MANUFACTURING SYSTEMS INDUSTRIAL ROBOTICS JEEVANA JOTHI RAMAKRISHNA NOOR AZNIDA BT ABDUL AZIZ ZALAIDA BT TALIB
Zalaida binti Talib Lecturer of Politeknik Banting Selangor MASTER MANUFACTURING SYSTEM, UPM 2006 DEGREE MECHANICAL ENGINEERING, UTM 1993 AUTHOR Jeevana Jothi a/p Ramakrishna Lecturer of Politeknik Banting Selangor SARJANA KEJURUTERAAN SISTEM PEMBUATAN, UPM 2017 SARJANA KEJURUTERAAN SISTEM PEMBUATAN, UTHM 2009 Noor Aznida Binti Abdul Aziz Lecturer of Politeknik Banting Selangor SARJANA MUDA KEJURUTERAAN PEMBUATAN DAN PENGELUARAN , UTHM 2007
Industrial Robotics by: Jeevana Jothi a/p Ramakrishna Noor Aznida binti Abdul Aziz Zalaida binti Talib Published by: Politeknik Banting Selangor Persiaran Ilmu Jalan Sultan Abdul Samad 42700 Banting, Selangor https://pbs.mypolycc.edu.my Copyright © 2021 Editor Mohd Azam bin Mohd Daud ISBN: INDUSTRIAL ROBOTICS
We are grateful for a number of friends, colleagues and also Politeknik Banting Selangor in giving us the opportunity to write an e-book and publishing it. We would not finish the e-book without the continual support and love despite time in encouraging us to start the work and publish it. Our heartiest gratitude to e-Learning Unit of PBS, who always share knowledge on e-book writing, encourage us and being our companion in the discussion of e-book writing. Last but not the least, thank you to the God for keeping us positive and hopeful in writing this e-book. INDUSTRIAL ROBOTICS i
This e-book is based on Manufacturing Systems (DJF 41052) syllabus for polytechnics students. This chapter covers only chapter two which is industrial robotics. the content in chapter two Manufacturing System are definition of industrial robotics which comprises laws of robotics, functions of robot and also advantages and disadvantages in having industrial robotics. Besides that, it also explain in detail about the components of industrial robotics which are base, manipulator arm, end effectors, actuators and also sensors. The most important are the robot design configuration and its workspace. This subtopics discusses about the five types of robot configurations such as Cartesian robot, cylindrical robot, SCARA robot, spherical robot and articulate robot. the drawing of the workspaces are also included for better understandings. Lastly it explains about the robot programming operation method which includes lead through, walk through, offline and online programming. Finally it discusses about the application of robot in different types of field. Besides the theory, there is also exercises to help students to test their knowledge in answering the questions. INDUSTRIAL ROBOTICS ii
TABLE OF CONTENTS 2.4 2.5 A. Laws of robotics B. Functions of robot C.Advantages and disadvantages 01 4 5 6 A. Base B. Manipulator Arm C. End effectors D. Actuators E. Sensors 2.3 Definition of industrial robotics Robot component system Robot design configuration and workspace A. Cartesian robot B. Cylindrical robot C.Articulated robot D Spherical robot D. SCARA robot Robot programming operation method A. Lead -through programming B. Walk- through programming C. Off-Lne programming D. On-Line programming Robot applications A. Welding process B. Spraying process C. Assembly process D. Inspection process E. Testing process F. Pick and place process G. Palletizing process Acknowledgement Abstract Table of contents i ii iii References 2.1 2.2 13 13 13 13 13 13 48 17 19 22 25 27 31 33 34 35 36 37 39 41 42 43 44 45 46 14
2.1 DEFINITION OF INDUSTRIAL ROBOTICS A machine capable of carrying out a complex series of actions automatically, especially one programmable by a computer (Wikipedia, 2021) ISO 8373 definition An automatically controlled, reprogrammable, multipurpose manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications (International Federation of Robotics, 2021) (RIA = Robotic Institute of America) Reprogrammable multifunctional manipulator designed to move materials, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks. (Robotics Inc.Com, 2021) INDUSTRIAL ROBOTICS 1
YEAR EXPLANATION 320 BC Aristotle : "If every tool, when ordered, or even of its own accord, could do the work that befits it... then there would be no need either of apprentices for the master workers or of slaves for the lords.” 1495 Leonardo da vinci sketched plans for a humanoid robot 1700-1900 Mechanical duck made by Jacques de Vaucanson 1913 Henry Ford installs moving conveyor belt assembly line in his car factory. 1920 Karel Capek created 'robot' to describe machines that resembles humans. 1932 Robot toy, 'Lilliput' was produced in Japan 1937 Alan Turing releases his paper which begins the computer revolution 1941 Isaac Asimov describes three laws of robotics in his book. INDUSTRIAL ROBOTICS 2
1950 Alan Turing proposes 'Turing Test' which determine a machine has the power to think for itself. 1954 George Devol and Joe Engleberger design the first programmable robot arm that become first industrial robot 1957 The Soviet Union launches 'Sputnik', the first artificial orbiting satellite. 1964 The IBM 360 becomes the first computer to be mass produced 1977 First Star Wars movie about robots is released 1986 First LEGO based educational products produced 1994 Carnegie universities eight-legged walking robot 1998 LEGO launches first Robotics Inventions System 1999 Sony releases first robotic dog 2000 Honda debuts ASIMO in its serie of humanoid robots 2005 Researchers at cornell University builds smallest robot helicopter (Science kids, 2021) INDUSTRIAL ROBOTICS 3
A. LAWS OF ROBOTICS Isaac Asimov's "Three Laws of Robotics" Robot cannot harm human and its operator Robot must always follow order given by human (Do not conflict with the First Law.) Robot must protect itself from the source of hazard (Not conflict with the First or Second Law.) INDUSTRIAL ROBOTICS 4
Drive The drive is the "engine" that drives the links (the sections between the joints into their desired position. Without a drive, a robot would just sit there, which is not often helpful. Most drives are powered by air, water pressure, or electricity. Controller Every robot is connected to a computer, which keeps the pieces of the arm working together. This computer is known as the controller. The controller functions as the "brain“ of the robot. The controller also allows the robot to be networked to other systems, so that it may work together with other machines, processes, or robots. Arm Robot arms come in all shapes and sizes. The arm is the part of the robot that positions the end- effector and sensors to do their pre-programmed business. Many resemble human arms, and have shoulders, elbows, wrists, even fingers. Each joint is said to give the robot 1 degree of freedom. So, a simple robot arm with 3 degrees of freedom could move in 3 ways: up and down, left and right, forward and backward. B. FUNCTIONS OF A ROBOT INDUSTRIAL ROBOTICS 5
End-Effector The end-effector is the "hand" connected to the robot's arm. It is often different from a human hand - it could be a tool such as a gripper, a vacuum pump, tweezers, scalpel, blowtorch - just about anything that helps it do its job. Some robots can change end-effectors, and be reprogrammed for a different set of tasks. Sensor Most robots of today are nearly deaf and blind. Sensors can provide some limited feedback to the robot so it can do its job. Compared to the senses and abilities of even the simplest living things, robots have a very long way to go. The sensor sends information, in the form of electronic signals back to the controller. Sensors also give the robot controller information about its surroundings and let it know the exact position of the arm, or the state of the world around it. INDUSTRIAL ROBOTICS 6
✓ Improved product quality ✓ Robots can be much more accurate than human ✓ Reduction of hazardous exposure for human workers ✓ Greater response time to inputs than humans ✓ Robots have repeatable precision unless something happens to them or unless wear out ✓ Robots need no environmental comfort. ✓ Robots work continuously without experiencing fatigue of problem ✓ Robots can process multiple tasks simultaneously. ✓ Robots replace human workers creating economic problems. ✓ Robots lack capability to respond in emergencies ✓ Robots are costly, due to Initial cost of equipment, Installation costs ✓ Initial set up of robot in industrial may require more training and expertise. INDUSTRIAL ROBOTICS 7
1. State three laws of robotics 2. Match the correct definition 3. List down THREE advantages and disadvantages in using industrial robot in manufacturing system. TUTORIAL ensor Sensor End effector Controller Drive Powered by air, water pressure or electricity A tool such as gripper Sends information in electronic signals Allows robot networked to other systems INDUSTRIAL ROBOTICS 8
CHECK YOUR ANSWERS!! 1. Three law of robotics Robot cannot harm human and its operator Robot must always follow order given by human (Do not conflict with the First Law.) Robot must protect itself from the source of hazard (Not conflict with the First or Second Law.) 2. Match the correct definition ensor Sensor End effector Controller Drive Powered by air, water pressure or electricity A tool such as gripper Sends information in electronic signals Allows robot networked to other systems INDUSTRIAL ROBOTICS 9
3.List down THREE advantages and disadvantages in using industrial robot in manufacturing system. Advantages • Improved product quality • Robots can be much more accurate than human • Reduction of hazardous exposure for human workers Disadvantages • Robots replace human workers creating economic problems. • Robots lack capability to respond in emergencies • Robots are costly, due to Initial cost of equipment, Installation costs CHECK YOUR ANSWERS!! INDUSTRIAL ROBOTICS 10
BASE MANIPULATORS ARM END EFFECTORS ACTUATORS SENSORS INDUSTRIAL ROBOTICS 11
BASE • The base is secured to a work area and motors, batteries and wheels are added • A mechanical part which consists joint and link that can be moved into different direction. it often consists of joints, actuators, sensors and controller which activated by actuators. one end of the chain is attached to the root base and another to tools to perform tasks. MANIPULATOR ARM • Special tooling that enables robot to perform specific tasks. A mechanism which is located on wrist of the manipulator that pick-up objects, grasp and manage movement. They are two types which are grippers (to grasp and manipulate objects during work cycle) and tools (to perform a process). END EFFECTOR INDUSTRIAL ROBOTICS 12
• Devices that cause rotary joint to rotate about their axes or drive pneumatic joint to slide along their motion axes. There are three types of actuation systems which are hydraulic actuating system, pneumatic actuating system and electrical actuating system. ACTUATORS • Devices that detect the information about robot manipulators work and interactions between robot manipulators and environments. Commonly SENSORS sensors are position, velocity, force and vision sensors. INDUSTRIAL ROBOTICS 13
2.3 SKETCH ROBOT DESIGN CONFIGURATION AND ITS WORKPLACE INDUSTRIAL ROBOTICS 14
FIVE TYPES OF ROBOT CONFIGURATION 4. SPHERICAL ROBOT 2. CYLINDRICAL ROBOT 1. CARTESIAN ROBOT 3. ARTICULATED ROBOT 5. SCARA ROBOT . INDUSTRIAL ROBOTICS 15
Considered in selecting an industrial robot: ✓ its purpose. ✓ fast of move. ✓ precision of movement. ✓ its collaborative robot. Configuration space or robot space can define in common term as Workspace. It’s mean the space in which the mechanism is working where the robot manipulator can reach by its end-effector to the set point. A key concept for motion is the position are every point in the system. Factor for Robot configuration: ✓ how an industrial robot will move ✓ and what limits its workspace. The main characteristics of the workspace are : SHAPE where the robot will work. Its relate the geometrical structure of the robot (interference between links) as well as properties of the DOF (quantity, type of joint and joint limits, both active and passive). DIMENSION influence the workspace, its related with of links of the robot and mechanical limitations joints. STRUCTURE is very important to assuring kinematic characteristics and interaction of the robot to its environment is suitable INDUSTRIAL ROBOTICS 16
Cartesian Configuration A Cartesian configuration can be defines as rectangular configuration. A Cartesian configuration can be defines as robots tool will be move in a linear motion along each of Cartesian coordinates( x,y,z). Its using rigid structure which their horizontal member supports both the ends and can handle heavy loads with high positioning accuracy . Figure 2.3.1 shown the configuration X, Y and Z movement and also the work space or work envelope ( volume cartesian. Figure 2.3.1 : Cartesian Workspace and volume INDUSTRIAL ROBOTICS 17
Applications: Cartesian robots can be used in sealing, handling for plastic moulding, 3D printing, and in a computer numerical control machine (CNC). Pick and place machines and plotters work on the principle of the Cartesian robots. They can handle heavy loads with high positioning accuracy. Figure 2.3.2 shows the application of Cartesian robot in industry Figure 2.3.2 : Robot handling for plastic moulding and sealing (Source : Plant Automation Technology) ADVANTAGES of cartesian are : ✓Highly accurate and speed ✓Less cost ✓Simple operating procedure ✓High payload ✓Very versatile working ✓Simplifies robot and master control system INDUSTRIAL ROBOTICS 18
CYLINDRICAL ROBOT Cylindrical configuration involves two moving elements which are rotary and linear Axis. Cylindrical robots have a rotary joint at the base and a prismatic joint to connect the link. Figure 2.3.3 shown the motion of cylindrical configuration, where a vertical column(Z Axis Movement ) where its can slide moved up and down along the column. The robot arm is attached to the slide so that it allow its tools to rotate around a central axis (Rotate Axis), rotationis must less 360 degrees. The tool can also move toward and away from the central axis, plus up and down the central axis . This motion is provided by a Pneumatic cylinder and the rotation is generally provided by a motor and gear. By rotting the column, the robot is capable of retrieving a cylindrical work envelope. This configuration creates a work- volume in the shape of cylinder. The Axis on cylindrical movement driven by pneumatic, hydraulic or electrically. 2.3.3 : Cylindrical Configuration INDUSTRIAL ROBOTICS 19
Figure 2.3.4 shown CYLINDRICAL WORKSPACE OR WORK ENVELOP and its related to cylindrical coordinate system. Cylindrical coordinate system is a three-dimensional coordinate system that specifies point position by the distance from a chosen reference axis, the direction from the axis relative to a chosen reference direction, and the distance from a chosen reference plane perpendicular to the axis. The latter distance is given as a positive or negative number depending on which side of the reference plane face the point. The origin of the system is the point where all three coordinates can be given as zero. This is the intersection between the reference plane and the axis. The axis is variously called the cylindrical or longitudinal axis, to differentiate it from the polar axis, which is the ray that lies in the reference plane, starting at the origin and pointing in the reference direction. The distance from the axis may be called the radial distance or radius, while the angular coordinate is sometimes referred to as the angular position or as the azimuth. The radius and the azimuth are together called the polar coordinates, as they correspond to a two-dimensional polar coordinate system in the plane through the point, parallel to the reference plane. The third coordinate may be called the height or altitude (if the reference plane is considered horizontal), longitudinal position, or axial position Figure 2.3.4 : Cylindrical workspace CYLINDRICAL WORKSPACE INDUSTRIAL ROBOTICS 20
✓ Deep horizontal reach into production machines is possible. ✓ The vertical structure of the machine conservers floor space. ✓ A very rigid structure is possible for large payloads and good repeatability. DISADVANTAGES ✓ Limited reach to left and right because of the mechanical constraint that limit the side of the horizontal actuator Figure 2.3.5 : Spot and Arc Welding Source : Robotics Businessreview APPLICATION CYLINDRICAL ROBOTS Its often used in tight workspaces for simple assembly, machine tending, pick and place or coating applications due to their compact design Figure 2.3.5 shown example application cylindrical robot in large industrial with long arms and higher payload capabilities handle sport welding on heavy body panels. Smaller robots weld lighter parts such as mounts and brackets. Robotics tungsten inert gas (TIG) and metal inert gas (MIG) welders can position the torch in the exact same orientation on every cycle. Collaborative robots work together with other large industrial robots on massive assembly lines. Robotic welders and handlers must collaborate to keep the assembly line moving. Robot handlers need to place panels at the precise location so the welding robot can perform all the programmed welds. ADVANTAGES INDUSTRIAL ROBOTICS 21
Figure 2.3.6 shown three major angular movement consisting of a base rotation (Axis 1) , Shoulder (Axis 2) and forearm (axis 3) joint Figure 2.3.6 : Jointed articulated geometry robot movement ARTICULATED ROBOT Articulated commonly referring to an industrial robot application. Sometimes it’s called jointed arm, revolute or anthropomorphic machine, have an irregular work envelope. Articulated arm robot consists of several rotational axes. This configuration of the robot exes produces a spherical operational space. Due to their axes of rotation, these robots have an unusually high degree of mobility. There are therefore suitable for assembly tasks which require complex joining motions to be performed. Articulated arm robots can be found frequently in the automotive industry, where they are used primarily to automate welding tasks as well as for for complex assembly and measuring task. Articulated arm robot is also known as vertical articulated arm robots. INDUSTRIAL ROBOTICS 22
Figure 2.3.7 Jointed articulated work envelope Source : jvejournal.com Figure 2.3.7 shown the irregular work envelope of articulated robot. As in previous arm designs, the orientation of the tool plate is provided by the three rations in the wrist. Straight-line motion along any of three joints: therefore, sophisticated controllers are generally required for this type of arm geometry. Electric drives with feedback control system are used on most machines. The human like movements of the jointedspherical arm create the following advantages for robotics application: ✓ Although it occupies a minimum of floor space, the robot achieves deep horizontal reach. ✓ High positioning mobility of the endof-arm tooling allows the arm to reach into enclosures and around obstruction. WORKSPACE ARTICULATED INDUSTRIAL ROBOTICS 23
Figure 2.3.8 : Articulated robot with gripper system Source : Mollers packaging Technology GMBH Figure 2.3.8 Shown application the Articulated robots with their high manoeuvrability, high performance and flexibility. Each articulated robot operated with a gripped specially designed for the application . Articulated robots score points with absolute adaptability and high manoevrability and are programable for multi-level application within production. APPLICATION ARTICULATED ROBOTS INDUSTRIAL ROBOTICS 24
SPHERICAL ROBOT Spherical Robots are often used in tight workspaces for simple assembly, die casting, injection moulding, welding, and material handling or coating applications due to their compact design. Figure 2.3.9 , Figure : 2.3.10 : Spherical work space or working envelope Source : Mwes engineered system Figure 2.3.12 : Packing and Pallet system Source : Mwes engineered system Figure 2.3.11 : Press Brake Automated Bending Source : Mwes engineered system APPLICATION OF SPHERICAL ROBOT Application of spherical robot in industry Shown in Figure 2.3.10 and figure 2.3.11 . INDUSTRIAL ROBOTICS 25
Figure : 2.3.13 : Spherical work space or working envelope Source : Control system design and integration The working envelope of this configuration sweeps out a volume between two partial spheres. There are physical limits imposed by the design on the amount of angular movement in both the vertical and horizontal planes. These restriction create conical dead zones both above and below the robot structure. Its shown in Figure 2.3.13 Shown Spherical work space or working envelope. Where the movement of robot Spherical robots or have an arm with two rotary joints and one linear joint connected to a base with a twisting joint. The axes of the robot work together to form a polar coordinate, which allows the robot to have a spherical work envelope. Polar Robots are credited as one of the first types of industrial robots to ever be developed.. The axes of the robot work together to form a polar coordinate, which allows the robot to have a spherical work envelope. WORKSPACE SPHERICAL INDUSTRIAL ROBOTICS 26
SCARA ROBOT SCARA is an acronym that stands for Selective Compliance Assembly Robot Arm or Selective Compliance Articulated Robot Arm. SCARA Robots function on 3-axis (X, Y, and Z), and have a rotary motion as well. SCARA Robots excel in lateral movements and are commonly faster moving and have easier integration than Cartesian Robots. Its shown in figure 2.3.14. Figure : 2.3.14 : SCARA machine Source : Control system design and integration WORKSPACE SCARA Operating the robot shown in figure 2.3.15, end effector at the front of the robot arm must be in a position and attitude appropriate to the processed workplace, as well as these positions and postures are synthesized by the movement of several arm joint. Robot motion control relationship between the variable space of each joint of the robot arm and the position and posture of the end effector, which is the robot kinematic model. Once the geometry of a robot arm is determined, its kinematic model can be determined, which is the basis of the robot's motion control. Figure : 2.3.15 : SCARA workspace Source : ia.omron.com INDUSTRIAL ROBOTICS 27
The SCARA configuration has a working envelope that can be loosely described as a heart or kidney shaped prism, having a circular hole passing through the middle. This allow a large area coverage in the horizontal plane but relatively little in the vertical plane. The SCARA configuration has a high degree of rigidity in vertical direction of motion and a certain amount of flexibility in the X-Y axis. As such it is especially suitable for precision assembly task. SCARA robot are amongst the fastest robots on the market. Figure 2.3.14 SCARA robot working envelope or work space. and figure 2.3.16 shown the application Figure : 2.3.16 : SCARA Workspace Source : Control system design and integration SCARA WORKSPACE INDUSTRIAL ROBOTICS 28
ADVANTAGES OF SCARA ROBOTS ✓ Compact structure, large operating range and small installation footprint. ✓ Has a high accessibility. Joint coordinate robots can move their hands into a closed space like a car body for work, and rightangle coordinate robots cannot do such work. ✓ No rails are required because there is no moving joint. Rotating joint are easy to seal, because of bearing parts are a large number of production of standard parts, resulting in friction and inertia is small, good reliability. ✓ The required SCARA drive torque is small and the energy consumption is small. ✓ Replace a lot of complex work that is not suitable for manpower and harmful to health. Figure : 2.3.17 : SCARA machine Source : Control system design and integration APPICATION SCARA ROBOT Use of a SCARA Robot allows a workpiece to be mounted in any orientation. Additionally attach a hopper to the parts feeder enables long-time continuously operation. It is also possible to replace the parts feeder with a tray or magazine, thereby increasing the degree of freedom of system construction. Typically, SCARA robots are used for assembly and palletizing, as well as bio-med application, electronics manufacturing , auto parts manufacturing and etc. Its shown in figure 2.3.17 INDUSTRIAL ROBOTICS 29
TUTORIAL 1. List types of robot configuration. 2.Explain characteristics of the working space ANSWER SCHEME 1. 5 types of robot configuration : i. Cartesian ii. Cylindrical iii. Articulated iv. SCARA v. Spherical 2. Explain characteristics of the working space i. The shape is important for the definition of the environment where the robot will work. The shape may vary depending on the geometrical structure of the robot (interference between links) as well as properties of the DoF (quantity,type of joint and joint limits, both active and passive). ii.Dimensions The major influence on the dimensions of workspace is exerted by the dimensions of links of the robot and the mechanical limitations of the joints (both active and passive). iii.The structure of workspace is defined by the structure of the robot and the dimensions of its links. Its important for assuring kinematic characteristics of the robot which are in relation with the interactions of the robot to its environment. INDUSTRIAL ROBOTICS 30
2.4 ROBOT PROGRAMMING A. LEAD THROUGH PROGRAMMING B.WALK THROUGH PROGRAMMING C. OFFLINE PROGRAMMING D. ONLINE PROGRAMMING INDUSTRIAL ROBOTICS 31
2.4 ROBOT PROGRAMMING Robot Programming is the defining of desired motions so that the robot may perform them without human intervention. identifying and specifying the robot configurations . Robot must be programmed to do useful works and perform its tasks a robot is an idiot waiting for you to make it work by the use of programming. Robot program is defined as a path of movements of its manipulator, combined with peripheral equipment actions to support its work cycle. The peripheral equipment actions include Operation of the end-effector. A robot programmer needs to understand the whole task and interfaces with its environment before starts a programming. Figure : 2.4.1 : Robot Programming Source : blog.robotiq.com INDUSTRIAL ROBOTICS 32
A. LEAD –THROUGH PROGRAMMING Teaching the robot via teach pendants that has toggle switches or contact buttons for controlling the movement of the robot. Allows a trained operator physically to lead the robot through the desired sequence of events by activating the appropriate pendant buttons or switches. Position data and functional information are "taught" to the robot, and a new program is written into memory The speed and termination type of the movement should be specified Figure : 2.4.2 : Lead-through Programming Particularly useful in pick-place, arc welding applications. Source : osha.oregon.gov INDUSTRIAL ROBOTICS 33
B. WALK-THROUGH PROGRAMMING Walk through method or manual (limited-sequence robots). A person doing the programming has physical contacts with the robot arm, actually gains control and walks the robot's arm through the desired positions. Each movement is recorded into the memory for the playback during production, including unintended motions. The main concern is on achieving the correct positioning sequences. Cycle time and speed can be changed later, when necessary. A high precision in generating paths cannot be achieved (Manual operation) - Highly skilled operator required. Optimum trajectory velocity cannot be achieved Movements are stored in the sampled time - required large memory. Mainly used in spray painting, arc welding, grinding, deburring and polishing Figure : 2.4.3 : Walk-through Programming Source : osha.oregon.gov INDUSTRIAL ROBOTICS 34
C. OFFLINE PROGRAMMING The programming for the required sequence of functions and positions is written on a remote computer console. Then transfer to the robot controller. The robot programming language is to make it easy for this purpose. Teaching by teach boxes has been used in all of these areas. But this method cannot provide the close control needed in many cases. When sensory information is required to assist in robot control, there is a further problem of transferring the sensory information to the robot. For these reasons ,it is desirable and often essential that computer programming done in advance control robots. This is called off-line programming or pre-programming to differentiate it from the programming that occurs during teaching. Figure : 2.4.4 : Offline Programming Source : osha.oregon.gov INDUSTRIAL ROBOTICS 35
D. ONLINE PROGRAMMING Online Programing means teaching on the real robot. The close connection of teaching, programming and testing allows to evaluate various solution approaches directly on the real robot in the shortest possible time. Online programming use robot to generate the programme and teaching the robot through a sequence of motion that can them be execute repeatedly. Figure : 2.4.5 : Online Programming Source : osha.oregon.gov INDUSTRIAL ROBOTICS 36
2 . 5 ROBOT IN MANUFAC TURING S Y S T EM INDUSTRIAL ROBOTICS 37
2.5 ROBOT APPLICATION IN MANUFACTURING SYSTEM Spot Welding Robot Arc Welding Robot WELDINGPROCESS SPRAYINGPROCESS ASSEMBLY PROCESS INSPECTION PROCESS TESTINGPROCESS PICK & PLACE PROCESS INSPECTION PROCESS TESTINGPROCESS INDUSTRIAL ROBOTICS 38
WELDING PROCESS Welding is a manufacturing process in which two pieces of metal are joined usually by heating and fusing. The welding operations performed by robots are thermal processes in which the metals are joined by melting or fusing their contacting surfaces. Figure : 2.5.1 : Welding Process Source : www.automate.org INDUSTRIAL ROBOTICS 39
WELDING PROCESS Accordingly, there are two types of welding operations performed by the robots : 01 Spot-welding Robots 02 Arc-welding Robots Some materials resist electrical currents, precluding them from other forms of welding. This situation frequently occurs in the automotive industry for piecing together parts of an automobile body. To overcome the issue, robotic welders use a variation of resistance welding to connect a pair of thin metal sheets in a single spot. One of the most common types of robotic welding is the arc process. In this method, an electric arc generates extreme heat, which melts the metal. Molten metal joins parts together, solidifying into a stable connection after cooling. When a project requires a large volume of accurately conjoined metals, arc welding serves as an ideal application. INDUSTRIAL ROBOTICS 40
SPRAYING PROCESS The unhealthy and unpleasant environment of the painting booth in industry made this process an ideal candidate for the application of robots. The solvent materials that are used in spray painting are toxic, and therefore the operators must be protected by masks and be provided with fresh-air ventilation. The painting area must be dust-free and temperature-controlled, and consequently the painting booth is small in size and inconvenient for the operators. Furthermore, the noise arising from the air discharge through the painting nozzles can cause irreversible damage to the ears. For all these reasons, spray painting became one of the first applications of robots. The requirement for robots in spray painting are different from those of other robot applications, and therefore many robot manufacturers offer a robot dedicated to this one application. Figure : 2.5.2 : Spraying Process Source : roboticpaint.com INDUSTRIAL ROBOTICS 41
ASSEMBLY PROCESS Assembling with industrial robots are mainly used for small products such as electrical switches and small motors. Robotised assembly systems are programmable and therefore provided a cost-effective solution for the a ss e m b l y o f s m a l l b a t c h siz e s a n d f o r b a t c h e s containing different products. Although industrial robots require the same fixtures, feeders, and other equipment for positioning the parts as conventional assembly machines, simpler workpiece feeder and f i x t u r e s m a y b e u s e d b e c a u s e o f r o b o t s ’ programmability feature. Furthermore, tactile or optical sensors may be added to the assembly robot to tackle more complex assembly tasks. Some assembly tasks require the participation of more than one robot. In order to reduce the cost per arm, there are systems in which several cartesian arms can use the same base and share the same controller. Assembly robots can be designed in any coordinate system, cartesian, cylindrical, spherical, or articulated. However, many tasks require only vertical assembly motions, such as the assembly of printed circuit boards. Figure : 2.5.3 : Asssembly Process Source: www.assemblymag.com INDUSTRIAL ROBOTICS 42
INSPECTION PROCESS Assembling with industrial robots are mainly used for small products such as electrical switches and small motors. Robotised assembly systems are programmable and therefore provided a costeffective solution for the assembly of small batch sizes and for batches containing different products. Although industrial robots require the same fixtures, feeders, and other equipment for positioning the parts as conventional assembly machines, simpler workpiece feeder and fixtures may be used because of robots’ programmability feature. Furthermore, tactile or optical sensors may be added to the assembly robot to tackle more complex assembly tasks. Some assembly tasks require the participation of more than one robot. In order to reduce the cost per arm, there are systems in which several cartesian arms can use the same base and share the same controller. In order to reduce the cost per arm, there are systems in which several cartesian arms can use the same base and share the same controller. Figure : 2.5.4 : Asssembly Process Source: www.automate.org INDUSTRIAL ROBOTICS 43
TESTING PROCESS Robotic Test Automation allows production teams to focus on faster delivery of innovation, rather than getting bogged down in business process definition, and creation and execution. This robots automate repetitive tasks, reduce margins of error to negligible rates, and enable human workers to focus on more productive areas of the operation. Figure : 2.5.5 : ACCUBOT system can conduct non-destructive testing of composite components Source: www.compositesworld.com INDUSTRIAL ROBOTICS 44