Robots

Industrial Robots

• General purpose, programmable machine that processes certain anthropomorphic characteristics

• It can be programmed to perform a useful task repeatedly

Application of Robots

• Material transfer and handling

• Machine loading and unloading

• Welding

• Spray coating

• Inspection

• Processing operations

• Assembly

Material Transfer and Handling

• Material transfer applications are those in which the robot is used to move workparts from one location to another.

• Examples of material transfer robot operations:

  • Pick & place operation

  • Stacking operation

  • Handling radioactive materials

• Advantages:

  • Heavy, complicated and delicate jobs can be easily handled

  • Worker is free from repetitive tasks

  • Reduces material transfer idle time

Machine loading and unloading

• Robot is required to supply a production machine with raw parts and/or to unload finished parts from the machine.

Advantages:

• Human labour is relieved form hot and unsafe environment as in die-castings, forgings

• Reduces machine loading and unloading time

• Increases productivity

Welding

• The applications logically divide into two basic categories, spot welding and arc welding.

• Spot welding is a process in which metal parts are fused together at localized points by passing a large electric current through the two parts at the point of contact.

• Several types of arc welding processes can be accomplished by industrial robots, like gas metal arc welding or MIG welding

• Advantages:

  • Higher productivity

  • Improved safety and quality of work

  • Greater quality of product

Spray Coating

• Automobile and appliances industries require the application of some form of paint.

• Usually human workers apply this form of paint, the most common method is spray painting, which has many health hazards like fumes, mist, noise, fire hazard and possible cancer danger.

• For these reasons, specialized industrial robots are being used more and more frequently to perform spray painting.

• Advantages:

  • Safety of operations from hazardous environment

  • Lower energy consumption

  • Less coating material usage

  • Higher Productivity

Processing Operations

• This is a miscellaneous category in which the robot is used to perform some manufacturing process other than welding, spray painting, assembly and inspection operation.

• Operations like drilling, boring, reboring, grinding, milling, riveting, polishing, deburring, etc.

• Advantages:

  • Increased productivity

  • Reduced machining time

Assembly

• Included operations like parts mating, parts joining, adhesive works, crimping, etc.

• Advantages:

  • Higher productivity

  • Reduced rejected parts

  • Less wastage of materials

  • Fast operations

Inspection

• Traditionally inspection function has been a very labour intensive activity - slow, tedious, boring and not 100% accurate

• Use of robots overcomes these problems.

• Robots may use gauges or mechanical probes, optical sensors to perform dimensional checking

Six Degrees of Freedom

• The purpose of the robot is to perform a useful task.

• To accomplish the task, an end effector is attached to the end of the robots arm.

• The robot arm must be capable of moving the end effector through a sequence of motions.

1. Vertical traverse

   • Up and down motions of the arm, caused by pivoting the entire arm about a horizontal axis or moving the arm along a vertical slide

2. Radial traverse

   • Extension and retraction of the arm (in and out movement)

3. Rotational traverse

   • Rotation about the vertical axis (right or left swivel of the robot arm)

4. Wrist swivel

   • Rotation of the wrist

5. Wrist bend

   • Up or down movement of the wrist, which also involves a rotational movement

6. Wrist yaw

   • Right or left swivel of the wrist

Additive Manufacturing

• Additive manufacturing is the formalized term for what used to be called rapid prototyping and what is popularly called 3D Printing

• Referred to in short as AM, the basic principle of this technology is that a model, initially generated using a 3D CAD system, can be fabricated directly without the need for process planning.

• Other manufacturing processes require a careful and detailed analysis

• In contrast, AM needs only some basic dimensional details and a small amount of understanding as to how the AM machine works and the materials that are used to build the part.

• The key to how AM works is that parts are made by adding material in layers; each layer is a thin cross-section of the part derived from the original CAD data.

• All commercialized AM machines to date use a layer-based approach, and the major ways that they differ are in the materials that can be used, how the layers are created, and how the layers are bonded to each other.

• Such differences will determine factors like the accuracy of the final part plus its material properties and mechanical properties.