CAD-CAM & CNC laser cutting
CAD-CAM software translates CAD files (digital working drawings) into CNC programs that can be loaded into the laser cutting machine.
CNC programs
CNC stands for Computer Numerically Controlled. A CNC program is essentially a digital text file with instructions for the laser cutting machine.
This CNC file defines, among other things, which material the machine has to cut, which coordinates the cutting head has to follow and at what speeds the cutting head has to move. The CNC program also contains the so-called cutting parameters for laser cutting. The most important cutting parameters are the power [W] delivered by the laser source, the gas pressure [bar] applied for the cutting gas, and the height [mm] at which the focal point of the laser beam must be located.
Offline programming
The CNC programs are programmed offline. This means the CNC programs are made on computers while the laser cutting machine is in production. The laser operators always have several CNC programs ready that they can start at the machine. They do this in the order prescribed by the schedule of the production orders to be produced.
CAD-CAM software
The CNC program is made with CAD-CAM software. CAD stands for Computer Aided Design. CAM stands for Computer Aided Manufacturing.
The CAD-CAM software we use can “unfold” a 3D file of a bent sheet metal part into a flat state. We call this flat sheet the “flat pattern”. The “flat pattern” is what the sheet metal part looks like when it is cut on the laser, before it is bent on a press brake.
This flat pattern is then given a processing plan for laser cutting. This processing plan defines where the laser has to pierce and which path the laser head has to follow. The cutting parameters are also set for every outer and inner contour. The part is, in effect, “tooled”. In jargon we call the result a “GMT” file, and it is stored in a part archive. By producing parts with the same tooling in every production run, we promote consistent laser cutting quality. It allows us to continuously improve the cutting programs based on feedback from our factory and customers.
MES software
MES stands for Manufacturing Execution System. The MES software is linked to the schedule, which prescribes which parts have to be produced in which quantities. The MES software then groups all sheet metal parts to be cut by material. All parts of the same material can then be “arranged” in a metal sheet by loading the GMT file from the part archive. We also call this process “nesting”. These “nestings” are the final CNC programs that the machine operators can load into the machine to start laser cutting.