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Design Guide

Direct Metal Laser Sintering

Our design guidelines for Direct Metal Laser Sintering (DMLS) include important information to improve part quality, minimize costs, and reduce overall manufacturing time. By following the guidelines, you can produce high-quality parts, reduce expenses, and improve productivity.

If you have any questions regarding our design guidelines, you can contact our technical team by telephone, email or chat with us online.

Download Guidelines as PDF

Overview

Direct Metal Laser Sintering uses a laser to fuse particles of metal together into a solid shape, layer by layer. It can produce parts in Stainless Steel 316L, Aluminum, and Titanium Ti64. 


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Maximum Build Volume
Varies by Material

Aluminum (AlSi10Mg) - 400mm x 300mm x 400mm (15.75" x 11.81" x 15.75")
Stainless Steel (316L) - 280mm x 280mm x 350mm (11.02" x 11.02" x 13.78")
Titanium (TC4) - 150mm x 150mm x 200mm (5.91" x 5.91" x 7.87")

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Tolerances
Best achievable tolerances - <100mm:  ±0.2mm, <200mm: ±0.3mm, <300mm: ±0.4mm, 300-400mm: ±0.4-0.5mm

If your parts require specific tolerances, an engineering drawing must be provided when requesting a manual quote, otherwise parts will be printed on a ‘best-effort’ basis. Parts designed with thin, flat planes will likely warp, so this should be avoided if tight tolerances are required.

 

Polishing removes approximately 0.1mm of material.

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Layer Height
20 - 80 microns

Standard layer height varies by material

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Surface Finish
Visible Layer Lines

Layer lines are visible on faces at a low angle relative to the build plate. Metal supports are removed, which may leave subtle marks in the surface of the part.

Metal 3D printed parts are shot peened to a surface uniform roughness of 200 - 400 Ra after support removal.

Wall Thickness

Thicker geometries and walls with variable thickness are at risk of deformation due to shrinkage and stress. In general, follow wall design rules for injection molding to achieve a more uniform and consistent part.


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Minimum Wall Thickness
0.8mm (0.031")

Supported walls are connected to two or more sides and are thick enough to support the model.

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Minimum Unsupported Wall Thickness
1mm (0.039")
Unsupported walls are connected on only one side or edge.
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Minimum Pin Diameter
1.5mm (0.059")

The minimum pin size depends on a combination of parameters such as; part orientation, nozzle diameter, and length of the pin.

Minimum Detail Size

The quality of engraved and embossed features depends heavily on part orientation and the resulting thermal effects of printing. Try to place fine details away from overhanging faces that require support, since touchpoints can interfere with intricate geometry.


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Debossed Details
Minimum depth: 0.5mm ( 0.019")

Debossed details are recessed features on your model. These features should be no shallower than 0.5mm (0.019").

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Embossed Details
Minimum depth: 0.5mm ( 0.019")

Embossed details are raised features on your model. We recommend a thickness of 1mm (0.039”) & depth of 0.5 mm (0.019”)

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Text
Minimum point size: 14pt

0.5mm minimum line thickness and 0.5mm depth or a minimum font size of 14 is suitable for every direction.

Bold Sans Serif font is recommended.

Part Clearances

The mechanical performance of printed assemblies is sensitive to variables such as print orientation, layer height and machine tolerances. It is best to test and refine any mated parts before committing to a full production run.


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Minimum Clearance
0.5mm (0.019”)

Clearance is the distance between two moving parts on hinges, joints, mating parts, etc.

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Minimum Press Fit
0.3mm (0.004")

For a tight press fit, add a small offset, and chamfer the leading edge to ease entry. Always print an initial test part to dial in dimensions.

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Printed Linkages
Minimum: 0.6 mm (0.023")

This defines the minimum allowed gap between a bush and a bolt, to avoid bonding of the hinge parts.

Holes & Gaps

Hole accuracy can vary depending on print orientation, thickness of surrounding material and support structures. For tight tolerances, consider printing center marks and post-machining them instead.

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Minimum Hole Size
1mm (0.039")
Holes less than 1mm are likely to fuse. Smaller holes should be post-machined rather than 3D printed.
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Minimum Gap Size
0.8mm (0.03”) - 1.2mm (0.047")

Wall thickness: 0.3mm (0.011”) - minimum gap width: 0.8mm (0.03”)
Wall thickness: 3mm (0.11”) - minimum gap width: 1mm (0.04”)
Wall thickness: 6mm (0.22”) - minimum gap width: 1.2mm (0.047”)

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Minimum Drain Hole Size
4 mm (0.015” )

Hollow walls and enclosures will be filled with metal powder, and must be designed with escape holes so that the powder can be removed during cleaning. Physical support may be left inside and be unable to be removed.

Part Geometry

Part geometry can be optimized for 3D printing to reduce material usage, increase strength and rigidity, and take advantage of machine capabilities.


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Fillets

Fillets can be used to reduce stress concentrations and increase the strength of your part. 

When designing fillet features across inside and outside corners, it is best to have them share a common center point in order to maintain a consistent wall thickness.

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Bosses and Ribs
Bosses and ribs are an effective way to add strength and stiffness to a part while keeping material consumption to a minimum, this can also reduce build time and use less support material. 
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Support Structures
DMLS parts are partially supported by surrounding powder, but also require printed supports to counteract their increasing weight as they print. These supports are made with the same material and must be removed with metal cutting tools, which may affect the surface finish. 
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Infill
Infills are not applicable for DMLS 3D Printed parts. Walls are printed solid throughout.

Threads & Inserts

Threads can be printed but functionality is not guaranteed. They can be tapped for greater accuracy. As a general rule, avoid printing hardware.

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3D Printed Threads

Threads can be sintered directly into parts depending on the size of the thread and print orientation. Threaded sections should be printed vertically and should have sufficient clearance to allow a tap or die to be used.

Smaller threads should be left to be drilled and tapped rather than printed.

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Tapping & Threading

Design parts with holes sized for tapping, or center marks for drilling a pre-tapped hole. You may need to reference a tap and drill chart to figure out which hole size corresponds to a given thread. 

Tapping removes material, puts pressure on the surrounding geometry, and fastener locations are often points of stress, so make sure there is enough material surrounding the tapped hole.

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Inserts
Inserts are not required for metal parts. 

Post Processing

While printed parts are highly functional and accurate, there are a variety of ways to modify them after printing to enhance durability or aesthetics.

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Sectioning, Joining, and Bonding

Parts too big to fit on the print tray can be split in CAD and printed in multiple parts, then glued or press fit.  Use joinery features, such as tongue and groove, to ensure the sections are aligned and bond tightly. 

Depending on orientation, material and other properties, an offset may be required to make sure the parts fit together properly. We recommend printing a small test part to dial in the offset before printing the full set of parts.

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Post-Machining
Parts can be machined to tighter tolerances using traditional or CNC subtractive manufacturing equipment.
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Coatings
Parts can be treated with standard metal coatings (anodization, powder coating etc)
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Vapor Smoothing
Not applicable for DMLS.