DIRECT METAL LASER SINTERING (DMLS)

About Metal 3D Printing

Metal 3D printing produces parts by fusing together metal powder layer by layer to form a metal part. It is often chosen as an alternative to CNC machining or metal casting because it can produce parts with the strength and durability of metal while also taking advantage of the design freedoms afforded by 3D printing. Metal 3D printing can produce complex designs including lattices and topology-generated structures, both which are impossible to manufacture via traditional CNC machining.

Sinterize Advantage

At Sinterize, we have wide range of capabilities offerred through single, easy-to-use platform so you spend less time sourcing parts and more time on design innovation.

Overview

The DMLS machine begins sintering each layer—first the support structures to the base plate, then the part itself—with a laser aimed onto a bed of metallic powder. After a cross-section layer of powder is micro-welded, the build platform shifts down and a recoater blade moves across the platform to deposit the next layer of powder into an inert build chamber. The process is repeated layer by layer until the build is complete.

Support structures are automatically generated and built simultaneously in the same material, and are later manually removed. An initial brushing is manually administered to parts to remove a majority of loose powder, followed by the appropriate heat-treat cycle while still fixtured in the support systems to relieve any stresses. Parts are removed from the platform and support structures are removed from the parts, then finished with any needed bead blasting and deburring. Final DMLS parts are near 100 percent dense.

This technology combines the design flexibility of 3D Printing with the mechanical properties of metal. From tooling inserts with cooling channels to lightweight structures for aerospace, any application that involves complex metal parts potentially benefits from Metal 3D Printing.

DMLS materials are generally accepted to be equal or better than those of wrought materials. DMLS is also ideal when the geometry or structure of the part is not possible in any other process (for weight saving designs using honeycomb or lattice structures for example). SINTERIZE can also produce parts for implant medical applications. We also offer a number of secondary services such as painting, post machining and measurement and inspection, to further enhance the finish of your 3D-printed project design.

Applications

materials

Aluminium AlSi10mg

TENSILE STRENGTH (MPA)	PART DENSITY	SURFACE ROUGHNESS	MELTING TEMPERATURE °C
340	2.67 g/cm3	Ra 6 - 15 µm; Rz 50 - 100 µm	600 °C

Maraging Steel

TENSILE STRENGTH (MPA)	PART DENSITY	SURFACE ROUGHNESS	MELTING TEMPERATURE °C
2080	8.0-8.1 g/cm³	Ra 4-6.5 µm; Rz 20-50 µm	800 °C

Stainless Steel 316L

TENSILE STRENGTH (MPA)	PART DENSITY	SURFACE ROUGHNESS	MELTING TEMPERATURE °C
62.63	7.9 g/cm3	Ra 4 µm; Rz 20 µm	1200 °C

Inconel 718

TENSILE STRENGTH (MPA)	PART DENSITY	SURFACE ROUGHNESS	MELTING TEMPERATURE °C
1210	8.15 g/cm³	Ra 4 – 6.5 µm, Rz 20 - 50 µm	1400 °C

Cobalt Chrome

TENSILE STRENGTH (MPa)	PART DENSITY	SURFACE ROUGHNESS	MELTING TEMPERATURE °C
1350	8.3 g/cm³	Ra 4 -10 µm; Rz 20 – 40 µm	1450 °C

Titanium Ti64

TENSILE STRENGTH (MPA)	PART DENSITY	SURFACE ROUGHNESS	MELTING TEMPERATURE °C
1075	4.41 g/cm3	Ra 5 - 9 µm; Rz 20-50 µm	1100 °C

Design Rules

Minimum Wall Thickness: 0.8 – 1.2 mm

Minimum Details Size: 2 mm (for text/ hole diameters etc)

Layer Thickness: 0.02 mm – 0.08 mm

Max Dimensions: 250 x 250 x 325 mm.

Standard Accuracy: ± 0.2% (with lower limit on ± 0.2 mm).

Lead Time: Minimum 3 to 8 working days for dispatch

Surface Finish: Rough surface, which can undergo finishing stages as per requirement

post processing

Basic: Powder Removal, Heat Treatment, EDM Wire Cut, Bead Blasting, Polishing.

Add On: CNC Machining & Painting

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Frequently Asked Questions

Which is cheaper 3D metal printing or casting?

It depends on 2 factors quantity & complexity of parts. For < 10 parts DMLS is cost effective. When the requirement is mass i.e. > 1000 casting will be cheaper.

For simple geometries like a 50 mm Dia x 50mm Length shaft DMLS cost 15,000 bucks where as in casting or machining it may cost max 2,000 bucks. So for complex geometries DMLS will be cheaper.

How does DMLS printing costing works?

DMLS 3D Printing costing is divided in 3 steps. Pre-processing, 3D printing and post processing. Pre-processing activity includes designing, part feasibility, reverse engineering. Secondly, in the printing phase, the cost is dependent on number of factors such as build hours, support structure required, material, orientation of part etc. Finally, in the post processing phase, activities such as heat treatment, surface finish ,CNC machining, EDM etc activities do contribute. Every part doesn’t have to go through all above mentioned activities. Number of activities required depend on case to case basis.

How much accuracy we can achieve in DMLS parts?

3D printed parts produced with DMLS process are quite accurate. This process can achieve near net shape of a part with 0.2 mm (200µm) accuracy. Additionally, CNC machining can be done for further improvement up to 5-10 µm.

How is the surface finish of metal 3D printed parts?

Parts have Ra values ranging from 7-12 µm depending on the material, but we can alter the value by post processing activities. These activities are capable of producing ‘Matt Finish’ and ‘Mirror surface finish’ where matt finish hardly removes any material from the surface, around 200-300 mg. However, mirror surface finish needs 0.5-1 mm additional stock for achieving 1-2 Ra value. Matt finish can achieve up to 3-5 Ra.

Is heat treatment compulsory for metal 3D printed parts?

In most of the cases, heat treatment is compulsory. During metal 3D printing process, residual stresses generated within the part geometry can lead to product failure while in application, and therefore, stress relieving heat treatment cycle is a must for functional parts. On the other hand, parts which are merely showpieces/non-functional can be delivered without being heat treated.

Why geometries like threading's are not recommended to print in DMLS?

Threads have several over hangs where non removable supports were generated & pitch also cannot be maintained in printing. Recommended process is, printing a plane hole without threads & later doing tapping.

Why inert gases are used in DMLS 3D Printing?

Inert atmosphere is needed while sintering metal powders to avoid oxidation process. To maintain inert atmosphere we use Argon or Nitrogen gases.

At what temperature parts are printed in DMLS ?

In DMLS, chamber temperature will be of max 200°C. A 400 watt laser exposes on loose powder & generates 1500°C – 2000 °C at 80 microns dia spot.

What are the common difficulties we face in DMLS printing?

Warpage while printing flat geometries.
Features breakoff due to improper supports.
Powder blockage

Why production lead time for DMLS is more than SLS/MJF?

After DMLS printing there are a series of secondary process involved which comes time. Below mentioned are series of steps we do in DMLS printing process.

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Sinterize Holdings LLC
15093, Starry Night Ln
Frisco, Texas
USA – 75035
Email: info@sinterize.com