3 Shop Pattern

Report No: 03 Shop: Pattern

Title :

Study & Observation the Pattern Shop.

Pattern: In the case of casting machine parts, pattern is necessary. At the time of making any pattern from sample or drawing, allowance should be considered. The difference between pattern and sample is that in pattern allowance is considered and this allowance depends upon the material with which it should be made. Materials and their uses, advantages & limitations:Material

Application (use)

Advantages

Wood

Master pattern

Easily available, low cost, Shrinkage & expansion of light and easy handling. wood pattern.

Wax

Jewellery,

toys, Complicated

Limitations

job,

easily Can be scratched.

complicated show removable and more accuracy pieces, dolls etc. Metal

Toys, show pieces, More dolls, etc.

Plastic

possible. accuracy

and

large Quite expensive.

production possible.

Toys show pieces, Light, easy handling, low cost Can not be used for large dolls, etc.

and more accuracy.

production.

In the case of choosing any pattern material three points should be considered: •Cost of production •Production rate •Accuracy For preparing any pattern the following allowances should be considered: 1. Matching allowance 2. Drafting allowance 3. Finishing allowance At the time of preparing the master pattern, double allowances should be considered: one for the master pattern and another for the metal pattern. Metals to be used for making metal pattern: •Cast iron (shrinkage allowance 1% that means 1/8 inch per ft) •Cast steel (shrinkage allowance 2% that means ¼ inch per ft) •Stainless steel (shrinkage allowance2½ % that means 5/16 inch per ft)

There are eight types of patterns as follows: 1. Solid pattern 2. Split pattern 3. Skeleton pattern 4. Loose pattern (1 piece, 2 pieces and 3 pieces) 5. Follow board pattern 6. Match plate pattern 7. Sweep pattern 8. Gate pattern Pattern can be made for any job from both drawing and sample. But more accuracy can be achieved for making the pattern from drawing. Engineering drawing can be divided as assemble drawing and working drawing. Machines that are found in the Pattern Shop of BITAC:Machine

Main parts

Operation

Mortrizer Machine

Tool post, body, handle, bed & Carriage. Bobbin, table, body & motor.

Used for cutting groove and making core box. Used for inside finishing.

Bobbin Sander Machine Disc Sander Machine

Table body, base, motor & circular plate. Wood Jointer Machine Table, attachment, roller with bed, motor & body. Circular Saw Machine Cutting blade (Diameter 14 inch, max. rpm 2500) Wood Jointer thickness Table, 3 Rollers ( 1 roller consists of 2 Machine blades) ( 1 roller pulls of wood) ( 1 roller files wood) Disc and bobbin sander Machine Wood turning Machine Jig and Saw Machine Band Saw machine

Table, Motor, 2 wheels, Blade, Table, Table, Motor

Used for outside finishing. Used for finishing surfaces. Used for parting

flat

Used to plane wood.

Used for here emery cloth Here chisel is the only cutting tool. Used for designing Used for cutting, Straight, Round, Curve Etc.