Practical Know-How

3D Printing Enables Tool-Free Assembly

| Editor: Alexander Stark

Lauda does not need an automated 3D printing factory, finer surface structures or complex finishing processes. Additive manufacturing occupies a small but efficient niche at the company.

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On this desktop printer, Lauda produces, for instance, clips for tool-free assembly.
On this desktop printer, Lauda produces, for instance, clips for tool-free assembly.
( Source: Simone Käfer )
  • The temperature control unit manufacturer has already developed 100 products, which it manufactures on its 3D desktop printer.
  • One of these products is a fastening element that saves a great deal of time during assembly.
  • There had been a long learning period before the small series production could start. After two years of practice, the number of misprints has drastically decreased.

For almost five years, since April 2014, an Ultimaker 2 has been used in the R&D department at Lauda. The 3D desktop printer processes filaments made of PLA and ABS. But metals would actually be more interesting, because the company produces temperature control units for ranges from -100 to 300° C, which are used in medical, chemical and laboratory processes, as well as for testing electrical appliances and batteries for electric cars. Lauda devices can also be found in Elon Musk's Space X space company. "We don't yet have a business model for a metal printer of around 100,000 euros," says Johannes Schierholt, explaining the reason for choosing a 3D plastic printer. Schierholt headed the R&D department at Lauda. In addition, the complexity of additive manufacturing with metals is an obstacle and the technology is not yet mature enough. "But we're keeping an eye on it," he adds. 3D metal printing would significantly expand the areas of application in additive manufacturing at Lauda. This is because plastics cannot withstand temperatures of up to 300° C. Nevertheless, the designers at Lauda have now developed around 100 different components, which they use in their own devices.

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Not Designer Goods but Industrial Components

Lauda temperature control units are not mass-produced products. Usual quantities are ranging between 200 and 2000 per model and year, but also small series with 20 devices and individual productions are part of the everyday business. This suits additive manufacturing perfectly - and Lauda knows how to use it. For example, the designers developed a fastening element that Lauda did not produce before: a clamp. That sounds not very spectacular and very familiar. But "with the clip we have achieved a completely tool-free assembly," explains Christian Wörrlein, designer and Lauda's 3D printing expert. This is because the clip fastens the pipes through which the liquids flow and which connect the components of the temperature control units as heat exchangers, compressors and throttle valves. Not many clips are required per unit, perhaps 300 pieces of one size per year and 100 of another size. Before the clips were developed, sheet metal had to be bent, holes drilled, the sheet metal fastened with a screw and nut, secured with another bracket until finally the pipes were fastened. "Today the clip is turned into a lasered sheet metal and the pipe is clipped onto it," Wörrlein describes the process. This leads to immense time savings during assembly.

But time is not only saved in assembly. The production of the clips also saves time with the Ultimaker. When the assembly needs a new batch, the printer is set up in the afternoon, prints overnight and the clips are ready in the morning. Postprocessing is not necessary. “These are not design pieces, they are industrial components," Schierholt sums it up.

Finding the Right Base for Printing Process

But, for them to be able to enjoy the benefits, they also had to invest time. “You have to read the operating instructions, align the construction panel and find a suitable base," says Wörrlein. He had to find a base to which the print parts could adhere - and be easily removed after printing. The adhesion is due to the delay. If the components do not adhere properly to the plate, the outer edges of the components bulge upwards as soon as the plastic cools down and contracts. “If the adhesion to the plate is lost, the component detaches, you have to break off the print and at least one component is lost," Wörrlein describes the problem with the distortion. The solution was found in a usual packing tape.

Employees Must Familiarize Themselves with the Technology

A classic for the use of additive manufacturing is prototype construction. Here, too, Lauda has embraced the advantages. They often use 3D-printed prototypes to test fluid properties of hydraulic applications or the flow angle of a pump chamber. “Normally media with a temperature of up to 300° C flow through these chambers," explains Schierholt, "but for testing we use with water." Whether pump impeller or its counterpart, the pump chamber, Wörrlein simply prints them. However, simple printing doesn't work after all. "The first attempt usually fails - even today," admits Wörrlein. “Despite our experience, distortion can cause a spot to detach or the printer has not yet been perfectly adjusted. But in the second or third attempt the result is usually successful." When he started it about two years ago, it was the tenth or twentieth attempt. Experience is therefore an important factor. "To do this, you have to give your employees the space they need to familiarize themselves with the technology," emphasizes Schierholt.

Additional Information

A Self-Aligning Building Plate

The newest 3D desktop printer in the Ultimaker family is the S5. It has a construction volume of 330 mm × 240 mm × 300 mm as well as a dual extruder and prints layer thicknesses down to a minimum of 20 µm. The feeder is equipped with a filament flow sensor that automatically stops when the filament needs to be filled and continues printing. According to the manufacturer, this is done without affecting the print quality. The building panel is easier to adjust and aligns itself continuously during printing. Printable materials include PLA and engineering plastics such as nylon and PC. For quick configuration, settings have been made to ensure complete geometry freedom, industry-standard material properties, reproducibility, long uptime and an integrated workflow.

This article was first published by MaschinenMarkt.

Original: Simone Käfer / Translation: Alexander Stark

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