Smart safety delivers flexibility and productivity in automated thermostat housing manufacture

As manufacturers continue to pursue higher productivity, greater traceability and improved operational efficiency, machine safety has become a critical element of automation projects. Increasingly, safety systems are expected not only to protect personnel but also to support uptime and production continuity.

The objective for the thermostat housing manufacturer was to increase production efficiency while maintaining stringent quality standards and implementing a safety system that supports uninterrupted production. The requirement was for a modular architecture that would allow operators and maintenance personnel to intervene in individual sections of the line without bringing the entire system to a standstill.

Achieving this balance between safety and availability represented one of the key engineering challenges of the project.

A highly automated manufacturing process

The completed production line measures approximately 14 metres in length and incorporates 16 workstations organised into five functional production zones. While the process is largely automated, operators remain involved at key stages, namely component loading and final product handling.

With an average cycle time of approximately 35 seconds per part, the system delivers high-volume production while maintaining comprehensive quality control throughout the process.

Zone 1: loading and pre-assembly - The process begins with the manual loading of components into a roto-friction welding station. Following gasket insertion, the assembly is transferred onto a pallet and enters the production flow.

This area is protected by safety light curtains and interlocked access guards, enabling operators to work safely during loading operations while maintaining protection throughout automatic machine operation.

Zone 2: automatic assembly - In the assembly section, components such as springs, bulbs, sensors, seals and forks are automatically fed and assembled into the product.

Integrated quality checks ensure assembly integrity throughout the process. Importantly, any localised component jam only affects the relevant section of the line rather than bringing the entire process to a halt, helping maintain overall productivity.

Zone 3: testing and traceability - The assembled units undergo a comprehensive sequence of inspections, including pneumatic leak testing, electrical verification and continuity checks.

Approved products are then laser marked to provide full traceability throughout the product lifecycle.

Zone 4: intelligent sorting - The system automatically separates conforming and non-conforming products. Rejected parts are categorised according to the root cause of failure, whether arising from assembly issues, electrical faults or testing errors.

Zone 5: final inspection and packing - At the final station, operators verify product completeness, read the Data Matrix code and fit protective caps before the components are prepared for shipment.

Independent zone operation minimises downtime

One of the defining characteristics of the line is its zone-based architecture. Each production zone can operate independently, allowing maintenance work or fault recovery to be carried out in a specific area without interrupting the remainder of the process. This significantly reduces downtime and improves Overall Equipment Effectiveness (OEE).

Pneumatic power is supplied locally via dedicated air handling units (AHUs), while a central AHU in the main control cabinet distributes filtered compressed air at a constant pressure of 6 bar throughout the installation.

To ensure personnel safety, every workstation incorporates a combination of protective measures, including:

- Emergency stop circuits providing Category 0 machine shutdown and pneumatic isolation.

- Fixed guards protecting areas requiring infrequent maintenance access.

- Interlocked movable guards equipped with electromagnetic safety switches.

- Safety light curtains creating an invisible protective barrier around hazardous zones.

Together, these measures provide comprehensive protection while enabling rapid intervention when required.

Defining the safety requirements

Given the scale and complexity of the installation, several key safety objectives were established:

- Independent management of all five production zones.

- Continuous monitoring of emergency stops, guard switches, interlocks and safety light curtains.

- Safe electrical and pneumatic isolation within individual sections of the line.

- Expandability for future machine developments through scalable safety I/O.

- Reduced wiring complexity and simplified programming.

Each zone required dedicated safety inputs and outputs, local diagnostics capability and, in some areas, additional functionality for robot integration.

ReeR MOSAIC provides the safety platform

To meet these requirements, the machine was equipped with the ReeR MOSAIC modular safety controller platform.

At the centre of the system is the MOSAIC M1S COM controller, featuring: eight digital safety inputs; two pairs of OSSD safety outputs; four test outputs; and dual RJ45 communication ports supporting EtherCAT, PROFINET, EtherNet/IP and Modbus TCP. The modular architecture allowed the safety system to be precisely tailored to the application's needs.

Distributed safety control

Additional MOSAIC modules were deployed throughout the installation, including: MI16 and MI8 modules for collecting signals from emergency stops, interlocks and safety light curtains; MO4 modules for controlling safety outputs connected to actuators, pneumatic valves and isolation devices; and MCT1 and MCT2 communication modules for linking distributed safety stations via the MSC bus.

This distributed architecture enables safe, selective control of each production zone while maintaining comprehensive diagnostics and system visibility.

In practice, operators can isolate and access a specific area of the line without shutting down the entire installation. Maintenance activities and fault recovery can therefore be completed more efficiently, reducing production losses while maintaining compliance with machine safety requirements.

Safety as a productivity enabler

This application demonstrates how modern safety technology can contribute directly to manufacturing performance. By combining modular machine architecture with distributed safety control, the installation achieves a balance between operator protection, machine availability and production efficiency.

As manufacturers increasingly seek to maximise uptime while maintaining the highest safety standards, projects such as this highlight an important principle of modern automation: effective safety systems are no longer simply a compliance requirement; they are a key contributor to productivity, flexibility and operational excellence.