IMSTec’s fully automated weight determination system targets weighing applications in particular for medical devices such as orthopaedic implants. The key component of the weighing system is a high-precision balance. The balance is suitable for remote control in an automated system environment. For enhanced stability and accuracy the weighing system comprises means for vibration isolation.

The vibration isolation consists of a base plate made of granite which is placed on 4 damping elements. For protection of the balance against surrounded air flow and additional environmental influences the weighing system is contained in a compartment. The load/unload of parts to/from the balance is accomplished by a robot system. An overload protection device avoids mechanical damage of the balance.
For design and protection purposes the Weighing Station base module is enclosed with a construction made of bended and bolted sheet metal profiles covered with powder-coating. Depending on clean room class or request, all covers can be provided in stainless steel Station sides and windows have unmovable transparent Polycarbonate windows (Makrolon) allowing the view to the process area.

As part of a fully automated system parts are load- & unloaded in the weighing station by a robot.  To ensure a save transfer and process application parts are screwed on a transfer fixture equipped with an RFID tag used for part traceability through the process. The overload protection mechanism prevents potential overload burden during robotic load/unload operations.

During the load process the bracket is in its upper position. The product is placed on the centring fixture. After the robot is retracted the compartment sliding door is closed and the bracket slide moves down to its lower position in order to release the product for the weighing procedure (see Figure 1). After weighing is completed, the bracket is moved back to the upper position and the unload process takes place. A presence sensor ensures correct part position.

For quality control the weighing system is monitored on a regular basis (frequency of monitoring to be specified by corresponding recipe) or at request via HMI panel. For monitoring two special monitoring weight samples are used which cover the full measurement range.  The monitoring weight samples are stored in a closed compartment in order to protect them against environment impact such as contamination. Process sequence, parts disposition and data management is executed by the LAS & PLC station software.