Lamination molding resin-coated sand and lamination molding...

Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Particulate matter

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

C427S508000, C427S221000

Reexamination Certificate

active

06335097

ABSTRACT:

INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. HEI 10-197754 filed on Jul. 13, 1998, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lamination molding resin-coated sand suited for lamination molding and a lamination molding method using the lamination molding resin-coated sand.
2. Description of the Related Art
In recent years, the development of the lamination molding technique (as disclosed by, for example, U.S. Pat. No. 4,247,508) is underway. With this lamination molding technique, a sand application step of applying resin-coated sand and forming a sand layer and a laser radiation step of radiating a laser beam to the sand layer to thereby form a solidified layer are alternately repeated, thereby sequentially forming many solidified layers and eventually forming a two-dimensional article.
The resin-coated sand, which has been conventionally provided by means of this lamination molding technique, is obtained by coating sand particles with resin and used for molding a shell casting mold by means of the shell molding method. Therefore, with the lamination molding technique using the above resin-coated sand, the enhancement of accuracy for the shape and dimensions of a formed article is limited. In the shell molding method, the cavity of a heated mold is filled with resin-coated sand, thereby thermally curing the resin of the resin-coated sand which contact with the cavity molding surface of the mold and forming a shell casting mold.
Namely, the sand particles of the resin-coated sand as conventionally provided have relatively large diameters, i.e., about 200 to 300 &mgr;m so as to ensure the discharge efficiency of discharging gas generated from the shell casting mold. Due to this, as shown in
FIG. 7
, a sand layer formed by the lamination molding technique, is thin and part of sand particles 53× quite likely protrude from the surface of the sand layer
500
. If so, the irregularity of the surface of the sand layer
500
tends to increase. Besides, a cured layer, into which part of the sand layer
500
is formed, tends to have an irregular surface. For these reasons, there is a limit to the enhancement of accuracy for the shape and dimensions of a formed article. Further, the shell molding method is intended to thermally cure the resin soon after the resin-coated sand contacts with the high temperature cavity molding surface of the mold. The fusion temperature of the resin is, therefore, as low as 70 to 80° C.
With the above-stated resin-coated sand, the enhancement of accuracy for the shape of an article formed by lamination molding has its limit. So does the enhancement of the quality of the formed article have its limit.
SUMMARY OF THE INVENTION
The present invention has been made under these circumstances. It is, therefore, an object of the present invention to provide a lamination molding resin-coated sand and a lamination molding method capable of advantageously enhancing the accuracy and quality of a formed article.
A lamination molding resin-coated sand according to the present invention is a lamination molding resin-coated sand used for lamination molding for forming a laminated article by laminating sand layers in thickness direction, and wherein sand particles coated with resin are about 20 to 100 &mgr;m in diameter and generally spherical.
A lamination molding method according to the present invention is comprising a step of preparing resin-coated sand of generally spherical sand particles each having a particle diameter of 20 to 100 &mgr;m and coated with resin; a sand application step of applying the resin-coated sand to form a thin sand layer; a laser radiation step of radiating a laser beam onto the sand layer to cure the resin; alternately repeating the sand application step and the laser radiation step until sand layers are laminated in thickness direction and an article is formed.
The resin-coated sand of the present invention is advantageous to the enhancement of accuracy for the shape and dimensions of a formed article as well as the quality of the article. The lamination molding method of the present invention is advantageous to the enhancement of accuracy for the shape and dimensions of a formed article as well as of the quality of the article, even if sand layers are thin.


REFERENCES:
patent: 3962491 (1976-06-01), Sato et al.
patent: 4247508 (1981-01-01), Housholder
patent: 4691756 (1987-09-01), Suzuki et al.
patent: 4888240 (1989-12-01), Graham et al.
patent: 5204055 (1993-04-01), Sachs et al.
patent: 5718279 (1998-02-01), Satoh et al.
patent: 0 555 896 (1993-08-01), None
patent: 0 776 713 (1997-06-01), None
patent: 6-126377 (1994-05-01), None
patent: 8-90147 (1996-04-01), None
patent: WO 95/30503 (1995-11-01), None
patent: WO 96/30195 (1996-10-01), None
patent: WO 97/29148 (1997-08-01), None
Communication dated Nov. 23, 1999 (1 page).
European Search Report Nov. 16, 1999 (2 pages).

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Lamination molding resin-coated sand and lamination molding... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Lamination molding resin-coated sand and lamination molding..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lamination molding resin-coated sand and lamination molding... will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-2854152

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.