In this third of a series of articles looking at the challenges surrounding machine building, Dan Rossek and Richard Wilkins of Omron examine how safety can be an enabler for increased productivity and reduced total cost of ownership. There are few issues in machine design that are more emotively loaded than safety, and it is
Located in Barcelona, Bagel Systems S.L.L. is a company that designs and sells machinery for the graphics arts sector, particularly industrial laminating machines.
Laminating is the process by which a plastic film is applied to any type of surface. In the specific case of laminating in the graphics arts, the plastic film is applied to paper or paperboard in 90% of all cases. Among the company’s latest developments, one stands out for its innovation. The Digifav laminating machine provides strength, protection and an aesthetically appealing touch and appearance for products such as photo books, book covers, business cards, postcards, posters, packages and even bags. Digifav machines can laminate spreads with weights between 130 g/m2 and 350 g/m2 and have been designed to be used with sheet formats between 200 x 200 mm and 520 x 750 mm.
Laminating consists of using film made of bi-oriented polypropylene, nylon or polyester with an adhesive layer on one of its sides. The adhesive layer is activated by a heat generated device called a calender roller and the pressure applied by a different roller referred to as a counter calender roller, usually made of neoprene or silicon and located right below the thermal roller, against which it exerts pressure.
The equipment consists of three modules:
• feeder module
• main module
• cutting module
The head of the feeding module takes one sheet and transfers it to the intake of the main module, where it is retained by the detection stops. Once the formatting conditions have been applied, the stops and wheels lower, activated by the same piston. The sheet then advances, and the machine feeds in the next sheet.
When the detection stops are lowered, the sheet is inserted and passes through the calender roller and the pressure roller, which are in contact. It is here where the heat causes the plastic to adhere to the surface of the paper, after which it is then transferred to the cutting module.
In the cutting module, the perforated micro wheel makes small holes on the margin of the previously laminated paper. The roller located in this module makes a scissor-like movement, and automatically applies a gentle tug, which is enough to separate the plastic sheet from the continuous laminating roll. The final result is a pile of perfectly separated, individually laminated sheets.
Technical solution: Complete integration of Omron technology
For the manufacturing of Bagel Systems machines, Omron products are used for the control and activation part of the machine, providing quality and reliability as if it were part of the machine itself.
The main difficulty lies in the movement carried out by the feeder module, which is the most sensitive part of the machine and requires maximum precision. The entire machine control system is governed by an Omron CP1E programmable logic controller, whose performance in terms of speed and reliability is more than adequate for this type of application. The machine and the user communicate thanks to an Omron NQ3 human machine interface, which offers a wide range of possibilities to carry out this communications task: function buttons, alarms, displays and more, all implemented on the display itself, meaning a considerable reduction in analogue button devices.
The machine incorporates two JX Series frequency inverters to manage all of the machine positioning. This guarantees maximum precision of movement. The inverters are controlled by the CP1E programmable logic controller, through the digital inputs from the inverter themselves.
The device that heats the plastic, the calender roller, is filled with thermal oil; control is fairly critical, since thermal inertia is responsible for ensuring a precise operating temperature for a perfect laminated finish. For this reason, an Omron E5CN series temperature controller has been used, providing a precision of ±0.1oC to ensure proper thermal control.