ADAMSON UNIVERSITYCollege of EngineeringMechanical Engineering
Department
ME ELECTIVE 3
Exercise No. 1CUTTING DEVICE
Villanueva, Christian Meguel C._______________________________
201113338 .
Section57034
Date of SubmissionJuly 21, 2015
Engr. Arnaldo D. ValinoInstructorI15%
P15%
DOR15%
SOA15%
C10%
F/N10%
PDS20%
Score100%
ProblemUsing a cutting device, sheets of papers are to be cut to
size. By pressing two pushbutton switches, the cutting blade is
advanced and the sheet of paper is cut. After releasing one
pushbutton switch, the cutting blade is returned to its start
position.
Objectives
At the end of this exercise, the students are expected to:1.
Draw and design the pneumatic and electric circuit diagram for the
cutting device.2. Carry out the pneumatic and electric circuit
diagram construction.3. Examine the principle of the indirect
actuation with AND-function of input signal.
IntroductionPneumatics has been playing an important role as a
technology in performing mechanical work for so long. It is also
useful in the development of automation solutions. In the
automation and operation of such machineries and installations,
generally complex logic interconnections and switching systems are
used as control. The controls systems are made up of interaction
among the processors, sensors, control elements, and actuators that
could be in pneumatic or partly pneumatic systems. Technological
advancements in the design, materials and manufacturing processes
have made their way to further improve the quality and variations
of pneumatic components and thereby contributed to their widely
spread use in automation. And in this exercise, the students were
able to use a quite simple switching system in the operations of
such indirect actuation of a double-acting cylinder with
AND-function of input signal.
Procedure
1. First step: Make a circuit diagram of the indirect actuation
of the pneumatic system. In this exercise, AND-function is used as
an input signal. It will be shown in the Preliminary Data Sheet
section.2. Second step: Plot the circuit diagram into the Festo
Fluidsim software in a pc. Then after plotting the diagram,
simulate to verify the effectiveness of the diagram or if its
functioning the way it should be. Make sure all the connections are
correctly place and that the symbols or components are correct. It
will be shown in the next section.3. Third step: After testing
plotted and simulated diagram using Festo Fluidsim, thats the time
when it could be actuated in the pneumatic training workbench. In
this exercise, interconnections between two pushbuttons, two relay
valves and 5/2 way valve with solenoid (spring-returned) are used
which will be shown in the next section too.4. Fourth step: After
securing all connections, perform the task that was mentioned in
the problem.
Setup of the Apparatus
Fig 1: Festo FluidSim Simulation
Fig. 2: Actual indirect actuation of a double-acting cylinder
with AND-function of input signal
DiscussionPneumatic control systems can be designed in the form
of pneumatic circuits like that of the one performed in this
exercise. A pneumatic circuit is formed by various pneumatic
components, such as cylinders, directional control valves, flow
control valves, etc. just like those that are used in the entire
exercise.
A pneumatic circuit diagram uses pneumatic symbols to describe
its design. Some basic rules must be followed when drawing
pneumatic diagrams. And these are the basic rules:1. A pneumatic
circuit diagram represents the circuit in static form and assumes
there is no supply of pressure. The placement of the pneumatic
components on the circuit also follows this assumption.2. The
pneumatic symbol of a directional control valve is formed by one or
more squares. The inlet and exhaust are drawn underneath the
square, while the outlet is drawn on the top.Each function of the
valve (the position of the valve) shall be represented by a square.
If there are two or more functions, the squares should be arranged
horizontally (Fig. 3.1 & 3.2).
Fig. 3.1: 3/2 directional control valve (normally closed
type)
Fig. 3.2: 3/2 directional control valve (normally closed
type)
3. Arrows "" are used to indicate the flow direction of air
current. If the external port is not connected to the internal
parts, the symbol is used. The symbol underneath the square
represents the air input, while the symbol represents the exhaust.
Fig. 3.1 & 3.2 shows an example of a typical pneumatic valve.4.
The pneumatic symbols of operational components should be drawn on
the outside of the squares. They can be divided into two classes:
mechanical and manual.5. Pneumatic operation signal pressure lines
should be drawn on one side of the squares, while triangles are
used to represent the direction of air flow (Fig. 4)
Fig 4: Pneumatic operation signal pressure line
AND FunctionAnother name for an AND function is interlock
control. This means control is possible only when two conditions
are satisfied. A classic example is a pneumatic system that works
only when its safety door is closed and its manual control valve is
operated. The flow passage will open only when both control valves
are operated. The circuit diagram of the AND function that was used
in this exercise was shown in the Setup of the Apparatus and
Preliminary Data Sheet sections.
ConclusionPneumatics plays a very essential role in the
automation processes in the different fields today and also in the
development of such technologies that calls for the application of
pneumatic systems in the operation such as manufacturing companies
and other fields specializing in mechanical operations. However,
there are advantages and disadvantages in using pneumatics in such
operations. Air is practically available everywhere in unlimited
quantities so that really matters if one is considering the
availability for the usage of pneumatics. Also, compressed air is
relatively insensitive to temperature changes. This ensures that
reliability of pneumatics in the operation, even under extreme
conditions. And also, the ease of operation and the safety of using
pneumatic systems are really evident in this exercise. And so its
no surprise why pneumatics is very widely-used from most of major
industries down to small enterprises. On the other hand, there were
some few noticeable down side in using this as it was observed in
the course of the exercise. Firstly, the noise level is quite
disturbing. The noise from exhaust air is loud. Hence, silencers or
noise reduction equipment and hearing protection is recommended
during operation. And also the preparation of such compressed air
is quite delicate and requires due care; dirt and condensate should
not be present. Anyway, the overall use of pneumatics is quite good
for all applications. Its versatility, safety and ease of operation
makes it a very good option when choosing for a control system for
vast applications. Overall, the advantages of using pneumatics are
more justifiable and made more weight than that of its
disadvantages.
References:
https://en.wikipedia.org/wiki/Pneumatics
http://www.pneumadyne.com/
https://www.fer.unizg.hr/_download/repository/PNEUMATIKA_labs_Festo_eng.pdf
https://resources.hkedcity.net/res_files/201101/20110128101153_259037.pdf
