Manufacturing And Production Technology — Part 1 MCQs with Explanations

Right hand spiral reamers should be selected for blind holes. - Additionally a right hand spiral also helps bridge interruptions such as cross-holes or keyways. - A right hand spiral reamer may cut slightly oversized holes due to the aggressive flute geometry. - They perform very well in highly ductile materials.

Stellite alloys are composed of various amounts of cobalt, nickel, iron, aluminium, boron, carbon, chromium, manganese, molybdenum, phosphorus, sulfur, silicon, and titanium. Stellite preserves hardness up to a temperature of 1100°C

G02 – Circular interpolation in a clockwise direction G91 – incremental dimension

Assumption in Merchant's Force Circle: - The chip is considered in equilibrium under action of two equal and opposite collinear forces. -The stress is maximum at the shear plane and it remains constant. - The shear takes place in a direction in which the energy required for shearing is minimum

In order to achieve a specific surface finish in single-point turning, the most important factor to be controlled is Cutting Speed other parameters will impact on the surface finish: -Minimize Deflection and Chatter, Keeping Tool Rigidity Up -Use Balanced Tooling to Reduce Vibration -Minimize Runout

-continuous chip with built up edge. a built up edge (BUE) is an accumulation of material against the rake face, that seizes to the tool tip, separating it from the chip - Discontinuous chips are formed during machining of brittle metals while continuous chips with built up edge are formed during machining of ductile materials at low cutting speed

Ductile material Produces Chips with built up edge. Built up edge (BUE) is an accumulation of material against the rake face, that seizes to the tool tip, separating it from the chip.

A 15 mm drilling machine means that it can drill a hole of maximum diameter 15 mm.

the material that makes up the tools and inserts, is actually grains of tungsten carbide, along with particles of other materials, cemented together using the metal cobalt as a binder. There are several tungsten ores that can be mined and refined into tungsten or made into tungsten carbide

In Taylor tool life equation as (VT n = c) V = velocity of the cutting tool (m/min), T = tool life (min) c, n,, taylors coeffiecients The value of n for carbide tools is 0.20 to 0.25

In Taylor tool life equation as (VT n = c) V = velocity of the cutting tool (m/min), T = tool life (min) c, n,, taylors coeffiecients The value of n for ceramic tools is 0.40 to 0.55

For machining a cast iron workpiece by a high speed steel tool, the average cutting speed is 22 m/min and for a mild steel is 30 m/min

For machining a cast iron workpiece by a high speed steel tool, the average cutting speed is 22 m/min and for a mild steel is 30 m/min

Specific energy in metal cutting, defined as the energy expended in removing a unit volume of workpiece material. The specific cutting energy used for establishing the machinability of the metal depends upon its - Coefficient of friction -Micro-structure -Work hardening characteristics

The cutting speed of a drill depends upon the -Material of drill -Type of material to be drilled - Quality of surface finish desired

The size of Abrasive grain required in a Grinding wheel depends on the amount of material to be removed, desired finishing, and the hardness

Flank wear occurs on the relief (flank) face of the tool. Flank wear occurs as a result of friction between the progressively increasing contact area on the tool flank.

Grinding is a machining process that involves friction between the grinding wheel and the workpiece , which generates a significant amount of heat at the point of contact. This high temperature causes localized thermal expansion of the grinding wheel material near the contact area, while the rest of the wheel remains relatively cool. The uneven expansion creates thermal stresses within the wheel structure. If these thermal stresses exceed the wheel’s tensile strength , cracks begin to develop, leading to possible wheel failure. Grinding hard materials (Option B) increases the heat generation, but the root cause of cracking remains the excessive temperature rise . Low wheel speed (Option C) generally reduces heat generation, so it is not a cause. While high wheel speed (Option D) can contribute to heat and stress, the primary and most direct cause of cracking is the high temperature developed at the contact point . Hence, the correct answer is High temperature developed at the contact of the wheel face and work .

Machining of titanium and its alloys is considered difficult due to several material-related challenges that affect cutting performance and tool life. The primary reason is the chemical reactivity of titanium at high temperatures. During machining, the cutting zone experiences extremely high temperatures, and titanium has a strong tendency to react chemically with most cutting tool materials such as carbide or high-speed steel. This results in welding, diffusion, and adhesion between the tool and the workpiece, causing rapid tool wear, built-up edge formation, and poor surface finish. Additionally, titanium has a low thermal conductivity , which means heat generated during cutting does not dissipate easily. Most of this heat concentrates at the tool tip, further accelerating wear and reducing tool life. However, the main factor making titanium machining difficult is the chemical reaction between the tool and the work material , not high thermal conductivity or low contact area. Therefore, the correct answer is Option B: Chemical reaction between tool and work .

The angle formed by the leading edge of the land with a plane having the axis of the drill, is called Helix or rake angle The rake angle is the angle of the surface of a cutting tool tip over which the removed chips flow. The rake angle is the angle between the front or cutting face of the tool and a line perpendicular to the workpiece

The obtuse angle, included between the chisel edge and the lip as viewed from the end of a drill, is called Chisel edge angle It is the angle included between the chisel edge and lip of the twist drill when measuring on a plane normal to the axis.

Segmental Chips- It means chips become broken pieces before it departs from the cutter. It is often happened in high brittle materials, such as cast iron or bronze. Such as discontinuous chip caused by higher friction coefficient or higher soft ductile materials, it means poor cutting conditions

In Oblique cutting, cutting edge travels, making an angle with the normal of cutting edge. In oblique cutting system, the cutting edge of the tool May not clear the width of the workpiece

The velocity of tool along the tool face is known as Chip Velocity

The Diamond Shape is a critical feature that helps with machining inaccuracies and smoother locating operation. A diamond locating pin is used in jigs and fixtures because It helps in assembly with tolerance on centre distance

Burnishing is the plastic deformation of a surface due to sliding contact with another object. It smooths the surface and makes it shinier. In metal machining, the work-tool contact zone is a zone where heat is generated due to Burnishing friction

The snag grinding is doneTo remove considerable amount of metal without regard to accuracy of the finished surface

The most common application of spot facing (spot facing) is facing the area around a bolt hole where the bolt's head will sit, which is often done by cutting a shallow counter bore, just deep enough "to clean up"—that is, only enough material is removed to get down past any irregularity and thus make the surface flat.

Counter sinking is used to enlarge the upper part of (a cavity), especially by chamfering, to receive the cone-shaped head of a screw, bolt. The operation of making a cone-shaped enlargement of the end of a hole is known as Counter-sinking

Explanation: The correct answer is Option B: Producing a large hole without drilling . Let's break down why: * Trepanning is a machining operation that cuts a circular groove to create a hole. * Instead of removing all the material inside the hole like drilling, trepanning removes only a ring of material. * This is especially useful for making large diameter holes where drilling would be inefficient or require specialized equipment. * Think of it like cutting out the shape of a donut – you only remove the donut itself, not the whole area. Now, let's look at why the other options are incorrect: * Option A: Finishing a drilled hole: While trepanning *could* potentially be used for very precise finishing, it's not its primary purpose. Other processes like reaming are better suited for finishing. * Option C: Truing a hole for alignment: Truing a hole for alignment is usually done with tools specifically designed for that purpose, not trepanning. * Option D: Enlarging a drilled hole: While trepanning *could* technically enlarge a hole, it's not the most common or efficient method. Boring is usually the preferred method for enlarging existing holes. Therefore, trepanning is primarily used for creating large holes without needing to drill away all the material.

Taper Turning can be done in Lathe by tailstock setover method, in which the tailstock is moved from its middle position to one side of the bed, making the work-piece tilted wrt the lathe axis and feed. Thus, when the tool moves, it cut the workpiece at an angle to its axis, creating a taper. The tail stock set over method of taper turning is preferred for Long slender tapers

The correct option is "Globular transfer". In the metal arc welding process, globular transfer refers to the mode of metal transfer where molten metal crosses the arc in the form of comparatively large drops. The frequency of transfer is relatively low, usually 100 drops per second or less . These large drops are often bigger than the electrode diameter and fall across the arc due to gravity. Globular transfer is generally associated with high welding currents and is less stable compared to spray transfer, producing more spatter and less smooth welds. Why not the others? "Spray transfer" involves a fine spray of very small droplets at a much higher rate than 100 drops/sec, resulting in smooth welds with minimal spatter. "GMAW practice" (Gas Metal Arc Welding) is the overall welding process, not a specific mode of metal transfer. "Dip transfer" (short-circuiting transfer) occurs when the electrode tip touches the molten pool, and metal transfer happens in small droplets during short-circuits, not in large drops. Therefore, the correct answer is Globular transfer .

Friction welding (FRW) is a solid-state welding process that generates heat through mechanical friction between workpieces in relative motion to one another, with the addition of a lateral force called "upset" to plastically displace and fuse the materials

A lathe center, often shortened to center, is a tool that has been ground to a point to accurately position a workpiece on an axis. They usually have an included angle of 60°, but in heavy machining situations an angle of 75° is used.

A machine taper is a system for securing cutting tools or toolholders in the spindle of a machine tool or power tool. A male member of conical form (that is, with a taper) fits into the female socket, which has a matching taper of equal angle The taper on the lathe spindle is 1 in 20

In Down milling operation, the cutting force is maximum when the tooth begins its cut and reduces it to minimum when the tooth leaves the work.

The machinability rating is determined by measuring the weighed averages of the normal cutting speed, surface finish, and tool life for each material. The factor considered for evaluation of machinability is - Cutting forces and power consumption - Tool life -Type of chips and shear angle

When the temperature of a solid metal increases, its intramolecular bonds are brake and strength of solid metal decreases. Due to decrease its strength, the elongation of the metal increases, when we apply the load i.e. ductility increases

In lapping operation, the amount of metal removed is 0.005 to 0.01 mm

The narrow zone surrounding the shear plane in machining is termed as primary shear zone. The area surrounding the chip-tool contact region is called the secondary deformation zone. This zone consists of a part of work material (uncut chip) and a part of chip.