LCA SAFETY MAINTENANCE and CASE STUDY

LOW COST AUTOMATION
UNIT NO 5

1. Safety, fault-finding and
maintenance and Case Study
By
Mr. C.R. Jadhav

2. Fault Finding Instruments
•The fundamental steps in the logical diagnostic process for all type of
equipment are:
(1) Symptom analysis
(2) Equipment Inspection
(3) Fault stage location
(4) Circuit checks
(5) Repair or replace
(6) Perform test

4. •Multimeter-
•A typical multimeter can measure AC and DC
Voltages, Resistance and Current.
•Faults can generally be categorized into
either open circuits or short circuits.
•Open circuits occur when there is a break in
the circuitry. This could be a broken wire,
loose connection, burned out component,
etc.

5. •Using a Voltmeter
•Voltmeters are the best tool to use for
finding open circuits
•The negative (neutral or ground if on AC)
supply is preferable. Test through the
affected circuit with your other lead, making
sure all necessary switches are closed. The
wire or device between the last point you
test full voltage and the first place you don’t
get full voltage is where the open circuit is
located.
•Don’t forget about checking the neutral
path. When you get full voltage at the
positive terminal of a device that is
supposed to be operating.

6. •Using an Ohmmeter to find Short Circuits
•Short circuits allow voltages and currents to
flow in the wrong parts of a circuit, which
causes malfunctions.
•The most common type of short circuit is a
short to ground.
•Next disconnect and remove a wire at the
component you have identified as your
most probable cause. Then connect one
lead of the ohmmeter to a ground point
and the other lead to the suspected
component. If your meter reads very low,
then the fault is below the open point.
Otherwise the fault is above the open
point.

7. •Using an Ohmmeter to find Open
Circuits
•connect one lead of the ohmmeter
to a ground point and the other
lead to the suspected component.
If your meter reads infinity, then
the fault is below the open point.
Otherwise the fault is above the
open point.

8. •Using an Ammeter
•With an ammeter, you can measure the current flowing through a
circuit. This can be very useful when your other test instruments
(voltmeter and ohmmeter) are not appropriate.

9. Other instruments to find out faults
•Volt-ohmmeter: Measures voltage and resistance.
•Megohmmeter: Tests insulation resistance.
•Circuit breaker & relay test set: Checks the operation of circuit breakers and
relays.
•Vibration amplitude meter: Detects vibrations in machinery which can indicate
issues.
•Centigrade thermometer: Measures temperature in Celsius.
•Tachometer: Measures the rotation speed of an object.
•Hook-on ammeter: Measures electric current.
•Magnetic compass: Used for detecting magnetic fields.
•Mechanical voltage tester: Checks for the presence of voltage.
•External shunt ammeter: Measures current with high accuracy.

10. •Growler: Used for testing armatures for shorts.
•Phase sequence indicator: Determines the sequence of phases in
three-phase systems.
•Motor rotation indicator: Confirms the correct rotation direction of
motors.
•Hook on wattmeter and power factor meter: Measures electrical
power and power factor.
•High potential test set: Applies high voltage to test insulation.
•Insulating liquid test set: Assesses the quality of insulating liquids.
•Hydrometer: Measures the specific gravity of liquids.
•Industrial Analyzer: Analyzes industrial processes.
•Thermal Image Camera: Detects heat patterns and variations.

11. Case study: Low cost automation for Assembly
line automation
•Types and configurations for automated assembly lines-
•The principal configurations are
(a) in-line assembly machine,
(b) dial-type assembly machine,
(c) carousel assembly system, and
(d) single-station assembly machine.

12. The in-line assembly machine
•It is a series of automatic workstations located along an in-line
transfer system.
•It is the assembly version of the machining transfer line.
•Synchronous and asynchronous transfer systems are the common
means of transporting base parts from station to station with the in-
line configuration.

13. dial-type machine
•Base parts are loaded onto fixtures or nests
attached to the circular dial.
•Components are added and/or joined to the
base part at the various workstations located
around the periphery of the dial.
•The dial indexing machine operates with a
synchronous or intermittent motion, in
which the cycle consists of the service time
plus indexing time.
•Dial-type assembly machines are sometimes
designed to use a continuous rather than
intermittent motion. This is common in
beverage bottling and canning plants, but
not in mechanical and electronics assembly.

14. Carousel assembly system
•Represents a hybrid between the circular work flow of the dial-type
assembly machine and the straight work flow of the in-line system.
•The carousel configuration can be operated with continuous, synchronous,
or asynchronous transfer mechanisms to move the work around the
carousel.
•Carousels with asynchronous transfer of work are often used in partially
automated assembly systems.

15. single-station assembly machine
•Assembly operations are per formed on a base part at a single
location.
•The typical operating cycle involves the placement of the base part at
a stationary position in the workstation, the addition of components
to the base, and finally the removal of the completed assembly from
the station.
•An important application of single-station assembly is the component
placement machine, widely used in the electronics industry to
populate components onto printed circuit boards.
•For mechanical assemblies, the single-station cell is sometimes
selected as the configuration for robotic assembly applications.

16. single-station assembly machine.

17. Parts delivery at workstations
•The parts delivery system typically consists of the following hardware:
•Hopper
•This is the container into which the components are loaded at the
workstation.
•A separate hopper is used for each component type.
•The components are usually loaded into the hopper in bulk.
•This means that the parts are randomly oriented in the hopper.

18. •Parts feeder.-
•This is a mechanism that removes
the components from the hopper
one at a time for delivery to the
assembly work head.
•The hopper and parts feeder are
often combined into one operating
mechanism.
•A vibratory bowl feeder, pictured in
Figure is a very common example of
the hopper-feeder combination.
Vibratory bowl feeder

19. Selector and/or orientor
•These elements of the delivery system
establish the proper orientation of the
components for the assembly work head.
•A selector is a device that acts as a filter,
permitting only parts in the correct orientation
to pass through.
•Incorrectly oriented parts are rejected back
into the hopper.
•An orientor is a device that allows properly
oriented parts to pass through, and reorients
parts that are not properly oriented initially.
•Several selector and orientor schemes are
illustrated in Figure Selector and orientor
devices are often combined and incorporated
into one hopper-feeder system.
(a) Selector and (b) orientor devices used with
parts feeders in automated assembly systems

20. Feed track
•The preceding elements of the delivery system are usually separated from
the assembly work head by a certain distance.
•A feed track moves the com ponents from the hopper and parts feeder to
the location of the assembly work head, maintaining proper orientation of
the parts during the transfer.
•There are two general categories of feed tracks: gravity and powered.
•Gravity feed tracks are most common. In this type, the hopper and parts
feeder are located at an elevation above that of the work head. Gravity is
used to deliver the components to the work head.
•The powered feed track uses vibratory action, air pressure, or other means
to force the parts to travel along the feed track toward the assembly work
head.

21. Escapement and placement device.
•The escapement removes components from
the feed track at time intervals that are
consistent with the cycle time of the
assembly work head.
•The placement device physically places the
component in the correct location at the
workstation for the assembly operation.
•These elements are some times combined
into a single operating mechanism.
•In other cases, they are two separate devices.
Several types of escapement and placement
devices are pictured in Figure (a) and (b) horizontal and vertical devices for
placement of parts onto dial indexing table; (c)
escapement of rivet-shaped parts actuated by work
carriers; (d)

22. (d) and (e) two types of pick-and-place mechanisms that use suction cups to pick up parts.

23. parts delivery system

24. Vibratory feeder
•A vibratory feeder is an
equipment that uses vibration
to feed material through a
process or a machine
controlling the rate of flow.
•Vibratory feeder utilize both
vibration and gravity to move
material forward.
1. load carry element
2. flexible elements
3.Base
4. Rubber pads
5. Magnetic core
6. Coils
7. Force acting on armature
8. tray
9. safety switch
10. Storage hopper
11. movable shutter

25. Rotary disk feeder

26. Orienter

27. Centrifugal feeder

29. Part transfer/ Transportation system
•The work part transport system moves parts between stations on the
line.
•work flow can actually take several different forms: (1) in-line, (2)
segmented in-line, and (3) rotary.

30. (a) L-shaped, (b) U-shaped, and (c) rectangular. Key: Proc = processing operation, Aut = automated
workstation, Wash = work carrier washing station.

31. Rotary Indexing mechanism