People often don’t know much about the importance of pattern in iron casting. Patterns have a direct impact on the design, manufacture and cost of iron casting. An iron casting is only as good as the pattern from which it is made. And there lies its importance.
We give you a peek into what patterns do, how they are made and how including the foundry early in the planning process can achieve the best results, and save time and money.
What is a pattern?
A pattern is just a precise model of what is to be cast. Earlier, they used to be made of wood, but now they are made of other materials like fibreglass, plastics, etc. To make a pattern, first you have to create a sand mould, which should exactly resemble the pattern. The metal is then poured into this mould. This will result in the formation of a sand mould around the pattern. The pattern that is formed is separated and this will leave a dent or a hole into which molten iron is poured to form the casting. Mould making involves packing sand firmly around the pattern which is held in a box. For several castings the pattern can be recycled many times and therefore needs to be strong enough to withstand the procedure.
For a perfect iron casting, the mould has to be perfect. Good patterns can save time, money and achieve greater consistency throughout the casting process. An advantage of a pattern in wood is that it can be used hundreds of times to make new sand moulds.
The customers can choose any pattern or design. Some designs will be complicated to cast while others will be simple and easy. A complicated cast will cost more as well.
The pattern should be a perfect replication of the original design. To be cost effective, it should have the minimum wastage. To ensure quality and cut down production cost you must tell the pattern maker or workshop about the design process in advance.
The method of pattern making is also important. Use the right method to ensure that the metal flows into the mould precisely. It should flow neither too fast nor too slow. It should not be too hot or too cold as well.
Pattern makers need excellent skill to duplicate exactly the article to be cast. They also need to have a good knowledge of the foundry process.
For making a precise pattern, they need exact drawings with the correct measurements. Patterns can also be made by looking at photographs with detailed measurement references shown. Using a faulty or tainted original can only mean a faulty or tainted casting. If at all you are using the original casting, you have to use it for making a pattern after restoring it to its old glory.
Patterns are important in iron casting as they are planned to guarantee the best outcome in terms of imitation, minimising waste and cost of manufacture.
Post time: 04-03-2017