Climate Monitoring of Solder Paste Storage

Turck Beierfeld is monitoring the climatic conditions of the solder paste storage with a system from its own company – with IM18-CCM50 control cabinet guards, CMTH condition monitoring sensors and data dashboards via Turck Cloud Solutions

At the Beierfeld site, Turck has now been able to directly implement a recently launched innovation and automate the handling of solder pastes in electronics production. The company in eastern Germany operates an SMT production facility for printed circuit boards, in addition to many other production lines. In the SMT process, solder paste is applied very thinly (<150 micrometers) to the circuit boards with printers. The printed circuit board is then fitted with the components and soldered in the subsequent reflow process.

Climatic conditions of the solder pastes influence quality

To achieve the best possible quality of the solder joint, the solder paste must be stored within a certain temperature range. On average, the paste must only be processed at 23 – 27 degrees Celsius – at a humidity of 40 – 60 percent (depending on the manufacturer). After the printed circuit boards have been printed, no more than eight hours must elapse before the circuit boards are soldered in the oven.

An IM18-CCM50 monitors the temperature and door closure in each of the four refrigerators
Solder pastes are inserted in front of the printer, the CMTH next to it detects the ambient conditions
The CMTH sensor transmits the temperature and humidity values to its IO-Link master via IO-Link
IP67 power supply unit and the IP67 switch provide a cabinet-free connection between sensors and the MES
The graphical dashboard enables to see the status of the refrigerators and the other workstations
The compact TBEN-S IO-Link master brings the sensor’s data into the production network
“Brain” of the system: The Linux-based IM18-CCM bridges the gap between OT and IT

Manual tracking of solder pastes

Together with his team and project manager Linda Galle, Christian Seliger, responsible for the Research and Development business unit at the Beierfeld site, planned and implemented the automated recording and documentation of paste handling. The monitoring of the climate in the refrigerators was implemented with Turck’s IM18-CCM50 condition monitoring system. One of these control cabinet guards with an integrated Linux computer is located in each of the five refrigerators. With their integrated sensors, they detect the distance to the refrigerator door and the temperature in the cabinet. The devices are also able to measure air humidity, but this is not important in this application, since only closed paste containers are in the refrigerators.

The temperature and humidity in the printers, on the other hand, are very relevant, so the CMTH combined temperature-humidity sensor records these variables there. Each of the three stand-alone solder paste printers has one of these condition monitoring sensors, and another sensor records the conditions at the workstation where the pastes are stored for acclimatization. Each CMTH sensor is connected to a compact TBEN-S IO-Link master, which transmits the data to the production network. The TBEN-L5-SE-M2 managed IP67 switch also integrates all IM18-CCM50s into the production network.

With their open Linux operating system, the IM18-CCM50 devices are designed for the installation of OEM software, allowing users to implement their own software solutions. They form the brain of the system, which handles the storage and the communication – with the sensors, the network and the Turck Cloud. To monitor the refrigerators, only network drivers and scripts for collecting sensor data are installed on the condition monitoring platform. The IM18-CCM50 transmits the data of the integrated sensors as well as the CMTH sensors directly via Ethernet to the Turck Cloud.

Clear dashboards in the Turck Cloud display climatic conditions

Today, this first project phase of solder paste tracking is automated to ensure that the temperatures in the refrigerators, at the acclimatization workstation, and in the printers comply with the specifications. The times when the pastes are stored and removed are currently still documented by hand or recorded by scanning the QR codes on the containers. If humidity or temperature increase, this is indicated to the employees on the dashboard in the Turck Cloud. Long-term trends can also be identified in addition to the current values. In future, it would be possible for the MES to be connected to implement trend detection and analyze correlations between data series.

“The condition monitoring solution based on the IM18-CCM that has now been implemented was only the first step on the way to the fully automated monitoring of the storage and use of solder pastes. In the follow-up project, we will connect our MES and thus complete the digitalization and automation of our production. In this way, we can maintain quality at the highest level even when operating at maximum capacity, and avoid unnecessary costs due to overlaid solder pastes,” Christian Seliger sums up.

Outlook: RFID-supported seamless solder paste tracking

In the second expansion stage, the tracking of pastes will be implemented directly with RFID tags on each container, which at the same time enables the recording of correct acclimatization before opening the containers. Since the IM18-CCM devices then communicate directly with the MES, which controls the production orders for the printers, the system can immediately check whether the paste container used has been correctly stored and acclimatized before the PCBs are printed, or block use if the required conditions have not be maintained. If all data is available in the MES, further information could also be obtained from it, for example, to uncover weak points and sources of errors.

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