Abstract: When a powder-sintered laminated resin model of powdery resin fabricated according to sintering/laminating shaping technique is applied to lost wax precision casting, casting products have rough finished surface causing a marked drop of commercial value. Thus, there is provided a method for smoothing the porous uneven surface of powder-sintered laminated resin model, comprising a resin impregnation step of dipping the powder-sintered laminated resin model (A) in a two-pack reaction hardening type urethane resin solution (B) with work time of 1 to 5 minutes and viscosity of 7 to 30 Pas and effecting pressure reduction so as to impregnate the surface of the resin model (A) with the two-pack reaction hardening type urethane resin solution (B) and a resin hardening step of updrawing the powder-sintered laminated resin model (A) having been impregnated with the two-pack reaction hardening type urethane resin solution (B) from the two-pack reaction hardening type urethane resin solution (B) and hardening the same.

Abstract: A process for producing a resin model for use in lost wax precious casting, comprising at least a hardened resin layer forming step of injecting two-pack reaction hardening type urethane resin solution (A) of 1 to 3 minutes of a working life, through a casting port (4) of a resin model forming mold (2) furnished with internal space (3) whose configuration is identical with that of product, into the internal space (3) in a volume amounting to 5 to 20% of the volume of the internal space (3), closing the casting port (4) and rotating the resin model forming mold (2); a resin model forming step of repeating the hardened resin layer forming step 3 to 6 times at intervals of 3 to 4 minutes so as to effect laminating of hardened resin layers (11), thereby obtaining resin model (12) having internal space (30) provided at a core region thereof; and a demolding the resin model (12) from the resin model forming mold (2).

Abstract: An object of the invention is to establish a mass-production type method for manufacturing in which a complicated shaped model with a hollow part can be molded integrally.

Abstract: In order to satisfy the requirements for satisfactory levels of melting•burn-off characteristics in response to heat application, high temperature burn-off characteristics and ease of residual ash removal that a resin model should assure as an alternative to a wax model, the burn-off resin model according to the present invention, which can be used in the lost wax process, is manufactured by forming a liquid resin compound containing 1 to 30 wt. % of a plasticizer (D) and 1 to 20 wt. % of a wax component (E) blended into a double fluid reactive setting liquid urethane resin (C) constituted of a multifunctional polyol component (A) and a multifunctional polyisocyanate component (B) and then by setting the liquid resin compound within a working life of 5 minutes or less.

Abstract: A form for manufacturing a resin mold has a frame housing a master model corresponding in shape to a product to be molded and having a space defined therein for receiving the ultraviolet-curable resin poured therein around the master model. The frame is made of an ultraviolet-permeable material. When ultraviolet radiation is applied outside of the frame to the frame, the ultraviolet-curable resin in the frame is cured into a resin mold. The resin mold can easily and quickly be manufactured. The resin mold can also reliably be clamped by a clamping jig for producing a high-quality molded product.

Abstract: A molding apparatus includes a molding die having a cavity therein corresponding to the outer shape of a product to be reproduced, and a cast molding device for pouring an ultraviolet curable liquid resin into a cavity of the molding die. An ultraviolet light irradiating device is provided for irradiating ultraviolet light from the outside of the molding die, wherein the ultraviolet curable liquid resin in the interior of the molding die becomes hardened. A transport mechanism is provided for conveying the molding die between the cast molding device and the ultraviolet light irradiating device. Accordingly, an operator is not required to lift and carry the molding die, and the die can be swiftly and easily conveyed by means of the transport mechanism.