Site: D-MEC, Ltd.
Design Model Engineering Center
25 Miyukigaoka, Tsukuba City
Ibaraki 305, Japan

Date Visited: 11 December 1995

JTEC/WTEC Attendees: R. Brown (report author), J. Beaman

Hosts:

Eijiro Tagami

Dr. Takashi Ukachi

Tsuyoshi Watanabe

Junichi Kuzusako

OVERVIEW

D-MEC was established in February 1990 by Japan Synthetic Rubber Co., Ltd. (JSR), the largest rubber company in Japan and the fourth largest in the world. In UV curable resins, JSR with Japan Fine Coatings (JFC) has had a 14-year standing alliance with DSM Resins in Chicago through a joint venture company. Sony is also closely allied with D-MEC's activities. Its operations are located in Tokyo within its Precision Process Systems Department.

D-MEC's product line includes three models of stereolithography units. The equipment and software are supplied by Sony Corporation and the resins are supplied by JSR. Located in JSR's special resin development facility in Tsukuba City, D-MEC has a staff of 10 and is a 100%-owned subsidiary of JSR. All three models of D-MEC's stereolithography units were operating in this facility at the time of the JTEC/WTEC team's visit.

METHODOLOGY (COMMERCIALIZATION)

In the Sony/JSR alliance, Sony is responsible for software development and for design and construction of the hardware; JSR is responsible for resin development; and D-MEC is responsible for process development and system integration. In addition, D-MEC maintains a networking business system that has 7 D-MEC stereolithography centers in Japan and 11 industrial members. D-MEC's plans are to increase the number of centers to 10. D-MEC also operates a CAE analytical service center, but this is small and not a significant portion of its business.

NEEDS, OBJECTIVES, PLANS

D-MEC has plans to further develop hardware, software, and resins. Sony could not divulge its plans for hardware improvement, other than it intends to develop a completely new machine, capable of higher speeds and precision. Lowering cost is also an objective, based on customer feedback.

Sony recognizes that Japanese designers have been slow to embrace 3D solid modeling and is developing proprietary design software to make it easier for designers to migrate from 2D systems. It is also developing software to make it easier to work with 3D CAD surface modeling systems. As an example, it has automatic thickness-adjustment software that will generate stereolithography surface models from 2_D CAD files.

JSR is focused on developing resins that can produce (1) greater dimensional accuracy and strength, (2) less 30-day warpage, and (3) filled resins for mold applications. The team asked our hosts what customer needs are being fulfilled by their stereolithography machines. They indicated that some companies acquired units to become familiar with the technology rather than to solve immediate problems; however, when D-MEC demonstrated the plastic injection molding of parts from stereolithography glass-filled molds, customers became much more serious about using stereolithography, as they recognized the potential of being able to quickly mold 100 or more parts in a common plastic such as ABS.

MATERIALS

Plastics

Part of JSR's development program is devoted to formulating resins with greater product accuracy and mechanical properties, lower 1-day and 30-day warpage, and lower price These are also MITI's objectives for funding the development of a new resin.

A portion of JSR's resin development work is supported by MITI through the Center for Plastic Materials. JSR is the only company developing UV-curable resins under an ¥800 million 4-year MITI program. The target properties MITI set for a new resin developed under this program were formulated in 1993 and are stated in Table D-MEC.1. JSR's current degree of success in meeting these targets is also indicated in the same table, identified as the "present level" column.

D-MEC's standard resins are polyurethane acrylates. The company offers at least six grades for different model-building applications and stereolithography units, as listed in Table D-MEC.2. Resin SCR 510 was specifically developed for use with the D-MEC high-definition SCR 1000HD stereolithography unit. The properties of these resins are compared in Table D-MEC.3 with JSR's new resin (SCR 600) developed under the MITI-sponsored program. Dimensional accuracy as a function of 0-, 7- and 30-day measurements after building are given in Figure D-MEC.1.

Table D-MEC.1.
Performance Target Values for SL Resins

Table D-MEC.2
D-MEC's Standard SCR Resins

Table D-MEC.3
Properties of D-MEC Resins Compared to JSR's SCR 600 Resin


Fig. D-MEC.1. Dimensional accuracy of D-MEC resins.

JSR is developing epoxy-based UV-curable resins to reduce warpage. These are not yet being offered commercially. JSR is also developing a glass-filled (70% glass beads) acrylate resin (no urethane) for use in building prototype molds for vacuum and injection molding applications. A glass-filled resin mold was on display that can make up to 180 ABS parts by injection molding before heat distortion becomes unacceptable. Several examples of silicone rubber molds were also shown that were made using a stereolithography master.

Metals

Developing metal parts is a consideration. On display were examples of a cast iron engine intake manifold or exhaust headers made by investment casting from a stereolithography master.

Ceramics

D-MEC does not appear to have an active program in building ceramic parts.

APPLICATIONS

Castings

As described above, the team's hosts showed us examples of a large engine part made by investment casting.

Tooling

See discussion above on glass-filled molds.

Medical

On display were examples of human skulls produced from medical tomography data. The team's hosts felt this will be a growing area, as the government health care agency is funding development work in this field for use in hospital applications. Toshiba medical imaging equipment is the standard in Japan. Data output is in an HPGL format that is compatible with D-MEC's translation software. They thought cost will be an issue in practical medical applications.

MACHINE DESIGN

The Sony machine can be described as a conventional stereolithography unit design. Its features include the following:

Descriptions of the three stereolithography units D-MEC offers may be found in the Sony brochure Solid Creator: Three Dimensional Solid Model Creator. Data on statistical accuracy is given above in Figure D-MEC.1.

D-MEC performs raster scanning by interleaf scanning in the horizontal direction and in the next layer alternate interleaf scanning in the vertical direction. No special stitch pattern raster scanning such as in StarWeaveTM is used.

CAD STANDARDS, INFRASTRUCTURE AND PART SHAPE ACQUISITION

Sony offers software that will automatically translate 3D surface models to its machine format. The program will automatically repair small cracks and allow manual repair of larger ones. Sony's exchange software interfaces with DESIGNBASE, FRESDAM (Sony CAD), CATIA (surface, solid) CADDS (CV), Intergraph, and Caelum. In addition, Sony offers STL, IGES, and HPGL translators. The Sony brochure Solid Creator depicts their compatibility with other CAD software in graphic form.

REFERENCES

Sony Corporation. n.d. Solid Creator: Three Dimensional Solid Model Creator.


Published: September 1996; WTEC Hyper-Librarian