Date: Tue Jun 13 2000 - 18:48:55 EEST


Please send me your mailing address and I will send you complete information
on the COLAM process. I received a folder mid last year with updated photos
and product information.

Karl Denton
Lead Engineer
Williams International

        -----Original Message-----
        From: Marshall Burns []
        Sent: Monday, June 12, 2000 2:26 PM
        Subject: Re: COLAMM

>I've heard about a system called COLAMM from the Japanese company
>but I can't find any informations about it.
>Can anybody provide me with infos about that system?
>Dipl.-Ing. Holger Löffler

        Dear Holger,

            Below is an excerpt from my book on the Mitsui COLAMM. Remember,
        was published in 1993, so it's not quite up to date.

        Best regards,
        Marshall Burns
        President, Ennex Corporation
        Los Angeles, USA, (310) 397-1314

        Excerpt from "Automated Fabrication" by Marshall Burns
        Copyright (c) 1993, Ennex Corp. All rights reserved.

        The COLAMM: Mitsui

            The Mitsui Engineering and Shipbuilding Company of Tokyo, Japan,
        offering a photopolymer fabricator called the COLAMM
        Laser-Active Modeling Machine) in 1991. The company reports having
sold one
        unit to a job shop. Data on the machine were not received in time
        inclusion in Chapter 2. A brief description is given here of the
        used in that system and of some other interesting work that has come
out of
        the Mitsui labs.

            The COLAMM is unique in that objects are built from the top
down, rather
        than bottom up. This "ascending suspension" method is illustrated in
        2-11. The first (top) cross section of the object is created by
        from below, a thin layer of resin between a transparent window plate
and the
        underside of a suspension plate. The chemistry of the materials
involved is
        such that the cured polymer adheres to the suspension plate, and not
to the
        window plate. The first layer is thus affixed to the suspension
plate, which
        is raised by an increment to allow a new layer of resin to flow onto
        window for scanning. The object is thus built suspended from the
        suspension plate.

            This technique may allow faster laser scanning by curing the
resin at an
        interface with glass, not air, since isolation from oxygen improves
        photosensitivity of the resin. (For more on this subject, see
        through a Contact Window below.) However, since the object grows in
        suspension and each layer must therefore support all new layers
below it,
        the method probably requires some kind of supporting mechanism, as
shown in
        Figure 2-11, in order to be practical for shapes with narrow necks.

            In the late 1980s, Mitsui explored several alternative
approaches to
        photopolymer-based automated fabrication before deciding to focus
        exclusively on the technique described above. The following ideas
        described in Mitsui patent applications, but the company has stated
that it
        does not intend to pursue these directions in the near term.

            One Mitsui idea combines photocuring with robotically guided
        Photopolymer resin is ejected from a nozzle and immediately cured by
        incident light. What makes this idea most interesting, however, is
that the
        nozzle is fed from various input ports, so that it is capable of
ejecting a
        variety of resins or mixtures of resins. The results can be
variations in
        color and other physical properties.

            Other proposals from Mitsui involve modifying the profile of the
        incident light beam to cure rectangular blocks rather than the
        "bullets" formed by a Gaussian laser, passing the incident light
through a
        screen resulting in the microscopic dispersal of cured regions in an
        matrix, and mixing the photocuring resin with short fibers or other
        material to reduce curing distortion.

        For more information about the rp-ml, see

For more information about the rp-ml, see

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