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Oct 15, 2024

Cabinet-free automation ‘changes the world of machine-building’ - Drives&Controls

Image: Beckhoff The MX system’s double-row baseplate is installed on the base frame, simplifying wiring and facilitating diagnostics. Each machine module has its own baseplate onto which the various

Image: Beckhoff

The MX system’s double-row baseplate is installed on the base frame, simplifying wiring and facilitating diagnostics. Each machine module has its own baseplate onto which the various function modules are attached.

The German machine-builder Schirmer Maschinen makes profile processing machines used for a variety of applications, especially for producing windows and doors. The machines can make parts for window frames and sashes in a continuous process from PVC profile bars that are about 6m long. As far as possible, all drilling, milling and punching operations are carried out on the raw bar, followed by cutting and processing of the ends.

While the profile bars are being processed, reinforcement profiles are cut to size on a separate line with the option to automatically insert and position them in a PVC profile. This is followed by further processes such as screwing in the profile and reinforcement, drilling, milling, and inserting and screwing in the locking mechanisms.

Schirmer was founded in 1979 and employs around 250 people. It specialises in automated machines based on largely standardised process modules that create customer-specific systems with high outputs and flexibility in terms of profiles and processes. The company was reportedly Beckhoff Automation’s first customer, and after being a Beckhoff user for almost 40 years, became a member of the group in 2016.

Schirmer’s machines have to handle a wide variety of frequently changing profile geometries. The conversion process takes place automatically. “Manual set-up is definitely out of the question for us,” says Schirmer’s MD, Ludger Martinschledde. Many stops and brackets have to be positioned on a fully automatic basis. “Last year, for example, we implemented a line with a total of 210 axes,” Martinschledde recalls.

The electrical equipment that Schirmer has used in its machines to date reflects current standards. Drive amplifiers, power supplies, power distribution and PC-based control technology are all installed in control cabinets. There are typically several of these stations set up along the machine, with cables routed and connected from two or three process modules.

EtherCat I/Os are used in sub-distributors that collect actuator and sensor signals from the process modules. However, combining several process functions in one control cabinet and using sub-distributors to which the signal lines are clamped rather than plugged in, is a compromise for modular machine-building.

“This means that most of the electrical installation and commissioning will only take place during final assembly, which is precisely when we are aiming to commission the system as quickly as possible before taking it apart again for delivery,” Martinschledde explains. Schirmer regards the discrepancy between the modular machine concept and the central control cabinets as an obstacle to more efficient project workflows.

When Martinschledde and Schirmer’s design engineers heard about an alternative approach that achieves automation without control cabinets – Beckhoff’s MX-System, announced in 2021 – they were intrigued.

That is how Schirmer became a pioneer in adopting the cabinet-free technology, with the main aim of optimising lead times and processes involved in machine building. Instead of the control cabinets that used to stand next to its machines, baseplates for the new system are mounted directly onto the steel frames of the process modules. The sub-distributors’ tasks have either also been accommodated in the new system, or have been replaced by decentralised I/O modules (EtherCat Box modules), also from Beckhoff. This combination of the MX-System and EP box modules allows all cables to the motors, sensors and valve terminals to be pluggable.

The crucial advantage of the new approach for Schirmer lies in restructuring its internal processes. The pluggable system allows the machine-builder to install all of a machine module’s electrical components during pre-assembly and to connect them using pre-assembled cables. Another crucial aspect is that, during pre-assembly, the machine modules are accessible from all sides, making it easier to lay and connect the cables.

“This saves a lot of time and significantly increases the efficiency of our workflows,” explains Martinschledde. “This not only applies to assembly, but already begins with planning, preparatory work, and material provision in the production phase.”

The system’s function modules also eliminate the need for complex wiring of numerous sub-components that is typical of conventional control cabinet designs. This avoids wiring errors and streamlines the number of parts needed. As a result, the required components – baseplates, modules and pre-assembled cabling – can be picked from a warehouse for pre-assembly after the electrical planning stage.

The aim, according to Martinschledde, is “to achieve an order-independent warehouse that we can manage with minimum stock levels, requirements, and replenishment times”.

Schirmer’s initial development project revealed two further insights: last-minute change requests are much easier to implement and need less effort (even at a late stage); and with modular commissioning, any functional errors can be detected early and rectified without time pressure.

In the final assembly phase, the machines take up a large area of Schirmer’s floorspace, so processes have to run quickly to make room for the next systems. Martinschledde notes that the upstream processes – particularly electrical installation and partial commissioning – significantly reduce downtime and increase space efficiency. This allows Schirmer to assemble, inspect, and deliver more systems in the same area.

As a machine-builder which exports 75% of its output, a universal automation system is another important aspect for Schirmer. Previously, it had to consider the installation location during electrical planning and material procurement, but the new machines can be used worldwide without needing time-consuming modifications because the MX System is IEC-, UL- and CSA-compliant. This is unlike conventional control cabinets, and is helping Schirmer to increase its levels of standardisation.

The cabinet-free automation technology also offers potential benefits for end-users, including improved accessibility to their machine structures, and space-saving due to the elimination of the cabinets. Production facilities can be located closer together on the shop floor, optimising space without, for example, violating escape route requirements.

A ten-fold reduction in the number of components needed also reduces the size of spare parts stores. Beckhoff is launching a diagnostics app for the MX-System that will make it easier for maintenance personnel to find and rectify faults. “The end-to-end pluggability and the use of the diagnostic app as a replacement for the multimeter means that specially trained electricians are not required to connect or replace the MX System modules,” explains Beckhoff product manager, Daniel Siegenbrink.

Schirmer’s adoption of the cabinet-free system has resulted in significant advantages and optimisations across its process chain. For example, the electrical planning workload has been cut by around 50%, with the usual two to three weeks of assembly time cut to just a few hours. Ludger Martinschledde also expects a significant reduction in downtime at the final assembly stage.

The new machine was presented for the first time earlier this year at the window industry’s Fensterbau Frontale trade fair.

Martinschledde believes that the technology will lead to a new era of control cabinet-free automation. The cabinet-free approach “is changing the face of design and installation in the world of machine-building,” he argues. “We are fully on-board with transitioning our machines to control cabinet-free automation with the MX-System, and this will also apply to the product lines for aluminium and steel profiles in the future.”