A-28
Exercise 12
Problem description Two double-acting cylinders (1A) and (2A) press together two electrically
heated bars and, in doing so, join two thermoplastic sheets by welding.
The thickness of the sheets varies between 1.5 mm and 4 mm. The
seams may be of any length. The piston force of both cylinders is limited
via a pressure regulator. Value set p = 4 bar (=400 kPa).
By actuating a push button, two double-acting cylinders are made to
advance in parallel with their exhaust air restricted. To assist regulation,
pressure gauges have been fitted between the cylinders and the one-
way flow control valves. The end positions of the cylinders are interro-
gated.
After a time of t = 1.5 seconds, the bar moves back to the initial position.
The return stroke may be instantly initiated by means of a second push
button.
Abbreviated notation 1A+
1A–
2A+ 2A–
Fig. 12/1: Positional sketch
2A
1A
TP101 • Festo Didactic
C-51
Solution 12
Welding machine for thermoplastics Fig. 12/2: Circuit diagram
1A 1S1 1S2 2A 2S1 2S2
1Z 2Z
1V2 2V2
1V1 2V1
0V4
0V5
0V1 0V3
0V2
2S1
2S2
0S1 1S1 0S2 1S2
TP101 • Festo Didactic
C-52
Solution 12
There are three roller lever valves in the set of equipment of “Basic level
TP101". For building the circuit shown, four roller lever valves are
needed. As an expedient, roller lever valve (2S2), for example, could be
omitted..
Fig. 12/3: Displacement-
step diagram 0S1
1 2 3=1
1 1S2
1A
0
1S1
0V2
t
1 2S2
2A
0
2S1
C-53
Solution 12
Initial position Solution description
In the initial position, both cylinders (1A) and (2A) assume the retracted
end position. The roller lever valves (1S1) and (2S1) are actuated. Final
control elements (1V1) and (2V1) and directional control valve (0V4) are
in the left-hand switching position.
Step 1-2
When push button (0S1) is operated, first directional control valve (0V4)
and then final control elements (1V1) and (2V1) are reversed. Both cyl-
inders advance with their exhaust air restricted. In the forward end posi-
tion, roller lever valves (1S2) and (2S2) are actuated. The cylinders
remain in the forward end position. The pilot port of time delay valve
(0V2) is pressurised via the two roller lever valves (1S2) and (2S2). The
valve is required to switch when a time lag of t =1.5 seconds has
elapsed.
Step 2-3
After the time delay valve (0V2) has switched through, the three identical
5/2-way double pilot (bi-stable) valves reverse. The cylinders move into
the retracted position and there again actuate the roller lever valves
(1S1) and (2S1).
Push button (0S2)
If 3/2-way valve (0S2) is operated, the three identical 5/2-way double
pilot (bi-stable) valves(1V1), (2V1) and (0V4) are reversed; the cylinders
return to the retracted end position.
TP101 • Festo Didactic
C-54
Solution 12
Fig. 12/4: Circuit design 1A 2A
1S1 1S2 2S1 2S2
1Z 2Z
1V2 2V2
1V1 4 2 2V1 4 2
14 14 12
5 1 3 5 1 3
0V5
0V4
4 2
14 12
0V1 5 1 3 0V3
2
0V2
12
1 3
2 2S1
2S2 2
1 3
1 3
0S1
2 2 1S1 0S2 2 1S2 2
1 3 1 3 1 3 1 3
TP101 • Festo Didactic
Republic of the Philippines
CAMARINES SUR POLYTECHNIC COLLEGES
Nabua, Camarines Sur
C-55
Solution 12
There are 3 roller lever valves in the set of equipment for “Basic level
TP101". To build to the circuit diagram shown, you need four roller lever
valves. As an expedient, roller lever valve (2S2), for example, may be
omitted.
The components – service unit with on-off valve (0Z1) and manifold (0Z2)
are no longer shown..
Components Description Components list
0S1 3/2-way valve with push button, normally closed
0S2 3/2-way valve with push button, normally closed
0V1 Dual pressure valve
0V2 Time delay valve, normally closed
0V3 Shuttle valve
0V4 5/2-way double-pilot valve
0V5 Pressure regulator with pressure gauge
0Z1 Service unit with on-off valve
0Z2 Manifold
1A Double-acting cylinder
1S1 3/2-way roller lever valve, normally closed
1S2 3/2-way roller lever valve, normally closed
1V1 5/2-way double pilot valve
1V2 One-way flow control valve
1Z Pressure gauge
2A Double-acting cylinder
2S1 3/2-way roller lever valve, normally closed
2S2 3/2-way roller lever valve, normally closed
2V1 5/2-way double pilot valve
2V2 One-way flow control valve
2Z Pressure gauge
Reduce the pressure from the pressure regulator (0V5) in steps of p = Follow up
1 bar (= 100 kPa). Observe the behaviour of the cylinders and the
readings on the pressure gauges.
Regarding the note on the opposite page: Replace the fourth roller lever
valve (2S2) by a roller lever valve with idle return. Investigate the
behaviour of the control system with different settings of one-way flow
control valves (1V2) and (2V2).
TP101 • Festo Didactic
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