3D Metal Printing – An Overview

3D printing is a technology which has captured the headlines, with stories about the increasingly sophisticated projects that can be built. Although it may seem relatively new, the technology has been around for some time having first emerged commercially during the 1980s. Laser printing with metal powders has proved more challenging than other materials and for widescale adoption has relied on a series of technological breakthroughs, which make the use of metal 3D printers an everyday occurrence in many manufacturing businesses.

3D metal printing as a technology has gone from strength to strength and it now has the ability to be used practically for laser printing with metals across a great range of projects and functions.

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How does a 3D metal printer work?

Metal 3D printing is a type of additive manufacturing technology, not subtractive which means that material is gradually added to get the finished result rather than being taken away (such as in turning or milling). No contact tools (such as a chisel, hammer or drill) are required, the process is entirely contactless and managed remotely via the power of a laser beam.

The 3D metal printing process

A 3D metal printer needs a CAD (computer aided design) to start the process, creating a detailed image from all angles of the desired design. Once the CAD software has been used to complete the design, it then needs to be converted into a .STL (stereolithography) format to enable the 3D metal printer to interpret the instructions.

The metal printing process is a multi-layered additive approach, just like other forms of 3D printing and requires the design to be sliced very finely on the horizontal plane before it can start to be built. The 3D metal printer receives its instructions from the computer which instructs the Laser what shape to trace out across the metal powder. The Laser then pulses and heats up the powder which subsequently creates a solid form of the object. This is how 3D printing in metal begins.

Once this initial base has been laid out the 3D metal printing process begins again, each layer typically no more than 0.1mm thick. This very gradual additive process is how metal 3D printers create the final product, with the heat from the Laser forming a solid shape. This process is known either as Direct Metal Laser Sintering (DMLS) or Selective Laser Melting (SLM), depending on the heat used and whether the powder is melted completely or just heated enough to fuse together.

What can be made with metal 3D printers?

The possibilities which open up with metal 3D printers techniques are almost limitless and designs which were either impossible or extremely expensive to make are now far more viable.

A 3D printed metallic space fabric produced by NASA

A 3D printed metallic space fabric produced by NASA

Through metal 3D printers, metal can be shaped far more easily, and incredibly complex and intricate designs are far more achievable. This could be as complex as tubes within tubes, hollow middles with undercuts and overhangs, or just superfine layers previously too delicate to cut. The 3D print will take on the shape which the Laser is instructed to form, which means the only real limitation is what you can design or imagine!

What’s the difference between 3D rapid prototyping and 3D laser printing?

When it comes to 3D metal printing, UK media coverage has been immense, putting the technology firmly in the limelight and showing off exactly what could be possible – even going as far as showing a house that was constructed this way.

But although the printer works in the same way as a 3D rapid prototype, there is a large gulf in quality and performance. Both are built on the same core concept, but a rapid prototype machine is designed to handle larger sizes and will be pinpoint accurate by comparison.

3D printing with metal is far more complex than using other materials, and more expensive too. The extremely high temperatures mean that 3D printing in metal is far less accessible to home users than plastic, for example. There are a number of metal 3D printers suitable for home use but laser printing on metal is not normally available other than in industry.

Rapid prototyping has a variety of potential applications. It’s frequently used to create “proof of concepts” and physical models to evaluate fully CAD designs. Using prototypes, products can be tested for endurance and environments (e.g. extremes of heat and cold). Similarly, rapid prototyping can be used for short production runs of both tooling and parts (perhaps limited editions, country variants, for niche industries, or for spares).

The art of the possible, a 3D printed spinal disc replacement

The art of the possible, a 3D printed spinal disc replacement

What are the benefits of 3D printing?

With metal 3D printers, and other materials have far more flexibility and the ability to create cheaper and more complex moulds becomes possible.

There are a number of benefits of using a 3D printer or rapid prototype machine:

  • Greater range of shapes and designs possible. The complexities which are possible with 3D printing couldn’t be achieved via other Complex and unusual designs are especially used in both the jewellery and fashion industries
  • More cost-effective. For manufacturing, 3D printing provides an economical option which can be individually tailored to meet requirements (this is especially the case for low volume batch runs)
  • Strong and robust finish. As the design is created as a continuous piece rather than having multiple welds and joins, there are no weak spots making the eventual product stronger overall
  • The ability to work with such eye-wateringly small slices at a time means designs can be created which are super-thin, or hollow even, reducing the weight of a product. This is particularly beneficial in industries such as aerospace, which crave for lightweight products (e.g. turbos and turbines) to improve aerodynamics, whilst also reducing fuel consumption
  • No waste. Almost all the powder left unused in the process of 3D printing can be saved and used again (apart from a little dust residue). Unlike traditional machining methods, there’s zero waste which means it’s an eco-friendly With traditional subtractive methods, an object is manufactured into shape from a solid block, with the waste materials cut and drilled out, which are often wasted, at tremendous cost. This helps any organisation using 3D printing to reduce its carbon footprint
  • Although a mould may still take a couple of days to print – for more complex designs at least – this is an extremely rapid process by comparison to other methods
  • Easy to tweak. If you need to change the design, the process is simple and only requires a few buttons to be pressed rather than an expensive and lengthy re-design
  • No need to stock expensive designs. With 3D printing, providing you have the materials to run the machine, there’s no reason for any item to be out of stock. All you need is the .STL file and you can print a product whenever you need one. This also means the .STL file can be mailed to other offices or external partners for printing too. This also saves on stockholding costs, which greatly aid cashflow in manufacturing businesses
A 3D printed model of stainless steel fastener prototypes

A 3D printed model of stainless steel fastener prototypes

More to come…

The 3D printing industry is just starting to hot up and despite the many recent developments, the speed of research means that there’s a very good chance this type of technology is quickly going to snowball. This means the technology will become far more commonly used in everyday manufacturing as further uses are identified.

Related articles

Also, be sure to read the following SPI Lasers articles about 3D printing technologies:

Contact SPI Lasers to discuss 3D printing and laser printing on metal

To find out how we can improve your 3D metal printing processes with our Continuous Wave fiber laser models please call SPI Lasers today on +44 (0)1489 779696 or you could complete our online enquiry form. Our team are waiting to speak to you and can advise on all aspects of 3D printing of metal. To subscribe to future updates, click this link.

 

 

Image Credits: Jet Propulsion Laboratory – NASA, United States Government and Top 3D Shop Inc

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