Direct metal laser sintering of metal parts
Highlights
DMLS is an additive process, similar to the laser sintering of plastics but working with a variety of metal powders. It is currently possible to produce parts in Maraging Steel, Bronze composite, 17-4 SS, Cobalt Chrome and Titanium.
As with other RP processes complexity is not an issue, although in this context the process requires supports that are built using the same material as the part. Thus for some geometries support removal may be challenging.
To really extract the benefit from the process the part geometry needs to be designed with the process in mind, and not transplanted from another manufacturing technique. However, unless DMLS is being viewed as a production technique (RM) this is seldom the case and compromises are required.
Data format for DMLS is STL.
Process Features
Accuracy
As a guide only allow ± 0.125 mm for the first 25mm, plus an additional ± 0.05mm per 25mm thereafter.
Minimum Feature Size
This is component and orientation specific.
Layer Thickness
Most materials build at between 20 and 40 micron layers.
Bed Sizes
Bed size is 250 x 250 mm.(200 mm in z)
Post Processing
Parts will have supports removed as standard and are then shot-peened.
Description
The process is very similar in principle to laser sintering of plastic powders, except that the laser power and temperatures used are very different, and that supports feature.
Applicability is a function of component size, volume and complexity. Both part size and volume have a dramatic effect on price, whilst complexity is easily handled. Complexity has more effect on alternative technologies, especially where multiple technologies are required to achieve it, giving DMLS an advantage.
Alternative technologies to consider are CNC machining or investment casting.