JAE provides intelligent measurement and correction

It was supplied to Volkswagen for measuring and adjusting prism-section steel connecting rods used in the top storage of a cabriolet. The system ensures that dimensional differences between the mounting points on the chassis and securing points on the top are within tolerance.

Resistance behaviour

Due to the rod's geometry and the process by which it is manufactured, individual rods have differing resistance behaviour. This complicates process automation because it requires the system to respond in different ways depending on the component’s mechanical behaviour. The rods multiply variations introduced by the securing point by 20 to 30, so the mechanical securing process is critical for success. In addition, once the rod is secured, it vibrates at low frequency, which must be filtered out. To complicate matters, the measurement process must be performed without contact, necessitating laser techniques.

The machine comprises two stations that are capable of operating together or individually. A central assembly houses a die to secure the part. Each station is controlled by an Omron  frequency converter and incorporates cradles to support the rod, laser measurement and a linear guide with shaping fork actuated by an Omron servo motor.

When the machine starts, it first moves all elements to the idle position and runs a zero search for the axes. On an Omron touch screen, the operator selects the program, downloads it to an Omron programmable logic controller, and initiates the automatic cycle. The operator then places the rods in the stations, and actuates the start button. The machine performs measurement and shaping and indicates the result using green and red lights.

Advantages of using Omron control devices

The programming and calculation capacity of the programmable logic controller simplified the performance of complex calculations. The use of function blocks with structure language was also a crucial tool in this application. The graphical resources of the touch screen enabled all process parameters and information to be integrated without losing clarity or ease of use.