Reliability Reliability may be defined as the probability, or degree of confidence that a product will perform a specified number of times under prescribed conditions. For example, the reliability of an electrical changeover switch may be defined as 0.9999. This may hold true only when it is operated with an input voltage of 440 volts AC, in an environmental temperature range of 0 to 80 degrees C, with humidity less than 90 percent, if its housing has never been opened, if it has been operated less than 1 million times, and if its is less than five years old. Even if any one of these conditions is violated, then the reliability concepts goes off. When parts are interdependent, and especially when there is a large number of them, achieving a high degree of reliability for a product presents and real challenge. Maintainability Maintainability refers to the ability of the user Continue reading
Production Management Concepts
Production Planning and Control
Planning and control are interrelated and interdependent. Planning is meaningless unless control action is taken to ensure the success of the plan. Control also provides information feedback which is helpful in modifying the existing plans and in making new plans. Similarly, control is dependent on planning as the standards of performance are laid down under planning. Therefore, production and control should be considered an integrated function of planning to ensure the most efficient production and regulation of operations to execute the plans successfully. Production planning and control may be defined as the direction and coordination of the firm’s material and physical facilities towards the attainment of pre-specified production goals in the most efficient available way. It is the process of planning production in advance of operations, establishing the exact route of each individual item, part or assembly, setting starting and finishing dates for each important item Continue reading
The Seven Wastes of Lean Manufacturing
There are differing opinions on how many ‘types’ of waste an organisation might have. Current thinking suggests, seven, eight, or even nine depending on the nature of the organisation and the type of work carried out. Originally, there were said to be seven types of waste, and these were largely found in manufacturing organisations. They can be listed as: Overproduction Excess inventory Waiting (lost time) Unnecessary motion Unnecessary transportation (double handling, or moving excess stock) Re-work (poor quality) Over-processing (over-engineered) In each instance, it is recognized that even incremental improvements can help an organisation to increase its efficiency and reduce its costs. These savings and improvements are typically realized in a greater proportion of better quality output, meaning that even small improvements can have an exponentially large positive outcome. It is also noted that each one of these seven types of waste can be tied to different types Continue reading
Batch Production – Meaning and It’s Key Characteristics
Batch production is one of manufacturing methods where limited quantity of each type of product is authorized for manufacture at a time. It is characterized by the manufacture of a limited number of products produced at periodic intervals and stocked in warehouses as finished goods awaiting sales. Typical examples of such batch production are process industries such as pharmaceuticals, paints, chemicals, medium and heavy engineering industry engaged in the manufacture of electric motors, switch gear, heave motor vehicles, internal combustion engines; manufacturer of readymade garments etc. Characteristics of Batch Production Short Runs: Short production runs and frequent changes of setup also characterize batch production. The equipment and the assembly setup is used for a limited number of parts or assemblies and is then changes to make a different product. The production is generally made to stock. In project production, each project has a definite beginning and a definite end. Skilled Continue reading
Experience Curve
Experience curve is the systematic reductions in the production costs that occur over life of a product. There is a relationship between the scale of production and the size of the unit cost of the product, known as the effect of experience. Graphical representation of experience effect (created on the basis of cumulative production and average cost) is called experience curve. A number of studies show that a product’s production costs decline by some characteristics about each time accumulated output doubles. E.g. in aircraft industry, where each time accumulated output f airframes was doubled, unit costs typically declined to 80 percent of their previous level. That is the production costs of the fourth airframe would be 80 percent less of the production costs for the second airframe, the eighth airframe’s production costs is 80 percent less of he fourth’s, the sixteenth’s airframe costs is 80 percent less of the eighth’s Continue reading
Manufacturing Systems – Meaning, Components and Selection Factors
Production is a conversion function by which goods and services are produced. A typical production system comprises of three main components: Inputs, Transformation process and Output. Inputs are men, materials, machines, instructions, drawings, and paper work and instructions. The Transformation Process involves operations, mechanical or chemical, to Change/convert inputs into outputs. It also includes activities that assist conversion, Output is goods and services (e.g. products, parts, paper work, served customers etc.) The combination of operations and activities stated above employed to create goods and services are known as manufacturing system. A manufacturing system therefore may be looked upon as an independent group of sub-systems, each sub-system performing a distinct function. Different sub-systems may perform different functions, yet they are inter-related and require to be unified to achieve overall objectives of the organization. Manufacturing system needs to interact with both internal and external environment. The internal environment is the combination of Continue reading