In its 2020-21 fiscal year, Niehoff tallied sales of 248 million euros and employed 960 people at 12 locations worldwide. Some 95 percent of the company’s output is exported.

Niehoff’s machinery requires some sophisticated controls. Even a process as seemingly simple as winding cable onto a spool requires careful control of speed and tension. Wiring up those controls is the job of Thomas Linder, head of control cabinet production at Niehoff. Control cabinets require a lot of wires. There are different types, lengths, colors and connectors. Prepping it all efficiently and error-free is a challenge.

So, when Linder discovered Digital Lean Wiring (DLW) software from Komax AG, he was keen to get started. DLW software helps engineers prepare assembly data for automated prefabrication of wires, even for a batch size of one. DLW provides several interfaces for importing and preparing data. For example, engineers can export a wire list from design created in 3D CAD software. Alternatively, engineers can use 2D drawings or high-resolution images of the mounting plate. Based on those 2D graphics, engineers can route and connect wires virtually on the screen. On that basis, DLW calculates the wire lengths of each connection, generates the assembly data, and loads it onto a wire processing system. 

In Niehoff’s case, that system is a Zeta 630 fully automatic wire processing machine from Komax. The Zeta 630 has two process modules and can store 36 different wires in a wire changer. The machine allows just-in-time processing in batch or sequence production of various wires for cabinet building without changeover. The CM 1/5 GS module can process five different ferrules, while the CM Duo can process sleeves ranging in size from 4 to 6 square millimeters. The sleeves provide wiring information so technicians can carry out wiring without an electrical diagram.

Equipped with the three blade pairs, the Zeta 630 can process cross-sections of 0.22 to 6 square millimeters in sequence. DLW software sends the processing parameters to the machine, which automatically sets itself up without any manual programming effort.

Prior to automation, the task was more involved. “Traditionally, the electrician first identified each individual wire according to a paper circuit diagram,” explains Linder. “To which class does the wire belong? Is it a power or control circuit? Accordingly, the electrician then selected the right color and cross-section and consulted the plan to determine which components were to be connected. According to the intended laying path, the electrician measured the wire in the control cabinet, cut it to that length, and then inserted the wire ends into an automated machine, which stripped it and pressed on a sleeve. As a final step, the ends were connected to the components.”

Doing it that way was time-consuming. “It was mainly the time factor; the throughput times were too long,” says Linder. “For one thing, we had to bring the corresponding 100-meter wire reels from the kanban shelf to the wiring station for all the wires. Then we had to laboriously prepare the wire list for production, because our CAD software only generated a connection list from the system.”

As order volumes increased, it became apparent that Niehoff needed to automate the process. “The major challenge was the enormous increase in order volumes,” says Linder. “Our customers are beating a path to our door. More cables and wires are needed. Not just in electric cars. Just think of the charging infrastructure in cities and regions. For this purpose, a large number of cables with large cross-sections need to be laid.”

Compounding the problem is the ongoing labor shortage. “It is becoming increasingly difficult to find qualified personnel. Every automation step brings a bit of relief,” says Linder.

To date, the system has been working well. “We export a wire list from ECAD with the ‘start-end’ designation and import it into Excel,” explains Manuel Epple, who is responsible for data preparation, preassembly and wire assembly at Niehoff. “There, we specify the wire color and cross-section and import the list into DLW. DLW generates the bundle sequence according to internal specifications. The wire end treatment is defined—ferrule or half stripping. Each wire on the list is routed completely by hand in DLW. There’s no more back and forth with the wire reels, because now the Zeta 630 delivers the wires to the assembly location in a box, with the wires arranged in a wiring-optimized sequence and ready for assembly.

“We have put together simple production rules in the wiring team. I prepare the wire sequence in DLW in a component-optimized manner. The Zeta 630 assembles the wires exactly according to these specifications, then labels and bundles them. All of this simplifies and speeds up installation enormously.”

Niehoff recently began working with the latest version of the software, DLW 21.x. “In the previous version, I still had to route each individual wire virtually,” says Epple. “Now, I can route several wires semiautomatically at the same time. ‘Group routing’ is a major step forward, as it offers the greatest time advantage. For example, I can mark all 20 wire ends in a wire bundle, place them on a potential terminal and wire them virtually with just a few clicks. There are also significant improvements in the filter options. Thanks to these, I can find the component names and their terminals, or connections, much faster. What’s more, I can sort all of this better.”

Automation has saved Niehoff a considerable amount of time. “On average, a control cabinet has 250 wires. Depending on the size, the processing time is now 2 to 3 hours. Preparation now takes an average of 40 seconds rather than 72 seconds. In other words, the improvement has been 40 to 60 percent.”

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For more information on wire processing, read these articles:
Automating Control Panel Assembly
Ink-Jets for Marking Wire
What’s New With Cut, Strip and Crimp Machines