The materials specialist company Schunk is now also a service provider for 3D metal printing. Schunk, a supplier of series-production solutions for metal powder pressing and injection moulding as well as other technologies, has expanded its expertise to include 3D metal printing at its facility in Thale, Germany. This expansion of the metal injection moulding process chain in the field of additive manufacturing makes sense with regard to future bionic construction applications and topology optimisation. Component characteristics and cost-effectiveness require different process technologies and manufacturing strategies when it comes to 3D metal printing. In 2020, Schunk expanded its expertise to include the composite extrusion modelling process (CEM) by acquiring an ExAM 255 multi-material 3D printing system from AIM3D. The first results of this development partnership can now be seen, as Christian Stertz, project manager for systems engineering at Schunk explains.
Development partnership between Schunk and AIM3D
The aim of the cooperation between Schunk and AIM3D covers three strategic approaches:
1. Material developments, such as copper materials and nickel-based materials,
2. Further development of plant technology, for example extruder cooling or vacuum clamping table applications
3. Marketing and acquisition for Schunk as a supplier of 3D metal parts with production batch sizes right down to single items.
The focus here is on rapid prototyping and low-volume production, where batches are too small for conventional sintering technology. The creation of copper components using 3D printing is one such development project. Christian Stertz, project manager for systems engineering at Schunk, describes what makes printing with copper so special.
3D metal printing with copper
3D component development in copper is of strategic importance to Schunk, as there are only a few suppliers on the market. The conductive material is required for certain components in the electronics industry. However, the range of industries and applications is wide, including applications focusing on thermal management, primarily in mechanical and plant engineering. There are also applications with an emphasis on low-loss energy transmission, such as e-mobility, welding and hardening technology, as well as in the field of energy supply. Pure copper as well as copper alloys are utilised in these applications. According to Christian Stertz, the ExAM 255 system from AIM3D featuring CEM technology enables thermal or electrical conductivity advantages to be retained in 3D printing processes. He sees this as a unique selling point, highlighting better and higher conductivity values on the surface and within the components compared to other additive manufacturing processes. In addition, the CEM process offers material price and resource conservation benefits.
Projects using copper at Schunk
For example, Schunk has developed induction hardeners (inductors) for gear wheels in the automotive sector and for chain wheels on chainsaws. This involves induction hardening of a component through partial surface hardening for the highest mechanical requirements. The physical properties of these copper components are a density of approx. 8.5 g/cm³ (rel. approx. 95-96%) with 75-80% conductivity (% IACS). The density values achieved are comparable to metal injection moulding (MIM) processes. The density of the copper, in particular, affects conductivity as well as mechanical properties, such as hardness or wear resistance. Christian Stertz emphasises the benefits of this AM process compared to conventional manufacturing strategies. The high degree of geometric freedom allows for internal channels or undercuts. In addition, bionic structures that save weight and material while increasing functionality also enable cost savings. As is the case with any AM process, using CEM systems from AIM3D results in savings on machining and tooling costs as it is not a mould-based process. However, the following also applies: the CEM process tends not to be suitable for very simple geometries and for large batches, since well-established series-production processes such as MIM are more advantageous in these cases.
Market trends in the field of 3D metal printing
Christian Stertz, project manager for systems engineering at Schunk, sees strong AM process potential in a very diverse range of market segments:
• Transport solutions in aerospace, automotive, rail and shipbuilding; parts for drive units, interior/exterior components as well as reengineering solutions.
• Medical technology for prostheses and instruments
• Mechanical and plant engineering
• Sports equipment
• The construction industry
• Consumer goods.
Christian Stertz: “With the further development of customer demands regarding new design and material options, such as bionic design, the range of 3D printing technologies will also continue to evolve. Certain applications favour processing with certain AM methods. Niches will also emerge and competition that squeezes out niches using established processes will continue to drive technology development forwards.”