Casting Questions and Answers – Types of Pattern

 1. Which of the following factor is not considered while selecting a kind of pattern?

  1. Quantity of casting
  2. Types of moulding method
  3. Shape of the casting
  4. Nature of moulding process

Answer.2. Types of moulding method

Explanation

The selection of pattern materials depends on the following factors.

(i) Number of castings to be produced

(ii)) Method of moulding, i.e. hand or machine

(iii) Method of casting to be used

(iv) Dimensional accuracy of the component

(v) Design and shape of the component.

Types of moulding method are the function of pattern maker that must keep while making a pattern.

 

2. The common type of pattern used in casting is/are

  1. Solid pattern
  2. Split pattern
  3. Match plate pattern
  4. All of the above

Answer.4. All of the above

Explanation:-

Types of pattern According to the design of casting, the complexity of shape, moulding process and accuracy, the pattern types are as follows:

(a) Solid pattern (Single piece)

(b) Split pattern

(c) Loose piece pattern

(d) Cope and drag pattern

(e) Match plate pattern

(f) Gated pattern

 

3. Which type of pattern should be used for making the stuffing box of the steam engine?

  1. One-piece pattern
  2. Split Pattern
  3. Sweep pattern
  4. Gated pattern

Answer.1. One-piece pattern

Explanation

Solid pattern

  • A solid pattern is also called a one-piece pattern
  • It is the simplest type of pattern.
  • It is made from one piece and does not contain loose piece or joints.
  • It is inexpensive.
  • It is used for making a few large size simple casting.
  • The one-piece pattern is usually made up of wood or metal depending upon the quantity of castings to be produced.
  • The stuffing box of the steam engine may be cast with the help of a one-piece pattern.

 

4. The given figure below resemble which of the following pattern?

 

  1. Split Pattern
  2. Sweep pattern
  3. Solid pattern
  4. Gated pattern

Answer.4. Solid pattern

Explanation

Solid pattern:-It is the simplest form of pattern which is exactly like the desired casting.  When using this type of patterns, moulding operations like cutting runners and risers has to be manually cut separately. So mould process is inconvenient and time-consuming. So such patterns are used for producing few large castings.

A one-piece pattern is made from one piece and does not contain loose pieces or joints. A one-piece pattern is usually made of wood or metal depending upon the casting to be produced. The stuffing box of a steam engine is an example of one piece pattern. As an example, if a cylindrical pin with a circular head has to be cast a one-piece pattern shown will be adequate.

 

5. The following figure represents which pattern?

  1. Follow board pattern
  2. Skeleton Pattern
  3. Sweep Pattern
  4. Segmental pattern

Answer.4. Segmental pattern

Explanation:-

Segmental Pattern:- The segmental pattern is functionally similar to a sweep pattern in the sense, that both employ a part of the pattern instead of a complete pattern, for getting the required shape of the mould. The segmental pattern is in the form of a segment and is used for moulding parts having circular shapes.

To create the mould, it is rotated about the post in the same way as in sweep pattern. But it is not revolved continuously about the post to prepare the mould. Rather, it prepares the mould by parts. When one portion of the mould is completed, the pattern is lifted up and moved to the next portion to make the next segment of the mould. This process is continued until the entire mould is completed. Big gears and wheel rims etc. are produced with the help of segmental patterns.

 

6. For complicated casting process which pattern is commonly used

  1. Solid pattern
  2. Split pattern
  3. Gated pattern
  4. Loos piece Pattern

Answer.2. Split pattern

Explanation:-

Split pattern

Patterns of intricate (complicated shape) castings cannot be made in one piece because of the inherent difficulties associated with the moulding operations. Such patterns are then made as split or two-piece patterns.

The two-piece pattern is made of two halves separated at the parting line so that one part will produce the lower half of the mould (drag) and the other, the upper half (cope). The two parts which may or may not be the same size are held in the proper relative positions by means of dowel pins. These dowel pins match with the precisely made holes in the drag half of the pattern.

Taps and water stop-cocks are produced with the help of a split pattern.

 

7. Which of the following option is true for the given statements?

Statement 1: Certain patterns cannot be withdrawn once.

Statement 2: Loose piece patterns are used in this situation

  1. Both statements -1 and statement – 2 are true and statement – 2 is the correct explanation of statement – 1
  2. Both statements -1 and statement – 2 are true but a statement – 2 is not the correct explanation of statement – 1
  3. Statement -1 is true and statement – 2 is false
  4. Statement -1 is false and statement – 2 is true

Answer.1. Both statements -1 and statement – 2 are true and statement – 2 is the correct explanation of statement – 1

Explanation:-

  • Certain patterns cannot be withdrawn once they are embedded in the moulding sand, such patterns are usually made with one or more loose pieces for facilitating their removal from the moulding box and are known as loose piece patterns.
  • Loose parts or pieces remain attached to the main body of the pattern with the help of dowel pins.
  • The main part of the pattern and the loose pieces of the pattern are removed from the sand separately.
  • A loose piece pattern involves more labour and consumes more time in the moulding operation.

 

8. Which of the following pattern is used to make a piston ring and IC engine?

  1. Gated Pattern
  2. Two-piece pattern
  3. Match Pattern
  4. Cope and Drag Pattern

Answer.3. Match pattern

Explanation:-

Match plate pattern 

  • When split patterns are mounted with one half on one side of a plate and the other half directly opposite on the other side of the plate, such pattern is called match plate pattern.
  • The match plate with the help of locator holes can be clamped with the drag.
  • The match plate has a runner and gates also attached to it.
  • After the cope and drag have been rammed with the moulding sand, the match plate pattern is removed.
  • Cope and drag are then assembled and this completes the mould.
  • Piston rings of IC engines are produced with the help of match plate pattern.

 

9. Another form of split type pattern is

  1. Cope and drag pattern
  2. Gated Pattern
  3.  Sweep pattern
  4. Loos piece Pattern

Answer.1. Cope and Drag Pattern

Explanation:-

Cope and Drag Pattern

  • A cope and drag pattern is a split pattern having the cope and drag portions each mounted on separate match plates.
  • These patterns are used when in the production of large castings, the complete moulds are too heavy and unwieldy to be handled by a single worker.
  • The patterns are accurately located on the plates so that when the two separately made mould halves are assembled together, the mould cavity is properly formed.
  • For a higher rate of production, each half of the pattern is mounted on a separate moulding machine, one operator working on the cope part of the mould and the other on the drag part of the mould.

 

10.  In a two-piece pattern moulding arrangement, what keeps the alignment between the two parts of the pattern?

  1. Cope
  2. Drag
  3. Dowel pins
  4. Cheek

Answer.3. Dowel Pins

Explanation:-

A pattern having, two pieces to form a mould cavity is known as a two-piece pattern or split pattern or cope and drag pattern.

The upper and lower parts of the two-piece pattern are accommodated with the help of dowel pins in the cope and drag portion of the mould. Dowel pins are used for keeping the alignment between the two pieces at the parting line.

 

11. When an operator required bulk casting of the circular section then which pattern he will generally prefer?

  1. Cope and drag pattern
  2. Gated Pattern
  3. Split pattern
  4. Sweep pattern

Answer.4. Sweep pattern

Explanation

Sweep pattern:-

  • A sweep pattern is preferred for producing large castings of circular sections and symmetrical shapes.
  • A sweep pattern consists of a wooden board (or any other material) having a shape corresponding to the shape of the desired casting and arranged to rotate about a central axis (spindle).
  • When the board 1s rotated about the spindle, the desired shape is obtained in the mould.
  • A sweep pattern avoids the necessity of making full, large castings of circular sections and costly three-dimensional patterns. A sweep pattern saves a lot of time as compared to make a full pattern.
  • The manufacture of large kettles of cast iron requires a sweep pattern.

 

12. The following figure represents which pattern?

  1. Solid pattern
  2. Skeleton Pattern
  3. Gated Pattern
  4. Split Pattern

Answer.2. Skeleton Pattern

Explanation:-

When a few and large-sized castings are required, it is not advisable to use a large solid pattern of that size, as it will require a lot of wood and time to make a full pattern. In such cases, a skeleton pattern in the hollow form, consisting of a wooden frame and strips.

The skeleton pattern is made in two halves, one for the cope and the other for the drag. After taking the impression, the cope and drag are assembled together with the core in position to form the complete mould. The skeleton patterns are used for castings of hollow cast iron pipe.

 

 13.  Which of the following pattern operation is cheapest?

  1. Solid pattern
  2. Gated pattern
  3. Match plate pattern
  4. Skeleton pattern

Answer.1. Solid Pattern

Explanation

A solid pattern is the simplest and cheapest of all patterns as is made in a single piece. Depending upon the shape and size, it can be moulded in one or two boxes. It is used to a limited extent in production only. Since its moulding involves a large number of manual operations like cutting gates, runners and risers, it is used for casting few components only.

 

14. Which pattern operation is used for manufacturing wheel rims?

  1. Follow board pattern
  2. Segmental pattern
  3. Sweep pattern
  4. Gated pattern

Answer.2. Segmental Pattern

Explanation:-

Segmental patterns resemble the shape of a segment and are used for circular work like rings, gears, wheels, rims, pulleys, etc. These are also known as part patterns, as only a part of the pattern is used to form a complete mould.

 

15. Which of the following is not a pattern but a device?

  1. Segmental Pattern
  2. Gated Pattern
  3. Follow board Pattern
  4. Sweep Pattern

Answer.3. Follow board pattern

Explanation:-

Follow board is not a pattern but is a device used for various purposes. It is used for supporting a pattern that is very thin and fragile which may break or collapse under pressure when the sand above is rammed. With the following board support under the weak pattern, the drag is rammed and the following board is withdrawn. Follow board also forms the parting line of the mould or casting.

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