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The correct CHOICE is (d) Plaster pattern

Explanation: Among plastic PATTERNS, WAX patterns and polystyrene pattern, it is plaster pattern which has the HIGHEST compressive strength. The CALCULATED compressive strength is as high as up to 285kg/cm^2.

Correct answer is (b) 12.5cm

The best I can EXPLAIN: a = 25cmb = 5cmc = 25cm

Modulus Mc =(a×b)/2(a+b) = Mc =(25×5)/2(25+5) = 125/60 = 2.0833cm

The RISER diameter D = 6 X Mc = 6×2.0833 = 12.5cm.

The correct option is (b) Dry CLEANING

Easy explanation: No dust or CHEMICAL or MOISTURE should be LEFT over the surface of the pattern for longer PERIODS hence time to time dry cleaning is a must.

The correct answer is (a) True

To explain: Intersecting surfaces forming junctions of METAL thickness are USUALLY joined with fillets in order to AVOID high stress concentrations in the metal casting. Shallow castings commonly have much SMALLER fillets, while the deep pockets and other interior complex corners may have larger fillets.

Right CHOICE is (c) Dowel pins

To explain I would say: Cope and DRAG are the portions of upper and lower PART of the split and CHEEK FORM the middle one. Dowel pins are used for the alignment work in the pattern.

Correct answer is (a) True

For explanation I WOULD SAY: In skeleton pattern, the skeleton is MADE up of wood and then sand is ADDED to the pattern. After PUTTING the sand, then the pattern is rammed.

The correct option is (C) Less than 0.1%

BEST EXPLANATION: In foam plastic, for making pattern, the sulphur LEVEL must be below 0.1%. If the levels are HIGHER than mentioned, it can be deleterious in manufacturing.

The CORRECT option is (a) RED

For explanation I would say: Provision of colour SCHEME MAKES it easy for one to detect the part and the operation to be performed on it. According to the AMERICAN pattern colour scheme, red colour is to be given for casting surfaces yet to be machined.

Right choice is (b) False

Explanation: Finishing allowance is generally provided for a MACHINING process, the FINISH and accuracy achieved in sand casting are usually poor and therefore when the casting is FUNCTIONALLY required to be of better surface finish, so the machining is required that is accomplished by PROVIDING finishing or machining allowance.

The correct option is (b) False

To elaborate: STRESSES cannot be eliminated COMPLETELY, only it can be reduced or distributed to the more part of the MATERIAL. Fillet Radius makes the casting stronger because it redirects stresses from being concentrated at a sharp internal corner and distributes them over the BROADER volume of the fillet material.

Correct answer is (a) One piece PATTERN

To explain: The given FIGURE here is depicting a one piece pattern. Here, as we see, there are no LOOSE pieces available or any joints that BRING it together. As there are no COMPONENTS or loose pieces attached to it, it is a one piece pattern.

Right choice is (d) TRAPEZOIDAL

For EXPLANATION I would say: Trapezoidal runner is most PREFERABLE in sound sand casting as it PROVIDES good FLOW with less distortion or splattering of molten metal.

The correct CHOICE is (d) Nature of MOULDING process

To EXPLAIN I would SAY: Nature of moulding process is a factor USED selecting pattern materials, whereas the quantity of casting, types of moulding method and shape of the casting are used for selecting a type of pattern.

The CORRECT answer is (c) Drag flask

The explanation: In finishing allowance, the entire CASTING is put in the drag flask to reduce the finishing allowance such that the dimensional variation and other defects due to the parting PLANE are reduced to a minimum. This part is WIDELY used in the casting process to make the casting economical and SUSTAINABLE.

Correct OPTION is (c) Other PATTERN maker’s tool

For EXPLANATION I would SAY: A mallet comes under other pattern maker’s tool, as this tool cannot be used for DRILLING, clamping or sawing or any other classified purpose.

Right answer is (b) Simple and straight

To EXPLAIN: The PARTING line needs to be simple and straight to CREATE a difference between UPPER part and lower part.

Right answer is (d) Skeleton pattern

Best explanation: Skeleton pattern uses the least AMOUNT of MATERIAL for the operations on pattern and therefore, it does not need a LOT of investment on its materials, MAKING it inexpensive.

The correct answer is (B) False

To explain: Sharp external corners can also produce CASTING defects. A misrun defect is basically caused by sharp external corners of the casting. External corners abruptly LOSE heat to the surrounding mould material and as a result, the corner might not fill COMPLETELY that result into a misrun defect.

The correct CHOICE is (d) Hand vice

For explanation I would say: Hand vice is one of the tools used for clamping processes. While, brace, counter sink BIT and ager bit are COUNTED among drilling tools or BORING tools.

Right option is (b) False

The explanation is: PROVISION of colour SCHEME makes it easy for one to detect the PART and the operation to be performed on it. According to the AMERICAN pattern colour scheme, pattern surfaces do not have any colour at all.

The correct choice is (c) The vertical faces must be tapered as well as the cavity must be created using loose PIECE

For explanation: Draft allowances well as loose piece NEEDS to be provided to the pattern in order to maintain the quality of the CASTING. The CORRECTED DESIGN is drawn below

Right answer is (c) Match plate pattern

Easiest explanation: Match plate pattern are USUALLY used for manufacturing small castings on a big scale. Hence, PISTON RINGS of the engine are MADE using this pattern.

The correct answer is (b) Less than 10mm

Explanation: Radius of the fillet in order to ALLOW filleting sharp ANGLES, MUST be less than 10mm, in all classes of pattern. If the radius EXCEEDS this value or goes below it, there WOULD be defects in the cast.

Correct option is (d) Drum TYPE elements

The explanation is: Drum type elements are made using circular WOODEN WORKPIECE of a pattern set, while the remaining ONES are made out of the rectangular wooden workpiece.

The correct option is (b) Yellow strips on BLACK background

For explanation: PROVISION of colour scheme MAKES it easy for one to detect the part and the operation to be performed on it. According to the American PATTERN colour scheme, yellow strips on the black background is to be GIVEN for machined openings of core prints.

The correct CHOICE is (d) They must be stored in FOAM

To EXPLAIN: Foam has the ability to absorb shocks and SUDDEN impacts to a very higher EXTENT. Hence, Fragile patterns are stored while wrapped in foam.

Right option is (b) False

Explanation: Sharp corners in casting design PRODUCE VARIOUS defects in the castings and instead of strengthening, it makes the breaking of pattern MATERIAL. Proper filleting reduces hot SPOTS in the casting and eliminates defect from the casting. FILLETS aid in the removal of the pattern from the mould and also strengthen the pattern.

The CORRECT choice is (a) True

Explanation: To avoid the problem of sharp corners, usually concave junction or fillet is added, where the two CASTING surfaces meet. This fillet mixes the two intersecting surfaces and MODIFIES internal corner into a rounded corner. This ef¬fectively avoids the SMALL volume of sand in the corner that reduces hot spots in the casting.

The correct choice is (b) False

The explanation is: The TERM used for rounding-out of external edges of the PATTERN is basically known as radii, and the rounding-out of internal corners of the pattern is known as the fillets on the pattern. Fillets are mainly provided to MAKE uniform HEATING and cooling of the casting MATERIAL and also for the less stress concentration.

Right option is (d) Centre bit

The BEST I can explain: Centre bit is COUNTED among drilling and boring tool, whereas, bock plane, scrub plane and spokeshave are DIFFERENT types of wood PLANING TOOLS.

The CORRECT option is (b) Trammels

Easy explanation: A TRAMMEL is a MEASURING, marking and layout TOOL. While C-clamp, bar clamp, and hand vice are TOOLS which are used for clamping process.

The CORRECT answer is (d) To 3D PRINT the design for making the pattern

The best I can explain: The PRINTING of a design is executional operation of that casting design. The design is meant for study the casting structure and modify it ACCORDINGLY if NEEDED.

Correct choice is (C) Iron and carbon

The explanation is: Steel is an alloy of carbon and iron. Carbon is present in the alloy up to 2% by weight and it takes up INTERSTITIAL SITES of the microstructure of iron. There are three TYPES of alloys classified in this, high alloy steel, low alloy steel and medium alloy steel.

Right OPTION is (a) White Pine

Easiest explanation: White Pine is USED most WIDELY for making PATTERNS because, white pine wood is soft and it is also observed that, it is comparatively easy to work on this wood. Also, this wood is comparatively CHEAP.

The CORRECT answer is (b) Establishment of parting line

Easiest explanation: While selecting a PATTERN, pattern ESTABLISHING a part line is counted under functions of the pattern, and not under the criteria for selecting it. Whereas all the other REMAINING are factors used for choosing the RIGHT pattern materials.

The CORRECT choice is (b) Prevent cavities due to shrinkage

Explanation: The risers also known as FEEDERS are used to decrease the phenomena of shrinkage during SOLIDIFICATION of the molten METAL.

Right option is (b) PROVIDE feed to the molten material

The explanation is: These external ELEMENTS are added to the pattern or mould CAVITY to enhance the flow of molten metal,hence, to enhance the casting PROCESS.

Correct option is (d) SOMETIMES used to carry the mechanism to melt the metal/material which is to be poured into the CAVITY

For explanation I WOULD say: The PATTERN never CARRIES or includes the mechanism to melt the metal, which needs to be poured into the cavity. This job needs to be done externally.

Correct ANSWER is (C) Molten metal

Easiest EXPLANATION: Molten material is POURED into the mould cavity to make a casting, after solidification and hence, it does not constitute the PATTERN.

The correct answer is (d) Type of cooling rates to be provided

To EXPLAIN: The type of cooling rates DEPENDS upon the required STRENGTH in the casting, which cannot be controlled by the type of any pattern. Proper chills are to be used for that PURPOSE.

Correct OPTION is (a) Core

Explanation: The illustrated part in the diagram is core. The core in a PATTERN is used to CREATE HOLES or hollow cavities.

The CORRECT choice is (d) Only the dimensions that are perpendicular to the parting plane

Easiest explanation: The DRAFT allowance is USED for those dimensions which are perpendicular to the parting plane, to give out a TAPERED FACE which is machined later.