Method of Smoothing Surface and Process of Lost Wax Precious Casting with Resin Model Having Its Surface Smoothing by the Method

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.

1 - 5 . (canceled)  
   
   
       6 . A method for smoothing a surface of a powder-sintered laminated resin model with a porous rough surface comprising: 
 a resin impregnation step of dipping said powder-sintered laminated resin model (A) in a two-pack reaction hardening type urethane resin solution (B) with a work life of 1 to 5 minutes and viscosity of 7 to 30 Pas and then decreasing pressure so as to impregnate said surface of said resin model (A) with said two-pack reaction hardening type urethane resin solution (B); and    a resin hardening step of bringing up said powder-sintered laminated resin model (A) impregnated with said two-pack reaction hardening type urethane resin solution (B) from said two-pack reaction hardening type urethane resin solution (B) and hardening said resin model (A).    
   
   
       7 . The method for smoothing a surface according to  claim 6 , wherein said two-pack reaction hardening type urethane resin solution (A) preferably comprises multifunctional polyol component (a), multifunctional polyisocyanate component (b) and a plasticizer component (c).  
   
   
       8 . The method according to  claim 7  wherein an average functional group of the multifunctional polyol component (a) is in a range from 2.0 to 4.0, an average functional group of the multifunctional polyisocyanate component (b) is in a range from 3.0 to 5.0, and a ratio NCO/OH is in a range from 0.7 to 1.0.  
   
   
       9 . The method for smoothing a surface according to  claim 7 , wherein: 
 said two-pack reaction hardening type urethane resin solution (A) preferably contains a plasticizer component (c) of 10-30% which is in a liquid state at normal temperature and polyether chains having a chemical structure indicated in the chemical structural formula as follows at 5-35 wt % thereof.                          
   
   
       10 . The method for smoothing a surface according to  claim 6 , wherein: 
 said two-pack reaction hardening type urethane resin solution (A) preferably contains a plasticizer component (c) of 10-30% which is in a liquid state at normal temperature and polyether chains having a chemical structure indicated in the chemical structural formula as follows at 5-35 wt % thereof.                          
   
   
       11 . The method for smoothing a surface according to  claim 6 , wherein: 
 said plasticizer component (c) is preferably micro-dispersed through phase separation at raid reaction hardening of the two-pack reaction hardening type urethane resin solution (B).    
   
   
       12 . The method for smoothing a surface according to  claim 7 , wherein: 
 said plasticizer component (c) is preferably micro-dispersed through phase separation at raid reaction hardening of the two-pack reaction hardening type urethane resin solution (B).    
   
   
       13 . The method for smoothing a surface according to  claim 9 , wherein: 
 said plasticizer component (c) is preferably micro-dispersed through phase separation at raid reaction hardening of the two-pack reaction hardening type urethane resin solution (B).    
   
   
       14 . The method for smoothing a surface according to  claim 10 , wherein: 
 said plasticizer component (c) is preferably micro-dispersed through phase separation at raid reaction hardening of the two-pack reaction hardening type urethane resin solution (B).    
   
   
       15 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 6 .  
   
   
       16 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 7 .  
   
   
       17 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 9 .  
   
   
       18 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 10 .  
   
   
       19 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 11 .  
   
   
       20 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 12 .  
   
   
       21 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 13 .  
   
   
       22 . A process for lost wax precision casting using said powder-sintered laminated resin model having a surface smoothed by said method according to  claim 14.