Laser drilling is an extremely complex thermophysical process in which laser interacts with matter.Therefore, there are many factors affecting the quality of laser drilling.In order to obtain high quality holes, the parameters affecting the quality of the holes should be analyzed and understood according to the general principle and characteristics of laser drilling.
1. Drilling strategy:
The first step is to understand the drilling materials and requirements in detail.
The second step is simulation experiment and detection.
The third step is to design convenient and fast fixture;
Step 4: Design the program;
The fifth step is to carry out effective drilling and necessary testing.
2. Main parameters affecting the punching quality
Laser drilling is an extremely complex thermophysical process in which laser interacts with matter.Therefore, there are many factors affecting the quality of laser drilling.In order to obtain high quality holes, the parameters affecting the quality of the holes should be analyzed and understood according to the general principle and characteristics of laser drilling.These parameters include the energy of the laser pulse, the pulse width, the defocus, the repetition rate of the pulse, and the properties of the processed material.
3. Auxiliary process
In order to improve the precision of laser drilling, some auxiliary technological procedures and measures are sometimes needed, including the following five points:
(1) Applying a positive pressure on the surface of the workpiece, or installing a low pressure tank on the reverse side of the workpiece, can help to remove the vaporized material and increase the discharge of the liquid phase during the drilling process.
(2) A photoelectric detector is installed at the safe position under the workpiece to timely detect whether the workpiece penetrates or not.
(3) The use of liquid film or metal platinum cover workpiece, can reduce the taper of the hole, and prevent liquid spatter
(4) In order to prevent the accumulation of melt in the hole in time, the material whose vaporization temperature is lower than the melting temperature of the processed material can be placed behind the processed workpiece.
(5) Using laser as a processing tool to punch pores in the workpiece, and then using other methods to achieve the required accuracy.At present, the general use of emery machining, punch, wire aperture finishing, chemical corrosion methods, and so on.
The depth of the hole is controlled to improve the output energy of the laser. With a reasonable pulse width (the better the material and thermal conductivity is, the shorter the pulse width is), the larger hole depth can be obtained by using the fundamental mode (a single mode with gaussian light intensity distribution).Deep holes with small aperture should be irradiated by laser for several times and perforated with an objective lens with short focal length (15 ~ 30mm).
(1) The aperture size control USES a laser with a small divergence Angle (0.0010.003rad). The small aperture can be obtained by shortening the focal length or reducing the output energy.For high melting point.The material with good thermal conductivity can realize the micro hole machining with the aperture of 0.01 ~ 1mm, and the minimum pore diameter can be up to 0.001mm.
(2) Controlling the depth of the hole can improve the output energy of the laser, adopt a reasonable pulse width (the better the material and thermal conductivity is, the shorter the pulse width is suitable), and apply a single mode with gaussian distribution of light intensity of the fundamental mode to obtain a large hole depth.Deep holes with small aperture should be irradiated by laser for several times and perforated with an objective lens with short focal length (15 ~ 30mm).
(3) To improve the roundness of laser machining hole, the laser mode adopts the basic mode processing, the focusing lens USES the spherical aberration objective lens, and the optical axis of the lens coincides with the optical axis of the beam, the workpiece is suitable to deviate from the focus, and the selection of appropriate laser energy can improve the roundness of processing.
Generally, the taper of the hole increases with the increase of its aperture ratio. The taper of the hole can be reduced by adopting measures such as appropriate laser output energy or multiple irradiation with small energy, short focal length, small lens refractive index and reducing the Angle between the incident ray and the optical axis.
In the
laser cutting machine using flight path, only the cutting head moves along the Direction of X and Y and the position of the working table is fixed in the cutting process. In addition, there is a transmission form of fixed optical path flight beam with hinged movable arm, which is called constant flight path and abbreviated as constant light path.
In terms of the driving mode of the equipment, the X and Y axes are equipped with unilateral servo motors and corresponding reduction gear, and the X axes are driven by high-precision pinion and rack, and the X axes are driven by both sides with servo motors and corresponding reduction gear. The high-precision pinion and rack drive structure is adopted, and the double-gear drive mode is adopted to eliminate the reverse clearance.The servo motor is directly driven by high-precision ball screw, and it is driven by direct gear and rack of disk motor with large inertia.There are also linear motor directly driven by the structure.
The lasers configured by the equipment should be selected according to the user's processing performance, processing material, shape and size, etc. The lasers available for selection include CO2 axis fast-flow laser, RF board debugging laser, swirling laser, solid laser and fiber laser, etc.
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