Features
WJ-400H (Intensifier Pump)
Pump
It is an intensifier pump.
Ultra high water pressures are generated from intensifier based pumps. There are two fluid circuits running in a typical intensifier pump. They are water circuit and hydraulic fluid circuit. This pump is designed based on intensification principle which is, pressure is equal to force divided by area.
Water Circuit
General tap water runs, through a filter system, into the water circuit which is composed of booster pump, intensifier pump and shock attenuator. After filtering, the water enters into the booster pump maintained at certain water pressure to ensure the intensifier is always filled with water. After leaving from the boost pump, the water is delivered to the intensifier pump and is pressurized. The water then flows through a shock attenuator which is a large vessel used to dampen the pressure fluctuations created during sudden water pressurization at the intensifier pump. The back and forth action of intensifier piston creates pulsating flow of water at very high pressure. The shock attenuator cylinder acts as a high pressure surge vessel and is used to help the water flow more uniform resulting in smoother cut. This is to guarantee the water jet stream exiting the jewel orifice is steady and consistent. The water stream would visibly and audibly pulse and thus, marks would be left on material being cut if no shock attenuator is used.
Hydraulic Circuit
This circuit is composed of an electric motor, hydraulic pump, oil reservoir, manifold and piston biscuit and plunger.
The hydraulic pump is powered by the electric motor. Oil is hydraulically pumped from the reservoir and is then pressurized. Hydraulic fluid is introduced alternately into one side and then another. The hydraulic piston alternately pressurizes the water using small diameter plungers at each end of the intensifier assembly. A series of check valves allows low pressure water into the plunger cylinder when the plunger retracts and then directs the pressurized water into the outlet manifold when the plunger moves into its compression stroke. The hydraulic fluid pushes on large piston to generate high force on smaller plunger. This plunger pressurizes water to a level that is proportional to the relative cross-sectional area of the larger piston and the small plunger.
The pump comes with a dual pressure feature. This is benefit when piercing or drilling is done on brittle materials. Pump pressure is slowly increased to avoid sudden shock acting on brittle materials such as glass and ceramic. There is no more rapid pressure change. Damage risk is reduced and thus, production yield is higher and brittle materials waste is minimized.
Working pressure could be adjusted manually when necessary.
Plumping
Pressurized water flows to the nozzle (cutting head) through this strong stainless steel plumbing which is resistant to high pressure.
The plumbing is long enough providing nozzle free movement when it is traveling in X-Y directions over workpieces.
Cutting Head
The pressurized water flows through the plumbing arriving at this nozzle which is installed in a carriage moving transversely on a cantilever.
The cutting head is mainly composed of jewel orifice, Venturi chamber and mixing tube.
Pressurized water flows through the jewel orifice forming a water jet stream. Abrasive particles are feed into the cutting head where they come across to the water stream inside Venturi chamber. Like a bullet in a rifle, the abrasive particles are accel
Jewel orifice
It has a tiny opening. Pressurized water coming from the plumbing will flow into this orifice. This specially design and made orifice is used to convert the pressurized water into extremely high velocity water stream.
The orifice could be sapphire or ruby which is cost effective and meanwhile, hard enough to resist long term wearing against water erosion.
Venturi Chamber
After the water stream passes through the orifice, it travels downwards and enters into this small Venturi chamber at a very high velocity.
Meanwhile, abrasive is feed sideward into this chamber where Venturi effect creates a vacuum to pull abrasive and air downwards leaving the chamber.
Mixing tube
When the abrasive and water leave the Venturi chamber, the water accelerates the abrasive and enters into a long and hollow cylindrical mixing tube where they are mix with each other. The mixture of abrasive and water form a coherent stream while exiting
Jewel orifice and mixing tube are in perfect alignment to assure the water jet passes directly down to the center of the mixing tube and thus, abrasivejet is not diffused, cutting quality is excellent and mixing tube lasts longer.
When the components are replaced, the alignment is rectified automatically and no tedious job is required. This makes maintenance easy and meanwhile, guarantees water quality consistent.
Thanks to sophisticated cutting head design, replacements of parts and components are easy and quick.
Motion Equipment
This motion system consists of X-Y movement mechanisms and structures allowing cutting heads to move freely along both X and Y directions over work pieces.
It employs a floor mounted X-axis and a cantilevered Y-axis mounted to the X-axis carriage. Cutting head is mounted to a carriage on the Y-axis. Limit stoppers are equipped to prevent the carriages from over travel.
The axis runs on specially treated high precision ball bearing linear screw and guide rail. The mechanisms are self-lubricated.
Catch tank and cutting table are totally separated from the X-Y motion structure.
The advantages of this floor-mounted cantilever system with separate working table are,
- There is no external frame or rails of a gantry. Operators are easily access to the cutting table.
- Flexible free space is available for easy loading and unloading of work pieces. This gantry free designed is beneficial especially when work pieces are large and heavy.
- The cantilever beam moves at only one end. Eliminates the need for a precision dual-drive system required by a gantry beam.
Control System
It is a numerical control system with CAD/CAM pre-installed. The designs are done in an AutoCAD and are then stored in dwg files. These dwg files are then exported to the NC system which automatically converts the dwg files into numeric files that the system can read. The machine then understands to where cutting head moves in X, Y and Z directions.
A servo system is employed. It controls servo motors which run in X and Y axis. The servo system assures higher cutting accuracy, faster speed, higher throughput and meanwhile, it is more reliable.
There are several logics for safety precautions.
- When filter is blocked, machine stops.
- When it is lack of water, machine stops.
- When pressure is too low, machine stops.
- When pressure is too high, machine stops.
Catcher Tank
This catch tank is used to collect water and abrasive during water jet cutting.
A working table is mounted on top of the tank. It is used to support workpieces on which they are loaded. The working table is a grating.
The catch tank and working table are placed beneath the cantilever where the cutting head moves freely over work pieces.
Abrasive Feeding Device
This system is used to feed precise amount of abrasive to cutting head automatically. If necessary, the amount of abrasive is adjustable manually.
