LHMT
Because being near matters

The primary market is in Central Europe, but they are also active in Asia, the US and Canada. Currently, machines are mostly going to customers in the medical industry, while sales in the automotive industry are declining, especially in Germany.

Drive technology for maximum performance

LHMT produces many things in-house, including processing the aluminum sheets for the systems and producing the axes. Sheet metal, steel and turned parts, or even guide rails, come from selected suppliers – as does the drive technology. That is supplied by STÖBER Antriebstechnik GmbH + Co. KG, just a few kilometers away in Pforzheim.

“I learned of STOBER’s synchronous servo motor with hollow shaft in a trade journal,” Handte says of his first experience. That was in 2018. “We had a ball screw spindle with a driven nut installed in our multi-axis loading and unloading unit for handling. We were able to replace the entire belt drive and nut bearing with the synchronous servo motor with hollow shaft.” STOBER was not only a supplier but also provided supported during the configuration and commissioning. Due to the proximity and excellent collaboration, LHMT commissioned other projects. The entire machine range had to be converted to a modular system in order to meet customer requirements for delivery times and investment costs. “Our right-angle servo gearbox or planetary gearbox are installed with synchronous servo motors and different drive controllers in almost every system,” says STOBER sales employee Guido Wittenauer, who has assisted LHMT from the very beginning.

A flash-cutting machine is set up in the production hall that is about to be delivered. “During flash-cutting, a cutter is used to trim pressed multi-layer PCBs to size, for instance. This gives our customers burr-free edges and higher-value boards at the same time – before they are transferred for further processing steps, such as scoring,” explains Handte. Next to it is a multi-axis loading and unloading unit, which automatically picks up untrimmed boards from a load carrier. “Using a robot at the flash-cutting machine, we can link the systems,” explains Pfrommer. “For both machines, the focus is on dynamics and speed – as well as precision for flash cutting.”

Strong support

For the swivel unit at the loading machine, a right-angle geared motor from a different supplier was used initially. To increase efficiency and save space in construction, STOBER provided right-angle servo gearboxes from the KS series along with synchronous servo motors from the EZ series. This compact unit offers ideal installation dimensions and a high power density. “Thanks to their rugged bearings and high-quality gearing, gearboxes from these series are extremely durable and tip-resistant,” explains Wittenauer. “They can be used in continuous operation without any problems – even at high speed levels.” One of the most important features of the KS series is its very high torsional stiffness. And thanks to its bearing position on the gearbox output, this was no longer necessary on the system.

STOBER also provided support during the configuration. “The comprehensive collaboration convinced us to use servo drives from the drive specialist in the systems,” says Handte. “For a two-axis system, we were ultimately able to install the compact SC6 stand-alone controller as a dual module for up to two drive axes,” adds Wittenauer.

To guide panels into or retrieve them from the slotted boards in the loading and unloading units, LHMT added another servo axis and a tilting axis. STOBER also provided support in the configuration and implementation here. Handte says, “In 2021, we were able to project, build and commission a complete processing system with drive controllers and drives from STOBER.”

Highly dynamic and flexible

For the flash-cutting machine, linear drives from a third-part supplier were used in the x- and y-axes, as well as for the rotary axis and 6.5-kilowatt cutter spindle. “For the control of these axes, we supplied drive controllers from the SI6 series,” says STOBER expert Wittenauer. “For the user to be able to work with the machine cost effectively, dynamics and speed are extremely important.” The faster the processes are, the more productive the machine is. The time factor plays a critical role for customers to be able to be competitive. The highly dynamic controllers perform even in challenging motions. STO (Safe Torque Off) and SS1 (Safe Stop 1) functions are integrated. They are certified in accordance with EN ISO 13849, for example, and can be used without function tests that interrupt production. The drive controller has a width of 45 millimeters and is designed as a multi-axis drive controller. Wittenauer says, “A single SI6 can control up to two axes. Thanks to the multi-axis drive design, the number of axes to be controlled can be freely scaled.”

A ball screw is installed in the z-axis. STOBER supplied a synchronous servo motor for this. “Since 2024, LHMT has also offered a unit with four cutter spindles as an automation component. STOBER also supplied drive controllers from the SI6 series for this.