Industrial Robots And Manufacturing Automation.

Abstract

Automation started out as an assembly line of workers doing the same repetitive task all day long. Some of the jobs were very boring, dirty, unpleasant, and possibly dangerous. After the introduction of the first robot in 1961, automation began to advance in ways people could only imagine.

Each of the six basic styles of robot used in industry today were designed with different applications in mind. Some of the robots were designed for assembly, others are more suited for simple pick and place applications, while a select few are capable of carrying heavy loads over a large area.

The operations of the robots have also advanced from simple hard-stop, one-function, hydraulic actuated robots to the more sophisticated, high-precision, servo controlled robots that can be reprogrammed to do many different jobs.

Robots have greatly increased production, the quality of the parts, and the safety of workers. The main reason for the use of robots is to make a company profitable while producing a high quality part at competitive prices.

The number of robots used in industry increases every year as more companies realize their many benefits. Robots are the future of the manufacturing industry. As the performance and flexibility of robots increases and their prices continue to drop, many companies will uses these added incentives to invest in the future. Soon every company that has an application for a robot will be forced to invest in one, to stay competitive in the world market.

1

Introduction

The Robotics Industry Association defines a robot as "a reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks" (Zalda 8). In short, a robot is a machine that is programmed to perform a variety of tasks in place of humans.

The first industrial robot, built in 1961, was a mechanical arm used to load presses. After the development of the computer and the CNC (Computer Numerical Control) in the 1970's, the world saw great advances in the development of robotic control and the quality of robot manufacturing. As a result, there has been acceptance of the industrial robot world wide, improving the productivity and quality standards of industry (Hodges 3-5).

Robots accomplish a wide variety of tasks in both fabrication and assembly production. As workers, they have several advantages: they never get tired, they never get board, or distracted, and they are less sensitive to their surroundings. In short, for any job that is unpleasant, boring, or dangerous the ideal worker is a robot (Williams 192).

Automobile assembly lines account for 40% of the robots found in the world. The robots are used to stamp out and machine car parts, weld the parts together, and paint them. Robots are what enable automakers to produce cars faster and at a lower cost (Time 100).

The total number of industrial robots operating in the United States today is around 116,000 (Weimer 25). This report will describe the six basic types of robot, how they operate, and why they are so valuable to the manufacturing industry.

2

Collected Data

Types of robots used in Industry

Cartesian

The Cartesian Robot system consists of three linear axes that move at right angles to each other on a rigid structure capable of handling heavy loads. These robots are commonly used for pick and place applications including tool loading, part stacking and part assembly (Hodges 18-29). An example of a Cartesian Robot is shown in Appendix A, Figure 1.

Gantry

The Gantry Robot system is very similar to the Cartesian Robot. Both have the same axes arrangement, but the Gantry Robot has an additional support for more rigidity. Gantry Robots are capable of transferring loads, up to 1000 lb over a large work area very quickly (Hodges 18-20). An example of a Gantry Robot is shown in Appendix A, Figure 2.

Cylindrical

The Cylindrical Robot system has three axes. The first axis is a rigid structure that is able to rotate 300o about its base. The other two axes are linear travel joints, one in the vertical plane and one in the horizontal. These robots are capable of lifting heavy loads and are useful for simple material transfer and assembly, but are restricted to areas close to their base (Hodges 13-30). An example of a Cylindrical Robot is shown in Appendix A, Figure 3.

Polar

The Polar Robot system has three axes that are used to cover a large work area. The first two axes are rotary joints and third is linear. Unfortunately, these robots cannot reach near there base and can only be used when there is a limited amount of vertical movement

3

required. The Polar Robot is very popular in the automotive industry and has been used since the 1960's for spot welding and loading machines (Hodges 13-30). An example of a Polar Robot is shown in Appendix A, Figure 4.

Articulated Arm

The Articulated Arm system is a robot that is made up of all rotary joints. This robot is the one that most resembles a human arm. The Articulated Arm is the most widely used robot because of its ability to reach every part of the work area. This robot is also a good candidate for use in harsh environments and in clean rooms. The rotary joints are completely sealed from the environment, preventing them from becoming contaminated or the joints contaminating the environment (Hodges 13-31). An example of an Articulated Arm is shown in Appendix A, Figure 5.

SCARA

The Selective Compliance Assembly Robot Arm (SCARA) is an extension of the Articulated Arm idea. The SCARA robot has rotary motion about its base, two smaller rotaries for the first and second joints on the arm, and a linear vertical travel. These robots are very fast and accurate to one thousandth of an inch. These robots were originally designed for assembly work, but can be used for welding, drilling, soldering, or any light to medium load that does not require high vertical movement (Hodges 21-31). An example of a SCARA robot is shown in Appendix A, Figure 6.

4

Robot Control

Actuators

Actuators are what make the robot

...