Hardening is a standard heat-treatment process used to strengthen the mechanical properties of parts or materials. It involves heating the product above a transformation temperature for the particular metal or alloy, then rapid cooling that causes the softened material to convert to a harder and stronger state. The cooling (quenching) step is done in the air or by quenching the part in oil, water, or another liquid, depending upon the alloy of the material.
After hardening, the materials usually are tempered or stress-relieved to improve dimensional stability and durability.
The furnaces used for hardening processes are frequently expected to remain functional for 20 years or more, which induces stress to the structure and many of its components. Fan blades or pumps, for example, can fail unexpectedly, forcing unplanned downtime and loss of productivity.
SBS Corporation developed the WatchDogg to prevent such breakdowns. It’s a cloud-based monitoring system with up to 12 different sensors that monitor all critical process parameters such as temperature, humidity, or pressure, and all to support predictive maintenance efforts.
All furnace status data is stored in a cloud and can be conveniently accessed from any smartphone, tablet, or PC. This ensures early detection of malfunctions. Plant operators can respond to alerts in time to maximize furnace availability.
“Monitoring crucial system components in hardening furnaces is essential to minimize system failures,” explained Roland Caminades, managing director of Avion Europa GmbH, a European distributor of the monitoring system. “If, for example, the quenching oil is too moist, this can lead to longer cooling times and, if maintenance work is delayed, to fires in the hardening shop. Many of our customers are therefore already using our AquaSense sensor to measure the moisture content of their quenching oils. However, there are significantly more parameters that have an influence on furnace availability.”
WatchDogg was designed to manage the incoming data simultaneously from multiple measuring instruments, continuously.
If there is no worker near the furnace during its operation, sirens or alarm lights may be missed. Because WatchDogg is a cloud-based monitoring system, the collected data is processed in a central processing data and made available via an Ethernet or mobile phone connection. The information is available anytime and anywhere, with advanced warning of malfunctions.
“The choice of measuring processes and sensors depends on the measured parameter,” according to Caminades. “WatchDogg can be connected to completely different sensors to monitor the most important parameters in hardening furnaces, such as pressure, temperature, vibration, flow-rate, or relative humidity.”
Sensors do not necessarily need to be installed in the furnace but can also measure the critical values indirectly. A vibration sensor can be used to detect when a fan blade is no longer running smoothly in the bearing, even though the frequency changes slowly and the cause may not be immediately recognizable. The same applies to pumps and other mechanical components.
Sensors are individually set to the desired tolerance range in advance to provide a timely warning of the imminent malfunction. “As soon as the parameters deviate from the target values, the user receives a message on a computer connected to the cloud and can take immediate countermeasures,” he said. “This makes it possible to plan maintenance for a specific component at an early stage, and the operation can significantly reduce the costs for spare parts inventory.”
For data management, the collected process data is stored in the cloud as milliampere values. The system does not translate the data into a readable message until the signal is transmitted to the defined recipient — ensuring data and system security.
Thanks to its compact design, the cloud-based monitoring system can be mounted on a wall or integrated into an existing control cabinet. “Old furnaces can be easily fitted with the system by an in-house electrician. They will receive all circuit diagrams required to wire up the system and connect the sensors,” Caminades said.
In the basic configuration, the WatchDogg initially contains only the signal translator. However, the system can be expanded, step-by-step with additional sensors as required. In the basic version, this is also possible later on with up to 12 data channels. If required, two systems with a total of 24 data channels also can be combined with each other.