The aim of the production engineer has always been to s […]
The aim of the production engineer has always been to see that the output increases somehow or other; particularly in mass production. The technique of plastic bucket heat transfer machine has also been introduced to achieve the same motive.
In order to fully understand the technique of transfer machining it is better to discuss the problems faced by production engineer from time to time and to study as to how the solutions were found to overcome these problems.
1. The first thing thought of, for increasing the output was to increase the speeds and feeds to their maximum and the introduction of jigging; both aiming at reducing the machining time. The maximum speed was achieved by introduction of cemented carbides and further reduction of machining time after this was possible only by considering other factors.
2. Then the attention was drawn towards the reduction of the time in handling of the components during their passing from one operation to another. This aspect became more important when it was realised that the unnecessary movements lead to operator fatigue which ultimately resulted in still further lowering of the output.
To achieve this, means were introduced to eliminate the need for lifting heavy work and fixtures, these including the simplification of clamping by the large-scale introduction of air operated clamps, quick action and cam type clamps etc. Extensive use was also made of conveyors and lifting trucks to transport the heavy work from one station to other at the level of the machine.
3. Other important problem faced was the conservation of floor space as considerable area is generally occupied by work between the operations from machine to machine. This wastage was eliminated by the use of conveyors and using long belts running upto roof so that these carried a large enough ‘float’ of components to ensure that no machine ever ‘starved’.
Another obvious remedy was to place machines more closely together, but maximum saving in this direction was not achieved until the introduction of the transfer system.
Another solution to this problem was given by using ‘flow production’ laying down lines of machines and equipment arranged in sequence of operations so that the work flowed straight on from one machine to the other.
4. Realising the labour problem, it was thought of eliminating it completely by introduction of such arrangements as automatic feeding of work to the machine, automatically operating the machine and automatically unloading it. This ideal was achieved in several stages.
The first was introduction of hand transfer machining’, in which number of machine heads are mounted along or around a common table and a work is manually slided along the table from station to station and loaded and unloaded into the fixtures, often with the aid of lifting devices.
The system of hand transfer machining’ was later improved by making the provisions of automatically moving, loading and unloading ‘the work’. This system is known as ‘automatic transfer machining’. It will thus be noted that the basic difference between the automatic transfer machining and the ordinary automatic machines is that the former is capable of automatically transferring work from station to station and of dealing with large and heavy components of awkward shapes.
The next logical development in this direction was to build a number of such automatic transfer machines into a single line to perform a complete sequence of operations, or even completely machine the components (automation).
Although this system is largely employed for lighter operation such as drilling, tapping, reaming, spot facing etc. but there is no limit and it can be easily linked with the heavy machines (broaching, boring processes etc.) and also the means of automatically inspecting the work may be incorporated. The system is by no means limited to machining; extremely efficient lines have been developed for assembly purposes, and for press shop use.