Drying systems and subsequent processes after electroplating are energy-, time- and cost-intensive. The manufacturer of high-precision deep-drawn parts and innovative forming solutions STÜKEN, based in Rinteln, Germany, wanted to significantly optimise all three parameters – and automate the entire subsequent process after surface treatment. Our solution lay in the combination of centrifuge drying and heat pump technology – and in the additional implementation of a highly efficient and complex solution for reloading the dried parts into different container sizes.
Objective 1 of surface treatment: Saving energy and drying in the low temperature range
STÜKEN has been using WMV centrifuges as drying systems since 1990. “In the previous stand-alone solutions, the wet parts that came out of the electroplating process had to be manually transferred for subsequent surface treatment,” explains WMV project manager Sascha Meuser. He was in charge of the project right from the start. “The treated components were then dried with a lot of heat for around half an hour. The parts were too hot for packaging. They had to be stored for a while to cool down.”
STÜKEN wanted to automate and speed up this complex process. Energy savings were the top priority. This was closely followed by the desire for drying in the low temperature range. The ideal temperature for the parts after drying in the drying system should be between 37 and 42 degrees. “This should ensure that no more condensation forms on the packaged parts,” says Meuser.
Combining centrifuge and heat pump technology for maximum efficiency
“Our initial tests based purely on centrifuge technology were not effective,” recalls the project manager, who has been on board at WMV since 2015. “The drying process, as an essential part of the surface treatment, required sufficient volume flow, which we could only manage using complicated pipework with additional fans.” The solution: optimising the drying process using heat pump technology from the dryer manufacturer Harter.
STÜKEN already had experience with energy-saving heat pump drying from Harter. We also had previous experience with the dryer manufacturer. So, we suggested to STÜKEN that they dry with heat pumps in the low-temperature range. “In our in-house Research & Development Center, we tested the STÜKEN components extensively and continuously with an Airgenex heat pump module from Harter,” says Meuser. By the end of commissioning, we were able to successfully realise the desired drying parameters in the new drying system: Thanks to the targeted air flow, the entire range of parts from STÜKEN – right down to micro parts – can be dried homogeneously. In addition, a humidity sensor ensures that the humidity values remain within the desired range to guarantee efficient, even, and gentle drying of the material.
The new STÜKEN drying system fulfils all performance requirements
Three new swivel centrifuges with a new dual system have been installed in the new drying system. The function is unique on the market. It combines dry, energy-saving air from the heat pump module and enables complicated parts to be dried with an additional heating module. A continuously adjustable EC air circulation fan on each centrifuge housing ensures optimum air circulation.
The new drying system is optimised for the throughput of 2 electroplating lines:
- Each swivel centrifuge can be adapted to the range of parts
- Speed, angle of inclination and circulation intervals are automatically adjusted to the part geometry via PLC control
- Condensation drying takes place in the low temperature range of 50°C
- Saves 50% of the drying time
- Approx. 12.5 KW nominal power of the drying system in production operation enables energy savings of approx. 75%
- Process monitoring via humidity sensor
Objective 2 of surface treatment: Filling the complex range of parts into the correct containers
The task was to dedicate five different container sizes and therefore also different numbers of containers per half pallet to the respective batches in the correct sequence and to palletise them at the same time.
We were able to overcome this challenge in collaboration with AMT Automatisierungstechnik GmbH, and the whole thing was given a logic via the SAP interface and the master computer system.
“As a team, we managed to solve the complex manual refilling process and convert it into an automated process. The very first trial with STÜKEN in our production was a success,” recalls Meuser.
A fully automated solution and relief for employees
The pilot project combining centrifuge and heat pump drying developed into an almost fully automated solution. The higher-level master computer visualises and logs whether the actual values are achieved at each step. A barcode scanner is also used to ensure that each batch is filled into the correct container. “This also makes it easier for the employees who are responsible for the subsequent processes,” explains Meuser.
Only the transfer process from the electroplating basket to the centrifuge basket is manual. “We can’t automate this process for purely structural reasons,” says Meuser, ” there’s simply not enough space.”
Quote Stüken
“The cost of energy for the manufacturing industry in Germany has increased significantly in the recent past. Another major challenge is diversification in rapidly changing global markets such as electromobility. STÜKEN is currently working purposefully on these and other transformations towards a Production System 4.0. Last year, we took another important step towards energy efficiency and flexible automation with the new drying system from WMV.”
