Direct Metal 3D Printing: Technology Overview
Direct metal 3D printing – also called Selective Laser Melting (SLM) – works similarly to selective laser sintering (SLS). In SLS a laser heats the powder but does not allow it to exceed its melting point, meanwhile, in direct metal 3d printing the melting point is exceeded. As a result, the printed metal parts have similar physical and mechanical properties as conventional metal parts. Therefore, the technology can be used to create realistic metal prototypes or small batch series of metal parts.
The technology is quite versatile and can be used with many different metals, however most aluminum, steel and titanium are the most commonly used.
History
Developed between 1995 and 1999 Direct metal 3D printing is a relatively young 3D printing technology. Several companies and institutes worked on this technology at the same time. The first working printer working featuring laser melting technology was introduced in Karlsruhe, Germany in 1999.
The term ‘SLM’ was coined by the company SLM Solutions. SLM Solutions is a spin-off of several companies that were involved in the development of this technology. Today, SLM Solutions is one of the leading providers of metal 3D printers.
Patent drawing of the first SLM Machine from 1995
Direct Metal 3D Printing: Process
In a first step, metal powder is applied to a built platform. Once the material is evenly distributed, a laser selectively melts the first layer into the powder. The built platform lowers by one layer height (typically between 30 and 50 µm), a new layer of powder is subsequently applied to the platform, and the laser selectively melts the second layer of the model. Due to the melting process, the powder fuses with the layer below, so that step-by-step the model is created.
In laser sintering with PA12 (Nylon), the powder on the built platform is compacted by a thermic process. Therefore, the physical model can be created without the use of any support structures. In laser melting with metal powder, this compacting is not possible to the same extend, therefore support structures are required.
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Example Direct Metal 3D printing. Source: YouTube, BEGO
Direct Metal 3D Printing Applications
Unlike other metal 3D printing technologies, the laser melting process creates parts which are mechanically comparable to conventionally produced metal parts. As a result the technology has been universally applied to both prototypes and small-series production of parts in the following industries:
- Aerospace
- Dentistry
- Medical Implants
- Automotive Components
- Jewelry
- Machine parts
Direct metal 3D printing allows easier fabrication of geometries which would be challenging or even impossible for conventional production methods.
Direct Metal 3D Printing: Materials
We offer the following choice of materials:
- Stainless Steel: Stainless steel combines great hardness and high ductility with corrosion resistance. It is suitable for parts requiring high strength.
- Aluminum: Aluminum is a light metal (density ~2.7 g/cm³) which can be easily processed. It is a good choice for parts requiring low weight with good strength.
- Titanium: High strength, low density, corrosion resistant and bio-compatible make titanium an excellent choice for applications in medical implants, jewelry, and aerospace.
More detailed information about these metals are available on our page 3D printed metals.
With direct metal 3D printing are even thin wall thicknesses possible (image: 0.3 mm)
Direct Metal 3D Printing: Cost & Prices
Direct Metal 3D printing is a state-of-the-art technology and requires sophisticated equipment. Printers are thus expensive to both purchase and operate. The main cost factor for steel and aluminum is printing time and post-production time; material use is a less critical factor. For smaller pieces, the price of printing one item or printing multiple copies is often similar.
For Titanium the raw material cost is significantly higher than steel or aluminum. Therefore, the incremental cost for an additional copy of your part is higher than in aluminum or steel.
Due to the complexity of the technology, we do not offer instant pricing quotes for 3D printed metal parts. We kindly ask you to send us a manual request – we will get back to you within one business day.
Submit a manual quote, attaching your model (or a drawing), as well as the intended material and quantity. If you have questions, please contact us.
Direct Metal 3D Printing: Printers
Your parts will be produced on a Type SLM 280 HL machine from SLM Solutions – it has a maximum build space of 248 x 248 x 350 mm.
Printer SLM 280 HL by SLM Solutions GmbH
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