Wilson Implementation of Robot Systems

An introduction to robotics, automation, and successful systems integration in manufacturing
1. Auflage 2014
ISBN: 978-0-12-404749-5
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 242 Seiten

Based on the author's wide-ranging experience as a robot user, supplier and consultant, Implementation of Robot Systems will enable you to approach the use of robots in your plant or facility armed with the right knowledge base and awareness of critical factors to take into account.This book starts with the basics of typical applications and robot capabilities before covering all stages of successful robot integration. Potential problems and pitfalls are flagged and worked through so that you can learn from others' mistakes and plan proactively with possible issues in mind.Taking in content from the author's graduate level teaching of automation and robotics for engineering in business and his consultancy as part of a UK Government program to help companies advance their technologies and practices in the area, Implementation of Robot Systems blends technical information with critical financial and business considerations to help you stay ahead of the competition. - Includes case studies of typical robot capabilities and use across a range of industries, with real-world installation examples and problems encountered - Provides step-by-step coverage of the various stages required to achieve successful implementation, including system design, financial justification, working with suppliers and project management - Offers no-nonsense advice on the pitfalls and issues to anticipate, along with guidance on how to avoid or resolve them for cost and time-effective solutions

Mike Wilson is president of the British Automation and Robotics Association (BARA), director of the Processing & Packaging Machinery Association (PPMA), vice chairman of the Engineering and Machinery Alliance (EAMA) and former chairman of the International Federation of Robotics (IFR). Mike has a 30 year career working with robots as a user, supplier and advisor. He is an experienced automation consultant, working throughout Europe, North America and India across a variety of industries as managing director of Creative Automation Solutions Ltd.

Autoren/Hrsg.

Wilson, Mike

Inhaltsverzeichnis

1;Front Cover;1
2;Implementation of Robot Systems: An introduction to robotics, automation, and successful systems integration in manufacturing;4
3;Copyright;5
4;Contents;6
5;Acknowledgements;8
6;Dedication;10
7;About the Author;12
8;List of Figures;14
9;List of Tables;16
10;Chapter 1: Introduction;18
10.1;Chapter Contents;18
10.2;1.1. Scope;19
10.3;1.2. Introduction to Automation;21
10.4;1.3. Evolution of Robots;23
10.5;1.4. Development of Robot Applications;28
10.5.1;1.4.1. Automotive Industry;28
10.5.2;1.4.2. Automotive Components;32
10.5.3;1.4.3. Other Sectors;33
10.5.4;1.4.4. Future Potential;33
10.6;1.5. Robots Versus Employment;34
11;Chapter 2: Industrial Robots;36
11.1;Chapter Contents;36
11.2;2.1. Robot Structures;38
11.2.1;2.1.1. Articulated Arm;39
11.2.2;2.1.2. SCARA;41
11.2.3;2.1.3. Cartesian;43
11.2.4;2.1.4. Parallel;44
11.2.5;2.1.5. Cylindrical;45
11.3;2.2. Robot Performance;45
11.4;2.3. Robot Selection;48
11.5;2.4. Benefits of Robots;50
11.5.1;2.4.1. Benefits to System Integrators;51
11.5.2;2.4.2. Benefits to End Users;52
11.5.2.1;Reduce Operating Costs;52
11.5.2.2;Improve Product Quality and Consistency;53
11.5.2.3;Improve Quality of Work for Employees;53
11.5.2.4;Increase Production Output Rate;53
11.5.2.5;Increase Product Manufacturing Flexibility;54
11.5.2.6;Reduce Material Waste and Increase Yield;54
11.5.2.7;Comply with Safety Rules and Improve Workplace Health and Safety;54
11.5.2.8;Reduce Labour Turnover and Difficulty of Recruiting Workers;55
11.5.2.9;Reduce Capital Costs;55
11.5.2.10;Save Space in High-Value Manufacturing Areas;55
12;Chapter 3: Automation System Components;56
12.1;Chapter Contents;56
12.2;3.1. Handling Equipment;57
12.2.1;3.1.1. Conveyors;58
12.2.2;3.1.2. Discrete Vehicles;59
12.2.3;3.1.3. Part Feeding Equipment;60
12.2.3.1;Bowl Feeders;61
12.2.3.2;Linear Feeders;62
12.2.3.3;Blow Feeders;62
12.2.3.4;Bandoleer Feeders;63
12.2.3.5;Magazine Feeders;63
12.3;3.2. Vision Systems;63
12.4;3.3. Process Equipment;66
12.4.1;3.3.1. Welding;67
12.4.1.1;Spot Welding;67
12.4.1.2;Arc Welding;68
12.4.2;3.3.2. Painting;73
12.4.3;3.3.3. Dispensing of Adhesives and Sealants;74
12.4.4;3.3.4. Cutting and Material Removal;74
12.5;3.4. Grippers and Tool Changers;76
12.6;3.5. Tooling and Fixturing;79
12.7;3.6. Assembly Automation Components;81
12.8;3.7. System Controls;83
12.9;3.8. Safety and Guarding;86
12.10;3.9. Summary;89
13;Chapter 4: Typical Applications;92
13.1;Chapter Contents;92
13.2;4.1. Welding;93
13.2.1;4.1.1. Arc Welding;93
13.2.2;4.1.2. Spot Welding;95
13.2.3;4.1.3. Laser Welding;97
13.3;4.2. Dispensing;98
13.3.1;4.2.1. Painting;98
13.3.2;4.2.2. Adhesive and Sealant Dispensing;100
13.4;4.3. Processing;102
13.4.1;4.3.1. Mechanical Cutting;102
13.4.2;4.3.2. Water Jet Cutting;103
13.4.3;4.3.3. Laser Cutting;103
13.4.4;4.3.4. Grinding and Deburring;104
13.4.5;4.3.5. Polishing;106
13.5;4.4. Handling and Machine Tending;107
13.5.1;4.4.1. Casting;108
13.5.2;4.4.2. Plastic Moulding;109
13.5.3;4.4.3. Stamping and Forging;110
13.5.4;4.4.4. Machine Tool Tending;111
13.5.5;4.4.5. Measurement, Inspection, and Testing;114
13.5.6;4.4.6. Palletising;115
13.5.7;4.4.7. Packing and Picking;116
13.6;4.5. Assembly;117
14;Chapter 5: Developing a Solution;120
14.1;Chapter Contents;120
14.2;5.1. Determining Application Parameters;121
14.3;5.2. Initial Concept Design;123
14.3.1;5.2.1. Arc Welding;124
14.3.2;5.2.2. Machine Tool Tending;128
14.3.3;5.2.3. Palletising;131
14.3.4;5.2.4. Packing;134
14.3.4.1;Primary Packing;134
14.3.4.2;Secondary Packing;136
14.3.5;5.2.5. Assembly;138
14.3.6;5.2.6. Other Applications;140
14.3.6.1;Spot and Laser Welding;140
14.3.6.2;Painting and Dispensing;140
14.3.6.3;Material Removal;141
14.4;5.3. Controls and Safety;141
14.5;5.4. Testing and Simulation;143
14.6;5.5. Refining the Concept;145
15;Chapter 6: Specification Preparation;150
15.1;Chapter Contents;150
15.2;6.1. Functional Elements of a Specification;151
15.2.1;6.1.1. Overview;152
15.2.2;6.1.2. Automation Concept;152
15.2.3;6.1.3. Requirements;152
15.3;6.2. Scope of Supply;154
15.3.1;6.2.1. Free Issue;154
15.3.2;6.2.2. Safety;154
15.3.3;6.2.3. Services;155
15.3.4;6.2.4. Project Management;155
15.3.5;6.2.5. Design;155
15.3.6;6.2.6. Manufacture and Assembly;156
15.3.7;6.2.7. Predelivery Tests;156
15.3.8;6.2.8. Delivery;157
15.3.9;6.2.9. Installation and Commissioning;157
15.3.10;6.2.10. Final Testing and Buy-Off;158
15.3.11;6.2.11. Standby;159
15.3.12;6.2.12. Training;159
15.3.13;6.2.13. Documentation;159
15.3.14;6.2.14. Warranty;160
15.3.15;6.2.15. Other Items;160
15.4;6.3. Buy-Off Criteria;160
15.5;6.4. Covering Letter;161
15.6;6.5. Summary;162
16;Chapter 7: Financial Justification;164
16.1;Chapter Contents;164
16.2;7.1. Benefits of Robots;166
16.2.1;7.1.1. Reduce Operating Costs;166
16.2.2;7.1.2. Improve Product Quality and Consistency;167
16.2.3;7.1.3. Improve Quality of Work for Employees;167
16.2.4;7.1.4. Increase Production Output;168
16.2.5;7.1.5. Increase Product Manufacturing Flexibility;168
16.2.6;7.1.6. Reduce Material Waste and Increase Yield;168
16.2.7;7.1.7. Comply with Safety Rules and Improve Workplace Health and Safety;169
16.2.8;7.1.8. Reduce Labour Turnover and Difficulty of Recruiting Workers;169
16.2.9;7.1.9. Reduce Capital Costs;169
16.2.10;7.1.10. Save Space in High-Value Manufacturing Areas;170
16.3;7.2. Quick Financial Analysis;170
16.3.1;7.2.1. How Conservative Is the Calculation?;171
16.3.2;7.2.2. What Is the Technical Risk?;171
16.3.3;7.2.3. Is the Solution Flexible?;171
16.3.4;7.2.4. What Is the Driver for the Investment?;172
16.3.5;7.2.5. Is the Solution Future Proofed?;172
16.3.6;7.2.6. Competitive Position?;172
16.3.7;7.2.7. Company Attitude to Automation?;172
16.3.8;7.2.8. Project - Go or No Go?;173
16.4;7.3. Identifying Cost Savings;173
16.4.1;7.3.1. Quality Cost Savings;174
16.4.2;7.3.2. Reduced Labour Turnover and Absenteeism;175
16.4.3;7.3.3. Health and Safety;175
16.4.4;7.3.4. Floor Space Savings;175
16.4.5;7.3.5. Other Savings;175
16.5;7.4. Developing the Justification;176
16.6;7.5. Need for Appropriate Budgets;177
17;Chapter 8: Successful Implementation;180
17.1;Chapter Contents;180
17.2;8.1. Project Planning;181
17.3;8.2. Vendor Selection;184
17.4;8.3. System Build and Buy-Off;187
17.5;8.4. Installation and Commissioning;189
17.6;8.5. Operation and Maintenance;191
17.7;8.6. Staff and Vendor Involvement;192
17.7.1;8.6.1. Vendors;193
17.7.2;8.6.2. Production Staff;193
17.7.3;8.6.3. Maintenance Staff;194
17.8;8.7. Avoiding Problems;195
17.8.1;8.7.1. Project Conception;196
17.8.1.1;Project Based on an Unrealistic Business Case;196
17.8.1.2;Project Based on State-of-Art or Immature Technology;196
17.8.1.3;Lack of Senior Management Commitment;196
17.8.1.4;Customers Funding and/or Timescale Expectations Are Unrealistic;196
17.8.2;8.7.2. Project Initiation;197
17.8.2.1;Vendor Setting Unrealistic Expectations on Cost, Timescale or Capability;197
17.8.2.2;Customer Failure to Define and Document Requirements;197
17.8.2.3;Failure to Achieve an Equitable Relationship;197
17.8.2.4;Customer Staffs Lack of Involvement;197
17.8.2.5;Poor Project Planning, Management, and Execution;198
17.8.2.6;Failure to Clearly Define Roles and Responsibilities;198
17.8.3;8.7.3. System Design and Manufacture;198
17.8.3.1;Failure to ``Freeze´´ the Requirements and Apply Change Control;198
17.8.3.2;Vendor Starting a New Phase Prior to Completing the Previous One;199
17.8.3.3;Failure to Undertake Effective Project Reviews;199
17.8.4;8.7.4. Implementation;199
17.8.4.1;Customer Failure to Manage the Changes Implicit in the Project;199
17.8.5;8.7.5. Operation;199
17.8.5.1;Inadequate User Training;199
17.8.5.2;Customer Fails to Maintain the System;199
17.8.5.3;Customer Fails to Measure the Benefit of the Project;200
17.9;8.8. Summary;200
18;Chapter 9: Conclusion;202
18.1;Chapter Contents;202
18.2;9.1. Automation Strategy;205
18.3;9.2. The Way Forward;208
19;References;212
20;Abbreviations;214
21;Bibliography;216
22;Appendix;218
22.1;User Requirements;221
22.1.1;Specification;221
22.2;Contents;222
22.3;A.1. Overview;223
22.3.1;A.1.1. Current Welding Operation;223
22.3.2;A.1.2. Automation Concept;224
22.4;A.2. Requirements;225
22.4.1;A.2.1. Products;225
22.4.2;A.2.2. Tolerances and Quality;225
22.4.3;A.2.3. Fixtures;226
22.4.4;A.2.4. Cycle Time and Availability;226
22.4.5;A.2.5. Welding Equipment;226
22.4.6;A.2.6. Controls and HMI;227
22.4.7;A.2.7. Enclosure;227
22.5;A.3. Scope of Supply;228
22.5.1;A.3.1. Free Issue Equipment;228
22.5.2;A.3.2. Safety;228
22.5.3;A.3.3. Services;228
22.5.4;A.3.4. Project Management;229
22.5.5;A.3.5. Design;229
22.5.6;A.3.6. Manufacture and Assembly;229
22.5.7;A.3.7. Pre-delivery Tests;230
22.5.7.1;Cycle Time and Availability Calculations;230
22.5.8;A.3.8. Delivery;232
22.5.9;A.3.9. Installation Requirements;232
22.5.10;A.3.10. Installation and Commissioning;232
22.5.11;A.3.11. Final Testing and Buy-off;233
22.5.12;A.3.12. SAT Procedure;233
22.5.12.1;Cycle Time and Availability Calculations;233
22.5.13;A.3.13. Documentation;234
22.5.14;A.3.14. Training;235
22.5.15;A.3.15. Spares and Service Contract;235
22.6;A.4. General;235
22.6.1;A.4.1. Contacts;235
22.6.2;A.4.2. Clarifications;236
22.6.3;A.4.3. Environment;236
22.6.4;A.4.4. Preferred Vendors;236
22.6.5;A.4.5. Warranty;236
22.6.6;A.4.6. Standards;237
23;Index;238

Leseproben

Chapter 2

Industrial Robots

Abstract

This chapter provides more detail on industrial robots commencing with the accepted definition. The various configurations are introduced, including articulated, SCARA, cartesian, and parallel or delta. The typical applications and market shares for each configuration are discussed. The key issues regarding robot performance, including working envelope and repeatability, are discussed together with the main points to consider when selecting robots. This includes a review of the typical contents of a robot data sheet. The benefits that robots can provide are also discussed, both for system integrators and end users. This includes the 10 key benefits that robots can provide for a manufacturing facility.

Keywords

Robot configuration

Articulated

SCARA

Cartesian

Parallel

Delta

Working envelope

Repeatability

Chapter Contents

2.1 Robot Structures   21

2.1.1 Articulated Arm   22

2.1.2 SCARA   24

2.1.3 Cartesian   26

2.1.4 Parallel   27

2.1.5 Cylindrical   28

2.2 Robot Performance   28

2.3 Robot Selection   31

2.4 Benefits of Robots   33

2.4.1 Benefits to System Integrators   34

2.4.2 Benefits to End Users   35

Reduce Operating Costs  35

Improve Product Quality and Consistency  36

Improve Quality of Work for Employees  36

Increase Production Output Rate  36

Increase Product Manufacturing Flexibility  37

Reduce Material Waste and Increase Yield  37

Comply with Safety Rules and Improve Workplace Health and Safety  37

Reduce Labour Turnover and Difficulty of Recruiting Workers  38

Reduce Capital Costs  38

Save Space in High-Value Manufacturing Areas  38

An industrial robot has been defined by ISO 8373 (International Federation of Robotics, 2013) as:

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.

Within this definition, further clarification of these terms is as follows:

• Reprogrammable – motions or auxiliary functions may be changed without physical alterations.

• Multipurpose – capable of adaptation to a different application possibly with physical alterations.

• Axis – an individual motion of one element of the robot structure, which could be either rotary or linear.

In addition to these general-purpose industrial robots, there are a number of dedicated industrial robots that fall outside this definition. These have been developed for applications such as machine tending and printed circuit board assembly and do not meet the definition because they are dedicated to a specific task and are therefore not multipurpose.

As mentioned in Chapter 1, the first application of an industrial robot was at General Motors in 1961. Since that time, robotic technology has developed at a fast pace and the robots in use today are very different to the first machines in terms of performance, capability, and cost. There have been various mechanical designs developed to meet the needs of specific applications, which are described below.

These different configurations have resulted from the ingenuity of the robot designers combined with advances in technology, which have enabled new approaches to machine design. The most significant of these was the introduction of electric drives to replace the use of hydraulics and the increasing performance of the electric drives, providing increased load-carrying capacity combined with high speed and precision.

Initially, hydraulics was used as the primary motive power. Hydraulic power was capable of providing the load-carrying capacity necessary for the early spot welding applications in the automotive industry. However, the responsiveness was poor and the repeatability and path following capabilities limited. For the first installations the robot technicians were required to start work early to turn on the robots, so they were warmed up prior to production starting, to ensure the robots performed repeatably from the first car body to welded.

Pneumatics were used to provide a low cost power source; however, this again could not achieve high repeatability due to the lack of control available. Hydraulics were also used for the early paint robots because electric drives could not, at that time, be used in the explosive atmosphere of the paint booth, caused by the use of solvent-based paints. Painting, by the nature of the application, carrying a spray gun with a 12 inches wide fan, about 12 inches from the surface, did not require the repeatability and control necessary for other applications; therefore, this proved to be a successful application for robots.

Electric drives of various different types have been used. DC servo motors were initially the most prevalent. These however had limited load-carrying capacity, which did initially provide constraints for the use of robots for spot welding applications due to the weight of the welding guns. Stepper motors were also utilised for high precision, low load-carrying applications. Once AC servo motors became available these took over the majority of applications. Their performance has continually increased providing better control, high repeatability, and precision as well as high load-carrying capacity. AC servo motors are now utilised in almost all robot designs.

2.1 Robot Structures

An industrial robot is typically some form of jointed structure of which there are various different configurations. The robot industry has defined classifications for the most common and these are:

• Articulated

• SCARA

• Cartesian

• Parallel (or Delta)

• Cylindrical.

These structures and their benefits are described in more detail below. The structures are achieved by the linking of a number of rotary and/or linear motions or joints. Each of the joints provides motion that collectively can position the robot structure, or robot arm, in a specific position. To provide the ability to position a tool, mounted on the end of the robot, at any place at any angle requires six joints, or six degrees of freedom, commonly known as six axes.

The working envelope is the volume the robot operates within. This is typically shown (see Figure 2.1) as the volume accessible by the centre of the fifth axis. Therefore, anywhere within this working envelope the robot can position a tool at any angle. The working envelope is defined by the structure of the robot arm, the lengths of each element of the arm, and the motion type and range that can be achieved by each joint. The envelope is normally shown as a side view, providing a cross-section of the envelope, produced by the motion of axes 2–6 and a plan view then illustrating how this cross-section develops when the base axis, axis 1, is moved. It should also be noted that the mounting of any tools on the robot will also have an impact on the actual envelope accessible by the robot and tool combined.

Figure 2.1 Typical working envelope.

The first robot, a Unimate, was designated as a polar-type machine. This design was particularly suited to the hydraulic drive used to power the robot. The robot (Figure 2.2) provided five axes of motion; that is, five joints that could be moved to position the tool carried by the robot in a particular position. These consisted of a base rotation, a rotation at the shoulder, a movement in and out via the arm, and two rotations at the wrist. The provision of only five axes provided limitations in terms of the robot's ability to orientate the tool. However, in the early days, the control technology was unable to meet the needs for six axes machines.

Figure 2.2 Unimate robot.

2.1.1 Articulated Arm

The most common configuration is the articulated or jointed arm (Figure 2.3). This closely resembles the human arm and is very flexible. These are normally...