Lätzsch continues its success story with new PUR system
16.12.2020 | Gerhard Konrad

"As a system provider, we offer complete solutions from a single supplier and supply finished assemblies that only have to be installed. This means less effort for our customers and highly efficient transactions," says CEO Hans-Joachim Lätzsch. He considers this the key to the company's success. "We can now also offer our customers components made of formulations with solid flame retardant materials." 

Complete development from a single supplier

Stringent requirements exist for passenger transportation. Passenger safety takes highest priority. This is why only flameproof materials may be used in the passenger compartment. For assemblies installed in buses built by a major manufacturer, Lätzsch has developed a special polymethylpentene flame retardant compound. The PU structural foam complies with the flame retardant directive ECE118-03, which applies specifically to coaches. "The flame tests are carried out simultaneously with production in our in-house fire safety lab," Lätzsch explains. Lätzsch GmbH also handles the design engineering of the foam molds in-house. "This enables us to make our production very cost-effective. It also gives us the ability to carry out mold optimizations quickly and efficiently," says Lätzsch, describing his philosophy.

Partner in development and series production

Lätzsch made use of KraussMaffei's expertise in developing the mixing and metering technology for metering the flame retardant. "KraussMaffei's technicians and design engineers were reliable partners in implementing the necessary reconfigurations and expansions to our system. This was true both in the development phase for metering the flame retardant and developing and installing the system for series production," Lätzsch says. 

Polymethylpentene flame retardant compound with solid filler

The new system includes three foaming cells, a material processing unit with static mixers and two piston rods with 15l plungers. This makes it possible to have shots with very short cycle times, even for very large volumes. For metering the polymethylpentene flame retardant, the system features two wear-resistant high-pressure metering cylinders. The isocyanate is metered using a high-pressure metering unit with axial piston pump. Processing the polymethylpentene flame retardant compound requires a piston metering system, because abrasive, powdered fillers are used. This hybrid system enables fast and continuous foaming. 

Efficient work and short cycle times

Lätzsch had a system with two piston rods installed. One of the 15l plungers is ready for shots at all times, and there are no waiting times for raising the pistons. Both piston rods take in the polymethylpentene flame retardant compound from a shared raw material hopper. This ensures the uniform quality of the material.

Customized mixing head configuration

The metering of the flame retardant also requires a corresponding mixing head configuration. In this specific case, two 4-component poly-iso mixing heads (MK12/18 ULP-4K-F-80) and a 3-component mixing head (MK8/12 ULKP-3KV-80) were selected, which are fed using the hybrid twin-piston pump solution. 

Control and operation using the PUC08

A PUC08 HMI from KraussMaffei is used to control and operate the entire system. "This ensures that we always maintain the complete overview of the current status of our system's production cycle," Lätzsch says. In addition, the PUC08 records all process data and production parameters. The database is the basis for quality monitoring and process optimization and thus ensures higher production reliability. In addition, in case of service, the PUC08 is the basis for remote service over the Internet. 

Varied range of production

Lätzsch GmbH has extensive experience in production of foamed components for the vehicle interior. For driver's cabs, Lätzsch foams products such as floor mats, armrests, separating walls, handles and storage boxes. "In particular, our customers value our flexibility in producing short runs," says Lätzsch's CEO. "If necessary, we can produce the desired components very quickly and deliver them just in time." Lätzsch now has a total of thirteen foaming cabinets, ensuring plenty of capacity, even for large orders.

Expert in fiber composite components and logistics services

Lätzsch GmbH works in three business units of PUR processing, GRP/CFRP production manufacturing, the automotive service area as well as metal processing. Around 125 employees work together in production at the three locations in Saxony: Kitzscher-Thierbach, Neustadt and Streitwald.