Advantages & disadvantages of automation

The main advantages of automation are:

 Increased throughput or productivity.
 Improved quality or increased predictability of quality.
 Improved robustness (consistency), of processes or product.
 Increased consistency of output.
 Reduced direct human labour costs and expenses.

The main disadvantages of automation are:

 Security Threats/Vulnerability: An automated system may have a limited level of intelligence, and is therefore more susceptible to committing errors outside of its immediate scope of knowledge (e.g., it is typically unable to apply the rules of simple logic to general propositions).

Unpredictable/excessive development costs: The research and development cost of automating a process may exceed the cost saved by the automation itself.

High initial cost: The automation of a new product or plant typically requires a very large initial investment in comparison with the unit cost of the product, although the cost of automation may be spread among many products and over time.

Additional training and technical help is needed for the installation as well as maintenance.

Types of automation

Automation systems can be categorized based on the flexibility and level of integration in manufacturing process operations. Various automation systems can be classified as follows

Fixed Automation:-
- It is used in high volume production with dedicated equipment, which has a fixed set of operation and designed to be efficient for this set.
- Continuous flow and Discrete Mass Production systems use this automation.
- E.g. Distillation Process, Conveyors, Paint Shops, Transfer lines etc. A process using mechanized machinery to perform fixed and repetitive operations in order to produce a high volume of similar parts.

Programmable Automation:-
 - It is used for a changeable sequence of operation and configuration of the machines using electronic controls.
-However, non-trivial programming effort may be needed to reprogram the machine or sequence of operations.
-Investment on programmable equipment is less, as production process is not changed frequently.
 --It is typically used in Batch process where job variety is low and product volume is medium to high, and sometimes in mass production also.
- E.g. in Steel Rolling Mills, Paper Mills etc.

Flexible Automation:-

- It is used in Flexible Manufacturing Systems (FMS) which is invariably computer controlled. Human operators give high-level commands in the form of codes entered into computer identifying product and its location in the sequence and the lower level changes are done automatically. 

-Each production machine receives settings/instructions from computer. These automatically loads/unloads required tools and carries out their processing instructions.

 -After processing, products are automatically transferred to next machine. 

-It is typically used in job shops and batch processes where product varieties are high and job volumes are medium to low. 

Such systems typically use Multipurpose CNC machines, Automated Guided Vehicles (AGV) etc.

Integrated Automation:

-It denotes complete automation of a manufacturing plant, with all processes functioning under computer control and under coordination through digital information processing.

- It includes technologies such as computer-aided design and manufacturing, computer-aided process planning, computer numerical control machine tools, flexible machining systems, automated storage and retrieval systems, automated material handling systems such as robots and automated cranes and conveyors, computerized scheduling and production control.

-It may also integrate a business system through a common database. In other words, it symbolizes full integration of process and management operations using information and communication technologies.

-Typical examples of such technologies are seen in Advanced Process Automation Systems and Computer Integrated Manufacturing (CIM).

Defination of PLC

     A Programmable Logic Controller (PLC) is an electronic device that takes input from the plant / machine via sensors and transmitters, executes the logic programmed in its memory and generates the useful outputs on actuators to control plant / machine.

  A PLC is an example of a real time system since output results must be produced in response to input conditions within a bounded time, otherwise unintended operation will result.