CASE STUDY #7 Tray Loader & Unloader
For Solution Bags

The Challenge

A medical company, which produces saline solution, was looking at automating the process of loading the bags of saline solution onto trays for sterilization and then unloading them from the tray back on to the production line for the subsequent packaging process. The process used to be labor intensive due to the high production volume, requiring several operators, and the trays holding the bags of saline were heavy and difficult to handle.

To meet the customer’s requirements, PSB Tech encountered a few challenges. A key challenge was to have the flexibility of handling different models of the saline bags while ensuring that they were arranged in the desired orientation. Another obstacle was to design the system to fit into the existing tight space. In addition, the system has to handle the wet saline bags after they emerged from the sterilization chamber.

Working closely with the customer’s technical team, PSB Tech was able to resolve the challenges and delivered its first loader and unloader system in 2008. This was followed by a second and third system in 2012 and 2015, which was capable of handling a higher throughput.


  • • Throughput of up to 90 bags/min for bags of various sizes & configurations
  • • Able to arrange the bags of saline in a preferred orientation for optimal sterilization in the sterilizing chamber
  • • Able to lift and stack trays of saline, each weighing at least 100kg with the use of heavy duty robotic arms, thus eliminating the need of human labor
  • • Inline vision system included to ensure that the correct product is handled and loaded in the correct orientation
  • • Robot end effector is designed to handle both individual bag and the tray carrying the bags

The Result

PSB Tech developed a robotic system that were able to achieve what the customer wanted. The tray loader and unloader system transfers & arranges solution bags from production line to customized truck for sterilization. After the sterilization process, it then transfers the sterilized bags back on to the production line for final packaging.

The system enabled the customer to improve its productivity by replacing at least 20 operators over 3 shifts for manual handling of the bags. At the same time, as the system was able to ensure the bags are arranged on the tray in the preferred orientation for sterilization, it also enabled the customer to improve its yield as a result of reduction in number of rejects arising from mishandling of bags by hand.