The DML 40 and the DMU 60L, sister 100W YAG laser cutting machines made by DMG America Inc. (Schaumburg, Illinois), could be the first shot in a battle between lasers and ram-type EDM machines for die and mold machining applications. The DMG machines have a 0.004-inch diameter laser beam that can be precisely controlled to machine cavities and delicate features in a wide range of materials, including ceramics. DMG points out that the laser beam does not wear or break (unlike end mills), which ensures machining consistency and reliability. In addition, the laser does not require an electrode (unlike ram EDM), which reduces the time and expense of producing the finished die or mold.
In operation, laser pulses vaporize the material in thin layers of only 5 micrometers, resulting in surfaces with hardly any visible step marks. The laser "plows" through material at rates up to 0.79 cubic inch per minute. A sensor measures the amount of material being removed.
DMG attributes a large part of the success of its lasers to their Lasersoft 3D control and software, developed specifically for the machines, which direct the lasering process and machine movements (three optical and three mechanical axes). Programming starts with a CAD file of the part. The software separates the CAD data into layers, which are used to generate laser ghost lines. All calculations are done automatically by the user-friendly control, and the operator needs no special CNC skills.
Befitting their use as mold-making machines, the DMG machines can laser cut walls with draft angles up to 0 degrees. Surface finishes down to 1.3 micrometers can be achieved.
The DML 40 is a laser cutting machine exclusively. It has a working envelope that measures approximately 16 by 12 by 22 inches (XYZ). The work table measures approximately 12 by 16 inches. Maximum machining depth is 0.4 inch.
The DMU 60 L is a combination (milling and laser cutting) machine. Along with laser cutting capability, the machine offers conventional milling with a 20-horsepower spindle capable of speeds up to 12,000 rpm. DMG doesn’t belabor the point, but the prospect of a machine that can rough-mill to finish dimensions with a stock allowance and then finish machine to required size and surface finish with the laser in the same setup is going to make a lot of people sit up and take notice.