In this article we will discuss about:- 1. Meaning of Machine Moulding 2. Operations for Machine Moulding 3. Advantages 4. Limitations.
Meaning of Machine Moulding:
Moulding by hand is a slow and laborious process and also does not yield good results as it does not impart uniform hardness to the rammed mould. In machine moulding, the production become faster, labour is minimised and less skill is required.
The castings of good quality are produced as the moulds of greater uniformity can be produced by machine moulding. For mass production, the moulding machines can justify their initial cost and at the same time the quality of work will also be nice. However, the use of moulding machine is limited due to size and complexity of the job.
A moulding machine could be defined as a device consisting of several inter-related parts whose function is to transmit and modify various forces and motion so as to aid in the making of a sand mould.
Operations for Machine Moulding:
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The various basic operations to be performed for moulding are given below:
(i) Ramming of moulding sand by jolting, squeezing or slinging.
(ii) Rolling or rocking moulds or cores over through 180° (Inverting).
(iii) Rapping of pattern or core box by vibrating it.
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(iv) Drawing of pattern or core box by raising or lowering the pattern or core box.
Out of these operations the moulding machine performs the function of ramming of moulding sand around the pattern in one or more of the following ways depending upon the type and design of machine:
(a) Jolting
(b) Squeezing
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(c) Slinging
(d) Blowing.
A moulding machine is generally named by the function it performs. A comparative study of different machines is made in Fig. 3.56.
Advantages of Moulding Machines:
(a) These are best suited in mass production work.
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(b) Prove to be economical by reducing the slow hand operation and fatigue on workers.
(c) Semi-skilled persons can be employed whereas in hand moulding skilled artisans are required.
(d) The production rate is high, quality of moulds is better and hence castings with less defects are produced.
Limitations of Moulding Machines:
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(1) These can’t be used for bigger and complex jobs.
(2) For different types of moulds, the machines can’t justify their cost and hence are suitable only in mass production work.
(3) These lack flexibility for more specialised mould making procedure.
