With the rapid development of industrial technology, high-accuracy micro-holes are used in various industries. The development trend is small diameter, large depth, high accuracy, and a wide range of applications (such as high strength, high hardness, high toughness, high melting point Metals, ceramics, glass, polymer materials, crystals, etc.). Traditional micro-hole processing technologies mainly include machining, electric spark, chemical corrosion, ultrasonic drilling and other technologies. These technologies have their own characteristics, but they can no longer meet the higher needs of micro-hole processing. For example, machining is very inefficient for materials with high hardness and high brittleness, and it is difficult to machine holes smaller than 0.2mm; EDM can only process metal materials. Laser drilling has the advantages of high efficiency, small limit aperture, high accuracy, low cost, and almost no material selectivity. It has become one of the mainstream technologies for micro-hole processing. Ga
At present, the most commonly used processing method for laser drilling is galvanometer scanning, which can be layer-by-layer circular scanning or spiral scanning. However, the disadvantage of galvanometer scanning is that the taper cannot be avoided. As shown in Figure 1, during the hole making process, due to With the divergence and multiple reflections of the focused laser beam, the material ablation rate will drop sharply as the depth of the hole increases. Therefore, it is more difficult to prepare micropores with larger aspect ratios on thicker materials.
Therefore, it is challenging to obtain micro-holes with high depth-to-diameter ratio (≧10:1), high processing quality, zero taper or even inverted taper. For such needs, the most suitable processing method is to use a rotary cutting head module. The rotary cutting head can not only make the beam rotate at a high speed around the optical axis, but also change the inclination β of the beam relative to the surface of the material. By changing the value of β, the change from positive cone to zero cone or even inverted cone can be realized. At present, the commonly used rotary cutting head modules are concentrated in the four optical wedge scanning heads, Dove prism scanning heads and parallel flat-panel scanning heads. Their optical principles are similar, and the light beam entering the focusing lens is appropriately translated and tilted through optical devices. The rotation of the high-speed motor rotates the beam around the optical axis.
The two large-angle optical wedges on the left side of the figure can realize the translation of the incident beam, and the taper of the processing hole can be adjusted by changing the distance between the two; The angular deflection of the beam makes the focused spot deviate from the optical axis of the focusing lens. When working, the four optical wedges rely on the servo motor to rotate synchronously to realize the focal spot rotating and scanning around the optical axis of the focusing lens to remove the material on the circle, and at the same time, the micro-feed along the optical axis direction is finally realized with different apertures, tapers and depths. Processing. In order to realize the synchronous rotation of the four optical wedges and the adjustment of the distance between the two optical wedges on the left, the device generally adopts a complex squirrel cage structure.
The Dove prism is installed on a high-speed rotating hollow torque motor. One rotation of the prism can make the laser rotate and scan twice. The collimated laser beam enters the Dove prism and adjusts the optical wedge after passing through the front-end angular deflection and lateral translation. Finally, it is focused to the working plane through the focusing lens to realize circular cutting and scanning drilling. The three optical wedges compensate the processing and assembly errors of the Dove prism through deflection and rotation.
To sum up,the laser rotary cutting drilling technology has the advantages of small processing aperture, large depth-to-diameter ratio, adjustable taper, and good sidewall quality. As an advanced method of making holes, laser rotary cutting and drilling technology is combined with mechanical Machining has obvious advantages compared with EDM, which will help the development of the semiconductor industry.
Finally, the galvo scanner system is the key part to the laser drilling system. Sino-Galvo Tech. is the leading galvanometer scanner manufacturer. The laser welding machine equiped with our scanner system can reach the heighest precision leavel. Welcome to contact us for further information.
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