Plasma treatment spurs material development


​15,000 degrees. Even iron vaporises at that temperature. A plasma treatment device, acquired by VTT to enhance 3D printing, is opening up new opportunities while shortening industrial material and product development cycles.

VTT's Tampere unit has been exploring the potential of a plasma treatment device, manufactured by the Canadian company Tekna, since the autumn of last year. The first customer pilots have been completed and the results are promising.

Team Leader Tomi Lindroos is clearly pleased with the new tool.

– Our device is unique in Europe and is the only one marketed to outsiders, enabling anyone to bring along their powders and get to work.

VTT is using the equipment to seek new business opportunities.

– To become known, we need to be actively involved in fairs and conferences. In addition to European parties, we have held discussions with organisations in Taiwan and the United States.

Lindroos emphasises that this year's key goal is to enable Finnish companies to recognise the opportunities the new service offers for accelerating product development projects and developing business.

– Our critical customer base consists of the subcontracting chains of original equipment manufacturers.

Comprehensive service

Plasma treatment equipment is VTT's response to the industry's ever-increasing need for a broader range of 3D printing pilot environments, of greater than laboratory scale.

– There is high demand around the world for pilot environments that are larger than laboratory scale. Industrial companies are seeking environments that are close to final production, since this enables a faster transition from product development to production.

VTT's new plasma treatment plant accelerates industrial production processes and the creation of new products. The entire production chain, from raw materials to product, is accelerated and streamlined.

The plasma treatment equipment forms part the Powder Piloting Service of VTT. It provides customers with the opportunity to utilise both modern equipment and the more than 20 years of indepth powder material technology expertise accumulated by VTT's experts.

VTT's service operates on a one-stop basis.

– The idea is that materials are developed industrially on a rational scale and within the same chain, from material synthesis all the way to component creation. We also offer parallel process chains, whose suitability for manufacturing can be assessed, Lindroos explains.

VTT offers the entire range of services in the metallic materials production chain, such as alloy production, the manufacture of powders through various techniques, and powder modification for manufacturing processes.

Iron also vaporises

The plasma device enables the modification of many problematic materials into a suitable form for 3D printing. Most metal powder in the world is produced using water atomisation. The problem with this is the irregular shape of the powder particles, which makes the powder insufficiently fluid for 3D printing. Plasmatreated, water-atomised powder can be modified to make it clean, of highly uniform quality and ideal for 3D printing.

– The new equipment eliminates restrictions related to the melting point. The plasma device allows temperatures of up to 15,000 degrees, at which even iron vaporises. The raw material can also be a suspension, i.e. a powder with a liquid component.

The material is fed through a hot plasma flame. The substance is given different properties by varying its retention time in the hot flame. The throughput powder is turned into a perfectly round powder, with top-class fluidity and maximum suitability for 3D printing. High temperatures also vaporise the impurities in the powder, making the substance very pure.

A pure and round powder has no intrinsic value – the only decisive factor is its usability in 3D printing.

– We often subject a 3D-printed component to further processing such as heat treatment, hot isostatic pressing and surface modification. In other words, we prepare ready-to-use components for the customer. We also use conventional powder-metallurgical manufacturing methods such as the metal injection moulding, hot isostatic pressing and coating methods based on thermal spraying or laser coating.

Digital models accelerate product development

Plasma treatment devices form part of the digitalisation of product development and production. The need for physically constructed model components decreases when they and the materials used in them can be modelled on a computer and then 3D-printed.

VTT's major industrial customers are mainly seeking price competitiveness from new materials. However, the service is also targeted at start-ups that need a modern pilot environment for their innovations.

 – Spin-offs have limited scope for investment. Our environment is a good place for assessing matters before making large investments.

The first customer jobs have already been run on the equipment introduced last autumn. Experiences have been positive.

– We were initially anxious about the capacity of the equipment, but have produced very reasonable amounts of powder. We produce enough powder to 3D-print a single item each day, i.e five to ten kilogrammes at a time.

The three drivers of material development

Companies' need for improved features in their product components is the primary driver of new material development. Materials are subject to tough requirements: greater resistance to corrosion, pressure and heat fluctuations; increased hardness or toughness; and, in more and more cases, all of the above. VTT's research unit is responding to this cry for help by computer modelling new materials and their production.

The scarcity and price fluctuations of critical materials, such as cobalt, are another spur for the development of substitute and cheaper materials. In such situations, compromises can even be made with the material's properties if the replacement material is cost-effective and suitable enough for its intended use.

The third line of material development involves the utilisation of raw materials from industrial side streams, which also improves cost efficiency.

– Plasma treatment equipment can efficiently remove impurities from side streams, to provide clean raw materials suitable for a range of applications, says Tomi Lindroos of VTT.

3D printing is changing the world

3D printing is moving forward in leaps and bounds, and changing the world with its new applications. At this moment major beneficiaries are the consumer products, aircraft and car industries, and medical applications. VTT has experimented with the 3D printing of device components alongside partners such as Sandvik.

The technological benefits of 3D printing are most obvious in small series manufacturing. Countries with industry of this type, such as Finland, are particularly well placed to benefit from adopting the new technology. 3D printing allows considerable freedom in component design, enabling a completely new kind of product that is lighter and more effective.

Its advantages also include the delivery of customised products that match the customer's needs, lighter structures, and the manufacture of even nearimpossible objects at no extra cost. The technology enables the printing out of spare parts – for broken machinery and production equipment – on the other side of the world, if needed. The post-design logistics chain largely consists of a bit transmission at the very time the object is needed, bringing savings in transport and warehousing.

Larger objects can be printed out as the technology advances. An example of this is the American technology startup Apis Cor which, around a year ago, announced that it had developed a way of building cheap houses with a 3D printer.

Tomi Lindroos
Tomi Lindroos
Research Team Leader