In the laser cutting process, a lot of factors affect relative position between focus and processed metal, the workpiece surface is uneven, workpiece clamping method, machine tool geometric errors and the machine deformation under load force, the workpiece processing of thermal deformation can cause the laser focus and the ideal location for a given position (programmed position) deviations occur.
Some errors (such as machine tool geometric errors) regularity, can be compensated by the compensation method for the quantitative, but some error is a random error, can only be removed by line detection and control, these errors are:
What cause focus position error?
1. Geometry error
Laser cutting sheet or cover part, due to various reasons, the object has a bumpy surface, and due to thermal characteristics in the cutting process will produce a surface deformation of the sheet metal parts, for the one-dimensional laser processing, cover press-forming process will produce an uneven surface, the position and the ideal location for all of these, will have a laser focus with the surface of the object to be processed random changes occur.
2. The error generated by the workpiece clamping device
Laser cutting is on the needle workpiece table, due to manufacturing errors, time and wear and laser burns between the workpieces, needle beds will be uneven, this injustice will produce steel sheet and the focus of the laser random error between the positions.
3. Programming error
In the one-dimensional laser cutting process, machining path on complex surfaces by lines, arcs, and another fitting, curve fitting and these actual curve there are some errors, these errors so that the actual focal point and the relative position of the object surface and programmed position over a certain error. While others teach programming system will introduce some bias.
How to solve focus position error?
The laser cutting focus position online detection and control system is composed of controller, detection system and execution device and the like. The focus position detection control system is divided into two types: independent type and integrated type, also called manual focus adjustment and automatic focus adjustment.
Manual focus adjustment
The manual focus position detection and control system uses a separate coordinate axis to compensate focus position error. The mechanical structure is simple and the cost is low. It can be used with various CNC systems and laser cutting machines.
Auto focus adjustment
Autofocusing uses the combined motion of a feed axis or multiple feed axes through the laser cutting machine itself to compensate for focus position errors. This method has a relatively complicated structure and high cost, however, it is simple in operation and easy to adjust, and is required to be used in conjunction with a numerical control system.
The CNC software interface that supports autofocus controls the laser head to adjusts the focus by adjusting the parameters. This can reduce human intervention and make the focus position more accurate.
