For a producer of medical devices we realised an automation for clamping stretchable elements. In the original situation, the products were stretched onto the mould by hand. This manual process takes a lot of effort, requires training and a high degree of precision.
The wish for automation was deposited with STT. The challenge was to position the product on moulds as consistently as possible, while taking into account contamination of the product and the limited available production space at the customer’s site.
In a pre-engineering phase we looked into the best clamping method. Through an iterative process different clamping methods with 3D printed models were tested. Ultimately, the best concept was converted into a final design, which was later reused in the completed production machine.
The machine is placed in an STT Universal Cell. The cell can be opened from three sides and has integrated safety features, such as lockable doors and secure hoods. During production, the cell can be approached from two sides. With the moulds being imported and exported on one side and the product containers being processed on the other side.
The production machine can process a variety of products – of which the outer dimensions and ways of clamping differ. By selecting a ‘recipe’, the correct parameters are loaded. The operator then places a product on a special container and these are transported on a conveyor belt into the machine. The machine checks the type and orientation of the container, which minimises human error.
The scara robot, equipped with a special gripper, takes the product from the container and positions it on the central tensioner. The tensioner stretches the product after which the mould is pushed into the product from below. The product is then released from the tensioner and it retracts. The product is now correctly clamped and put back on an indexing table. Subsequently, the mould is checked for presence of the product. The status of the mould is recorded in the system, and the mould and product are transported to the output line where they can be removed by the operator.
This automation has reduced the cycle time for certain products by half and, due to the lack of human input, produces a very consistent result. With this machine, the customer has an ergonomic solution to increase their productivity.