There was a thread on the possible reduction of cnc machining because of the growth in "3D" printing. It appears that a German company [EOS] has developed a process to directly create plastic injection molds by laser sintering. Not only can you directly create the mold from a cad file, this process also allows very intricate coolant passages.
Thoughts and has anyone seen any molds made by this process? Materials? Surface finish?
Injection molding is the most widely used plastics processing technology. The process melts thermoplastics and forces them into a metal mold. After the plastics cool, the mold opens to reveal the finished part. To speed cooling, molders run liquid through cooling channels they drill into the mold.
Cooling channels work great when molding parts with regular features. Add curves and irregular geometries, and manufacturers run into problems. Straight drilled channels cannot follow the contours of the part. As a result, they remove heat unevenly, so operators must wait until the material farthest away from the cooling channel cools before they remove it from the mold. No wonder cooling time can account for up to 70 percent of each injection molding cycle. Uneven cooling can also warp parts and increase scrap rates.
This is where EOS comes in. The company?s equipment produces molds from 3-D CAD data by direct metal laser-sintering, fusing metal powders into solids one layer at a time. The company?s equipment has no problem creating cooling channels that curve, arch, and branch to conform to any shape, because channels are built into the mold as it is formed, not drilled afterwards.
------
Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).