A laser processing head based on dual-beam spatial characteristic adjustment

Abstract

The invention provides a laser processing head based on double-beam spatial characteristic adjustment. The laser processing head comprises an annular light path system and a central light path system, wherein the annular light path system comprises a first beam expansion collimating lens, a cone lens group and a focusing objective lens; the focusing objective lens outputs a fine annular focal spot generated after the focusing of a non-diffraction annular beam to the surface of a workpiece; the central light path system comprises a second beam expansion collimating lens, a first planar reflecting mirror and a planar reflecting mirror; the focusing objective lens focuses laser beams and then outputs a central fine round spot to the surface of the workpiece; the central fine round spot is positioned at the center of the fine annular focal spot output by the annular light path system. When the laser processing head disclosed by the invention is adopted for laser punching, good circular ring precision can be guaranteed, namely the laser processing head is particularly suitable for the processing of ring-shaped blind holes; besides, laser beams with different wavelengths can serve as two incident laser beams, so that the composite punching processing effect, which cannot be realized by the traditional pulse single-point punching and opening-cutting manners, can be achieved.

Description

technical field [0001] The invention belongs to the field of laser processing, and in particular relates to a laser processing head based on the adjustment of the spatial characteristics of double beams. Background technique [0002] Axicons include plano-convex (PCX) axicons and plano-convex (PCV) axicons. Plano-convex (PCX) axicons have a convex cone and a plane; plano-concave (PCV) axicons have a concave cone and a plane. They are used to produce a non-diffractive ring beam that increases in diameter with distance, yet maintains a consistent ring thickness. When used with a collimated Gaussian beam, a plano-convex (PCX) axicon will form an annular beam that approximates a Bessel beam and is suitable for a range of medical, research, measurement, and alignment applications. These axicons feature a precision fused silica substrate and are available uncoated as well as various AR coating options. A Bessel beam is a non-diffracting beam formed by a ring with equal power co...

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Problems solved by technology

[0005] Although the above two laser drilling technologies are widely used in the industrial field, they still have shortcomings for precision drilling, especially for micro-holes: 1) There are different drilling apertures for pulse single-point drilling and cutting. In the middle ground that is difficult to cover, in order to maintain sufficient energy density and hole roundness for pulse single-point drilling, the radius of the focal spot is generally below 50 microns, and the hole cutting requires a two-axis or three-axis interpolation movement of the motion mechanism to make the focal spot The spot moves relative to the workpiece, and for holes with too small diameter (for example, within 0.5mm), the precision of the motion mechanism is very high, which makes the cost of the laser drilling mechanism very high, and the roundness of the hole is often It is still not ideal; 2) Due to the existence of interpolation motion, the efficiency of cutting holes is far lower than that of pulse single-point drilling, and due to the limitation of the movement speed of the movement mechanism, excessive laser power cannot be used, which limits the use of high-power lasers. 3) For materials with anisotropic thermal conductivity, the focal spots of pulse single-point drilling and cutting holes are all Gaussian energy distributions, making the heat-affected zone inconsistent in different directions, which directly affects the roundness and The quality of the edge of the hole is prone to thermal stress deformation; 4) The high pulse energy of pulse single-point drilling and cutting all acts on the same position at the same time, causing violent melting, vaporization and plasma phenomena, and a large amount of laser energy is wasted in redundant In melting, vaporization and plasma absorption, the heat-affected zone increases, and it is difficult to improve the quality of drilling

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