Introduction of DMLS and SLM

Being able to quickly and cost-effectively produce complex metal parts, or part prototypes, is a problem in modern manufacturing, and metal 3D printing solves this problem very well. Whether it is a designer or a manufacturer, metal 3D printing is undoubtedly a best choice.

Among them, DMLS and SLM are the most widely used technologies.DMLS (Direct Metal Laser Sintering) and SLM (Selective Laser Melting) are two very similar powder bed fusion (PBF) technologies. Each technique melts a specified pattern of metal powder using laser beams. By repeating this process in successive layers, the machines build up complex parts, often using advanced metal alloys. DMLS is a trademark of EOS while SLM is a trademark of SLM Solutions. Both technologies fully melt metal powder instead of sintering it the way most metal 3D printing technologies do.

Attribute	SLM	DMLS
Laser point diameter	80 to 160 microns	40 microns (for smaller machines)
Number of lasers	Machines with 1,4, and 12 beams are available	4

8 design tips for Metal 3D Printing

Of course, in order to print reliable metal parts, we need to understand and follow some basic rules when designing. Let’s take a look at these 8 tips below.

1.Wall thickness 

The minimum wall thickness to ensure a successful 3D print with most materials is 0.5mm. 

2.Pin diameter

The minimum reliable pin diameter is 1mm.

Smaller diameters are possible, but will have reduced contour sharpness.

3.Hole size

For accurate prints with no support use hole diameters between 0.5 mm and 6 mm.

Support free building with hole diameters between 6 mm and 10 mm is orientation dependent.

Support structure is required when horizontal holes with diameter of 10 mm is used.

4.Escape holes

Holes are needed on hollowed metal parts so unmelted powder gets properly removed.

Bore hole diameter between 2 and 5 mm is suggested.

5.Overhangs

45º is the minimum angle where support material is not required.

6.Unsupported Edges

The maximum length of a cantilever-style overhanging surface is 0.5 mm.

An overhanging horizontal surface supported on both ends can be 1 mm long.

7.Embossed Features

Embossed details must be designed using a minimum height, otherwise, it will not appear visible. Such features should be at least 0.3mm. To ensure embossed details come out nicely, make them larger than the indicated.

8.Engraved Details

Because of the heat-dissipating from the laser into the surrounding powder during DMLS, text and engraved details are at risk of closing up and won’t be visible if not designed with a minimum depth and width. Engraved details should be at least 0.5mm deep and 0.5mm wide.

Commonly used post treatment

1.Polishing

The process of creating a smooth and shiny surface by rubbing it, leaving a clean surface with a significant specular reflection.

2.Sandblasting

Propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants.