Technological change offers very dynamic developments within mould making. In the middle of 2012, W. Fassnacht Werkzeug- und Formenbau, Bobingen, supplied its 1,000th generatively fabricated mould insert for conformal cooling. Within the space of five years the LaserCUSING technology has developed to become an important factor in Bobingen; working alongside the traditional manufacturing processes like, turning, milling and EDM. The reasons for the increasing importance of additive manufacturing with metals can be found daily in modern mould making.
With LaserCUSING, cooling channels can be placed very close to the surface of the contour of the mould. Complex parts with different wall thicknesses, including ribs and webs, can therefore be cooled "close to the action". It was back in 2008 that Fassnacht invested in LaserCUSING machines from Concept Laser from Lichtenfels. Conformal cooling systems are intelligently created, a few years ago this was not regarded as achievable in relation to the flow behaviour, but modern techniques make this easily possible today. In addition to a real reduction in the cycle time, both warpage and accuracy in the final part can also be greatly improved thanks to the cooling.
Conformal cooling: Design and cross sections
The cross sections of the cooling channels are >5 mm and, according to Wolfgang Fassnacht, are technically consistent and reliable. This means there is the possibility of placing them 2–3 mm below the mould contour surface, in order to achieve optimum cooling. The contrary, heat control, can also be performed via such channels, this for example is greatly illustrated in the case of parts with a requirement for a high-gloss finish. Certain moulds even have both tasks in separate circuits: Surfaces with a high-gloss finish are tempered and on the inner contour areas such as ribs, can be cooled in order to prevent warpage. Historically, moulds which have been produced at Fassnacht with this cooling technology, reach achievable and realistic reductions in the cycle time on series moulds of up to 40%. This technique offers enormous advantages in adding value for the production operation, bringing a level of understanding and control never available using conventional processes.
Issue of costs and speed in mould making
The short development times of modern moulds creates enormous time pressures for product developers, mould-makers and suppliers . The metal additive manufacturing process also allows for the possibility to fuse powder materials on top of original material layer by layer, commonly called “Hybrid Style”. This technique reduces the overall costs and time to build cores and inserts, focusing on using Additive Technology in areas of greatest requirement. Today’s hardness levels up to 52HRC are achieved, depending on the material, and works with Hybrid Style parts just as easily. When we consider conventional manufacturing processes, within any company a highly skilled and trained set of personnel are involved, and generally turning, and milling processes have to be continuously monitored. This is different with the additive manufacturing of metals: With the generative metal laser melting process, the mould-maker saves time in the design and manufacturing phase and it is also easier to incorporate possible requests for changes to be made. Once the parameters have been chosen, the LaserCUSING machine from Concept Laser can be operated unmanned 24 hours a day. In the case "hybrid technology" parts too, the mould-maker saves both time and costs. The formative residual geometry including the remaining cooling-channel design can be "fused" onto a prefabricated basic body, with predrilled feed and drain holes for the cooling, by means of LaserCUSING. With a mixed type of construction, this procedure has already proven to be the fastest and most economical method in many cases. The general rule is that generative technology produces a faster result – and is overwhelmingly cheaper.
Inserts for round parts
According to the experiences gained at Fassnacht, round parts in particular are very suitable for inserts based on metal additive manufacturing. Round mould inserts can be manufactured much cheaper with the LaserCUSING technology. This is because with integration of conformal cooling there is no need for any recesses and grooves for O-rings. It is therefore easier to construct the insert. As a consequence, the outlay on design, manufacturing and reworking is greatly reduced and consequently so are the overall costs Traditional methods, from the procurement of a steel rod from the warehouse through to finish use, are more complicated and expensive to manufacture than with LaserCUSING. At Fassnacht, the "generative approach" with a laser is very important in design and mould making.
Reducing part costs
There are numerous reasons for the trend towards conformal cooling, both technical and economic: "In production, moulds should earn money in terms of the unit costs and this is all the more true with large volumes," says Wolfgang Fassnacht. Process-reliable moulds which help to outsmart the physics and reduce cycle times enhance the creation of added value in production. The 1,000th mould insert for conformal cooling from Fassnacht demonstrates the success of this strategy adopted by mould purchasers and manufacturing specialists, but with the constant reminder that with all new technology and developments, it has to be a profitable and commercially viable.
Advantages of metal additive manufacturing in mould making
- Optimisation of the manufacturing costs
- Time saving during design and mould making
- Visual quality
- Cycle time reduction (with conformal cooling)
- Unmanned production.
- Reduced failed parts due to distortion or warpage
- Hybrid Build techniques
- Lower modification costs
- Construction of prototypes and samples
Mould Maker of the Year 2012
In the category "External mould maker with fewer than 50 employees", W. Fassnacht Werkzeug- und Formenbau won 1st place in 2012. The jury gave the following "special reasons" for its decision:
- One of the smallest companies in the competition.
- Similar structure to large companies, but much more streamlined, flexible and effective.
- Manufacturing technologies equivalent to those of large mould makers or better, but consistently integrated in the company, so the employees demonstrate much stronger innovative activities.
- A very wide range of parts and customers with the corresponding transfer of innovation know-how and technology.
- No dependence on particular customers or sectors.
- No bottlenecks caused by lots of rotation and training of the employees.
- Short pathways, leading to rapid agreement and thus time and cost benefits.
- Swift decisions.
- Personal contacts with customers and suppliers, in some cases through to the machine operators.
In just a few years since it was founded in 1990, the Swabian company Fassnacht developed into a mould maker which, although it is medium-sized, has become well known beyond the confines of southern Germany. And there are good reasons for this:
The company has so far competed six times in the "EXCELLENCE IN PRODUCTION" contest, which is staged right across Germany. The reward for its efforts came in 2004 with 2nd place and one year later with 1st place in the category: "External mould maker with fewer than 100 employees". In 2007 the company, which is based in Bobingen in Germany, was able to stand right at the top of the podium as the overall winner. In 2009 Fassnacht defied the economic crisis to once again claim an outstanding 2nd place result; in 2010 the company was able to celebrate its 20th anniversary and again rejoice at 1st place in a very strong field of competitors. Most recently, in 2012, Fassnacht claimed 1st place in its category as "Mould Maker of the Year 2012".
Another characteristic typical of such solid companies is career progression. Wolfgang Fassnacht started off small as a 25-year-old master mould maker. Working from a backyard workshop, one year later he moved into new rented premises in Königsbrunn. The company grew steadily and today it is able with a solid team of 20 employees to develop solutions for all mould-making requirements to manufacture injection-moulded products.
As "Made by Fassnacht" has gained a reputation, clients from a wide range of different sectors are coming to Bobingen: From the automotive and medical sector, from the packaging and household technology sector, and from the construction and electrical sector.
Fassnacht is synonymous with highly complex injection moulds, for example multi-component and thin-wall technology and insert mouldings of films. A consistently high quality standard and absolute flexibility in meeting customer requirements justify the company's reputation as being a fast and expert supplier of moulds. Reliability and clear agreements characterise the company's relationship with its customers.
The themes of hybrid construction and conformal cooling with mould inserts have since 2008 been an innovative subject in Bobingen. The additive manufacturing of metals (LaserCUSING) makes it possible to fabricate individual components and mass-produced components or cooling geometries with a hybrid design quickly and cost-effectively.
Fassnacht is a member of the VDWF (Association of German Tool and Mould Makers).
For more information, visit: www.concept-laser.de