Blasting machining method and blast machining device

Abstract

The disclosure concerns a blasting method achieving antistatic effect and increasing processing amount. In the method, 0.06 cc/min to 150 cc/min, that is, a relatively small amount of liquid is introduced into the blast nozzle and atomized by causing it to strike with the compressed gas flowing through the blast nozzle or the compressed gas ejected from the blast nozzle, and the atomized liquid is ejected together with the compressed gas and the abrasive onto the workpiece. Since the relatively small amount of the atomized liquid is quickly evaporated into water vapor, humidity in a working space is increased, thereby generation of static electricity is prevented. A vaporization heat is absorbed during evaporation then the workpiece is cooled, accordingly, absorption of strike energy from the abrasive due to softening of the surface of the workpiece is prevented, as a result, the processing amount is improved.

1 . A blasting method in which an abrasive is ejected together with a compressed gas onto a workpiece through a blast nozzle comprising the step of:
 introducing a liquid into the blast nozzle and atomizing the liquid by causing the liquid to strike with the compressed gas flowing through the blast nozzle or the compressed gas ejected from the blast nozzle, and ejecting the atomized liquid together with the compressed gas and the abrasive, an amount of the liquid introduced into the blast nozzle being 0.06 cc/min to 150 cc/min.   
     
     
         2 . A blasting apparatus for ejecting a stream of compressed gas supplied from a compressed gas supply source and an abrasive from a blast nozzle as a mixed fluid comprising:
 a liquid introduction path provided in the blast nozzle, having one end communicable with a liquid supply source and an other end opened in a compressed gas flow path in the blast nozzle or at an ejection port of the blast nozzle, the liquid introduction path being configured to cause a liquid introduced from the liquid supply source to strike with a stream of compressed gas flowing through the blast nozzle or a stream of compressed gas ejected from the blast nozzle to atomize the liquid, and   a flow rate control means provided between the liquid introduction path and the liquid supply source.   
     
     
         3 . The blasting apparatus according to  claim 2  wherein the blast nozzle is a suction-type blast nozzle provided with a nozzle tip directed in the ejection direction of a rear nozzle communicated with a compressed gas supply source, and with an abrasive introduction chamber communicated with an abrasive supply source between the rear nozzle and the nozzle, the blast nozzle being configured to create a negative pressure in the abrasive introduction chamber by ejection of a stream of compressed gas from the rear nozzle to suck an abrasive in the abrasive supply source, and eject the compressed gas and the abrasive as a mixed fluid, and
 the other end of the liquid introduction path is opened in a compressed gas flow path formed in the rear nozzle or in front of an ejection port of the rear nozzle. 
 
     
     
         4 . The blasting apparatus according to  claim 3  wherein the liquid introduction path is formed by a conduit inserted concentrically in the compressed gas flow path provided in the rear nozzle, and the other end of the liquid introduction path is opened at the ejection port of the rear nozzle. 
     
     
         5 . The blasting apparatus according to  claim 2 , further comprising a fixed quantity liquid supply means for supplying the liquid in the liquid supply source to the liquid introduction path in a fixed quantity. 
     
     
         6 . The blasting method according to  claim 1 , wherein the abrasive is ejected at an ejection pressure of 0.3 MPa to 0.5 MPa. 
     
     
         7 . The blasting method according to  claim 1 , wherein the abrasive is a nylon bead, an alumina abrasive, a high-purity alumina abrasive or a zircon grid. 
     
     
         8 . The blasting method according to  claim 1 , wherein an ejection amount of the abrasive is 2 g/min to 20 kg/min. 
     
     
         9 . The blasting apparatus according to  claim 2 , wherein a mesh material is provided in an opening at the other end of the liquid introduction path. 
     
     
         10 . The blasting apparatus according to  claim 2 , wherein the blast nozzle is a direct-pressure type blast nozzle, and
 the other end of the liquid introduction path is opened at a position where the ejection port of the blast nozzle is formed, or the other end of the liquid introduction path is opened in a compressed gas flow path in a rear nozzle provided in a body of the blast nozzle or in a compressed gas flow path formed through a nozzle tip attached to a distal end of the blast nozzle.   
     
     
         11 . The blasting apparatus according to  claim 3 , wherein the nozzle tip is constituted to have two divided nozzle tips coaxially and sequentially arranged in a longitudinal direction and a vent is formed at an interface between the nozzle tips. 
     
     
         12 . The blasting apparatus according to  claim 10 , wherein the nozzle tip is constituted to have two divided nozzle tips coaxially and sequentially arranged in a longitudinal direction and a vent is formed at an interface between the nozzle tips.