1. Material Transport Systems
Chapter 10

2. Objectives By end of the class, students should be able to:
Describe the five transport system that are commonly used in manufacturing
Explain characteristics of AGV (Guidance and traffic controls)
Explain characteristics of conveyors
Perform engineering analysis on material transport system

3. Material Transport system
Needed to transport materials (raw material, finished goods, WIP..etc) within manufacturing facilities and to/from warehouse or storage areas.

4. Common Material Handling Equipment
Features
Typical Application
Industrial truck (manual or powered)
Low to medium cost, low rate of deliveries/hr
Moving light loads and palletized containers
Automated guided vehicles system
High cost, flexible routing
Moving pallet loads and WIP
Monorails and other rail guided vehicles
Moving single assemblies or large qty
Conveyors
Various types
Moving product in manufacturing lines
Cranes and hoist
High lift capacity
Moving large, heavy items in factories

5. Industrial Trucks
(a) Two-wheel hand truck, (b) four-wheel dolly, (c) hand-operated low-lift pallet truck

6. Automated Guided Vehicles
AGVS is a material handling system that uses independently operated, self-propelled vehicles guided along a defined pathways.
Appropriate where different materials are moved from various load points to various unload points.

7. Application of AGVs
Driver-less train: Used in moving large quantity of materials over large distances
Unit load carrier and pallet trucks: Used in storage and distribution and Flexible manufacturing system

8. Vehicle Guidance Technology
Imbedded guide wires : Guided by equal intensity of electromagnetic field on two sensors.
Paint strips: Guided by optical sensors
Self Guided Vehicles: Operated without defined pathways but with beacons located throughout the facilities. Pathway can be changed by changing the navigation data.

9. Vehicle Management & Safety
Traffic Controls:
Onboard sensors
Vehicle will stop upon detecting obstacle
Sensors can be optical or ultrasonic
Zone controls
Operating rules that no vehicle will enter the zone if there is already occupied by another vehicles
Safety
Speeds normally slower than walking pace
vehicle automatic stop if it strays more than a short distance from specified path
Emergency bumper-the vehicle automatically stop if the bumper is activated.

10. Conveyor Types Belt conveyor Roller and skate wheel conveyor
Chain conveyor

11. Conveyor Types (a) Single direction conveyor
(b) Continuous loop conveyor

12. Conveyor Operation & Features
Powered conveyor can be divided into two:
Continuous conveyor moving at constant velocity
Asynchronous conveyor operating with a stop and go motion. Used :
As buffers
To allow differences in production rate between adjacent process
To accommodate different conveyor speed

13. Monorails/Other railed guided vehicles

14. Crane and Hoists

15. Analysis of Material Transport System
Based on MHI assumptions.
Focuses on 3 areas:
Charting techniques
Analysis of vehicle based system
Conveyor Analysis

16. Charting Techniques Purpose is to display the material flows
Two techniques:
From-To Chart

17. From-To-Chart To 1 2 3 4 5 From Note: loads/hr /Travel Distance 9/50*
9/50*
5/120
6/205
9/80
2/85
3/170
8/85
Note: loads/hr /Travel Distance

18. Flow Diagram
9/50 2 1
9/80
6/205
5/120
3/170 3 5
2/85 4
8/85

19. Analysis of Vehicle Based Systems
Assumption:
Vehicle operates at constant velocity ignoring acceleration and deceleration,
The time for typical delivery:
Loading at pick up station,
Traveling time to drop off station
unloading at drop off station,
empty traveling time of the vehicle
Therefore:

20. Analysis of Vehicle Based Systems
can be used to calculate:
Hourly rate of deliver per vehicle,
AT depends on
Availability of the vehicles, A
Traffic congestion, Tf
Efficiency of manual driver, E
Therefore

21. Analysis of Vehicle Based Systems
Number of vehicles required to satisfy specified delivery requirement,Rf
Total workload
Number of required vehicles

22. Example 1
An automated guided vehicle system has an average travel distance per delivery = 200 m and an average empty travel distance = 150 m. Load and unload times are each 24 s and the speed of the AGV = 1 m/s. Traffic factor = 0.9. How many vehicles are needed to satisfy a delivery requirement of 30 deliveries/hour? Assume that availability = 0.95 and worker efficiency = 1.0.

23. Example 2
Four forklift trucks are used to deliver pallet loads of parts between work cells in a factory. Average travel distance loaded is 350 ft and the travel distance empty is estimated to be the same. The trucks are driven at an average speed of 3 miles/hr when loaded and 4 miles/hr when empty Terminal time per delivery averages 1.0 minute (load = 0.5 minute and unload = 0.5 minute). If the traffic factor is assumed to be 0.90, availability = 100%, and worker efficiency = 0.95, what is the maximum hourly delivery rate of the four trucks? (1mile=5280 ft)

24. Back up

25. Pictures