TECHNICAL DESCRIPTION
FMS-200
FLEXIBLE AUTOMATED CELL
TRAINER
1 TECHNICAL AND FUNCTIONAL DESCRIPTION
From SMC, a world leader in Pneumatics, we introduce SMC International
Training. Our clear and wholehearted international vocation defines the objectives of this
company: the conception and marketing of training systems in the automation field to
satisfy the training needs of educative centres and companies all over the world .
An example of a Comprehensive Training System developed within the framework of this
project, constitutes the Flexible Assembly System FMS-200.
Figure 1: Flexible Automated Cell Trainer FMS-200
The flexible automation cell has been specially conceived for persons to acquire
professional capabilities in connection with the Occupational Groupings of Electricity/
Electronics and Maintenance, such as:
-
Installation, Electromechanical Maintenance and Line Transport.
Industrial Equipment Maintenance.
Automatic Control and Regulation Systems.
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It enables the development of various skills associated with pneumatic, electropneumatic, electrical, robotic and handling automatisms, programming and PLC
technologies, industrial communications, supervision, quality control and fault diagnosis
and repair. It also allows the study of a wide range of sensor types:
-
Magnetic detectors.
Inductive detectors.
Hall detectors.
Photoelectric detectors.
Reed detectors.
Photochromatic detectors.
Capacitive detectors.
Linear encoders.
Etc.
The system comprises a flexible automation cell which carries out an assembly
process involving a number of predetermined parts with a total of 24 different possibilities.
Figure 2: Turning mechanism
Figure 3: Turning mechanism components
Parts are transported between the different stations or layouts by an automated 4metre transfer line with corresponding stoppers and precision lifters-positioners. Parts are
mounted on pallets with a magnetic coding system.
The process stations or layouts function either independently of the transport
system, or integrated into it. The stations are situated around the transfer, and may be
withdrawn for re- positioning in a different order, moved for future extensions or work
in a completely independent and self-sufficient mode.
Each station has its own electrical panel, where the wiring system and PLC are fully
visible for study, while new elements may be fitted to the panel if desired. This electrical
control panel may be made entirely independent at each station for use in programmable
PLC training. In addition, students may design and build their own controls with different
PLCs and subsequently integrate them in the station, thereby developing a further series
of skills envisaged in the Training Cycles for those persons who form the target group for
the Cell.
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The front of each station incorporates the start, stop, and single and
continuous cycle pushbuttons.
The system is modular and may be extended, allowing future incorporation of other
process stations according to user needs.
The stations are mounted on aluminium sections, forming tables with a large
surface area and multiple slots to allow all types of extension and modification.
The assembly process performed (turning mechanism) is as follows:
Layout A: Feed body to which the other parts are assembled.
Layout B: Pick and Place bearing.
Layout C: Press bearing in hydraulically.
Layout D: Pick and Place shaft, and verify.
Layout E: Pick and Place cover.
Layout F: Fit screws.
Layout G: Robot screw driving.
Layout H: Unloading, storage and palletization of final assembly.
1.1 PLC WITH NETWORK COMMUNICATIONS SYSTEM.
The standard layout includes a PLC panel-mounted via a DIN track.
The PLC has inputs and outputs, timed and programmed interrupts, internal PID,
high-speed counters, etc. It incorporates a port for programming, and a port for
communication with other PLCs or PCs.
The PLCs which govern the cell stations communicate with each other via a
network, so that each station comes ready with the necessary adapter and
communications module.
1.2 PLC PROGRAMMING SOFTWARE (OPTIONAL)
This software enables programming of instructions and contact diagrams for all
standard PLCs in any desired layout. It allows ON LINE contact diagram monitoring
and modification. There are options to generate listings with comments, data reports and
memory listings. It incorporates help advice in all functions. The software includes
an operating manual and works under the Windows environment.
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2 PROCESS STATIONS
2.1 BODY FEED-POSITIONING
2.1.1 STATION FUNCTION
This first station feeds in the body which is the support for the turning mechanism,
and moves it to the pallet located in the transfer system.
This operation begins when the pallet is opposite the station, held in a determined
location by a stop on the transfer. Confirmation tha t the pallet is in the correct position is
provided by a microswitch which sends the appropriate signal to the PLC.
2.1.2 INTEGRAL PARTS
Station 1, like the others, may be divided into a series of modules. Each subdivision has been made by considering it as a set of components which performs a
specific operation within the process completed at the station. Starting out from this
consideration, a description is given below of the ordered sequence of actions performed
for assembly of the body, indicating the components involved in each operation.
- Body feed:
The feeder which supplies the body is of the
gravity feed type, in that the bodies are
stored in a stack so that when the bottom
one is removed, the next falls into place under
the effect of its own weight and that of the ones
above it.
The body is extracted by a pneumatic cylinder
which pushes against a pusher shaped to
match the profile of the
body.
An inductive sensor is used to detect no material
in the store.
Figure 4: Body-feed positioning
- Position verification:
The body contains a housing in which the other components are fitted. This housing must
always be facing upwards when the base is placed on the pallet. To check correct body
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orientation, a check is made by a cylinder which advances and inserts a cylindrical
part in the body housing. If the body is inverted, this part cannot enter the housing, the
cylinder cannot complete its stroke and the magnetic detector on the cylinder is not
activated.
A signal to this effect enters the PLC, resulting in an indication that the position of the body
is incorrect.
- Movement to transfer point:
A cylinder with a pusher at its end is used to situate the body at the point from which it is
loaded onto the pallet.
The cylinder is rectangular, to prevent the pusher from turning.
- Rejection of incorrect body:
If the verification process shows the position of the body to be incorrect, a single -acting
cylinder moves it towards a ramp, leaving the space clear for a new body.
- Placing body on pallet:
A two-axis manipulator is used to place the body
on the pallet lying on the belt conveyor.
Each axis carries a parallel rod cylinder.
The terminal element is a vacuum holding platform
with four suction cups to absorb possible lack of
alignment in height.
Figure 5: Placing body on pallet
Suction is created by a vacuum ejector fitted with a vacuum
switch which sends a signal to the PLC indicating that the part
has been correctly clamped.
Figure 6: Vacuum Ejector
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2.1.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 540 mm. Height 900 mm.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Composition of station modules:
Body feed module.
Magazine capacity: 12 bodies.
Actuators:
Double-acting pusher cylinder Ø16, Stroke:100mm (CD85N16-100B), with flow
regulators and initial-end position detector. Controlled by 5/2 way monostable solenoid
valve.
Sensors:
- Reed type magnetic detectors (D-C73L).
- Inductive sensor (OMRON E2EG-X2B1)
Position verification module
Actuators:
Double-acting cylinders Ø12, Stroke:50mm (CD85N12-50B), with flow regulators and
end position detector. Controlled by 5/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detector (D-A73CL)
Movement module
Actuators:
Rectangular section pusher cylinder Ø25, Stroke:200mm (MDUB25-200DM), with flow
regulators and end position detector. Controlled by 5/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detector (D-A73CL).
Inverted body rejection module
Actuators:
- Single-acting ejection cylinder Ø10, Stroke:15mm (CJPB10-15H6). Controlled by 3/2
way monostable solenoid valve.
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Pallet insertion module
Actuators:
Horizontal axis: Parallel rod cylinder Ø20, Stroke:150mm (CXSWM20-150-XB11), with
flow regulators and initial-end position detector. Controlled by 5/2 way monostable
solenoid valve.
Vertical axis: Parallel rod cylinder Ø15, Stroke:50mm (CXSM15-50), with flow
regulators and initial-end position detector. Controlled by 5/2 way monostable solenoid
valve.
Holding plate: 4 telescopic suction cups Ø16 (ZPT16CNK10-B5-A10), with ejector to
generate vacuum (ZU07S). Controlled by 3/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-Z73L)
- Vacuum switch PNP output (PS1100-R06L)
Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 14 inputs, 10 outputs.
- Supply module: 24V/60W
- PLC control:
• ?
CPU
• ?
Communication module for PLC network connection.
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2.2 BEARING HANDLING-FITTING LAYOUT
2.2.1 STATION FUNCTION
The operation carried out by the second station consists of picking the bearing and
placing it inside the housing formed in the body.
Figure 7: Bearing Handling-fitting layout
The task of placing the bearing is performed on the pallet brought by the belt
conveyor and carrying the body located at the previous station. The bearing fitting
operation requires the pallet carrying the body to be precisely situated in a predetermined
place. To achieve this precision, once the pallet has been retained by a stop, it is lifted by
a cylinder and centred at the same time by four pins which fit inside housings formed for
this purpose in the bottom of the pallet.
2.2.2 INTEGRAL PARTS
Bearing insertion requires a series of operations which are carried out by the following
modules:
- Bearing feed:
The bearings are held in
magazine. This consists
magazine with a pusher
bottom which extracts the
moment the cycle is to start.
a gravity feed
of a column
cylinder at the
bearing at the
Figure 8: Bearing feed
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In this case, there is a bearing proximity sensor
in the form of a microswitch which allows the
PLC to verify that a bearing really has been
extracted following the feeding procedure. This
makes
it possible to determine when the
bearings loaded in the feeder have run out.
Figure 9: Proximity sensor
- Transfer to measuring station:
A manipulator is used to move the bearing from the feed point to the place where the
following operation is to be performed. The manipulator uses a rack and pinion type rotary
actuator which describes an angle of 180º.
An arm is attached to the rotary actuator to move a two-finger parallel-opening gripper
which grips the inner part of the bearing. This arm houses a mechanism consisting of a
toothed belt and two pinions, the purpose of which is to change gripper orientation
throughout the turning movement, so that when the bearing reaches the point at which
it is deposited, it has no angle of inclination whatsoever.
Figure 10: Transfer to measuring station
- Height measurement:
As the station caters for the possibility of
feeding
bearings of differing heights, a
measuring module
is
included
to
differentiate between them.
The bearing is deposited on a platform,
on a centring device operated
by
a
pneumatic cylinder which locates it at a
very precise initial point.
Figure 11: Height measurement
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This platform is lifted by a rodless pneumatic cylinder such that the bearing contacts with a
touch trigger and gives a height reading. The touch trigger consists of a linear
potentiometer with an output processed via an analogue module included in the PLC.
After measurement, the lifter returns to its original position, at which time the ejector
cylinder pushes the bearing towards a collection bin if it is not of the desired height.
- Bearing insertion:
The final operation is performed by a manipulator comprising a rotary-linear unit with an
arm to which a two-finger gripper has been fitted. After picking up the bearing, the arm is
lifted, turns through 180º then drops down again to insert the bearing in the housing
formed in the body.
Figure 12: Bearing insertion
2.2.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 540 mm. Height 900 mm.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Composition of station modules:
Bearing feed module
Magazine capacity: 38 bearings
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Actuators:
Double -acting pusher cylinder Ø16, Stroke:100mm (CD85N16-100B), with
flow regulators and initial position detector. Controlled by 5/2 way monostable solenoid
valve.
Sensors:
- Reed type magnetic detector (D-C73L).
- Proximity detector: Microswitch OMRON V-166-1C5.
Measuring station transfer module
Actuators:
Rotary actuator: Double rack and pinion Ø50, ? max:180º ( MSQB50A), with flow
regulators and 0º, 90º and 180º position detector. Controlled by 5/3 way solenoid valve,
mid position closed.
Holding arm: Two-finger parallel-opening grippers (MHK2-16D). Controlled by 5/2 way
monostable solenoid valve.
Sensors:
- PNP type magnetic detectors (D-A93L).
Height measuring module
Actuators:
- Compact single-acting centring cylinder Ø12, Stroke:5mm (CQ2B12-5S). Controlled by
3/2 way monostable solenoid valve.
Vertical axis: Rodless cylinder Ø16, Stroke:250mm (MY1B16G-250), with flow
regulators and initial position detector. Controlled by 5/2 way bistable solenoid valve.
Incorrect part ejection: Double-acting cylinder Ø10, Stroke:40mm (CD85N10-40), with
flow regulators. Controlled by 5/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detector (D-A93L).
- Linear potentiometer NOVOTECHNIK TR25. B
Bearing insertion module
Actuators:
- Compact linear and rotary movement cylinder Ø32, Stroke:25mm (EMRQBS3225CB), with flow regulators and initial-end of travel detection for linear movement, and 0º
and 180º detection for rotary movement. Controlled by two 5/2 way monostable solenoid
valves.
- Holding arm: Two-finger parallel-opening grippers (MHK2-16D). Controlled by 5/2
way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-A73CL).
Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
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-
I/O station: 15 inputs, 13 outputs.
Supply module: 24V/60W
PLC control:
• ?CPU
• ?Analogic Card.
• ?Communication Card for PLC network connection.
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2.3 HYDRAULIC
BEARING
PRESSING LAYOUT
2.3.1 STATION FUNCTION
Following the bearing insertion operation performed by the preceding station, this
third station carries out the task of pressing the bearing firmly into the body to fix it
securely. In actual fact, this pressing operation is not actually carried out; instead, it is only
simulated so that the finished assembly may be dismantled easily and the component
parts reused.
In spite of this, the components included are all industrial grade and similar to those
used in numerous hydraulic applications. They allow the study of systems based on
hydraulic technology which incorporate real components integrated in an authentic
application.
A complete hydraulic unit as required to supply the press cylinder with high
pressure oil is installed under the table, avoiding the need for any additional hydraulic
installation other than the electrical and pneumatic take-offs from the central transfer.
Figure 13: Hydraulic Bearing Pressing Lay-out
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2.3.2 INTEGRAL PARTS
The pressing stage requires a number of operations to be performed, as detailed below.
- Insertion / extraction of assembly:
The first operation consists of moving the body
with the bearing inside it from the pallet retained
at the transfer to an unloading point inside the
station. This handling, and the reverse process of
unloading following pressing, are performed by
a pneumatic rotary
actuator.
Figure 14: Insertion/extraction of assembly
This actuator incorporates an arm with a set of four suction cups at its end, whose job is to
hold the part by means of an internal vacuum generated by an ejector. To keep the body
permanently horizontal throughout the turning movement, this arm incorporates a
pinion and toothed belt mechanism similar to that used at the bearing insertion station.
- Feed in to press:
The body to be fed in to the press is deposited on a platform fitted with two double -acting
pneumatic cylinders. The first effects the transfer from the loading/unloading point to the
press, while the second carries out the reverse operation following the pressing
operation.
- Pressing the bearing:
When the body with the bearing inside has been positioned under the hydraulic
cylinder, a protective screen operated by a pneumatic cylinder drops down. This protects
the user against any risk of accident, and also demonstrates a safety device widely used in
this type of application.
By means of a hydraulic 4/3 way directional control valve, the pressing cylinder now exerts
a force which may be regulated using the pressure limiting valve incorporated in the
hydraulic unit. After pressing, the cylinder returns to its original position, the screen is
lifted and the assembly is pushed to the unloading position.
Figure 15: Pressing the bearing
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2.3.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 540 mm. Height 900 mm.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Composition of station modules:
Assembly insertion/extraction module
Actuators:
Rotary actuator: Double rack and pinion type Ø50, ? max:180º (MSQB50A), with flow
regulators and 0º, 90º and 180º position detector. Controlled by 5/3 way solenoid valve,
mid position closed.
- Holding arm: 4 Suction cups Ø16 (ZPT16UN-B5), with ejector to generate vacuum
(ZU07S). Controlled by 3/2 way monostable solenoid valve.
Sensors:
- PNP type magnetic detectors (D-A93L).
- Vacuum switch PNP output (PS-1100-R06L).
Press feed module
Actuators:
2 Double-acting pusher cylinders Ø12, Stroke:125mm (CD85N12-125A), with flow
regulators and initial-end of stroke position detector. Controlled by 5/2 way
monostable solenoid valves.
Sensors:
- Reed type magnetic detectors (D-A73CL).
Bearing pressing module
Actuators:
- Protector: Double-acting parallel rod cylinder Ø15, Stroke:100mm (CXSM15-100), with
flow regulators and initial-end position detector. Controlled by 5/2 way monostable
solenoid valve.
- Pressing: Compact double -acting hydraulic cylinder Ø40, Stroke:50mm (CHDQH34050), with ATOS HQ012 flow regulators and initial-end position detector. Controlled by
ATOS DHI-0714 4/3 way solenoid valve, mid position closed.
Sensors:
- Reed type magnetic detector (D-Z73L and two D-A73CL).
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Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 18 inputs, 10 outputs.
- Supply source: 24V/60W.
- Net filter.
- Frequency converter
- PLC control:
• ?CPU
• ?Communication card for PLC network connection.
Hydraulic unit:
- Three-phase motor 380V/1.4A 0.37kW 1400rpm.
- Pressure gauge.
- Pressure limiter.
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2.4 SHAFT HANDLING-FITTING- MEASUREMENT-SELECTION
2.4.1 STATION FUNCTION
The fourth station follows the process needed to insert a shaft into the bearing fitted at a
previous station.
This station represents an increase in flexibility in that it allows variety in the assemblies
put together, in the form of being able to fit shafts of different materials; aluminium or
nylon.
Figure 16: Shaft station
The existence of these variants means that the extra operations of checking the type of
material and extracting ones which are not of the desired material are added to the normal
operations of feeding, handling and insertion.
2.4.2 INTEGRAL PARTS
The extra operations to be carried out involve an increase in the complexity of the station,
which means that its structure is noticeably different from previous stations. In this case,
the components are arranged on an 8-station index plate.
Successive operations are performed at these stations, a description of which is given
below:
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- Index plate:
This element is used as a system of alternating rotary movement, in the sense that
each turning movement moves the plate round by a number of degrees equal to the
circumference divided by the number of defined positions.
To achieve this effect, the system incorporates a pneumatic pusher cylinder with
back and forth movement giving the required angular advance.
Figure 17: Index plate
There are a further two stop cylinders which function alternately, one moving which holds
the plate during the turn, and another fixed cylinder which locks the plate in position when
movement has ceased. In this way, the plate is held firmly and the pusher cylinder can
return to its initial position to await a new cycle.
- Shaft feed:
The shafts stored in a gravity type feeder are deposited on the first plate station via a
step-by-step feed system involving two pneumatic cylinders. These cylinders are in a
permanent counterpoise position, so that while the lower one releases the next shaft from
the feeder, the upper one holds the rest in place.
Figure 18: Shaft feed
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- Shaft height measurement:
The shaft is not symmetrical and must therefore be
mounted on the assembly in a particular position.
The shaft is measured to check whether it has been
correctly inserted. A pneumatic cylinder fitted with
magnetic detector registers whether contact is made
with the shaft during outstroking, or whether the
cylinder is able to reach the end of its travel if the
shaft is not in its proper place.
Figure 19: Height measurement
- Placing shaft in correct position:
If the second station on the index plate determines that the shaft has been placed upside
down, a manipulator has the job of turning it round. This is achieved by holding the shaft
between a two-finger gripper, lifting it by a parallel rod cylinder, then turning it over using a
180º rotary actuator and replacing it in the correct position in the housing.
Figure 20: Placing shaft in correct position
- Shaft material detection:
The next operation at this station is carried out using two consecutive index plate stations.
The aim is to determine the material of which the shaft is made, it being necessary to
distinguish between aluminium and nylon. This is achieved by inductive and capacitive
detectors fitted to the third and fourth stations which enable the two types of materials to
be differentiated.
Figure 21: Shaft material detection
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- Removal of incorrect shaft:
As mentioned earlier, this station fulfils the potential to
work at a higher level of cell management by making a
choice of shaft material to be used for the various
assemblies. This means a need for some element to
reject the shaft if it is not of the type indicated, an
operation carried out at the fifth index plate station and
involving a manipulator which removes the shaft from
the plate on receiving the corresponding command.
This element takes the form of a two-axis
manipulator, at the extreme end of which is a suction
cup to hold the top part of the shaft. Each axis
comprise a parallel rod pneumatic cylinder used to lift
the shaft and carry it to a removal ramp. The shaft
is held by the vacuum technique consisting of a
suction cup, ejector to create the necessary vacuum
and a vacuum switch which sends a signal to the PLC
to indicate that the shaft is securely held.
Figure 22: Removal of incorrect shaft
- Shaft insertion in assembly:
Shaft insertion, carried out at the last of the index plate stations, is performed by a rotarylinear type manipulator. This rotary-linear cylinder makes it possible for a single
component to pick up the shaft, take it to the unloading point and insert it. The cylinder
offers the possibility of independently commanding rod instroking and outstroking as well
as turns to left or right.
It is this cylinder which turns an arm fitted with a suction cup used to holds the shaft
throughout the movement. As in the case of the other manipulators using the vacuum
technique, an ejector and vacuum switch are provided for the cylinder.
Figure 23: Shaft insertion in assembly
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Given that the operation of inserting the shaft in the bearing calls for a certain precision,
the pallet supporting the components and lying on the belt is, after being retained by a
stop cylinder, lifted by a further cylinder which incorporates centring pins for correct
positioning.
2.4.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 540 mm. Height 900 mm.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Composition of station modules:
Index plate module
Actuators:
Compact double-acting pusher cylinder Ø25, Stroke:40mm (CDQ2B25-40D), with flow
regulators and initial position detector. Controlled by 5/2 way monostable solenoid valve.
Stops: 2 Compact cylinders Ø16, Stroke:10mm (CQ2B16-10D). Controlled by 5/2 way
monostable solenoid valve.
Sensors:
- Reed type magnetic detector (D-A73L).
Shaft feed module
Magazine capacity: 17 shafts.
Actuators:
2 Double-acting cylinders Ø10, Stroke:10mm (CD85N10-10B). Controlled by 5/2 way
monostable solenoid valve.
Shaft height measuring module
Actuators:
Double-acting cylinder Ø12, Stroke:50mm (CD85N12-50A), with flow regulators and
end position detector. Controlled by 5/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detector (D-A73CL).
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Place shaft in correct position module
Actuators:
Double-acting parallel opening two -finger gripper (MHK2-16D). Controlled by 5/2 way
monostable solenoid valve.
Vertical axis: Double-acting parallel rod cylinder Ø15, Stroke:50mm (CXSM15-50),
with flow regulators and initial-end position detector. Controlled by 5/2 way
monostable solenoid valve.
Rotary actuator: Double acting ? max=180º (MSUB3-180S), with flow
regulators. Controlled by 5/2 way monostable sole noid valve.
Sensors:
- Reed type magnetic detectors (D-Z73L). Shaft material detection module
Sensors:
- Inductive detector: OMRON E2EG-X5B1.
- Capacitive detector: OMRON E2K-C25MF1.
Incorrect shaft ejection module
Actuators:
- Horizontal axis: Double -acting parallel rod cylinder Ø15, Stroke:100mm (CXSM15100), with flow regulators and initial-end position detector. Controlled by 5/2 way bistable
solenoid valve.
Vertical axis: Double-acting parallel rod cylinder Ø10, Stroke:50mm (CXSM10-50),
with flow regulators and initial-end position detector. Controlled by 5/2 way
monostable solenoid valve.
- Holding arm: Suction cup Ø8 (ZPT08UN-B5), with vacuum generating ejector
(ZU05S). Controlled by 3/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-Z73L).
- Vacuum switch PNP output (PS-1100-R06L).
Shaft insertion in assembly module
Actuators:
- Compact linear and rotary movement cylinder Ø32, Stroke:25mm (EMRQBS3225CB), with flow regulators and initial-end of travel detection for linear movement, and 0º
and 180º detection for rotary movement. Controlled by two 5/2 way monostable solenoid
valves.
Holding arm: Suction cup Ø10 (ZPT10CNK10-B5-A10), with vacuum generating
ejector (ZU05S). Controlled by two 3/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-A73CL).
- Vacuum switch PNP output (PS-1100-R06L).
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Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 20 inputs, 16 outputs.
- Supply source: 24V/60W.
- PLC control:
• ?CPU
• ?Communication card for PLC network connection.
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2.5 COVER HANDLING-FITTING-SELECTION LAYOUT
2.5.1 STATION FUNCTION
The fourth of the components to be assembled is a cover which is fitted into a
housing formed on the body for this purpose. The cover serves to retain the turning
mechanism shaft mounted at the previous station.
While the preceding station saw the introduction of a variant in the form of
different materials for the shaft, this station increases the number of variants by offering
the choice of three different materials for the cover: aluminium, white nylon and black
nylon, in addition to a choice of two different cover heights, giving a total of six possible
combinations for this particular assembly task.
The need for appropriate checks to determine which type of cover is to be mounted
at each station cycle means that this station is the most complex in terms of the operations
to be carried out. It is also essential that the station control coordinates part selection
operations in accordance with the commands supplied by the master responsible for
production management in the FMS-200.
2.5.2 INTEGRAL PARTS
The structure adopted for the cover
assembly process is similar to that of the
previous station. It is based on an 8- station
index plate to improve the method of working
at the station, as it saves space compared
with other spatial arrangements of work
stations, and also means that all handling
operations may be carried out simultaneously
to optimize the process in question.
Figure 24: Cover station
The operations to be performed and the components involved are described below:
- Index plate:
The 8-station index plate which moves round to effect the interchange of parts between
the different stations is of similar structure to that used at the preceding station.
24
It is operated by two cylinders, one fixed stop and one moving, together with a pusher
cylinder which produces the turning movement as previously described.
- Feed module:
A gravity feeder is used to store and feed the covers. It is operated by a pusher actuated
by a pneumatic cylinder and which carries out the part extraction process.
Figure 25: Feed module
- Loading station:
The material feed described above supplies the
covers which will later be mounted on the assembly
lying ready on the pallet. First, however, the cover
must be loaded on the index plate.
This
is
performed
by
manipulator
comprising a rotary-linear cylinder which lifts and
then turns an arm fitted with a
two-finger parallel opening gripper.
Figure 26: Loading station
The 180º turn effected by the manipulator leaves the gripper at the exact point of
unloading the cover at the first index plate station.
- Material detection stations:
As described above, this station offers the possibility of working with aluminium,
white nylon and black nylon respectively.
Figure 27:Inductive sensor
Figure 28: Capacitive sensor
Figure 29:Photoelectric cell
25
To differentiate the first of these types, the second index plate station is fitted with an
inductive pick-up which supplies a signal to the PLC only if the cover presented by the
plate, as it turns, is of aluminium.
Detection of the nylon covers necessitates the use of a different type of sensor, in this
case capacitive, which supplies a signal when the part detected is not made of metal.
The final cover differentiation process is that between black and white nylon, and for this
purpose a photoelectric cell as in figure 31 is fitted. This component only detects whitecoloured nylon covers.
- Cover measuring station:
The fact that covers of two different heights may
be used necessitates a height measuring
device. Owing to the teaching and training
objective for which the cell has been designed,
various solutions have been used to perform
similar operations, so that while components
such
as
pneumatic cylinders with correct
height detectors or analogue output touch probes
have been employed at other stations,
this
particular station uses a digital transducer
which provides a pulse output, as it is a
linear encoder.
Figure 30: Measuring station
The component used consists of a pneumatic cylinder which moves the probe until it
touches the cover. An integral linear encoder in the cylinder sends pulses which are
counted by a quick counter input at the PLC, making it possible to determine the distance
the cylinder advances until it makes contact with the cover. This information allows direct
determination of the height of the cover.
- Rejection of incorrect cover:
If the cover reaches the last-but-one index
plate station, and the various material or
height sensors have indicated that it is not
of the material or height indicated by the
central controller in charge of production, then
it must be rejected. This operation is
effected
at this station by a two-axis
manipulator, which picks the cover off the
index plate and deposits it on a removal ramp
if the corresponding signal is received.
Figure 31: Rejection of incorrect cover
26
The manipulator comprises two pneumatic parallel rod cylinders, at the end of which is a
suction plate with three vacuum -holding cups.
- Cover insertion:
As at the previous station, the final index plate station is where the cover is fitted onto the
assembly at a stop on the belt conveyor.
The manipulator used for this task is of identical characteristics to the one which deposits
the cover on the index plate. It has a parallel opening gripper to hold the cover, which is
lifted and turned towards the unloading point by a rotary-linear pneumatic actuator.
Figure 32: Cover insertion
2.5.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 540 mm. Height 900 mm.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Composition of station modules:
Index plate module
Actuators:
- Compact double-acting pusher cylinder Ø25, Stroke:40mm (CDQ2B25-40D), with flow
regulators and initial position detector. Controlled by 5/2 way monostable solenoid valve.
Stops: 2 Compact cylinders Ø16, Stroke:10mm (CQ2B16-10D). Controlled by 5/2 way
monostable solenoid valve.
27
Sensors:
- Reed type magnetic detector (D-A73CL).
Cover feed module
Magazine capacity: 19 covers.
Actuators:
Double-acting pusher cylinder Ø16, Stroke:100mm (CD85N16-100B), with flow
regulators and final position detector. Controlled by 5/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detector (D-C73L).
- Microswitch OMRON V-166-1C5.
Loading station module
Actuators:
- Compact linear and rotary movement cylinder Ø32, Stroke:25mm (EMRQBS3225CB), with flow regulators and initial-end of travel detection for linear movement, and 0º
and 180º detection for rotary movement. Controlled by two 5/2 way monostable solenoid
valves.
Holding arm: Two-finger parallel opening pneumatic gripper (MHKL2-16D).
Controlled by 5/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-A73CL).
Material detection stations module
Sensors:
- Inductive detector: OMRON E2EG-X5B1.
- Capacitive detector: OMRON E2K-C25MF1.
- Photoelectric detector: OMRON E3F2-DS30B4.
Cover measuring module
Actuators:
Double-acting cylinder with stroke reading Ø20, Stroke:50mm (CE1B20-50), with flow
regulators. Controlled by 5/2 way monostable solenoid valve.
Sensors:
Linear encoder integrated in cylinder.
Incorrect cover rejection module
Actuators:
- Horizontal axis: Double -acting parallel rod cylinder Ø15, Stroke:100mm (CXSM15100), with flow regulators and initial-end position detector. Controlled by 5/2 way bistable
solenoid valve.
Vertical axis: Double-acting parallel rod cylinder Ø10, Stroke:50mm (CXSM10-50),
with flow regulators and initial position detector. Controlled by 5/2 way monostable
solenoid valve.
28
- Holding arm: 3 suction cups Ø8 (ZPT08UN-B5), with vacuum -generating ejector
(ZU07S). Controlled by 3/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-Z73L).
- Vacuum switch PNP output (PS-1100-R06L).
Cover insertion module
Actuators:
- Compact li near and rotary movement cylinder Ø32, Stroke:25mm (EMRQBS3225CB), with flow regulators and initial-end of travel detection for linear movement, and 0º
and 180º detection for rotary movement. Controlled by two 5/2 way monostable solenoid
valves.
- Holding arm: Two-finger parallel opening gripper (MHKL2-16D). Controlled by 5/2
way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-A73CL).
Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 24 inputs, 16 outputs.
- Supply source: 24V/60W.
- PLC control:
• ?CPU
• ?Communication card for PLC network connection.
29
2.6 SCREW HANDLING-FITTING
2.6.1 STATION FUNCTION
This station carries out the final operation to fit components to the assembly
under construction, and involves the insertion of four screws in four threaded holes in the
base body of the turning mechanism.
The technology used to effect the movements at this station, based on different
pneumatic cylinders, means it is only possible to unload the screws at a single point. In
consequence, an additional component is needed for the transfer to give it successive
turns, so that four insertion cycles at this station will result in the four screws being fitted.
The components used for this particular operation are a pneumatic lifting cylinder
on which a similarly operated rotary actuator is fitted.
In contrast with preceding stations, where communication between the stations and
the transfer was limited to sending start messages and end of cycle indications, here there
is a greater need for coordination between the units. As a result, more use is made of the
possibilities offered by the PLC network for information exchange between the
different stations.
Figure 33: Screw handling-fitting station
30
2.6.2 INTEGRAL PARTS
The screw insertion function involves a series of operations which are described below.
- Screw feed:
The screws to be inserted are stored in a
vertical gravity feeder, from where they are
unloaded onto a housing via a step-by-step
feed system
involving
two
pneumatic
cylinders working in a permanent counterpoise
position, so that while the lower one instrokes
to let the next screw fall from the feeder, the
upper one outstrokes to hold the rest in
place. Both cylinders return to their original
position once the screw has dropped down.
Figure 34: Screw feed
- Transfer module:
The housing which receives the screws is situated on a double-acting parallel rod
pneumatic cylinder whose construction allows it to be fixed by plates at each end so that it
is the cylinder body which slides like a carriage.
This cylinder is used to transfer the screws from point at which they are fed in to the point
where the following module picks them up for fitting to the assembly.
- Screw insertion manipulator:
Once the items mentioned above have deposited a screw and transferred it to the pick-up
point, the pneumatic manipulator fits the screw into one of the holes in the turning
mechanism body retained on the transfer.
Constructed using two parallel rod cylinders, this manipulator has two degrees of freedom
corresponding to the horizontal and vertical axes. Its end effector is a parallel opening twofinger gripper, used to hold the screws.
Figure 35: Screw insertion manipulator
31
2.6.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 540 mm. Height 900 mm.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Composition of station modules:
Screw feed module
Magazine capacity: 38 screws.
Actuators:
2 Double-acting cylinders Ø10, Stroke:10mm (CD85N10-10-B). Controlled by 5/2 way
monostable solenoid valve.
Transfer module
Actuators:
Double-acting parallel rod cylinder Ø20, Stroke:100mm (CXSWM20-100), with flow
regulators and initial-end position detector. Controlled by 5/2 way bistable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-Z73L).
- Photoelectric cell OMRON E3X-A41.
- Fibre optic OMRON E32-TC200.
Screw insertion manipulator module
Actuators:
- Horizontal axis: Double-acting parallel rod cylinder Ø25, Stroke:200mm
(CXSWM25-200-XB11), with flow regulators and initial-end position detector.
Controlled by 5/2 way bistable solenoid valve.
Vertical axis: Double-acting parallel rod cylinder Ø15, Stroke:50mm (CXSM15-50),
with flow regulators and initial-end position detector. Controlled by 5/2 way
monostable solenoid valve.
Holding: Two-finger parallel opening pneumatic gripper (MHK2-16D) and openclosed position detector. Controlled by 5/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-Z73L).
- PNP type magnetic detectors (D-A93L).
32
Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 13 inputs, 9 outputs.
- Supply source: 24V/60W.
- PLC control:
• ?CPU
• ?Communication card for PLC network connection.
33
2.7 ROBOT SCREWDRIVER
2.7.1 STATION FUNCTION
All the preceding stations were of a design in which actuators based on fluid
technology predominated. These were primarily pneumatic components, although the
study of hydraulic technology was facilitated at the bearing pressing station.
With a view to matching the cell to all the most widely used techniques in industrial
automation, this station introduces a new though widespread technology, that of robotics.
The operation carried out by the robot consists of tightening the four screws fitted to
the body of the turning mechanism at the preceding station.
Figure 36: Robot screwdriver
2.7.2 INTEGRAL PARTS
Given the flexibility and numerous possibilities offered by the use of robots in
automating operations, at this station it is regarded as enough to use the element for the
operations needed to drive in the screws.
34
Control of the robot’s movements between the different points it has to reach is
carried out by a controller which has been specially designed for use with the particular
robot used. It performs the function of controlling all the move ments of all of the motors
incorporated in the robot, so that the latter moves to the defined positions with great
accuracy.
It is also possible to program the robot’s movements into the controller and thereby
specify what sequence of movements has to be followed for a particular process.
Programming is by means of specific software to be run on PC, which communicates the
transfer of information to the controller via a serial line.
There is also a programming console on which it is possible to enter a series of
commands, or to define the points to which the robot has to move.
The positional accuracy enables the tip of the electric screwdriver to be located on
each of the screws fitted in the body, before slowly screwing in the appropriate distance for
the screw to be properly fixed.
To avoid the possibility of uncontrolled movements during the programming phase
causing any type of accident, the station is protected by screening of aluminium
section with methacrylate see-through panels. This practically eliminates the risks
involved in handling components of this type.
2.7.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 540 mm. Height 900 mm.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Station elements:
- MOVEMASTER EX MELFA RV-2AJ MITSUBISHI 5-axis robot. Speed 2.1 m/s,
2500 storable positions, 0.02 mm accuracy, 10 speeds, 2 kg payload, 19 kg arm weight,
parallel (centronics) and series (RS-232) interfaces, 16 inputs (3 switches) and
16 outputs, 1 emergency stop input.
- Electric screwdriver .
- Methacrylate screening for user protection.
35
Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 7 inputs/ 7 outputs.
- Relay for screwdriver supply.
- Supply source: 24V/ 60W.
- Supply source: 5V/ 15W.
- Robot driver.
- Robot programming console.
- PLC Control:
• CPU
• ?Communication card for PLC network connection.
36
2.8 UNLOADING-STORAGE-PALLETIZATION OF COMPLETED
ASSEMBLY
2.8.1 STATION FUNCTION
One operation which is always present in flexible assembly systems, and to
which all operations lead, is that of storage. Once the turning mechanism put together by
the cell has been completed, at the final station it must be removed from the transport
system, leaving the now empty pallet to move towards the first belt to begin work on a new
assembly.
This particular finished product store uses a system based on two coordinate axes,
so that assemblies picked off the transporting belt may be distributed at any point on the
surface of the table which constitutes the station.
Figure 37: Storage station
37
2.8.2 INTEGRAL PARTS
As mentioned, the storage system consists of two position-controlled axes which
distribute the assemblies along the surface of the table. Over these is supported a third
vertical axis with which to pick up the parts.
- Vertical axis:
The system of holding the finished assemblies incorporates four suction cups which use
an ejector-produced vacuum to hold the assembly until it is positioned at its storage
point.
The vertical axis takes the form of a parallel rod cylinder on which the suction cups are
fitted.
Figure 38: Vertical axis
Figure 39: Pressure sensor
As at all the stations which make use of vacuum components, a pressure- sensing
element consisting of a vacuum switch is fitted. This supplies a digital signal indicating that
the ejector has produced the level of vacuum needed to hold the assembly firmly enough
to ensure that it will not drop off when moved by the other axes. In this case, however, a
digital vacuum switch has been incorporated which provides additional features such
as displaying the instantaneous value of pressure and vacuum, and the possibility of
greater accuracy than conventional units when programming the pressure value at
which the output signal is generated.
- Positioning axes:
The first task in storing the finished assemblies is to situate the vertical axis mentioned
above over a fixed pick-up point over the place where the pallet is retained facing the
station.
The finished assembly is then picked and lifted by the pneumatic cylinder forming the
vertical axis. The assemblies to be stored must now be positioned at various points over
the surface of the station table before being unloaded at these points.
The assemblies are moved and their position controlled by two linear motorized axes,
each of which consists of a motor-driven leadscrew-nut which translates the rotary motion
of the motor into linear displacement of the axis carriage.
38
The vertical pneumatic axis is attached to the first of these axes, this whole assembly
being mounted on the other motorized linear axis. The result is a three-axis system, two of
them being capable of positioning.
From the mechanical point of view, these components incorporate a precision leadscrew
with a recirculating ball system, together with two lateral linear guides of high rigidity and
precision, able to withstand the forces arising out of the loads acting on the carriage.
Axis movement and movement regulation is effected by alternating current servomotors,
with an absolute encoder to provide instantaneous reading of motor rotation. Control
is via two drivers which set up a closed loop position regulation system. This involves
encoder feedback and the position setpoint required at any particular moment supplied by
the PLC governing the station.
These components allow the study of electric motors used in applications which call for
position control,
increasing further the number of technologies associated with
automation which are dealt with by this flexible cell.
2.8.3 TECHNICAL DATA
Dimensions:
Table of slotted aluminium section, 900 x 650 mm. Height 990 mm.
Methacrylate screening for user protection.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge.
Pushbutton control:
Start, stop, reset pushbuttons. Emergency stop button, cutout selector, mode selector
(auto-man) and error pilot indicator.
Composition of station modules:
Vertical axis module
Actuators:
Double-acting parallel rod cylinder Ø20, Stroke:75mm (CXSWM20-75), with flow
regulators and initial-end position detector. Controlled by 5/2 way monostable solenoid
valve.
- Holding: 4 suction cups Ø16 (ZPT16CNK10-B5-A10), with vacuum generating ejector
(ZH10BS-06-06). Controlled by 3/2 way monostable solenoid valve.
Sensors:
- Reed type magnetic detectors (D-Z73L).
- Digital vacuum switch PNP output (ZSE4B-01-25L-Q).
39
Positioning axes module
Actuators:
- Linear actuators (LJ1H20RF20SC-500-RT-X13).
- Linear actuators (LS1H10RF10SC-500-LT-X13).
- 50 and 100 W servomotors.
Sensors:
- Reed type magnetic detectors (D-Z73L).
Electrical control panel:
- Mounted on perforated mesh 550 x 400 mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 15 inputs, 15 outputs.
- Linear actuator drivers.
- Supply source: 24V/60W.
- PLC control:
• CPU.
• Communication card for PLC network connection.
40
3 4-METRE TRANSFER LINE
3.1 TRANSFER FUNCTION AND COMPOSITION.
The transport system is a line 4 metres long which links the layouts to facilitate the
envisaged assembly process.
The various layouts are linked up with the line by a quick assembly mechanical
system.
The transfer follows a rectangular path, and is fitted with a control cabinet with
integrated PLC to organise and control the whole production sequence. This master PLC
controls the rest of the PLCs connected into the network.
Figure 40: Transfer
There is a longitudinal channel in the central area of the transfer to facilitate
electrical connections, air supply and connection between the transfer and the
various handling stations.
The transfer incorporates a pallet assembly to transport parts and assemblies
between the handling stations.
A safety button is fitted to the transfer to stop the whole system in case of
emergency.
41
The central panel includes the master PLC which controls the entire process.
All the transport system actuators, stoppers, lifters, positioners and pallet
transfers are operated by a system of solenoid valves connected to the central station.
Pneumatically-operated pushers unload the pallets from one section to another.
The stations are assembled using screwed joints incorporated for this purpose on
both station and transfer, enabling quick and precise assembly. In front of the
station, there is a mechanical stop to stop the pallets, an identification code reading
system and, depending on the particular process, a further series of elements for lifting,
centring, turning, etc.
Both the pallet retention point and the relative position of the station may be varied,
making it simple to modify the distribution of the component bases of the cell.
3.2 TECHNICAL DETAILS OF TRANSFER
Dimensions:
2 sections 3900 x 130 mm. Height 970 mm.
Air treatment unit:
Filter to 5 µm, pressure regulator and pressure gauge with incorporated pressure switch.
Drive:
2 Three-phase motors 230V/1.8A 0.37kW.
Composition:
Actuators:
8 Compact double-acting cylinders Ø32, Stroke:25mm (ECQ2B32-25D-XSE040).
Controlled by 5/2 way monostable solenoid valves.
3 Compact double-acting cylinders with guide Ø16, Stroke:30mm (EMGQM16-30),
with flow regulators . Controlled by 5/2 way monostable solenoid valves.
Two-direction rotary actuator ? max:90º (MSUB3-90S), with flow regulators.
Controlled by 5/2 way monostable solenoid valve.
42
2 Rodless double-acting cylinders Ø20, Stroke:200mm (MY1B20G-200), with flow
regulators and initial-end position detector. Controlled by 5/2 way bistable solenoid valves.
Sensors:
- Magnetic reed type detectors (D-Z73L and D-A93L).
- 24 capacitive detectors OMRON E2EG-X5MB1.
- 2 capacitive detectors OMRON E2K-X4MF1.
- 8 microswitches OMRON V-166-1C5.
10 Fieldbus input/output modules.
Electrical control panel:
- Cabinet-mounted 700 x 500mm. Depth 230mm.
- Accessible terminal plate with supply connections and coded I/Os.
- Thermal overload switch incorporated.
- I/O station: 5 inputs, 4 outputs.
- Fieldbus supply source.
- Supply source : 24V/120W.
Start, stop, reset pushbuttons. 1 emergency button, and 2 indicator pilots: on line and
emergency.
- 2 Three-phase motor supply contactors.
- Net filter.
- Frequency converter.
- PLC control:
• ?CPU
• Communication master Card
43