Module 6 : Pneumatic Systems

Lecture 6 : Applications of Pneumatic Systems

2. Case study B

A plastic component is to be embossed by using a die which is powered by a double acting cylinder. The return of the die is to be effected when the cylinder rod has fully extended to the embossing position and the preset pressure is reached. A roller lever valve is to be used to confirm full extension. The signal for retracting must only be generated when the piston rod has reached the embossing position. The pressure in the piston chamber is indicated by a pressure gauge.

2.1 Components used

The pneumatic components to be used to implement this task are:

2.2 Working

Fig. 6.6.2 Pneumatic circuit for embossing application

The proposed pneumatic circuit diagram for embossing application is shown in fig. 6.6.2. When the push button valve (S1) is pressed, the flow takes place through the valve and a signal is sent to the control port 14 of the direction control valve (V2). The left position of the direction control valve (V2) is switched-on and the flow enters at the piston-end of the cylinder (A). It causes the extension of the cylinder. Even if the push button is released the position of the DCV (V2) will not change due to its memory function. As the piston nears the end position, the roller valve (S2) is actuated and pressure line is connected to the pressure sequence valve (V1). During the embossing process the pressure at the piston-side of the cylinder (A) increases. This increase in pressure is indicated by the pressure regulator (Z1). When the pressure reaches to its pre-set value in the pressure sequence valve (V1), the 3/2 valve of pressure sequence valve switches and the signal is applied to port 12 of the DCV (V2). The right position of the DCV is actuated and the piston retracts. During the retracting movement, the roller valve (S2) is released and the signal at the control port 12 of the DCV (V2) is reset and the pressure sequence valve is also reset.