Abrasive water jet processing machine

Abstract

An abrasive water jet processing machine for jetting a fluid and performing a cutting includes a fluid supply device, an abrasive supply device, an injection pressure controller, wherein the abrasive supply device includes a reservoir hopper consisting of a pressure vessel for reserving the abrasive, an abrasive supply tube for communicating with the reservoir hopper and the nozzle, and an air purge device for supplying compressed air to the abrasive supply tube and the reservoir hopper; the injection pressure controller performs a two-stage control of controlling injection pressure in a piercing; and the air purge device includes a flow pressure controller for controlling flow pressure of compressed air passing through the abrasive supply tube, wherein the flow pressure controller controls the flow pressure in the piercing to be higher than that in the cutting.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an abrasive water jet processing machine, and particularly, to the machine for controlling flow pressure by which an abrasive is fed.[0003]2. Description of the Related Art[0004]Conventionally, an abrasive water jet processing machine uses negative pressure generated by high-speed water jet passing through an orifice, or a potential energy by a gravity of an abrasive, feeds the abrasive, mixes it in the water jet, ejects the jet from a nozzle, and cuts a workpiece (for example, Japanese Patent Laid-Open Publication Nos. JP H 7-1338 and JP 2008-194773).[0005]Furthermore, with respect to an abrasive water jet processing, in stopping water jet, when water flows back to an abrasive supply tube from a nozzle, or the tube is clogged, a processing quality is degraded; therefore, as means for detecting these, there exists a method of measuring pressure in the tube and determining the backflow an...

AI Technical Summary

Benefits of technology

[0011]The abrasive water jet processing machine according to the first aspect of the invention comprises the air purge device configured to load the flow pressure on the abrasive passing through the abrasive supply tube, and thereby, can use an increased air flow rate and stably supply the abrasive to the nozzle; therefore, the machine can stably feed the abrasive without excessively depending on any of negative pressure generated by the fluid passing through an orifice and a potential energy by a gravity of the abrasive. Moreover, the abrasive water jet processing machine can effectively prevent the backflow to the abrasive supply tube from a nozzle side by increasing pressure in the abrasive supply tube.

[0025]Because the abrasive water jet processing machine according to the invention can prevent the backflow of any of the fluid and the abrasive and stably supply the abrasive, the machine can set the proper processing conditions, respectively, in the piercing, and the cutting, and achieve the abrasive water jet processing high in quality.

Problems solved by technology

However, with respect to the method of using negative pressure generated by an orifice, or a potential energy by a gravity of an abrasive, and feeding the abrasive, since it is not possible to stably supply a sufficient amount of the abrasive from just after the start of water jet ejecting, and a required amount of the abrasive is not sufficiently mixed in the water jet, there exists a problem that a quality is degraded.

Particularly, with respect to a brittle material, CFRP (Carbon Fiber Reinforced Plastic), and the like, this causes in some cases a harmful effect such as a delamination in a piercing (penetration hole) which is a preceding process-of a cutting.

Furthermore, because pressure in the abrasive supply tube largely fluctuates according to water injection pressure and a supply amount of the abrasive, and it is not possible to accurately determine the backflow and the like, there exists a problem that a processing quality is degraded.

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