• Transfer line is a combination of individual machine tools sequentially arranged and integrated with interlocked controls and a transferring device to form an automatic machine
• The term transfer indicates the transfer of workpiece from one station to another station during the manufacturing process
• The unmachined workpieces are loaded at one end the machined workpieces leave the transfer line another end
• The transfer line or transfer machine consists of several machining heads or units fastened together by conveying units
• Transfer lines are commonly used in automobile industry, ammunition industry etc

• Transfer line machines are defined by following types

  i. In-line transfer machine

  ii. Rotary indexing table transfer machine

  iii. Drum type transfer machine

In-line transfer machine - It consists of a straight central bed into the sides of which the machining heads are fixed at a particular distance as shown - The parts of machine are conveyed along a track on the bed either with or without use of holding fixture called as pallet - Generally In-line transfer device is selected when the number of station exceeds 24

Rotary indexing table transfer machine

• When the space does not allow the work to be conveyed in a straight line then it may be more convenient to transfer the work around circular line
• Hence, in this system the workpieces are located on a circular table and are indexed around each successive machining station which are spaced as in case of in-line transfer machine

Drum type transfer machine

• It is similar in concept but different in configuration to the rotary table type machine
• In these machines, the work fixtures are fastened to the outer periphery of a drum
• The arrangement enables the workpieces to transfer around a circular path to work stations placed radially at equal distances
• The main limitation of this method is, the machining is horizontally from sides only and the lower station always remains idle as it is practically not possible to arrange a machining head to operate in the limited space under the drum