Direct Metal Laser Sintering

From: Lohner, Andreas (
Date: Tue Oct 21 1997 - 18:55:23 EEST


The DMLS (Direct Metal Laser Sintering) process was developed by EOS
GmbH of Munich, Germany, and has been commercially available since 1995
on the EOSINT M 250 laser sintering machine.

Its main application is the manufacture of mould inserts for plastic
injection moulding.

The philosophie of DMLS is to produce net-shape metal tools with the
required mechanical characteristics directly in the RP-machine, and to
keep the process chain from CAD to finished mould insert as short as
possible while maintaining a high level of precision. This is possible
by using a high power laser with high beam quality (200 W, focus
diameter =0.35 mm) and a specially developed, pure metal powder.
When the powder is exposed to the laser, the formation of a liquid metal
phase is activated as a binding agent. As soon as the applied energy is
sufficiently high to heat the powder to above its melting point, the
liquid metal compound passes into the surrounding cavities and wets the
high melting alloys. With the formation of porous and solid solutions,
the powder volume expands macroscopically to provide partial
compensation for the sintering shrinkage which has occurred. By
appropriate selection of the process parameters it is possible to build
a part with no net dimensional change in the building plane.

In several projects we showed that the inserts produced in the DMLS
process can be used in conventional injection moulding with standard
parameters and series plastic material. In every case, the intelligent
combination of Direct Metal Laser Sintering and conventional tooling
lead to a extreme reduction of time and costs.
Last week 15000 PA+30%GF parts have been produced on a completely
lasersintered mould consisting of 4 inserts without any abrasion on the
Service bureaus offering this technology
are listed in the EOS homepage at

Andreas Lohner
Product Manager EOSINT M

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