALS, AND OBJECTIVES

There is a need to automatically build patterns (for making plaster molds) for the jewelry industry, because of the declining number of skilled workers able to manually build these intricate wax parts. There is also a need to build patterns less expensively, since jewelry manufacturers are going overseas for cheaper labor. There is not a need for high accuracy in this application. Meiko executives believe that their apparatus, intended for jewelry applications, is affordable only by jewelry foundries with at least ¥1 billion in sales. There are approximately 10 such companies in the Yamanashi Prefecture, which accounts for a large proportion of jewelry manufacturing in Japan.

The Meiko executives were not optimistic about future sales, because the jewelry market is undergoing a contraction. In response, they are looking for new markets. They perceived medical parts as being potentially interesting. The automotive connector market was also interesting, but the relatively low accuracy and material property stability of the Meiko procedure would prevent them from competing.

Since most jewelry foundries cannot afford to purchase the Meiko machine, there is a need for affordable CAD systems so that the jewelry manufacturers can create CAD models for service bureaus. The CAD systems must also be easy to use, since the jewelry industry has little or no experience with such systems.

MATERIALS

The resin is manufactured by Shikoku Kaisei Industry and was developed by this company along with Koki Hiizumi of Meiko. Mr. Hiizumi characterized this material as an "acrylate-based resin." This resin does not age well, its dimensional stability is poor, and its mechanical properties degrade with time. It has a relatively low viscosity (140 cps), to facilitate recoating. They are also in the process of developing an epoxy-based resin called UCC1602.

APPLICATIONS

The primary application is for making patterns from which to produce plaster castings for making jewelry.

MACHINE DESIGN

As noted above, the Meiko machine is a photoresin-based system using a HeCd laser (10 mW, 325 nm, .08 mm spot size, manufactured by Ushio) delivered through a fiberoptic to a focusing lens that is manipulated by a screw-driven XY plotter. The laser costs about ¥2.5 million and is the cost-limiting component in this system. The recoating mechanism is a simple doctor blade, single-pass configuration. While the low-viscosity resin (140 cps) eliminates the need for a "deep-dip," a significant period of time is still required to permit the resin to level.

The working volume is 160 mm (X) x 120 mm (Y) x 100 mm (Z). Typical layer thickness are 50 µm with a range of 30-70 µm. The drawing speed is 80 mm/min. A typical ring pattern, which is built up vertically, takes about 2-2_ hours to build.

Meiko has applied for a number of patents. Meiko executives consider their Z movement patent as the most important for their technology.

CAD

The Meiko CAD modeling software, JCAD3, was developed by Professors M. Ito and S. Furukawa at Yamanashi University and by Mr. S. Shimizu and Mr. M. Abe at Yamanashi Technical Center. It is a surface modeler based on "S-curves." As previously noted, the goal was to create a low-cost, easy-to-use modeler for jewelry design applications. The JTEC/WTEC team did not have the time to go into the details of this CAD tool; however, we assume that its use is facilitated by making standard jewelry design features (e.g., facets, ring shapes, etc.) easy to add to the design model. The Meiko apparatus can accept either STL or DXF file formats.


Published: September 1996; WTEC Hyper-Librarian