Focus error problem of fiber laser cutting machine

Focus error problem of fiber laser cutting machine

There are many factors that cause changes in the relative position between the focal point and the surface of the processed object during laser cutting. The surface roughness of the processed workpiece, the clamping method of the work piece, the geometric errors of the machine tool, and the deformation of the machine tool under load, as well as the thermal deformation of the workpiece during processing, can all cause deviations between the laser focal point position and the ideal given position (programming position).

Why does focus error occur?

Some errors (such as geometric errors of machine tools) have regularity and can be compensated through quantitative compensation methods, but some errors are random errors that can only be eliminated through online detection and control.

Geometic eror ofworkpiess

The object of laser cutting is sheet metal or covering parts. Due to various reasons, the surface of the processed object has undulations and unevenness, and the influence of thermal effects during the cutting process can also cause surface deformation of the thin plate parts. For one-dimensional laser processing, covering parts also produce surface unevenness during the pressing process. All of these will cause random changes in the position of the laser focus and the ideal position of the surface of the processed object.

Eror generated by workpiess clamping device

The workpiece processed by laser cutting is placed on a needle shaped worktable. Due to processing errors, long-term wear and tear between the workpiece, and laser burns, the needle bed will have unevenness, which can also generate random errors in the position between the thin steel plate and the laser focus.

3.Errors generated by programming

In the process of laser cutting, the machining trajectory on complex surfaces is fitted through lines, arcs, etc. These fitted curves have certain errors with the actual curves. These errors cause certain errors in the relative position between the actual focus and the surface of the machining object and the ideal programming position, and some teaching programming systems may also have some deviations.

How to adjust the focus position
The online detection and control system for laser cutting focus position consists of a controller, detection system, execution device, and other parts. According to the relationship between the focus position detection control system and the system, the focus position detection control system is divided into two types: independent and integrated, also known as manual focusing and automatic focusing.

1.Manual focusing

The manual focusing focus position detection and control system adopts a separate coordinate axis for compensating and controlling the focus position error. The mechanical structure is simple and the cost is low, but it can be used in conjunction with various CNC systems and laser cutting machines.

Representing laser head products:

2.Autofocus

Automatic focusing uses the combined motion of one or more feed axes of the laser cutting machine itself to compensate for the focus position error. This method has a relatively complex structure and high cost, but it is easy to operate and adjust, requiring coordination with CNC systems. On the CNC software interface that supports automatic focusing, the laser head can be controlled to adjust its focus by adjusting parameters. This can reduce human intervention and make the focus position more precise.

Representative laser head products:

Corresponding systems for coordination

The automatic focusing laser head requires the cooperation of a professional intelligent laser numerical control system to meet the requirements of automatic focusing. Professional automation control software that allows for the free addition of axes and control signal modules, providing customized main design functions for customers.
Representative products: