Laser cutting and water cutting of titanium alloys

Laser cutting uses a focused, high-power-density laser beam to scan the surface of a workpiece and locally heat the material to thousands or even tens of thousands of degrees Celsius in a very short time , causing the irradiated material to quickly melt , vaporize , burn or reach the ignition point . At the same time, the molten material is blown away by the high-speed airflow coaxial with the beam , so as to cut the workpiece and achieve the purpose of cutting the material.

The main factors affecting the laser cutting effect:

1,Laser cutting process parameters

Parameters that measure the quality of laser cutting technology and machining mainly include laser power.

Laser cutting various

2. Cutting speed

Affects laser cutting speed. Generally speaking, the higher the laser energy, the smaller the material thickness, and the greater the cutting gas pressure, the faster the cutting speed, and vice versa.

During on-site operations, laser cutting speed should not be pursued blindly, but laser cutting quality should also be taken into consideration. Especially for some mechanical parts with strange shapes, a certain balance must be maintained between speed and quality to ensure product quality.

3. Gas pressure

The gas blown in laser cutting has the following functions: first, it is used to melt the cutting metal material and rely on the pressure of the blown gas to blow away the liquid metal to form a cut; second, the gas cools the raw material and can take away part of it from the cutting area energy. Therefore gas has an important impact on cutting quality. When processing titanium materials, inert gases (argon or nitrogen) need to be used to reduce the problem of oxidation contamination of the material.

The impact of laser cutting of titanium materials on finished products:

1, burrs. Laser cutting of titanium materials generally uses argon or nitrogen as the auxiliary gas. A little sticky slag will be produced at the bottom of the cut, but it is easy to remove. The cut will absorb oxygen and produce a hard and brittle oxide layer.

2, deformation. Since cutting titanium materials generates a lot of heat, the processing time of the product increases with time. The first product and the last product have different deformations. Failure to reduce the heat in time will cause product deformation.

As mentioned above, in our introduction to laser cutting of titanium materials, we know that laser cutting will generate heat, causing oxidation of the cutting surface. and product thermal deformation. In order to solve the above problems, we can also use water cutting technology when cutting titanium alloy.

Water cutting processing: It uses ultra-high pressure technology to pressurize ordinary tap water to a pressure of 250-400Mpa, and then passes it through a gemstone nozzle with an inner hole diameter of about 0.10-0.35mm to form a jet with a speed of about 800-1000m/s. High-speed jet, commonly known as "water jet". "Waterjet" has high energy and can be used to cut soft base materials.

Water cutting diagram

Water cutting of titanium materials generally involves adding an appropriate amount of abrasives such as quartz sand, emery, etc. to the "water jet" to enhance the cutting force.

When titanium material is cut by waterjet, it is first pierced, and then cut at a certain speed. Finally, the remaining energy of the sand flow is accommodated by the collector and dissipated by the waterjet during cutting. It is easy to see from the principle of water jet cutting that water pressure, sand flow and cutting rate are crucial parameters that affect the quality of material cutting.

Take the TC4/Gr5 plate as an example to make the following table:

TC4/G R 5	water pressure	sand flow	cutting rate
T<10mm	375 MPa	0.68kg/min	260mm/min
10 ≤ T ≤ 20	375 MPa	0.68kg/min	150mm/min
20 ≤ T ≤ 30	375 MPa	0.68kg/min	65mm/min
30 ≤ T ≤ 40	37 5 MPa	0.68kg/min	48mm/min

Water cutting titanium plate on site

Advantages of water cutting technology for titanium materials: Water cutting technology is a cold processing method with the characteristics of low workpiece temperature, no heat affected zone, and no thermal deformation during cutting.

Water cutting 30mm titanium plate products

The disadvantages are:

Due to the use of high-pressure water flow, the gemstone nozzle of the waterjet equipment wears out a lot and needs to be replaced in time.

Residues at the cutting edge of the cutting surface: For titanium plates that are too thick. For example: plates above 10mm will have bevels (see diagram).

Schematic diagram of water cutting defects