Basic Units Of Transfer Machining
Transfer machining is an automatic machine which indexes or transfers the workpiece and its fixtures from station to station while moving operations are performed on it.
It could be a combined material process and material handling machine. It could thus be considered as several machine tools linked together mechanically, electrically, or hydraulically.
TOP FIVE BASIC UNITS OF A TRANSFER MACHINING
The various components, mechanism, and accessories employed in the transfer machines include:
Machine Design
In general, the machine consists of simple heads incorporating minimum mechanism.
These may also incorporate provision for multi-spindle attachments and may be provided with hand feed and withdrawal mechanism.
They may also incorporate a lead screw for thread tapping purpose. The feed cycle often provides for fast approach and quick withdrawal.
Each head is generally a self-contained unit and can be operated as such when setting up, but is connected either electrically, mechanically, etc. with the machine so that it operates in unison with them.
i.e. the cycle of each machine commences simultaneously with those of others.
The machine is required to perform the following functions;
- Transfer the work from station to station
- Locate the fixture at each station and clamp it in position
- Move the tools rapidly then clear the work
- Return the tools rapidly to clear the work
- Unclamp the work from the fixture and indicate that the station is clear for an operator on the next workpiece.
Table
The heads are mounted on one or more sides of a long table on which the work is carried.
The table usually consists of rails, a static roller conveyor truck, or a combination of both and its frame carries the mechanism for transferring the work from one station to other.
The table is generally straight, although in some cases, it may be circular, U-shape, curved forward, and other shapes, to suit the local conditions.
Generally, roll-overs are also provided in the table line so that components could be rotated through 10 degrees to 108 degrees during its progress from station to station.
Work Holding
Although large and flat components can offer rest directly on the surface of the table, it is generally more convenient to mount the work on a platen, pallet or jig plate etc. which are specially designed to suit the components they carry.
These are provided with some form of clamping with the components on its carrier and then often for locating the carrier under the various machines.
Transfer Mechanism
A wide variety of transfer mechanisms are available for moving the platen from station to station.
It is to be noted that the distance between the centers of the machine heads must be identical.
And the stroke and position of the transfer pawls must be arranged to deliver every platen to a precise position under each machine.
Swarf Removal
A huge amount of swarf is produced due to a high rate of production, therefore, some means must be provided for regular removal of the swarf while the line is in operation.
It is common practice to provide gaps in the ways so that swarf falls below into some form of a conveyor and sliding ways of the tables are kept clean.
