DR3310 – 1.0 Automated Assembly and AGVs.pptx

Automated Assembly and AGVs

1. DR3310 – Manufacturing Technology 1.0 Automated Assembly and Automated Guided Vehicles (AGV) Welding Engineering Technician Program 1

2. Historical Review and Definition An assembly line is a production process that breaks the manufacture of a good into steps that are completed in a pre-defined sequence. Assembly lines are the most commonly used method in the mass production of products. Welding Engineering Technician Program 2

3. Historical Review and Definition The work comes to the worker rather than the worker having to leave the workstation. They reduce labor costs because unskilled workers are trained to perform specific tasks. Welding Engineering Technician Program 3

4. Ford and the Model T The assembly line developed by Ford Motor Company between 1908 and 1915 made assembly lines famous in the following decade through the concept of mass production. Economy of Scale caused the price of an automobile to fall drastically, and they weren’t only for the rich anymore. Cut in half ($825) in 1908 and down even more ($575) in 1912 Henry Ford was able to improve other aspects of industry by reducing labor hours required to produce a single vehicle, and increased production numbers and parts. 12.5 hours versus > 6 hours using assembly line Welding Engineering Technician Program 4

5. Ford and the Model T The assembly line compartmentalized tasks. People did the same basic tasks over and over. Efforts were made to ensure worker safety. Workdays were reduced to 8 hours (versus 9 h) Wages were increased from $2.83 /day to $5.00 /day! That’s 62.5 cents/hour versus 31.4 cents/hour. Nearly a 100% wage increase without a union! Welding Engineering Technician Program 5

6. Ford and the Model T People soon realized that some of these simple, repetitive tasks could be done by machines…. Welding Engineering Technician Program 6

7. Automated Assembly Welding Engineering Technician Program 7 Automated Assembly refers to a manner of producing goods by use of automated machinery or assembly robots. It is a systematic approach to assembling products that operates at least partly independent from human control. In most cases, automated machinery is used to produce products using standardized parts added in a specific series of motions or activities along the assembly line. In many technology firms, medical research facilities and clinical factories, automated assembly is an important part of the process. Less error, better cleanliness, faster, less cost, etc.

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9. Automated Assembly Welding Engineering Technician Program 9 In many factories today, automated assembly is used to create parts and then assemble a wide variety of consumer products, from foods to electronics. Workers are on hand to oversee the process and make sure that the flow of the assembly line is maintained for long periods of time to maximize the production of thousands of quality products in the shortest period of time. Much of the machinery used requires careful calibration and adjustments but does not require any other human interaction.

10. Automated Assembly Welding Engineering Technician Program 10 Large-scale manufacturing companies use larger automated assembly processes including the use of heavy robotic equipment to put together large products, such as automobiles. Assembly systems in these environments are operated by a central control center by just a few workers, but otherwise assemble vehicles independently during this process.

11. Automated Assembly Welding Engineering Technician Program 11 While this form of manufacturing may seem like it replaces human workers, it has improved assembly and reduced human injury and failure rates in many industries, while making vehicles more affordable for consumers.

12. Automated Assembly Line Welding Engineering Technician Program 12

13. Current Status Industries served by automated assembly equipment include aerospace, aeronautics, agriculture, automotive, computer, electrical, electronics, fiber optics, food and beverage, furnace and heat treat, general industry, medical, plumbing, microelectronics or semiconductor, and telecommunications. In 1987, International Standards Organization (ISO) 9000 standards were developed. Common certifications for automated assembly equipment include ISO 9001 and ISO 9002. Welding Engineering Technician Program 13

14. Advantages / Disadvantages Advantages: Assembly using relatively less skilled labor Much lower cost in mass production Simple repair with interchangeable parts Consistent, high quality Relieves workers of repetition / monotony Higher production rates Efficient use of materials Efficient handling of parts Improved safety Welding Engineering Technician Program 14

15. Advantages / Disadvantages Disadvantages: Large capital requirement, fixed costs Initial set up and troubleshooting Not suited to custom parts or frequent design changes (lack of flexibility) Not suited to a short product cycle Single failure shuts down entire assembly line Systems are complex If one machine goes offline, entire production may halt Benefit of employee input on making improvements is lost Welding Engineering Technician Program 15

16. Classification Assembly lines can be classified according to: The number of models assembled on the line. Distinguishes between a line that assembles a single model (Single-model Line) and a line which assembles several models simultaneously (Mixed-model Line). The line pace. On the basis of whether they are paced or unpaced . In paced lines, a mechanical material handling mechanism links the stations in a rigid nature and ensures that the product spends a fixed and identical amount of time at each station. In unpaced lines the products spend the time needed to complete the work at the station and are then moved downstream. Welding Engineering Technician Program 16

17. Principal Components Assembly systems are usually subdivided into several logical or physical components to alleviate complexity. The design team usually includes members from several departments Each responsible for one or more components. Welding Engineering Technician Program 17

18. Principal Components One possible break down is given as follows: Process design Line balance Test strategy Yield management Material Handling Maintenance policy Work in progress management Parts Procurement Human Resource Line Size Line Layout Information System Welding Engineering Technician Program 18

19. Machine Vision Defined as a process of applying computer vision to industrial application. Engineering discipline mainly concerned with industrial problems. Machine vision uses digital input/output devices and computer networks to control other manufacturing equipment such as robotic arms and equipment to eject defective products. One of the most common applications of Machine Vision is the inspection of manufactured goods such as semiconductor chips (counting objects), automobiles (searching for surface defects). Also applications such as control of Automated Guided Vehicles (AGVs). Welding Engineering Technician Program 19

20. Imaging and Machine Vision Systems Imaging and Machine Vision Systems can be described as the integration of image acquisition devices, computers, and imaging software. The automated manufacturing also requires application-specific material handling, Motion Controllers, Part-tracking Controllers and sensors, and control software. Welding Engineering Technician Program 20

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22. Today's high-speed, complex manufacturing systems require a machine vision system that can efficiently: collect data use historical information to provide context use the process data for automatic characterization and control of product quality and the manufacturing process By “knowing” what the normal operational parameters are, the control system can automatically take steps to correct malfunctions detected (sensed) by the machine vision system. Welding Engineering Technician Program 22 Control of Automated Systems

23. Control of Automated Systems The System may consist of: Image Acquisition Devices - Lighting to illuminate the object, Optics/Lens to couple the image to a camera sensor , a Camera to convert optical image to an analog signal, and for automated manufacturing a Trigger Sensor to initiate the image acquisition. Computer – Typically a PC with a CPU (decision-making and control), an Operator Console (the operator interface), and Imaging Hardware (typically an analog to digital converter and image processing). The automated manufacturing also requires an addition of I/O Interface, Material Handling and communications to customer process information and control system. Software – Operating System Software and Imaging Software (the user interface, image acquisition and processing, image analysis and decision-making, historical data collection and analysis). Welding Engineering Technician Program 23

24. Artificial Intelligence [AI] Traditionally, most industrial assembly is follows an unchanging program to describe and modify the machine moves. This method cannot perform the most complex tasks. There is an increasing need for integrating sensors feedback into the automated assembly systems to provide better perception and for improving the capacity of the machine to reason and make decisions intelligently in real time. Welding Engineering Technician Program 24

25. Automated Guided Vehicles (AGV) An automated guided vehicle or automatic guided vehicle (AGV) is a mobile robot that follows markers or wires in the floor, or uses vision or lasers. Welding Engineering Technician Program 25

26. AGVs increase efficiency and reduce costs by helping to automate a manufacturing facility or warehouse. Allows transport in areas unsafe for humans. The first AGV was brought to market in the 1950s, by Barrett Electronics of Northbrook, Illinois. It was simply a tow truck that followed a wire in the floor instead of a rail. Over the years the technology has become more sophisticated and today automated vehicles are mainly laser navigated e.g. LGV (Laser Guided Vehicle). Programmed to communicate (via an off-board server) with other robots to ensure product is moved smoothly through the warehouse, whether it is being stored or shipped. Late 1990’s, the port of Rotterdam, in the Netherlands, began moving ISO shipping containers with AGVs. Welding Engineering Technician Program 26

27. AGVs https://www.youtube.com/watch?v=XtcLW05wsNo Welding Engineering Technician Program 27

28. Classification of AGVs AGVS Towing Vehicles , the first type introduced and remain a very popular type today. Towing vehicles can pull a multitude of trailer types and have capacities ranging from 8,000 pounds to 60,000 pounds. AGVS Unit Load Vehicles , equipped with decks, which permit unit load transportation and often automatic load transfer. Welding Engineering Technician Program 28

29. Classification of AGVs AGVS Pallet Trucks , designed to transport palletized loads to and from floor level Welding Engineering Technician Program 29 AGVS Fork Truck , ability to service loads both at floor level and on stands or in a rack.

30. Classification of AGVs Light Load AGVS , vehicles which have capacities in the neighborhood of 500 pounds or less and are used to transport small parts, baskets, or other light loads though a light manufacturing environment. Designed to operate in areas with limited space. AGVS Assembly Line Vehicles , an adaptation of the light load AGVS for applications involving serial assembly processes. Welding Engineering Technician Program 30

31. Guidance AGVs transport an object from Point A to Point B. AGVs navigate manufacturing areas by using sensors. There are two main sensor types: wired wireless Welding Engineering Technician Program 31

32. Wired AGVs The wired sensor is placed on the bottom of the robot. A slot is cut in the ground and a wire is placed approximately 1 inch below the ground. The sensor detects the radio frequency being transmitted from the wire and follows it. Welding Engineering Technician Program 32

33. Two styles: magnetic or colored . The AGV is fitted with the appropriate guide sensor to follow the path laid out using the tape. One major advantage of tape over wired guidance is that it can be easily removed and relocated if the course needs to change. It also does not involve the expense of cutting the factory or warehouse floor for the entire travel route. Colored tape is initially less expensive, but lacks the advantage of being embedded in high traffic areas where the tape may become damaged or dirty. A flexible magnetic bar can also be embedded in the floor like wire but works under the same provision as magnetic tape and so remains unpowered (or passive). Welding Engineering Technician Program 33 Guide Tape

34. Laser Target Navigation The wireless navigation is achieved by mounting retro-reflective tape on walls, poles or machines. The AGV carries a laser transmitter and receiver on a rotating turret. The AGV has the reflector map stored in memory and can correct its position based on errors between the expected and received measurements. It can then navigate to a destination target using the constantly updated position. Welding Engineering Technician Program 34

35. AGV guidance via Inertial Navigation (gyroscope). A computer control system directs and assigns tasks to the vehicles. Transponders are embedded in the floor of the work place in locations “known” to the robot. The AGV uses these transponders to verify that the vehicle is on course. Welding Engineering Technician Program 35 Gyroscopic Navigation

36. Gyroscopic Navigation A gyroscope is able to detect the slightest change in the direction of the vehicle and corrects it in order to keep the AGV on its path. The gyroscope detects the inertial effects of turning. The margin of error for the inertial method is ±1 inch. Welding Engineering Technician Program 36

37. System Management Factories and warehouses using AGVs need to have some sort of control over them. There are three main ways to control and/or monitor the AGVs : locator panel graphics display central logging and report Welding Engineering Technician Program 37

38. System Management  A Locator Panel is a simple panel used to see which area the AGV is in. If the AGV is in one area for too long, it could mean it is stuck or broken down. Graphics Display shows real time location. It also gives the status of the AGV. [Ex., its battery voltage, unique identifier, and can show blocked spots.] Central Logging is used to keep track of the history of all the AGVs in the system. Central logging stores all the data (history) from these vehicles, which can be printed out for technical support or logged to check for “up” time (time functioning without input). Welding Engineering Technician Program 38

39. Vehicle Dispatch and System Monitoring Systems containing more than one AGV will require it to have traffic control so the AGVs will not run into one another. Welding Engineering Technician Program 39 Methods include zone control , forward sensing control , and combination control , each with its advantages and disadvantages.

40. Zone Control Zone control is most common because it is simple to install and easy to expand. Zone control uses a wireless transmitter to transmit a signal in a fixed area. Welding Engineering Technician Program 40

41. Zone Control Each AGV contains a sensing device to receive this signal and transmit back to the transmitter. If the area is clear the signal is set at “clear” allowing any AGV to enter and pass through the area. When an AGV is in the area, the “STOP” signal is sent and all AGVs attempting to enter the area will stop and wait for their turn. Welding Engineering Technician Program 41

42. Zone Control The carts can move between stations in this layout without programming and without a central control system. They direct themselves around the layout by interrogation of floor mounted route tags and trolley mounted data tags. Destination stations are uniquely identified with a zone and station number which the cart uses to select the correct path to follow after reading direction information from the floor at junctions; just like road signs on a highway. They even know when to give way to other carts so they won’t collide with one another or cause traffic jams. Welding Engineering Technician Program 42

43. Forward-sensing control uses collision avoidance sensors to avoid collisions with other AGVs in the area. These sensors include: sonic, which work like radar ; optical, which uses an infrared sensor; and bumper, physical contact sensor. Welding Engineering Technician Program 43 Forward-sensing Control

44. Combination control sensing uses collision avoidance sensors as well as the zone control sensors. This setup is better at monitoring and controlling the movements of AGVs making it more dependable and safer. Welding Engineering Technician Program 44 Combination Control

45. AGV Control AGVs can be very large and, when in motion, can present serious dangers to people and equipment. Welding Engineering Technician Program 45

46. Safety Issues AGV travel paths should be kept clear of materials / objects. Employees should be trained not to ride the AGVs. Instruct personnel to stay clear of an approaching AGV. Weighed cones or other portable obstacles can be placed where workers may be working on or near an AGV travel path. The training program should also include contractors that may come into a plant or warehouse to perform work. AGV travels paths should be clearly marked, including turning areas. "Virtual" bumper systems can increase productivity and system flexibility, and, improve plant safety with regard to object detection/avoidance. Welding Engineering Technician Program 46

47. Latest Trends This technology has been moving forward. There have been advances in navigation systems. (laser guided systems) Obstacle detection systems (Virtual bumper) Increased Speed and payload. E-Stop [Emergency Stop] - immediately stop if any contact is made with the bumper, and then wait for the obstruction to move before it resumes its route. Welding Engineering Technician Program 47