Improving the speed and efficiency of a can-packaging line

Bimetec, a Dutch company, traditionally specialised in mechanisation and control automation for the agricultural industry. Although they also offer machine renovations, repairs and maintenance, Bimetec focuses on new construction and innovation projects. Recently, Bimetec completely renovated two mechanical can-packaging machines at Bakker Brothers Seed. These canning lines consist of four activities: seed weighing, canning, check weighing, and labelling.

Two points on the line were specifically targeted for the renovation. First, Bimetec designed a new control cabinet for the check weighing station, where cans weight are verified before they are labelled. They installed a programmable logic controller (PLC) had to meet several requirements.

The control cabinet required a large touchscreen to enable the machine operator to easily and efficiently access the necessary menus and operations. For motion and frequency control, the PLC needed sufficient communication ports, including Ethernet, serial and CANbus. Furthermore, the PLC needed to be able to connect to both local and remote inputs and outputs. Secondly, Bimetec wanted to add a separate PLC to the labelling machine, so that it could be operated independently of the main system.

Influenced by prior experience Unitronics, Bimetec selected the Unitronics Vision1210 as the primary PLC. It not only met the requirements, but was also competitively priced. For the second, smaller PLC on the labelling machine, Bimetec choose a Unitronics SAMBA PLC with a 4.3-inch colour-touch HMI panel. Both PLCs are programmed in one, single-environment software package, an important cost saving advantage. A spokesperson from Bimetec stated: "Bimetec selected the Unitronics Vision1210 not only because it met a wide set of requirements, but was also favourably priced."

The Vision1210 controls the canning line; cans are led to a filling unit through carousel platform with the weighing and filling station installed overhead. A buffer, mounted above the station, fills the can with seeds. In order to meet the high production speed, Bimetec installed two filling stations; while one unit is being filled, the second unit is brought to the correct weight. Each filling unit has a Unitronics load cell module and the measurements from those modules are connected directly to the load cell strain gauge converter on the controller; the high sample rate of this converter enables efficient filling. Once the weight is confirmed, the cover is installed on the filled can before it moves to the labelling station.

The labelling station has a stand-alone PLC with touchscreen, the Unitronics SAMBA. Having a second touchscreen was a practical advantage, as the operator does not have to walk to the main panel every time they need to adjust a setting, saving time and effort. The label is attached and then the can's weight is checked again. If the weight is correct, then the can moves on to be packaged.

Bimetec designed the canning line so that it is possible to switch between the various types of seeds, can sizes, and types of label simply for increased flexibility. Using the touchscreen interface, the speeds of the conveyors and the filling weights can also be set. With the help of these improvements, the new canning line can now reach a speed of 750 cans per hour!

For more information about products including the Unitronics Vision1210 and 4.3-inch Samba PLC, please visit www.unitronics.com.