SCOPE: Mr. Krause, what possibilities does additive manufacturing offer today that were unthinkable a few years ago?

Tom Krause: I am often asked whether we can print a specific part. In principle, we can now produce any part that has a wall thickness of at least 0.7 mm and fits into our installation space. For example, we can easily print complex tooth structures that would otherwise have to be milled at great expense.

The big advantage over other manufacturing methods is that we don't have to worry about the type of design or the design of the mold. Even in injection molding, the design is very demanding in terms of how a component can be molded. All these aspects are eliminated with 3D printing - all you need is the 3D model.

Competitive even with large quantities

SCOPE: Do you only print individual parts such as prototypes or spare parts at Igus or do you also print larger series?

Krause: That is very different. We offer the production of individual parts. But it's worth producing large quantities, especially for gears or other wear parts. This is because the price depends very much on how many parts we can produce in the printer's installation space at the same time. With a very small part, for example, I can produce several thousand copies in one printing process and thus achieve a component price of less than one euro. This makes us competitive with injection molding prices up to a certain quantity. We have already produced batch sizes of up to 8,000 units using the laser sintering process.

For large components, we can produce smaller quantities at the same time, which increases the price accordingly. This is why other manufacturing processes are often more suitable for large components. Unless the parts are very complex and therefore very costly to produce using other processes, additive manufacturing is also very interesting.

SCOPE: How long does it take to print these 8,000 gears?

Krause: For a component with dimensions of 12 × 12 × 12 mm, for example, around 3,000 to 4,000 parts fit into one installation space. We can produce this number over the weekend - the printing time is around 30 hours. For larger parts, it is also a question of time if larger quantities are to be produced.

Laser sintering for high quality

SCOPE: And you always use the laser sintering process for your mechanical requirements?

Krause: Yes, exactly. We started with the FDM process, where you often have to work with a support material. This costs a lot of printing time and is not necessary with laser sintering. With laser sintering, we also achieve higher strength and greater accuracy. The printing speed is also up to 100 times faster. This reduces the manufacturing costs per component accordingly. We use the laser sintering process for around 90 percent of our orders. FDM is used for special requirements, for example when higher application temperatures are required. The material Iglidur J260 can be used up to 120 °C, while I150 is suitable for applications in the food sector. We process these materials using the FDM process.

SCOPE: Which printers do you work with, are there any in-house developments?

Krause: For laser sintering, we work with systems from EOS. We use the smaller devices because they allow us to achieve greater precision. We used to have one of these systems, but we recently started working with three in order to meet customer demand.

In the FDM area, we use various devices, in particular one we built ourselves for high-temperature materials. For example, we use it to process the material Iglidur J-350, which is actually an injection-molded plastic. However, we are now also able to use this in 3D printing.

SCOPE: How do you see additive manufacturing in the overall economic context? There are now so many application areas in which it is relevant; will production in general change?

Krause: 3D printing will certainly not remain a niche market. There are leaps in technology and more and more large companies are working on the development of new, more powerful devices. I assume that the market share of additive manufacturing will increase. Additive manufacturing is clearly in competition with turning and milling when it comes to small and medium quantities.

As far as injection molding is concerned, 3D printing can be an alternative for small components, as mentioned above, when it comes to quantities of around 10,000. A very important application of 3D printing is now the production of tools for injection molding. In addition, there is decentralized production directly on site: parts can be produced close to the customer without long delivery times. Warehousing can also be reduced. We also have around 20 3D printers in our branches worldwide, which we can use to supply customers directly and quickly on site.

SCOPE: What proportion of Igus' total production does 3D printing account for and what are you aiming for in the medium term?

Krause: I can't give you any concrete figures, but a simple comparison to show the relationship: We have around 450 injection molding machines and four professional 3D printers. Nevertheless, additive manufacturing is a very interesting area for us, because it's rare that quantities start in the five- or six-figure range. If, for example, a customer is developing a new product and does not want to spend a five-figure sum on a tool at this stage, additive manufacturing is the method of choice. Often, the first parts of a series are also additively manufactured and only go into injection molding production for higher quantities. This means that even with the relatively small number of 3D printers, their benefits for us are very high. They often make it possible for us to receive orders in larger quantities, as we can help the customer to optimize their product in various 3D printing iterations before they have it mass produced. 3D printing saves a lot of time and money, especially in the optimization phase. Just think of the geometry of a gear wheel: with conventional production, a new milling cutter has to be produced at great expense for every improvement.

SCOPE: How did Igus get into 3D printing?

Krause: We have been using laser sintering in development for more than 10 years. The speed alone made the process interesting for us. In the beginning, we simply experimented. We wanted to help our customers quickly and built our first FDM printer ourselves to gain experience. We then developed and tested different types of filament ourselves. We were looking for a longer service life, but also higher temperature resistance. That was actually our first business idea in this field - to bring new, improved filaments onto the market. Over time, it turned out that many customers lacked the hardware or capacity and were therefore interested in purchasing the components from us.

This then led us to laser sintering technology, as we were able to offer better qualities - smoother surfaces, lower tolerances. The process has been very well received by our customers and the plant has always been very well utilized. That is why we have now also purchased new equipment. Feedback from our customers is very important to us and helps us to further develop both the technical equipment and the components themselves. Of course, we also provide our customers with appropriate processing tips for the materials we offer.

Printing service with many options

SCOPE: Today you also offer 3D printing as a service. How did this idea come about?

Krause: Initially, many of our customers didn't have their own 3D printers. As a result, demand grew steadily. As mentioned, laser sintering quickly proved to be the more practical technology. For the FDM materials, for example, the Freeformer or an in-house 3D printer is used. Injection molding materials that can also be processed in 3D printing are also used.

SCOPE: How did you implement the print service in practice?

Krause: We receive many orders online. We had to develop a new system for this. We developed the corresponding tool together with our partners. We were then able to launch the web printing service at the beginning of 2016. All the customer has to do is upload their 3D model, specify the materials, tolerances and quantities as required and view the prices accordingly. This order then goes into the Igus shopping cart. The customer can also place other orders at the same time. The customer receives his component individually configured and quickly.

Igus also offers various online configurators that customers can use to dimension and specify their own components. The best example is gear wheels. Here, the customer enters their parameters such as the number of teeth or tooth module. With the help of the configurator, he then receives the optimum tooth shape and a 3D model suitable for printing at the same time.

SCOPE: Can you offer the same tolerances in 3D printing as in injection molding?

Krause: No, the technology is not that advanced yet. In 3D printing, the tolerances are currently around ±0.1 mm, in some cases even ±0.05 mm. In injection molding, the tolerances are lower. There is still a need for development here. But of course it always depends on the individual requirements. Apart from the tolerances, the latter are also very different. As mentioned, there is temperature resistance on the one hand, but abrasion resistance, food compatibility or ESD behavior are also often important criteria. We are also constantly developing our materials in these areas. Many gear shapes simply cannot be milled, or only at great expense. This is where we offer cost benefits with 3D printing.