By speaking about patterns used in casting, we’re referring to a specific type of replica of the object that needs to be shaped. We could say they’re an essential tool in this procedure, mostly used in making metal parts for various types of equipment needed in numerous fields.
A single pattern may have a considerable effect on the final product, which is why manufacturers need to be extra careful when choosing their design and implementing a particular type of mold, which ideally should be based on the final look of the desired object. Let’s go ahead and mention the most common ones
Another name for these is solid patterns. They’re quite affordable and mostly used for simple procedures and small-scale production. Large manufacturers tend to use them in situations when they need the simplest shapes and flat surfaces, such as rectangular blocks. The whole system of the single-piece pattern contains a flat surface that separates the plane, without which molding can become rather difficult.
These are also called split pieces and are used for intricate processes. As the name itself already says, there are two pieces of the scheme – one is molded in cope and another in drag, and these two sections are connected by a dwell pin. It’s mostly implemented in performing the hollow cylinder casting or in situations when it isn’t easy to remove the casting from the mold due to a huge depth.
When you have difficult and complicated processes to deal with, you can use a multi-piece type. These are perfect for such tasks as they always contain three or more components – upper, middle, and bottom parts. In the classic three-part piece, we call the upper part cope, the middle one a check and the bottom is a drag.
This one might be larger but is still a great choice since it’s simple in shape. Unlike the previous types, it definitely isn’t versatile and it’s rather pricey, yet, while it won’t be the best choice for cutting off the expenses, it may be quite efficient in extra sand removal. According to an article from dawangcasting.com that discusses various types of patterns, it’s used in industries of floor or pit welding, as it consists of nothing but the frames that highlight the area for casting. Yet, it can also be found in daily applications such as in making water pipes or simple turbine manufacturing.
Gate units are used to make multiple components inside one mold. A pattern like this is usually costly, but manufacturers tend to use it for small tasks specifically. First, the molten metal passes through a few gates and runners, after which it ends up in the pattern. They can be used in mass-producing procedures, as well as in molding machine production for joining different patterns. The advantages of this type are low molding time and the fact that molten metal is uniformly distributed.
6. Match plate
This kind is widely used in casting materials such as aluminum and in the general manufacturing industry, but also in piston rings of I.C . engines, having a wide scope in the rotor hub. Usually, it’s pretty expensive, but it always has a high yield and gives great accuracy. It can be considered as a split pattern since it has drag and cope areas on the opposite sides of the metallic plate. The best thing about it is that it requires much less work than the other units.
7. Loose piece
Sometimes, it might be rather challenging to remove a piece of the solid type that is above or below the parting plane of the mold. That’s what this type of pattern serves for – to allow projections to be made by loose pieces. However, the bad side of it – apart from being extremely expensive, it usually requires skilled use and management, which isn’t always applicable. Its shifting can be done by performing a ramming process, and it’s mostly implemented in the rotor hub and axle pin manufacture.
If you don’t have much time to complete your tasks and you want to do them in the simplest possible way, sweep units are the best option. They consist of three components: spindle, base, and sweep which is a wooden board of a convenient size they use to rotate along the edge and shape the cavity as rotational or circular symmetry. Large kettles, wheels and circular discs form only a tiny part of the products that have been produced by making use of these.
9. Cope and drag
These come in two separate plates – as its name already indicates. The separate parts can be separately shaped and they are combined to form the complete cavity, after molding parts. It’s very similar to the two-piece type and widely used in production types where molds are unhandy and heavy to handle, for example, in creating a water jacket – which is an important part of JCB – and in building flange pipes.
10. Follow board
This one is used for fragile casting structures that can break after the application of force. It consists of a simple wooden board used for the molding process, or as a base in the follow board. The follow board is on the bottom and drag is on top, while the pattern is in the middle.
The functioning of the sweep and segmental unit is almost the same. As its name suggests, it’s in the form of segments and mostly used for round or circular structures such as rims, pulleys, wheels, etc.
Yet, unlike the sweep ones, they can’t boast complete rotation – if you want to create mold, you can do that by partial rotating.
If you want the best design for a particular occasion, the best bet is to consider the proper material, which usually depends on the purpose of casting. Some factors you should certainly keep in mind when choosing a specific unit for your business are size, cost, and, of course – the shape of the product. Also, you need to keep in mind that the selection is based on factors such as the quality of the process and degree of finish. Consider all of these wisely, as in most cases all these aspects are going to determine the quality of castings – if done well, the procedure can bring huge success to your manufacture!