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Types of Pattern In Casting

Follow Board Pattern In Casting

There are 17 different types of pattern in casting used to create mould cavities in the sand casting process.

The list of 17 types of patterns in casting is as follows:

1. Single-piece pattern.
2. Split pattern.
3. Multi-piece pattern.
4. Cope and drag pattern.
5. Match plate pattern.
6. Loose piece pattern.
7. Gated pattern.
8. Skeleton pattern.
9. Shell pattern.
10. Segmental pattern.
11. Sweep pattern.
12. Built-up pattern.
13. Boxed-up pattern.
14. Self-Core Pattern.
15. Lagged up pattern.
16. Left-hand and right-hand patterns in casting.
17. Follow board pattern.

I have given a navigation menu below students can use to read types of patterns in sand casting.

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Single Piece Pattern

A single-piece pattern is used for creating a cavity for producing simple design casting which is mostly in the drag section of the mould.

I have written a detailed article with diagrams of single piece pattern with proper explanations, advantages, disadvantages, examples and applications.

 

Split Piece Pattern

A pattern that can be split along a parting line in the cope and drag section used to produce irregular casting that cannot be made by a single-piece pattern is called a split-piece pattern.

I have discussed detailed articles on split pattern in detail along with diagrams, advantages, disadvantages, applications, summary and differences between the split pattern and solid pattern.

Multi Piece Pattern

In the single-piece pattern, the pattern rests mostly in the drag section while the split-piece pattern is split along the parting line but in the multipiece pattern, the pattern is split into multiple pieces along cope, cheek and drag.

I have discussed the article in detail with diagrams on the multi-piece pattern or three-piece pattern which includes advantages, disadvantages, applications, MCQ questions & answers and uses of a multiple-piece pattern for producing casting cavities in the sand casting process.

 

Cope and Drag Pattern

Large-size complex casting that cannot be manufactured using a single-piece pattern, split-piece pattern and match plate pattern are cast using cope and drag patterns.

The cope and drag sides of the pattern are made separately and joined together making one single pattern in casting.

I have discussed with diagram cope and drag pattern in detail which includes application, material, advantages and disadvantages of cope and drag pattern in casting.

Match Plate Pattern

A match plate pattern is used for casting different shapes castings by mounting multiple split patterns on a metal plate called the match plate with screws and locating pins.

The match plate pattern allows the casting engineer to cast multiple small-size casting with different shapes on the match plate we have discussed above.

I have written a detailed article that you can read about match plate patterns in casting including advantages, design, disadvantages, application and summary.

I have explained in detail the article with diagrams discussing the match plate pattern which includes its application, advantages and disadvantages of gated patterns, and the difference between match plate pattern, split pattern and cope and drag pattern in the casting process.

Loose Piece Pattern

A loose piece pattern is a pattern designed in such a way that it allows the pattern to be withdrawn from the mould cavity easily for casting with a complicated design that cannot be taken out of the mould in one piece.

Loose piece pattern is explained in detail along with diagrams, design, applications, summary, advantages and disadvantages in the loose piece pattern in sand casting article.

Gated Pattern

Gated patterns are used to mass-produce small-size casting by attaching every mould cavity with a dedicated gate connecting to the common runner.

Molten metal enters into every mould cavity created by the gated pattern mass-producing casting.

I have explained in detail the article about the gated pattern which one can read with diagrams including its application, the difference between split and match plate patterns, advantages and disadvantages of gated patterns in detail.

Skeleton Pattern

The skeleton pattern is designed in such a way that large casting can be produced by making a mould cavity in a pit mould using just a skeleton without making an entire pattern saving a lot of pattern material and cost for making a sand casting.

I have discussed in detail the article on skeleton pattern in casting with examples, applications, diagrams, advantages and disadvantages.

Shell Pattern

The shell pattern is a pattern made from pouring a mixture of sand and resin on a heated metal pattern and then curing it at high temperature to strengthen it for producing large-size pipes and fitting type casting.

I have written a complete article about shell patterns along with applications, advantages and disadvantages, and the process of making patterns in shell pattern.

Segmental Pattern

Segmental pattern is a pattern made up of wood or metal used to make circular mould cavities such as rings, wheels and similar casting using a segment instead of using an entire pattern saving a lot of pattern material in the sand casting process.

Students can read the entire segmental pattern in the casting article which includes a diagram, application, design, advantages and disadvantages of the segmental patterns, and the difference between the segmental pattern and sweep pattern in casting.

Sweep Pattern

A sweep pattern is a pattern designed in such a way that it can create a symmetrical casting such as a bell-shaped mould cavity by using a "sweep" that revolves with a supporting spindle in the pit/floor mould for making a three-dimensional casting.

I have written a detailed article on the sweep pattern along with diagrams, applications, advantages, disadvantages and the differences between the sweep pattern and the segmental pattern.

Built-up Pattern

A built-up pattern in casting is built up of wood, metal and plastic pieces together to make a single pattern for producing mould cavities in the sand.

Special pulleys are made by joining segments of wooden, metal and plastic strips together, layering them and glueing them together. 

Flanges and other complex shapes are made in a similar way where wooden strips are cut and glued to make a single pattern.

The built-up pattern is made up of wood, metal and plastic material.

Lagged up Pattern

Lagged-up patterns are patterns used to make cylindrical shape casting using wooden strips called "lag" or "starve" which are glued and screwed together to the head as shown below.

Lagged-up patterns are applied to make cylinders and columns.

Self Core Pattern

The self-core pattern has a hollow structure in it allowing the formation of the hollow section in the mould during the mould-making process. The advantage of this pattern is that there is no additional requirement of core for producing a hollow structure in the casting process.

Cores are built into the final casting producing hollow sand casting products such as flange bodies in less time and saving the cost of core making.

This pattern is also called a shell hollow pattern as it can produce hollow sections in the final casting.

Boxed-up Pattern

The boxed-up pattern is used to make the casting with a regular outline and rectangular form.

The boxed-up pattern is made of wooden strips. These strips are joined together with glue, nails and screw to form box shape pattern.

Left Pattern and Right Pattern

Patterns are required to be made in pairs which cannot be reversed and need to be used in a left and right-hand form only.

Products such as paddles, racks, legs of machines and base of brackets.

Follow Board Pattern

During the sand ramming operation pattern has to undergo a lot of compressive forces under a ram during the mould-making process.

A supporting structure is required to support the pattern in the casting process. This supporting structure is called the follow-board pattern.

The follow-board pattern is not an actual pattern but a supporting structure used to support the pattern during the ramming operation to avoid breakage of delicate patterns during the mould-making process.

Types of Patterns In Foundry Summary

I have discussed and explained 17 types of patterns in casting used for creating a cavity in the mould in the sand casting process above. Here is a quick summary of pattern types.

Types Of Pattern	Pattern Detail
1) Skeleton pattern.	Produces large-size casting in lower volume in pit mould.
2) Split pattern.	The pattern is split along the parting plane/parting line in cope and drag part of the mould.
3) Match plate pattern.	Produces complex casting in mass volume.
4) Single/Solid pattern.	Used for prototype and small casting.
5) Multi-piece pattern.	Produces casting in cope, cheek and drag sections.
6) Segmental pattern.	Produces circular ring shape casting using not whole but segment of the pattern.
7) Loose piece pattern.	Easy pattern withdrawal of complex patterns without damaging the mould cavity.
8) Shell pattern.	Produces the most complex shape casting as compared to all patterns mentioned here.
9) Follow board pattern.	Not a pattern but a strong supporting structure during mould mould-making process.
10) Gated pattern.	Produces simple shape and small size casting in large quantities/volume.
11) Sweep pattern.	Symmetrically curved shape casting such as bells are produced.
12) Cope & drag pattern.	Produces casting in the cope and drag section of the mould only.
13) Boxed and Lagged pattern.	Used to produce box and pillar shape casting.

These patterns mostly find their majority application in the sand moulding process and have a few applications to make master patterns and wax patterns in the investment casting process only to create a mould impression.

These patterns are manufactured using various pattern materials and pattern-making techniques in the sand-casting process keeping various kinds of pattern-making allowances in mind. 

Depending upon size, shape, application, material, design, geometry, production volume, production rate, cost of manufacturing of pattern, pattern material, customer requirement, complexity, use and dimensional accuracy of final casting a pattern is selected in the sand casting process.

From a small-size prototype type casting to large blocks of sand casting, simple shape to complex shape casting can be easily produced using the abovementioned patterns.

These patterns find applications in the automobile industry to produce handles and piston rings, in the decorative industry to make sculptures and bells using sweep patterns, in the construction industry to make big metal blocks using skeleton patterns, in the oil industry to make valves using gated patterns, in machine tool industry to make flywheels, in commercial machine industry to make milling table using match plate pattern, in the aerospace industry to make aircraft engine parts using loose piece pattern, prototypes are made by single piece in new product development sectors.