Case Study

A company that prospers as complexity increases

Tumag

Mold manufacturer accelerates process and improves quality with NX

Keeping pace with plastics requirements

Consumers increasingly demand more from products. Styling and a pleasant feel can no longer be ignored, particularly with plastic components used in consumer electronics,medical and automotive applications. This necessitates a plastics production process that can combine functions and be capable of handling multiple plastic components simultaneously. The Belgian company, Tumag BVBA, specializes in complex molds that meet an ever-increasing number of requirements such as these.

Founded 35 years ago, Tumag is part of Citadel Industries, a consortium of some 40 companies active in a broad range of domains. Tumag is mainly active in the Benelux, but over the past few years its operations have expanded to the whole of Western Europe. “We are seeing increasing demand from the UK and Ireland especially, where the number of suppliers of complex molds has dropped in recent years,” comments Tumag account manager, Johan Linders. To keep up with growing customer demand while at the same time developing a competitive edge over low-wage countries, Tumag has widely automated the mold development and production processes using NX™ digital product development software, including NX CAM.

Early supplier involvement

“One of the reasons for our success is the emphasis we place on early supplier involvement,” Linders explains. “As technological possibilities keep increasing, it is important to advise customers early, during the product design stage, on aspects relating to production technology. Only then can a high-quality product be achieved.”

The main issue that must be discussed early in the design process is the integration of production considerations into the design. “To achieve a well-balanced design, it is important that the influence of the production process should remain invisible, and not impair functionality,” says Laurens Van Zoggel, a mold designer at Tumag. Van Zoggel deals with this subject a lot. “We look for ways to process draft angles, split lines and the application of 2K technology in the design, and discuss with the customer the pros and cons of the injection molding process,” he explains.

Once the product design has been established, it is presented to Tumag as a 3D model together with injection molding machine specifications and the environment in which the product will be made. “We import product designs into our NX system,” Van Zoggel continues. “Many of our customers use NX and we prefer to receive from them the intelligent NX geometry. This sometimes works out, but in many cases we get STEP or Parasolid files because the customer wants to be sure that the design cannot be tampered with, or because the customer simply does not work with NX.”

Standardized mold design process

To be able to design molds more efficiently, Van Zoggel and his colleagues have carried out widespread standardization in NX. “We have developed our own mold application over the years that includes standardized plates and components such as guides and centering devices,” Van Zoggel explains. “This application fully matches our needs. It allows us to set up the mold rapidly based on the 3D geometry and then detail it, complete with slide gates, sprue ejectors and injection points.”

In practice, consultation with the customer over the mold still makes use of 2D drawings to a large extent. Tumag is attempting to introduce changes in this respect. “3D data provides so much more detail than a 2D drawing,” comments Linders. “Furthermore, with the increasing complexity of molds it is not possible to represent everything in 2D.” While at present, the presentation is made with videoconferencing projectors mainly, Linders anticipates that in the longer term the Internet will also play a major part in discussions. Today the remaining factors standing in the way of online collaboration are the lack of exposure and regional restrictions in bandwidth in particular.

Tumag expects that the use of 2D drawings will be further reduced within the company as well. “We are planning to apply the ‘model-based definition’ concept in the near future,” says Van Zoggel. “We will then provide the complete design in 3D with mold and plate tolerances and dimensions. At that stage, we will be able to stop working in drawings, which will be generated from a 3D model at ‘the push of a button,’ and will therefore be up-to-date by definition. And in NX CAM we can then use the tolerance data from the design.”

Van Zoggel expects that this will speed the process even further. “The integration between the design and production is one of the reasons we use NX,” he says. “Even though we work mostly with non-intelligent customer geometry, thanks to NX we are able to implement modifications rapidly in the 3D geometry.” The geometry associativity within NX ensures that electrodes are automatically adjusted, for example. Furthermore, thanks to the CAD/CAM integration, NC tool paths are regenerated where necessary. “When we can also automatically process the mold and plate tolerances in the drawings and in the CAM programming, this reduces our lead time and improves quality while making things even easier for us.”

Continuous improvement

Once a mold design is ready, a bill of materials is issued via NX. “Since everything is custom-made and order-bound in our case, for the time being PDM does not seem to present sufficient value to us,” comments Van Zoggel. “Our mold application is managed and everything developed on this basis is a one-off.”

In addition, the design and documentation are always stored for service purposes. Even though the customers are supplied with all the drawings of the major spare parts, they cannot use this to comprehend everything due to the sheer complexity of the geometry. As Van Zoggel explains, “When a customer orders new parts, we find this data in no time. A new CAM program is made every time to ensure that no errors may arise as a result of selecting the wrong machine. Time is really of the essence in such projects since a production machine may be out of service.” The CNC machine tools controlled via NX CAM are operated in Heidenhain. These include 3-axis and 5-axis non-simultaneous milling machines, which are fitted with a Siemens 840D controller.

Tumag has various injection molding machines for the production of pilot runs and small numbers. “We have a 200-ton machine for 2K applications and single-shot machines with a closing strength of between 35 and 85 tons,” says Linders. “The customer approves the mold based on the pilot run, during which attention is paid to dimensions, surface quality, split lines, gating and film forming.” At the customer’s request, Tumag can also produce short series. This happens in special cases since its molds are generally developed with the precision and quality required for an output of millions of products.

In the short term Tumag will adapt NX further to meet individual and specific wishes. “With Knowledge Fusion, NX offers excellent possibilities for establishing relations between the required precision and the production sequence,” adds Van Zoggel. “The annotation generated from the 3D model is then used to establish in NX CAM the exact processing sequence and production tools that will ensure that accuracy is achieved.” Linders adds, “This allows us to safeguard not only the quality but also the knowledge within our organization. As far as we are concerned, NX is an invaluable tool in the engineering of precise and complex molds, which, after all, is Tumag’s business.”

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