Small perforations with large material thicknesses
When technical expertise and extensive experience become success factors: Perforated metal components with hexagonal perforations have a free cross-section of up to 85 % and therefore allow a particularly high level of air permeability. However, the production of filigree holes is a challenge in itself, especially with thicker materials. Today we ask expert Gerhard Bullinger, CEO at Solvaro, and Martin Schneider, Head of Engineering at Solvaro, what the technical challenges are and what solutions can be used to achieve precise and economical production.
Mr Bullinger, commercial vehicles can be quite rough in everyday use: stones fly onto the bodywork, dirt gets stuck and the engine is constantly running at full speed. OEMs use thicker materials of up to 2.0 mm for their radiator grilles. What does this mean for the development and production of the components?
There are two important principles in the production of perforated metal components. Firstly, thicker material is more difficult to perforate. And secondly, the smaller the perforation, the greater the challenge. Just imagine: With hexagonal perforations, we are talking about up to 184,000 perforations per square metre, so this is an extremely fine-meshed filter. A suitable tool is therefore initially required to produce such perforations. The challenge lies in maintaining the hole quality during the punching process, as unevenness and burrs inevitably occur when the punching tool breaks out of the metal sheet. Experience shows that the hole quality can be ensured by regular special grinding of the punches. The result is sharp edges that can then be rounded off in a controlled manner. This makes it possible to effectively prevent the effect of edge thinning.
In the manufacturing process itself, experience is the most important factor: this is where craftsmanship and a great deal of sensitivity are required. In practice, experienced manufacturing companies are already able to realise sophisticated Hv 2-2.5 perforations with a material thickness of 1.5 mm. Such perforations are in demand for high-performance tractors in the agricultural and construction industries, for example.
In order to overcome the challenges in production, however, extensive consultation is required first and foremost: the customer and the manufacturer must work together to define which perforation is ideal for the planned application. Free of specifications and conventions, it is important to define what the component should actually do. This specification then results in numerous requirements for the manufacturing process, from perforation to forming and coating.
The development process is always crucial when it comes to utilising synergies, as this is where the foundations are laid for subsequent production.
Mr. Schneider, agricultural and construction machinery are becoming increasingly individualised in terms of design, engineering and appearance – this also results in very customer-specific requirements for the perforated components. How does a supplier manage the balancing act between individual customer requirements and cost-effective series production?
That’s right, we develop each component for individual customer requirements. Nevertheless, we always manage to utilise synergies in the use of tools and machines. For example, we utilise synergies by producing different types of cooler grilles for a customer using just one deep drawing tool. The development process is always crucial when it comes to utilising synergies, as this is where the foundations are laid for subsequent production. It is very difficult to make synergy-orientated changes to the design later on.
Mr. Bullinger, is the development and production process largely standardised or do you advise each customer individually on the specific challenges, opportunities and risks?
Basically, we adapt to the customer and his processes, so development and production are very individualised and customer-oriented. From my point of view, it is important that the earlier the customer involves us, the better and more targeted we can advise and contribute our expertise. The entire development and production process then benefits from this early collaboration.
Mr. Schneider, let’s return to the technical aspects of thicker materials. The deep drawing of perforated metal components is considered to be demanding in terms of production technology. What are the special challenges for the supplier?
When it comes to simulating the deep drawing of perforated metal, all known processes reach their limits. This is because the amount of data to be calculated is simply too large due to the hundreds of thousands of holes – and the springback of the component is also unpredictable. Perforated metal behaves fundamentally differently during deep drawing than solid material, which means that empirical values cannot simply be transferred here. In addition, the different material thicknesses also react differently to deep drawing, which is why concrete empirical values with the material thicknesses are the only really valuable point of reference. Generalisation or calculation, on the other hand, is hardly possible. We have been producing numerous parts with different perforations and material thicknesses for many years – this is the basis for our in-depth understanding of the deep drawing process.
When manufacturing perforated metal components, it’s not just expertise and experience that matter – the equipment is also important. How do you approach the development of customised deep drawing tools?
The equipment really is crucial to the success of our projects. Deep drawing tools have to work with high precision – close cooperation with the customer is essential in tool development. Ensuring feasibility right from the start is crucial. This collaborative approach involves continuous communication and customer involvement to understand requirements, minimise risks, and incorporate feedback. At the end of the process, the manufactured tool should be ready for use in series production or very close to it.
Technical expertise and experience are of great importance in the production of perforated metal components with hexagonal perforations and greater material thicknesses. The challenges range from difficult perforations to demanding deep-drawing processes, requiring specialised equipment and craftsmanship. Close cooperation with customers and individual advice are crucial in order to fulfil customer-specific requirements and exploit synergies in series production.
Information on the expert
SOLVARO GmbH, CEO
Information on the expert
SOLVARO GMBH, Head of Engineering