Engineering plastics are much more than just substitutes.
The collaboration with Wagner, Waldstatt/Switzerland, began in a very traditional way, as HB-Therm contacted several companies in order to fundamentally rethink the existing, cost-intensive brass component with a complex CNC rework. Wagner was the only supplier that considered it feasible to manufacture the manifold as one continuous component - i.e. without additional parts. In addition to the technical conviction, the geographical proximity of the two companies also played a key role, as it enabled direct, personal communication and rapid coordination.
What makes the plastic part: complex, but simpler, more cost-effective and more sustainable
The new, cost-optimised solution made from a fibre-reinforced plastic fully meets the requirements - from mechanical strength values to temperature resistance and pressure tightness.
In continuous operation over a period of two years, which corresponds to around 18,000 operating hours, the solution was tested under the toughest conditions, which go beyond the usual loads in a real production environment.
The cooling water module withstood the continuous load without any problems. These test results prove that ever more demanding and advanced applications can be realised with the help of new technologies and the right choice of materials.
The advantages of plastic components are
- Cost savings due to the change of material as well as the complete elimination of cost-intensive CNC post-processing: a total of over 90% on the raw part without add-on parts. The new plastic injection-moulded parts can be produced ready-made, which significantly reduces production costs, especially by avoiding mechanical post-processing, and greatly reduces throughput times.
- Significant weight reduction of approx. 65% by substituting brass for plastic. The plastic alternative weighs just 1.5 kg in the complete version with attachments - compared to 4.2 kg for the corresponding brass version. This has a positive impact on transport, energy consumption and the ecological footprint.
- The integration of additional functions and the optimisation of the assembly process, for example through the complete demoulding of all holes as well as internal and external threads directly in the tool. In total, this results in a reduction in production time of over 35 minutes
- One-stop solution from development to series production. Reduction in the complexity of realisation, shorter replenishment times and lower risk of errors or misunderstandings in the supply chain.
- Internal processes such as material handling were optimised along the entire value chain and waste was reduced thanks to more efficient assembly principles. This is particularly important for HB-Therm, as the company itself is orientated towards lean manufacturing processes and demands the same from its suppliers.
- Overall, the use of plastic also results in greater sustainability. With a significantly reduced need for resources, particularly materials and energy, CO₂ emissions are also reduced (approx. 2 to 3 kg instead of 15 to 20 kg of CO₂ per unit). With 10,000 units, significant ecological added value is also achieved over the course of a year.
The project was implemented in several phases:
- Concept phase: The design was developed in close collaboration and based on the technical requirements for plastic injection moulding. Based on the strength and temperature resistance specifications, several plastic materials were evaluated and specified for prototype production.
- Prototype phase: Prototypes were created and subjected to extensive tests - such as long-term, burst pressure and CT scans - to validate the material properties and precise tolerances.
- Series phase: Based on the results from the prototype phase, Wagner was able to design the series mould and define the corresponding pre-holding dimensions. Frehner, which is also based locally, was commissioned to manufacture the series mould. This was followed by official sampling at Wagner, with adjustments also being made at short notice during the process.
The close coordination between HB-Therm and Wagner ensured that the extensive challenges - such as the adaptation of O-ring seats using CT analysis and the optimisation of wall thicknesses - could be solved in a timely and cost-efficient manner. The use of FEM simulations and practical laboratory tests ensured a high level of precision, particularly with regard to the tolerances of the planned bores and the various sealing surfaces.
Complex technical challenges: Solved!
However, the changeover also presented technical challenges. The pressure and temperature resistance of the plastic was initially scrutinised critically. It became apparent, for example, that continuous use at temperatures above 160° C can be problematic and that the injection moulding process has certain limitations when it comes to complex holes or the production of threads. However, this was invalidated by the selection of a suitable fibre-reinforced high-performance polymer, extensive simulations and endurance tests. The test series included load tests with up to six times the maximum permissible pressure as well as endurance tests at varying temperatures and different flow velocities. These tests confirmed that the plastic manifold functions reliably even under extreme conditions. The selection of a suitable plastic was a challenging and time-consuming process for the developers - with a successful outcome.
The entire hydraulic concept was revised with the changeover to the Series 6. The aim was to optimise pressure loss in the hydraulics and at the same time make assembly more efficient. These goals were achieved by switching from screw fittings to a plug-in system, which in turn saves both costs and time thanks to the simplified assembly process. This also applies to the components on the cooling water module. These are made from the same material and are also manufactured locally at Wagner - true to the motto "Everything from a single source".
The modular design of HB-Therm units is therefore unique. While many competitors rely on separate, bolted standard parts, HB-Therm integrates a large number of functions into individual modules. Put simply, HB-Therm hydraulics essentially consist of a cooling and heat transfer module, a pump, heating and cooling. This results in a clearly arranged interior, minimises space requirements, facilitates maintenance, simplifies the understanding of temperature control technology and is highly appreciated by all users in every respect. (Image Thermo-6 Hydraulics)
Due to the lower mechanical strength of plastic compared to metal, metal components, such as brass connection nipples, were deliberately used at critical points with high torques. This ensures that the typically high assembly forces, such as those that occur at the external connections, do not act on the plastic component but on the chrome steel rear panel. In addition, it is not recognisable from the outside that this is a plastic component. (Image comparison)
Optimised tool technology and production processes
Like the cooling water module itself, the injection moulding tool developed at Wagner for the distributor module is characterised by its high level of complexity. The mould works with four slides and contains 57 cores in various diameters and lengths in order to be able to produce all the necessary holes in a finished state (pictures of mould halves). Correct and adapted temperature control in the tool is very important for a stable, cycle-optimised process that is suitable for series production. For this reason, various temperature zones were defined in the mould and implemented with the corresponding temperature control holes. Due to the many necessary cooling holes and the hydraulic components that had to be integrated, many design challenges had to be overcome. The aim was not only to achieve optimum temperature control, but also to minimise cycle times (approx. 1 minute per shot). (picture conveyor belt)
In order to avoid reworking the injection moulded part, as was necessary with the previous metal version, and to be able to offer a ready-to-use solution, three thread unscrewing cores were also integrated, which are retracted and extended accordingly during the injection process. The external thread on the module is formed by the two mould halves and is required for the filter screen insert of the cooling water inlet. (The design and production were carried out in close coordination between Wagner and other local partners, whereby precise CT measurements and manual adjustments were used to ensure the required quality standards.
Cooperation on the cooling water module project
The collaboration on the "cooling water module" project was also very intensive and cooperative right from the start. Both sides continuously developed the original design further. The close coordination made it possible to solve even complex challenges - such as the precise drilling of the cooling valve - in a timely manner. In addition to the technical collaboration, the proximity of the two companies led to valuable synergies that had a positive impact on the entire development process.
Ultimately, the strategic decision in favour of Wagner, a Swiss supplier in the immediate vicinity, was also made because close, direct communication, fast response times and short supply chains were seen as decisive advantages. For HB-Therm, these advantages outweighed the supposed cost savings that would be possible with production abroad. (Group image)
On this basis, the partnership with Wagner could become even more intensive and grow further in the future. New technological developments could also lead to the production of further solutions from plastic and thus the substitution of other base materials - all this, of course, only if the quality remains the same or can even be improved.
Close cooperation built on trust from the outset
Wagner is a family-run company with a long tradition, founded in 1945 by Willi Wagner. Today, the company is managed by Silvan Halter, the third generation. Originally operating on a small scale in Waldstatt, the company went international in 2000 and now has joint venture locations in Romania, Bosnia and a strategic partner in India. With around 500 employees and a globally unique material neutrality - from thermoplastic injection moulding to zinc and aluminium die casting to hybrid solutions - Wagner is positioned as a technology leader that offers customer-specific, material-optimised solutions. The integration of all competences in central development and subsequent series production at various locations enable a high level of competitiveness. The company also attaches great importance to quality assurance, certified in accordance with ISO 9001, 14001 and IATF 16949, among others.
The long-standing and close partnership with HB-Therm is a mutual success story, as Wagner has also been successfully using HB-Therm temperature control units in its own production for years. HB-Therm has also been supplied with high-quality plastic components since 2020. The partnership-based exchange, which is based on a joint development approach, and the fast, competent customer support are particularly emphasised. This collaboration is described as a win-win situation in which both companies contribute their strengths to realise innovative and cost-efficient solutions.
HB-Therm Thermo-5 and Thermo-6 units are predominantly used in production at Wagner - 16 Thermo-5 and five Thermo-6 units are currently in operation. The new Thermo-6 units were easy to integrate - both thanks to their intuitive operation and the standardised OPC UA interface (EUROMAP 82.1, OPC 40082-1), which enables simple connection to injection moulding machines and other temperature control units. Thomas Greber, Head of Thermoplast at Wagner, comments on the benefits of the Thermo-6: "The units enable high-precision temperature control, minimise temperature fluctuations and offer rapid heating and cooling for our moulds. This precision is particularly important, as dimensional tolerances in the hundredths range must be maintained in some cases, as the application of the cooling water module shows. The units therefore work precisely, require little maintenance, are particularly energy-efficient and guarantee high cost security thanks to their lifetime warranty promise." (Image Thermo-6 Energy efficiency)
Sustainability and digitalisation are also an issue
Sustainability is also an integral part of Wagner's corporate philosophy at its sites. In addition to traditional energy efficiency initiatives such as the optimisation of heat consumption, the use of LED technology or the reduction of compressed air, the company also focuses on the use of energy-efficient machines and the development of sustainable material solutions. The company is also striving to further optimise production processes through digitalisation (production data acquisition, OEE evaluations, use of AI).
Silvan Halter, CEO of Wagner, comments: "The combination of innovative plastics, lightweight construction concepts and the continuous further development of production processes secures us long-term competitive advantages and opens up additional potential - for example in the area of metal replacement. The partnership-based cooperation with HB-Therm, characterised by an intensive and dynamic exchange, not only enables the continuous optimisation of existing processes, but also the realisation of pioneering projects in the field of plastics technology, as demonstrated by the cooling water module. With a view to future challenges and opportunities - such as increased digitalisation and the trend towards more energy-efficient production processes - the cooperation will be further intensified, as it offers numerous starting points for innovative solutions and design-to-cost optimisations for both partners."
