Several factors of focus position error in the cutting process of laser cutting machine: In the laser cutting process, there are many factors that can cause the relative position between the focus and the surface of the machined object to change, including the uneven surface of the machined workpiece, the clamping method of the workpiece, the geometric error of the machine tool, the deformation of the machine tool under load, and the thermal deformation of the workpiece during the processing. This will cause a deviation between the laser focus position and the ideal given position (the programmed position).
Some errors (such as geometric errors of machine tools) have regularity and can be compensated by quantitative compensation methods, but some errors are random errors and can only be eliminated by online detection and control. These errors include:
The object of laser cutting is plate or panel parts. Due to various reasons, the surface of the processed object is not uniform, and the influence of the thermal effect during the cutting process will also lead to the surface deformation of the plate parts. For laser processing, the surface of the panel will also be uneven during the stamping process, and the position and ideal position of the laser focus and the surface of the object to be machined will change randomly.
The workpiece of laser cutting is placed on the needle work table. Due to machining errors, long-term wear between workpieces and laser burns, the needle bed will appear uneven, which will also create random errors in the position between the sheet steel and the laser focus.
In the process of laser cutting, the machining path on the complex surface is fitted with straight lines, arcs, etc. There are some errors between the fitted curves and the actual curves. These errors can lead to certain errors in the relative position of the actual focus and the surface of the machined object, as well as in the ideal programming position. Some instructional programming systems also introduce some biases.
Laser focus position detection and control is one of the key technologies in laser cutting. For rapid cutting, the accuracy and rapidity of focus position detection will directly affect the control precision of focus position and machining quality. Capacitive sensor has the advantages of high sensitivity and fast response, and its nonlinearity can be overcome by linearization of computer system
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