The latest news on Wolfensberger AG
Thin-walled steel casting: The future of the Wolfensberger AG company?25.02.2015
We are working at a great pace on advancing development of a moulding and casting process for manufacturing thin-walled cast steel components. In sand casting, this could open the way for ensuring our future competitive strength.
The new process that we are striving to achieve pursues the aim of manufacturing cast steel components with wall thicknesses until 2 mm as sand castings which will offer us new and interesting market opportunities. For instance, under specific conditions, sheet-metal components which reach process and performance limits with the methods currently established could be replaced by freely designable, thin-walled cast steel components which can be designed to meet the loads occurring. Combined with the fact that it is possible to integrate specific functions, thin-walled cast steel components can be used to practice "applied lightweight construction" which can meet the guiding principle of the automotive industry – to constantly endeavour to achieve more and more efficient systems.
Thin-walled cast steel components can be used not only in environments characterised by sheet metal, such as a carbody. It is also possible to use them in the field of engine construction where there is a need for extremely efficient components of reduced weight and, equally, manufactured using an efficient and economical production process.
Initial promising customer contacts
We have already been able to develop initial prototypes with potential customers and the results and experience to date can be assessed as positive. However, all those involved are aware that a few more steps need to be taken, both technically and commercially. Part-specific reproducibility must be fully guaranteed and it must be possible to demonstrably comply with parameters as regards dimensional stability and quality requirements until any series production is launched. At the same time, we are reliant on certain quantities in order to be able to ensure the economy of part-specific production processes.
Development of a suitable production process is an investment that is clearly forward-looking. For instance, such development projects in the automotive industry take on average 5 to 7 years until the series-production stage. This is time that should be utilised to be able to use our expertise profitably in the sectors of material and process technology and to adapt our processes and structures to the new challenges we will face.
Section of a turbocharger casing
3D Printing System – Innovative Possibilities03.09.2013
The innovative 3D printing system allows new possibilities: Based on CAD data we are able to produce sand moulds and cores for prototypes, single spare parts and complex serial parts. Beside reduced development time and pattern costs our customers benefit from increased engineering opportunities.
Efficient prototype production07.11.2012
Produce initial samples quickly and efficiently with rapid prototyping!
Even though a 3-D representation of a casting provides significant reference points as early as the development phase, one or more version(s) of a component to be developed in physical form affords essential advantages. It can already be used in a suitable manner for field trials, for example, for loading and installation tests.
Without having to produce expensive patterns beforehand, Wolfensberger can manufacture sand moulds that are used to produce complex castings made of cast steel or alloyed cast iron , on the basis of edited 3-D data made available by the customer within a relatively short throughput time.
This method can also be used in series production. This means, for example, that expensive core boxes can be eliminated and areas critical as regards fluid dynamics can be mapped meticulously without mould parting lines and without mould mismatch.
One example from dozens of possible applications:
Caption to illustration:
A monobloc core (using layer construction, without core box, manufactured in one piece) which maps the complex interior contours of a Francis impeller. The major advantage is that this method eliminates the possibility of core mismatch, i. e. the omission of 13 individual core segments has a positive effect on component accuracy. Moreover, the inner contours which can only be accessed with great difficulty are mapped meticulously and with an excellent surface quality.
Have we aroused your interest? Contact us. We would be pleased to help you with our know-how.
CEO of Wolfensberger AG becomes new President of the Swiss Foundry Association (GVS)16.07.2012
Markus Schmidhauser, CEO of Wolfensberger AG, has been elected to the new President of the Swiss Foundry Association. Based on his precursor's preliminary work, during his upcoming three-year mandate he will put focus on the development of junior staff members, the benefits for the GVS members, the closer cooperation between the foundries as well as the image promotion of the foundry industry.
Full Service Specialist for customized cast solutions with steel and iron alloys26.06.2012
Switzerland has one of the highest wage levels in the world and in foundries wages account for a large proportion of turnover. Under these conditions, how do you manage to compete successfully on the international market, especially when an exceptionally wide range of alloys, small production runs and different forming processes are added to this?
"To be successful as a foundry in Switzerland you definitely have to offer your customers something special," maintains business economist Markus Schmidhauser, director of Wolfensberger AG in Bauma (Switzerland). Schmidhauser runs the medium-sized family business – now in its third generation – employing 270 staff at two works and also involving a joint venture in China. Despite the economic crisis and the huge appreciation in the Swiss Franc, turnover has increased by around 70% over the past 10 years. This success is mainly due to two factors. First, the company has a high level of expertise in developing sophisticated special solutions for customers in the areas of plant engineering, mechanical engineering and turbomachinery. The ability to integrate several areas in which the company has special technological skills and, by combining these factors, find optimum solutions for particularly tricky tasks is of key importance. Another important factor in the company's success is the consistent attention to the full service principle when addressing and meeting customer requirements.
Precision casting even at high unit weights...
"One of our important skills is a special precision casting process which can achieve levels of precision as great as those for investment casting," Schmidhauser added. From the customer's angle, the most important difference from investment casting is the unit weight – which can be up to 400 kg above the normal range for investment casting – and in the batch sizes. Whilst investment casting only pays off with comparatively high production runs due to the complex process of producing the wax model, the optimum number of pieces for the Exacast® process is only 5 - 200 units. As the ceramic moulding material does not react with the metal, a very wide range of materials can be cast, from simple cast iron to high-alloy steel grades and special materials e.g. based on nickel or cobalt.
The precision of the Exacast® process is due to a low-viscosity ceramic material for making the mould which reproduces all the contour details exactly and is characterized by a very smooth surface. After being moulded the "green" moulded parts are thermally hardened, assembled into the final shape using cores and then heated to a higher strength in a burning process. Because the cast is made in a hot mould, the metal runs into the smallest recesses and long narrow channels without solidifying. At the same time, casting in hot moulds reduces the feed problems common in sand casting so that difficult parts such as e.g. large differences in the wall thickness in impellers remain free of defects. Gases are able to escape thanks to the air-permeable moulding material, so that there is no need to clean the vent channels.
Another of the company's special services is an exceptionally efficient moulding technology for producing complex multi-blade flow control systems such as nozzle rings for turbochargers. These are required in numerous different variants. The manufacture of the necessary moulds only requires a few basic models thanks to carefully designed patterns which can be varied as required.
"We have wide-ranging experience in the use and development of alloys, even for the most difficult areas of application," explained Dr. Marc Borel, head of engineering at Wolfensberger AG. The company has a range of materials of up to 100 alloys, from simple cast iron and nodular cast iron via carbon and quenched and tempered steels to ultra-high alloyed materials for applications with extreme operational demands through wear, corrosion or high temperatures. Thanks to decades of experience in using alloys of these types in extreme environments such as chemical plants, annealing furnaces or plants for shredding and handling high wear raw materials, the experts at Wolfensberger are very familiar with the advantages and disadvantages of the individual materials and can give customers the correct advice. Special alloy compounds are also designed and tested to meet new challenges. Wolfensberger invests a lot of effort in looking for alternative material concepts, especially with the aim of minimizing the content of expensive alloying additions.
"We are also heavily involved in developing smart new solutions where the design challenge is the main focus," Dr. Borel revealed. An example of this is a pressure vessel for cleaning turbochargers in marine diesel engines. This contains a special granular material which is used to periodically remove the soot which gradually builds up on the blades of the turbocharger. The granules are shot into the turbocharger using compressed air while the engine is running. These vessels were previously welded, but this had several disadvantages such as the necessity of having to keep a very close watch on the welded seams. As an alternative to this, Wolfensberger cooperated with the customer to develop a single-piece hollow component cast from ductile cast iron with spheroidal graphite. One of the particular challenges was controlling the buoyancy of the large core, as even small displacements would have caused undue size deviations in the very thin walls of the vessel. Wolfensberger provided support throughout the development from the design and initial sampling to the approval by the classification authorities. The product is now in series production with Wolfensberger responsible for the whole manufacturing process including machining and installation of all components. The customer received the ready-to-install unit delivered to the assembly plant complete with the necessary certificate exactly at the specified delivery date.
...with the most advanced IT tools
"The use of an advanced simulation programme for this development also proved worthwhile for the comprehensive analysis and optimization of the casting process," Borel stated. The programme, which has been in use for a number of years, simulates all the casting processes during filling the moulds and solidification. The information it provides has been corroborated using validation tests. It is now routinely used for every new piece to enable series production to be started without any defects. The caster makes use of it to determine the filling and solidifying times, follow the solidification process, detect any defects or thermal stresses and assess the efficacy of remedial measures.
Another important IT tool is the rapid prototyping of sand grains. The computer is used to construct a monolithic core without using a core box. One important advantage of this is that the core cannot be misaligned, which benefits the component accuracy in complex internal geometries e.g. for impellers. In addition, projects like this can be carried out very quickly.
Machining and logistics
"A further important key competence of our company is its equipment for machining even the hardest and most difficult materials," Borel added. As most customers require machined parts which are ready to install, we invested in the relevant technology at an early stage, thus expanding our own level of added value. These operations have now been combined in a works of their own. Wolfensberger has plant and equipment which can machine the hardest abrasion materials containing special chromium carbides. We can even machine hard ceramics. In addition to machining our own cast products there is enough capacity to take on orders e.g. from other foundries.
Logistics are also of ever greater importance, as today's customers have an increasing tendency to want just a single contact person who will supply the whole service for a specific part or component directly to their production site on schedule and ready for use. As part of its full service philosophy, Wolfensberger also provides all the relevant services – either using its own resources or with the aid of trusted partners – including all logistic services from procuring components via packing to on time delivery.
Swiss quality – also when it comes to cost control
"Last but not least, over the last few years we have been able to achieve significant progress with cost control," Schmidhauser added. In line with the customary Swiss approach, the company had previously concentrated first and foremost on technological and quality aspects and only considered economic factors afterwards. However, the customers that you come across on the world market nowadays, while valuing quality are not willing to pay any price for it. These type of customers can only be won over if both the price and the product quality are in balance.
This is why, over the last few years, the company has promoted the Japanese model to systematically develop structures which can guarantee cost control at all levels. The aim is to establish a culture of ongoing improvement in the whole company based on the motto "no change, no chance". The company now has a continual improvement process (CIP) and its own "lean manager" whose job is to look into the options for optimization throughout the company's processes and to put the relevant suggestions into practice. This has led to continuous improvements. In the end this is of benefit not only to the customer but also to the company's own ability to compete.
Materials tailored to your needs12.04.2012
In order to meet the specific needs of your application with regard to an optimum choice of materials, the team of metallurgists at Wolfensberger provides you with support in the selection and targeted development of customised composite materials. In this way, the company realises precise material developments based on customer specifications for prestigious clients such as Daimler AG, Germany, and ABB Turbo Systems AG, Switzerland.
Here are two actual, practical examples:
1. Nitrogen-Alloyed Steels
By adding nitrogen to high-alloyed steels, strength and corrosion resistance can be increased while the content of the alloying element nickel – a significant cost factor – can be reduced.
Wolfensberger AG was among the first suppliers to introduce nitrogen-alloyed, corrosion-resistant steels with "duplex structure" into its product range in 1999. As a result, the company's know-how continued to develop and in recent years several more corrosion-resistant steels were developed based on customer requirements and included in series production.
A nitrogen-alloyed steel developed by Wolfensberger for the large turbocharger market as a replacement for a nickel-based alloy was released in 2010. Instead of containing 95% of the expensive alloying elements nickel, chromium, molybdenum and niobium, the new alloy contains only 32% of these elements. The micrographs show that the two alloys demonstrate comparable microstructures and hence the specification of the new alloy is met:
2. Wear resistant cast iron (also chilled cast iron and white cast iron)
Wear resist cast iron alloys are basically hard iron-chromium-molybdenum alloys with a carbon content of between 1.3% and 3.6%. Wolfensberger AG offers a choice of more than a dozen different alloys of this kind, covering the whole spectrum between high abrasion-resistance and high corrosion-resistance.
Worthy of note with regard to these alloys is that, after a special heat treatment process, they are extremely machinable and even M 3 threads can be provided. After machining, the castings are re-hardened (with low distortion) up to 65 HRC.
As a result of consistent further development of the heat treatment process, Wolfensberger today is able to soft anneal, process and re-harden most of these alloys in-house.
As opposed to surface-hardened or coated components, heavy duty castings demonstrate the same hardness over the entire cross-section. This allows greater stress rupture life which in turn means longer inspection intervals and low spare parts costs.
We would be pleased to help you select the right "wear resistant cast iron alloy" for your requirements or adapt it to your specific needs.
For a further discussion, please contact Dr. M. Borel of our Metallurgy Department marc.borelwolfensberger.ch.
Tailor made casting design by Wolfensberger15.09.2011
Our latest technical brochure addresses to our expertise in the matter of optimized casting designs, apt material selection, castability, cost optimisation and to many other vital issues in order to ensure a smooth transition of ideas to serial production.
Please have a look yourself …
Tailor made casting designs (Technical Bulletin No. 4)
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Right from our initial contact, we work together actively with you as a competent casting and materials-engineering partner.
Our specialists will advise you in all matters relating to casting processes, materials and machining. We also provide competent support for individual problems and develop new and innovative solutions in cooperation with you.
As experts in sand casting, precision casting Exacast® and machining, we offer many years of professional competence which has proven its worth over time.