Hydraulics and pneumatics
Complex Engineering Problem
Submitted by: Tasawur Ali
Registration No.: 2018-MC-262
Section: B
UNIVERSITY OF ENGINEERING AND TECHNOLOGY
LAHORE, FSD CAMPUS
Task Title:
In an industrial process a pneumatic based stamping machine is used to make a stamp on the objects. The
machine uses two cylinders one for clamping of the object and other to make stamp. The process is
performed in a sequence that the clamping cylinder (A) extends and clamp the object, the stamping
cylinder (B) extends and make a stamp on the object and retracts to its original position again the
stamping cylinder hits the object and make another stamp on it. At last, clamping cylinder retracts and
release the object. Thus the sequence performed by the process can be given by A+B +B -B +B -A -
Sequence:
A+B +B -B +B -A –
We have to make a sequencing circuit for this sequence.
Problem:
We cannot use two sensor at the same label with the same label. It results in trapped signal also fluid sim
software does not allow us to use two sensors with the same label.
Solution:
To overcome this problem, we use logic valve like AND, OR gates as shown in figure,
First of all will make the circuit for this,
Explanation:
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There are about 4 groups in the sequence i.e. A+B+,B-,B+,B-ATwo double acting cylinders which are controlled by a 5/2 valve with each cylinder.
The circuit has 4 pressure lines and each will be connect with the specific valve.
As there are three groups in the sequence so three valve will be used here.
These will be names as 1, 2, 3.
First of all connect the valve 1 and 2 with the 4 pressure line it is because when we attach the
compressor with the first valve.
Attach direct output to the pressure line 4 so from that pressure will be drawn on valve 2 and 3.
The other two inputs of valve will be connected to the pressure line 1 and 2 so that the output of
these two lines will be input of the other valve and so on. So all three valve will be connected with
each other.
Now we will connect the valve 1 with a push button valve that have AND gate. It means that
when both inputs will be 1 then valve I will be active otherwise not.
As first of all we have to retract cylinder A- so we will actuate the push button valve and actuate it
A-. When we push the button then a signal will generate and valve1 will active and this will
retract the cylinder to A- position.
When cylinder is retracted then we will extend the cylinder A+. We will do it by adding a 3/2
valve attach with the 5/2 valve to cylinder B and actuate it by giving the name A+. This will
extend the valve A+.
Now the cylinder is in extended state and we have to extend the second cylinder to B+ position so
we will add an actuator and signal it to b+ and connect it with the second pressure line. It is extend
the cylinder B+.
Other sequence is that we will retract the extended cylinder b+. For this purpose we have to add
an actuator with the valve 3 and give it a signal B- and attach with the pressure line 4. This will
active the B- and it will retract the extended cylinder.
Now there is a last group in which we have to retract the extended cylinder again. For this purpose
we add a double signal valve with the B- actuator which will again retract the cylinder as we did
with the B+ cylinder. So when the cylinder is retracted then again A- signal will active and it will
retract the A cylinder and the process will continue.
Truth table for And Gate:
Truth table for OR Gate:
Graph:
The graph for the expression will be as the zigzag part is the output for the system.
The zigzag part shows the extension and retraction of the cylinder.