Laser cutting equipment is widely used in the field of sheet metal processing. Generally, CO2 laser cutting machines or fiber laser cutting machines are used. For some workpieces, the use of laser cutting equipment has significant advantages!
Workpieces with many holes: For some workpieces with many holes, when using laser cutting equipment to face a specific plate thickness, as long as the diameter of the round hole of the workpiece is greater than or equal to the value of the corresponding minimum diameter, and the roughness and Laser cutting equipment can be used to directly unload materials within the guaranteed capacity of the cutting machine. The dotting function of the laser cutting equipment determines the position of the hole, saves the time for positioning holes for the subsequent hole drilling process, and also saves the production cost of the drilling template, which not only improves the production efficiency, but also improves the accuracy of the product.
Slender workpieces: Slender workpieces have certain requirements for straightness. The heat generated by the laser cutting equipment is relatively concentrated and the heat affected zone is small. When the length of the slender workpiece is more than 5500mm, the "micro-connection" function of the cutting equipment itself can be used to effectively control the straightness of the workpiece and effectively control the workpiece The thermal deformation.
Workpiece template: Laser cutting equipment makes blanking detection templates for some irregularly shaped workpieces, such as the support angle on the bulldozer ripper, the excavator arm and the big head plate on the boom, etc., which can improve the accuracy and effectiveness. There are also some rolled-formed workpieces. In the production and inspection of the workpiece, it is necessary to use a template that matches the arc to assist in the production and inspection, such as the curved plate of the bulldozer, the arm of the excavator, the bent plate and the bucket of the boom At this time, using the scribing function of laser cutting equipment can also mark the boundaries of arcs and straight edges on the template.
Workpiece crack arrest groove: The process gap reserved for this kind of crack arrest groove sheet metal parts is also called crack arrest groove or process hole. For some workpieces with higher requirements, you can use laser cutting equipment to reserve slits. For some special forms, the use of laser cutting equipment can reserve a slit when the workpiece is blanked to prevent the workpiece from being deformed during bending.
As a fast-growing high-tech industry, the laser industry has penetrated into all walks of life, and it is one of the key elements supporting the current manufacturing transformation and upgrading. With the continuous advancement of computer control technology and optical technology, laser processing that cuts well and cut quickly has become more and more accepted by users. However, in the process of laser cutting of medium and heavy plates, occasionally some problems will affect the processing quality. This article analyzes common problems and proposes corresponding improvement plans in order to help customers and friends.
1. Common problems in laser cutting of medium and heavy plates
1. The perforation problem of carbon steel thick plate
In thick plate processing, the piercing time accounts for a large proportion. Various laser manufacturers have developed rapid piercing technologies. The representative one is high-energy piercing (blasting). The obvious advantage of this method is the fast speed (1 second, with t16mm Take an example—the same below), but the defect not only affects the processing of small shapes, the huge energy injected during perforation increases the temperature of the sheet and affects the subsequent overall cutting process. However, if a low-power pulse is used for perforation, the time is very long (12 seconds), which will lead to a decrease in cutting efficiency and an increase in unit cost.
2. The quality of the cutting surface
Shows the cutting sections that are often encountered when processing medium and heavy plates. Such cutting is not only questioned about the quality of the finished product, but also accompanied by overburning and serious sticking, which can hardly reflect the value of laser cutting machines from other cutting methods.
3. The stability of the whole board processing
In the whole plate processing of steel, the phenomenon of poor processing in local areas often occurs. This phenomenon is sometimes very random, even when the processing equipment is in good condition. In order to deal with local faulty products, the entire work schedule was greatly affected.
2. olutions to the above problems
1. High Peak Perforation (HPP) program
As the name implies, it uses a high-peak pulse laser with a small duty cycle, supplemented by non-fuel sprayed on the surface of the material to remove the attachments on the edge of the opening, and control the reasonable frequency of the pulse while cooling and perforating. Its characteristic is that although the relative blasting time is a little longer (3 seconds), the hole diameter is small (approximately φ4mm), there is no adhesion on the edge of the hole and the heat input is lower, which is convenient for the subsequent normal cutting and processing, compared with ordinary The perforation efficiency is increased by 4 times.
2. Cutting section improvement plan
For carbon steel, an important factor to improve the cutting section is to control the heat input to the plate and ensure the full combustion of the laser irradiation part. In addition, since the best focus position of the thick plate is different during perforation and cutting, if the focus position of the laser cutting machine is fixed, the perforation quality and the cutting quality will decrease. The best focus position can be set by automatically adjusting the focus device to ensure the stability of perforation and cutting quality.
3.Plan to ensure processing stability
At present, in order to increase the operating speed of processing equipment, laser cutting machines usually adopt a structure commonly known as flying light path, that is, a form in which the material tray does not move while the processing head moves in the entire processable area. In order to compensate for the change in the relative position of the processing head and the light source, manufacturers try to ensure the consistency of the light spot within the processing range, and the use of a variable curvature refractor is a common choice. Although this method is simple in structure, it will change the depth of focus, making it difficult to cut medium and thick plates that are extremely sensitive to the depth of focus (it is necessary to keep the spot and the depth of focus unchanged). However, if the machine adopts the equal-length optical path method (the light propagation path between the light source and the processing head is the same length within the processing range), the focal depth change can be avoided, so that the spot and focal depth are kept consistent. In addition, the emphasis on heat input allows the heat accumulated in the plate to be controlled, and the stability problem is better solved.
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