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AM innovates industrial and medical markets

Leuven-based LayerWise focuses on Additive Manufacturing (AM), a powerful technology. A high-precision laser selectively heats metal powder particles, in order to quickly and fully melt to properly attach to the previous layer without glue or binder liquid. Using this digital approach, the optimum shape of complex circulation parts can be produced in a single manufacturing step. An AM part typically provides better performance and is more reliable than the complicated assembly it replaces. Furthermore, the AM technology is the right choice for small metal products, of which thousands can be produced simultaneously. This is why LayerWise offers favorable unit prices and short delivery times. In addition to countless industrial applications, the company manufactures revolutionary orthopedic, maxillofacial and dental implants. LayerWise produces high-grade parts in any preferred metal (alloy) using less material and no scrap, reducing unit weight by up to 80%.

As appeared in Fotonica Magazine

Traditional metalworking versus AM

Metal cutting, milling, EDM and other high-quality and efficient metalworking processes have a respectable track record on the production floor. Typical for these subtractive methods is that each in their own way is limited in removing part material, despite many tools and accessories.

LEFT: By building up metal parts in layers the most complex part shapes can be produced, including recess, ribs, cavities and internal features. RIGHT: The metal powder particles pinpointed by the laser quickly and fully melt so that the new material properly attaches to the previous layer, without glue or binder liquid.

Design engineers know metalworking processes inside out and take into account their specific limitations up-front. In a way, they design new parts knowing at the back of their minds the production method that will be applied. It would be better if they could concentrate on the functionality of the part to be produced. The geometric limitations of successive metalworking processes force designers to make choices that devaluate the functionality of the part or lead to a complicated assembly instead.

“At LayerWise we reverse the entire process,” says Jonas Van Vaerenbergh, director of the industrial division of LayerWise, a Leuven-based technology firm. “Our core business is additive manufacturing (AM), a technology developed to build up material in layers instead of removing it in different steps. In the meantime, we have optimised the process for a variety of metals and alloys, such as stainless steel, hardenable steel, titanium, aluminium and inconel.”

In the machine, a high-precision laser is directed to metal powder particles in order to selectively build up a 20 to 40 micron horizontal metal layer. The metal powder particles pinpointed by the laser quickly and fully melt so that the new material properly attaches to the previous layer, without glue or binder liquid.

The powerful fiber laser with high energy intensity operating in the inert area inside the machine guarantees that metal parts being built up exhibit a dense and homogenous material structure. CAD directly drives the machine without requiring any programming, clamping or tooling. The AM approach is capable of simultaneously producing metal parts of different shapes in series of up to 2500 pieces. As this impacts economics favourably, LayerWise is able to offer favorable unit prices and short delivery times.

LEFT: A new AM spring design for a scientific instrument allowed TNO to cut stress and weight 70%. RIGHT: The spring’s thin hollow spring coils with a triangular cross section reduce stresses and distribute these more evenly.

Unlimited freedom of shape

In addition to producing small components efficiently and cost-effectively, AM hardly imposes any limitations in terms of geometry. Van Vaerenbergh explains that the layered approach ensures that the laser gains systematic access to any location while building up parts. In this way, the most complex part shapes can be produced, including recess, ribs, cavities and internal features. “Usually, the products leaving our facility cannot be produced any other way. This is a different ball game for manufacturers because design rules are packed in, removing all obstacles in favour of extreme part optimisation.”

Take the burner component LayerWise produced for Diametal. Similar to machine manufacturers for food and pharmaceutical companies, this company is regularly challenged with producing complex circulation pieces such as mixers, inlet and outlet components, dispensers, coupling parts and heat exchangers.

The Diametal burner component contains 9 undercuttings and 6 internal cavities. LayerWise applied AM to manufacture this component as one unit in a single production step. This is called function integration, because this AM-produced component replaces multiple parts manufactured using conventional metalworking processes. Assembling these parts takes time, particularly because they need to be connected hermetically, reducing reliability alltogether.

Jonas Van Vaerenbergh explains that function integration makes AM fit for resolving miniaturisation, leakage and assembly issues. “Diametal was not charged for the shape complexity of the part because the production cost is dependent on the weight of the part, showing that AM offers superior products at a reasonable cost.”

A perfect example of efficient and flexible design was the production of a component that connects cooling ducts. Firstly, the additive manufacturing process realized 75% weight reduction. Secondly, designers were able to drastically reduce flow resistance by defining channel geometry using freeform surfaces. LayerWise produced the part exactly according to the functional CAD design, resulting in an improvement of the circulation properties by 80%.

According to Van Vaerenbergh, also the manufacture of injection mould inserts yields impressive results. “Thanks to AM’s freedom of shape, the cooling channels can be positioned in conformity with the mould shape. This is a major improvement compared to conventionally drilled holes. Optimized channel geometry and location ensure a better controlled cooling process that delivers higher-quality parts that do not warp and contain fewer hot spots. Imagine the economic advantage of reducing the serial production cycle time of moulded plastic parts by 15%.”

Focus on technology leadership

LayerWise is the first production centre in Belgium that exclusively focuses on this additive production process for metal parts. The company was founded by Jonas Van Vaerenbergh and Peter Mercelis, both of whom were closely involved in the development of additive manufacturing at the Katholic University of Leuven. LayerWise intensively collaborates with the university, and systematically invests 30% of its resources in Research and Development to push the boundaries of the technology.

“By bringing together technological expertise, production capacity and customer support, LayerWise occupies an unique position on a European level.” indicates Van Vaerenbergh. “Our engineers control AM to such an extent that they are capable of perfecting the technology and realize the most challenging specifications. Today we are able to produce with 15 micron geometric accuracy and build up walls as thin as 0.2 millimeters, something that is extremely difficult – if not impossible – using conventional technologies. Also the implementation of process control tools in and around the melting zone is important to guarantee highest part quality.”

For HyEngine, LayerWise modified and produced a valve lifter that goes into the 1-cylinder hydrogen engine of the Hy-Mega compact cargo vehicle. The new valve lifter ensures that the hydrogen supply to the cylinder is separated and timing-wise fully independent from the air inlet.
1. Through ‘reverse engineering’ of the original valve lifter, LayerWise engineers acquired a point cloud from which characteristic planes and directional vectors were derived automatically.
2. During CAD modeling, they split up the original part into two separate lifters with an optimum geometry.

By acquiring full control over the production process, LayerWise achieves a homogeneous micro structure with a relative density of up to 99.98%, for an increasing number of metals and alloys. Research shows that the mechanical properties are virtually the same as those of conventional metals. To prove this, LayerWise systematically carries out mechanical tests on the level of density, hardness, elongation and fatigue. In advance, the chemical composition of the bulk metal powders are examined in a chemical laboratory.

Orthopedic and maxillofacial implants

Besides industrial appliocations, LayerWise produces orthopedic, maxillofacial and dental implants. During a major maxillofacial reconstruction, sugeons inserted a zygoma manufactured by LayerWise. The complex shape of the implant was digitally derived through medical imaging and produced using AM. This approach offers the ability to restore the facial symmetry of patients nearly perfectly.

Concerning orthopedic implants, the process of building up metal in layers offers the possibility to design porous bone-replacing structures and integrate them into protheses. This allows for an excellent long-term fixation. In addition to personalised implants, designed on the basis of medical imaging, the AM technology is used for manufacturing medical instrumentation. For this purpose, LayerWise offers a number of biocompatible metal alloys.

Recently, LayerWise applied AM to produce an award-winning Titanium total lower jaw implant reconstruction, developed in collaboration with project partners from medical industries and academia. To treat a senior patient’s progressive osteomyelitis of almost the entire lower jawbone, medical specialists and surgeons opted for such a complete patient-specific implant the first time ever. AM technology specialists at LayerWise printed the complex implant design incorporating articulated joints and dedicated features.

The revolutionary patient-specific implant has been developed and produced under supervision of Prof. Dr. Jules Poukens, in collaboration with specialized industrial and academic parties in Belgium and The Netherlands. Just recently, the innovative implant was granted the ‘2012 AM-Award’ by the Additive Manufacturing Network in Belgium. The jury members of Sirris and VITO praised the fact that AM played a decisive role in the realization of this revolutionary mandible implant.

LEFT: The world’s first patient-specific total lower jaw implant, produced by AM specialist LayerWise. RIGHT: Surgeons replaced the entire lower jaw bone structure with a patient-specific total mandible implant.

LEFT: Titanium and features reduce implant weight. Cavities facilitate muscle diagastic attachment and ingrowth. RIGHT: X-ray images showing the AM-produced lower jaw reconstruction implanted into the patient.

“AM’s freedom of shape allows the most complex freeform geometries to be produced as a single part prior to surgery,” says Dr. ir. Peter Mercelis, director of LayerWise’ medical division. “As illustrated by the lower jaw reconstruction, patient-specific implants can potentially be applied on a much wider scale than transplantation of human bone structures and soft tissues. The use of such implants yield excellent form and function, speeds up surgery and patient recovery, and reduces the risk for medical complications.”

Prof. Dr. Jules Poukens of the University Hasselt: “The new treatment method is a world premiere because it concerns the first patient-specific implant in replacement of the entire lower jaw. The implant integrates multiple functions, including dimples increasing the surface area, cavities promoting muscle attachment, and sleeves to lead mandible nerves. The reconstruction is post-processed with polished joint surfaces and a bioceramic coating. Furthermore, the mandible implant is equipped to directly insert dental bar and/or bridge implant suprastructures at a later stage. I led the team of surgeons who implanted the AM-produced structure during a surgery of less than four hours at the Orbis Medisch Centrum in Sittard-Geleen. Shortly after waking up from the anesthetics the patient spoke a few words, and the day after the patient was able to speak and swallow normally again.”

Dental suprastructures

Using AM technology, DentWise (the dental division of LayerWise) designs and produces the most sophisticated implant bridges, including highly complex surface retentions and individual emergence profiles. After perfecting the method in collaboration with the Leuven University and passing clinical trials successfully, DentWise made dental AM implant structures available to dental technicians. They particularly appreciate the design freedom that’s associated with DentWise, and value the fact that they have access to superstructures that cannot be produced any other way.

A perfect passive fit is guaranteed, while achieving accuracies better than 20 microns at the implant interfaces. By applying its state-of-the art AM technology, DentWise is able to integrate the most complex surface retentions on the implant bridges. As the technology builds up material in ultra-thin layers, it can realize an individual emergence profile on each of the implant connections, perfectly following the gingival profile. DentWise suprastructures are manufactured using ultra strong titanium alloy (Ti6Al4V, grade V), which outperforms the commonly used titanium grade II in terms of mechanical properties.

LEFT: Through patented DentWise technology, the geometry and surface retention related limitations set by traditionally moulded or milled suprastructures no longer apply. RIGHT: As AM builds up material in ultra-thin layers, DentWise can realize an individual emergence profile on each of the implant connections, perfectly following the gingival profile.

LEFT: Based on the acquired patient-specific geometry, we design the personalised structure in software and start printing it in titanium straight-away. RIGHT: A perfect passive fit is guaranteed, while achieving accuracies better than 20 microns at the implant interfaces.

Peter Mercelis: “Although current CAD/CAM milling centres have set a new standard in terms of precision, they have limited dental technicians’ design freedom compared to classical lost-wax casting methods. At DentWise, we try to combine the best of both worlds; while maintaining and even extending the design freedom, we also achieve the highest precision on our implant suprastructures. This allows for the integration of additional features that are impossible to produce until now.

“The design and manufacturing service provided by DentWise starts from a physical model and tooth setup that are digitized using our high-end scanning systems,” explains Peter Mercelis. “Based on the acquired patient-specific geometry, we design the personalised structure in software and start printing it in titanium straightaway. After turning out the suprastructure, the dental technician finishes it off and completes the final prothesis.”

Growing along with the technology

Three years after its inception, LayerWise has grown considerably. Recently, the company appointed a number of European distributors. This is part of the strategy to operate on an international scale. “After propagating the AM technology and its advantages to different industries, companies realize that they can truly benefit from the technology,” concludes Van Vaerenbergh. “Additive metalworking processes change design and production rules completely. By realizing projects together with customers, we offer companies plenty of opportunity to create more added value and produce more cost effectively.”