Redefining design with additive manufacturing

Sandvik Additive Manufacturing is the Sandvik Group’s latest product area and it’s constantly developing and growing with more resources, capabilities, employees and customer requests, as the competitive landscape within additive manufacturing rapidly evolves.

“The metal additive manufacturing market is still very young and small, but it is an attractive high-growth market. In 2015, metal additive manufacturing was just beginning to move beyond an R&D and prototyping tool, into a manufacturing tool. In 2017, the move towards becoming a full-fledged production technology has accelerated, for example within aerospace, medical and tooling”, says Kristian Egeberg, President of product area Additive Manufacturing at Sandvik Machining Solutions, the business area Sandvik Coromant belongs to.

Mikael Schuisky, Operation Manager at Sandvik Additive Manufacturing, says Sandvik Group has a unique position.

“The Sandvik Group has the competence to provide a complete offer, from idea to finished product,” he says, also referring to the business area Sandvik Materials Technology, that is a world-leading supplier of metal powder used in additive manufacturing. “You can’t find many other companies with competence in everything from in-house powder production and development, AM-design, AM process selection and leading expertise in post processing-technologies, such as machining or sintering.”

Sandvik Group’s capability within both additive manufacturing and traditional, subtracting manufacturing through CNC machining, is also unique, says Egeberg, referring to Sandvik Materials Technology neighbor in Sandviken, Sandvik Coromant.

“Additive manufacturing is fantastic for certain applications, but for others, subtractive manufacturing will remain more cost-efficient,” he says. “We have the competence in-house to offer products and advice related to both areas.”

Schuisky says the initial discussion with customers around manufacturing method is central.

​“Ask a metal cutting company and then a printing company, and you will get completely different answers to the most suitable manufacturing method for your component,” he says. “As we have competence in both methods, our customers will get unbiased recommendations.”

Generally, additive manufacturing is the better choice when producing components with complex designs.

“Additive manufacturing totally redefines our approach to design and to what’s possible to produce in one piece, but it takes an open mind and quite some designing skills,” Schuisky says.

To clarify, he shows a component made from traditional metal cutting, and its equivalent, additively manufactured. They look like two completely different components.

“With a true understanding of what the component must achieve, you can design the part with structural strength and toughness exactly where it’s needed, without the restraints from traditional manufacturing design,” Schuisky explains. “Printing something that is designed for subtractive machining just doesn’t give you those advantages.”

Sustainability is a driving force

Components benefitting from being light will also find advantages in additive manufacturing. Weight reduction is a constant key issue for the aerospace industry, driven both by fuel cost and carbon footprint. The same is true for cars and trucks, and everything else that moves.

“Fuel consumption is one thing, but don’t forget handheld tools and other things that we are carrying, where a lighter weight would save shoulders and backs,” Schuisky says.

Apart from reduced fuel consumption and health wins, additive manufacturing offer several additional advantages. Fewer transports and production steps than traditional manufacturing, as well as the fact that it utilizes a lot less material than traditional manufacturing, both thanks to the design that requires less material, and to the actual production.

“When printing a component, approximately 95 percent of the powder you put into the process is used; the rest can be recycled in a new melt,” Schuisky says. “Compare that to traditional manufacturing where you start off with a chunk of material and reduce large amounts of chips.”

The possibilities with additive manufacturing are growing as the technologies mature. Meanwhile, Egeberg, Schiusky and their colleagues are fine-tuning the offering to ensure that it provides as much value for the customers as possible.

“Metallurgists, world leading powder producers, post processing and metal cutting experts. With 150 years in the metal industry, few understand the additive manufacturing value chain like we do. We have also made extensive investments in Research & Development in different AM process technologies the recent years – and today, we’re developing components for industrial use”, Egeberg concludes.

• Powder Bed Fusion: A laser or electron beam is used to fuse the powder, in a powder bed, under protective atmosphere or in vacuum.
• Binder Jetting: A binder is added to the powder bed in the shape of the component to be produced, in the following step the binder is cured and the greenbody sintered to full density.
• VAT Photopolymerisation: Liquid photopolymer in a vat (container) is cured by light-activated polymerization.
• Material Jetting: Building a structure by dropping the material.
• Material Extrusion: The material is dispensed through a nozzle.
• Sheet Lamination: The component is created by bonding sheets of material.
• Directed Energy Deposition: A laser or electron beam melts the powder or wire as it’s deposited on the surface.

The additive manufacturing pow(d)er

Without the right powder, additive manufacturing wouldn’t work. The quality and properties of the powder strongly influences the properties of the component. Simply put, there are three major aspects to consider: Selection of raw material, particle size and morphology.

There are five major alloy groups used in the additive manufacturing processes today; steel, cobalt chrome, nickel, aluminum and titanium.

“Depending on the manufacturing method and specification, the melt is transformed into the correct particle size and morphology in a so-called gas atomization process,” explains Peter Harlin, Senior Engineer at Powder Technology R&D at Sandvik Materials Technology. “Depending on what additive manufacturing process the powder is going to be used in, it needs to be sized so the powder particles can be used in the process.

“As an example, powder bed fusion laser requires the smallest particle sizes – down to a few microns, while directed energy deposition machines can handle substantially larger particle sizes – around 100 microns.”

This is also confirmed by Lars-Erik Rännar, Research leader for Additive Manufacturing at Sports Tech Research Centre, Mid Sweden University , who means that a clear trend going forward is the introduction of new alloys and tailored powder for additive manufacturing.

“For Sandvik, with their metallurgical expertise along with a comprehensive competence within powder solutions and additive manufacturing, this is a natural development. I am looking forward to ordering tailored powder from them in the future,” Rännar says.

When Japanese Hideo Kodama in 1981 came up with an idea to realize three-dimensional printing, inspired by a photo-hardening polymer technology, he was too far ahead of his time. It wasn’t until 12 years later, when MIT developed the first powder bed process using inkjet print heads that the term 3D printing began to be used.

Since then, a range of terminology has been introduced to describe the process of using a printer and CAD software to grow objects layer by layer: additive manufacturing, free form fabrication, rapid prototyping, layered manufacturing and direct digital manufacturing, to name a few.

Although most terms can be used interchangeably, there is one exception: While Rapid Prototyping (RP) means to produce a prototype of a new component, Additive Manufacturing (AM) provides opportunities for both prototypes and final components.

This difference is crucial as the first normally means that the component is produced as a copy of something that will be manufactured traditionally, using subtractive manufacturing, while additive manufacturing opens a world of design opportunities without the limitations of subtractive manufacturing.
A variety of materials can be used in additive manufacturing. Polymers and metals are the most common types of material and are particularly efficient for low-volume manufacturing and to minimize waste. Other materials with possibilities are, for example, medical and biochemical materials, glass and even chocolate.

For metal additive manufacturing, components with complex designs, or those benefitting from being light, such as parts for aircrafts, cars, trucks or medical applications, will find advantages, while components with simple designs, or where weight is not an issue, are better produced using traditional, subtractive manufacturing.

The aerospace and medical industries are particularly well positioned to see growth and success from additive manufacturing, although companies in a wide range of industries find value in the additive manufacturing process.
As the business scope for additive manufacturing expands, there’s a growing need for technical standards. To address this need, the International Organization for Standardization (ISO) and ASTM International have jointly created the Additive Manufacturing Standards Development Structure. It aims to coordinate the creation of standards related to materials, processes, equipment and finished-part properties while also supporting specific standards for aerospace, medical devices, automotive and other industries.

• 1981: The first plastic components produced by 3D printing were made in Japan.
• In 1984, two French inventors filed a patent for the stereolithography process, and the same year Chuck Hull from 3D Systems filed another patent for a slightly different approach that is still used today.
• In 1988, S. Scott Crump of Stratasys invented a plastic extrusion method.
• In 1993, MIT developed the first powder bed process using inkjet print heads. The term 3D-printing began to be used. The same year a dot-on-dot technique was delveloped.
• 1999: The first lab-grown urinary bladder augmentation organ is implanted in a human being.
• The term additive manufacturing started to be used in the first decade of the 2000s.
• The first additive manufacturing machines for metal powder came in 2001.