Question & Answer

A peripheral milling operation is performed on the top surface of a rectangular workpart which is 400 mm long by 60 mm wide. The milling cutter, which is 80 mm in diameter and has five teeth, overhangs the width of the part on both sides. Cutting speed = 70 m/min, chip load = 0.25 mm/tooth, and depth of cut = 5.0 mm. Determine (a) the actual machining time to make one pass across the surface and (b) the maximum material removal rate during the cut

A gundrilling operation is used to drill a 9/64-in diameter hole to a certain depth. It takes 4.5 minutes to perform the drilling operation using high pressure fluid delivery of coolant to the drill point. The current spindle speed = 4000 rev/min, and feed = 0.0017 in/rev. In order to improve the surface finish in the hole, it has been decided to increase the speed by 20% and decrease the feed by 25%. How long will it take to perform the operation at the new cutting conditions?

A NC drill press is to perform a series of through-hole drilling operations on a 1.75 in thick aluminum plate that is a component in a heat exchanger. Each hole is 3/4 in diameter. There are 100 holes in all, arranged in a 10 by 10 matrix pattern, and the distance between adjacent hole centers (along the square) = 1.5 in. The cutting speed = 300 ft/min, the penetration feed (z-direction) = 0.015 in/rev, and the traverse rate between holes (x-y plane) = 15.0 in/min. Assume that x-y moves are made at a distance of 0.50 in above the work surface, and that this distance must be included inthe penetration feed rate for each hole. Also, the rate at which the drill is retracted from each hole is twice the penetration feed rate. The drill has a point angle = 100°. Determine the time required from the beginning of the first hole to the completion of the last hole, assuming the most efficient drilling sequence will be used to accomplish the job

A two-spindle drill simultaneously drills a ½ in hole and a ¾ in hole through a workpiece that is 1.0 inch thick. Both drills are twist drills with point angles of 118°. Cutting speed for the material is 230 ft/min. The rotational speed of each spindle can be set individually. The feed rate for both holes must be set to the same value because the 2 spindles lower at the same rate. The feed rate is set so the total metal removal rate does not exceed 1.50 in3 /min. Determine (a) the maximum feed rate (in/min) that can be used, (b) the individual feeds (in/rev) that result for each hole, and (c) the time required to drill the holes.

A drilling operation is to be performed with a 12.7 mm diameter twist drill in a steel workpart. The hole is a blind hole at a depth of 60 mm and the point angle is 118°. The cutting speed is 25 m/min and the feed is 0.30 mm/rev. Determine (a) the cutting time to complete the drilling operation, and (b) metal removal rate during the operation, after the drill bit reaches full diameter.

A tapered surface is to be turned on an automatic lathe. The workpiece is 750 mm long with minimum and maximum diameters of 100 mm and 200 mm at opposite ends. The automatic controls on the lathe permit the surface speed to be maintained at a constant value of 200 m/min by adjusting the rotational speed as a function of workpiece diameter. Feed = 0.25 mm/rev and depth of cut = 3.0 mm. The rough geometry of the piece has already been formed, and this operation will be the final cut. Determine (a) the time required to turn the taper and (b) the rotational speeds at the beginning and end of the cut.

A facing operation is performed on an engine lathe. The diameter of the cylindrical part is 6 in and the length is 15 in. The spindle rotates at a speed of 180 rev/min. Depth of cut = 0.110 in, and feed = 0.008 in/rev. Assume the cutting tool moves from the outer diameter of the workpiece to exactly the center at a constant velocity. Determine (a) the velocity of the tool as it moves from the outer diameter towards the center and (b) the cutting time.

In a production turning operation, the foreman has decreed that a single pass must be completed on the cylindrical workpiece in 5.0 min. The piece is 400 mm long and 150 mm in diameter. Using a feed = 0.30 mm/rev and a depth of cut = 4.0 mm, what cutting speed must be used to meet this machining time requirement?

A cylindrical workpart 200 mm in diameter and 700 mm long is to be turned in an engine lathe. Cutting speed = 2.30 m/s, feed = 0.32 mm/rev, and depth of cut = 1.80 mm. Determine (a) cutting time, and (b) metal removal rate.

There are 23 correct answers in the following multiple choice questions (some questions have multiple answers that are correct). To attain a perfect score on the quiz, all correct answers must be given. Each correct answer is worth 1 point. Each omitted answer or wrong answer reduces the score by 1 point, and each additional answer beyond the correct number of answers reduces the score by 1 point. Percentage score on the quiz is based on the total number of correct answers.

22.1 Which of the following are examples of generating the workpart geometry in machining, as opposed to forming the geometry (two best answers): (a) broaching, (b) contour turning, (c) drilling, (d) profile milling, and (e) thread cutting?

22.2 In a turning operation, the change in diameter of the workpart is equal to which one of the following: (a) 1 x depth of cut, (b) 2 x depth of cut, (c) 1 x feed, or (d) 2 x feed?

22.3 A lathe can be used to perform which of the following machining operations (three correct answers): (a) boring, (b) broaching, (c) drilling, (d) milling, (e) planing, and (f) turning?

22.4 A facing operation is normally performed on which one of the following machine tools: (a) drill press, (b) lathe, (c) milling machine, (d) planer, or (e) shaper?

22.5 Knurling is performed on a lathe, but it is not a metal cutting operation: (a) true or (b) false?

22.6 Which one of the following cutting tools cannot be used on a turret lathe: (a) broach, (b) cutoff tool, (c) drill bit, (d) single-point turning tool, or (e) threading tool?

22.7 Which one of the following turning machines permits very long bar stock to be used: (a) chucking machine, (b) engine lathe, (c) screw machine, (d) speed lathe, or (e) turret lathe?

22.8 The twist drill is the most common type of drill bit: (a) true or (b) false?

22.9 A tap is a cutting tool used to create which one of the following geometries: (a) external threads, (b) flat planar surfaces, (c) holes used in beer kegs, (d) internal threads, or (e) square holes?

22.10 Reaming is used for which of the following functions (three correct answers): (a) accurately locate a hole position, (b) enlarge a drilled hole, (c) improve surface finish on a hole, (d) improve tolerance on hole diameter, and (e) provide an internal thread?

22.11 End milling is most similar to which one of the following: (a) face milling, (b) peripheral milling, (c) plain milling, or (d) slab milling?

22.12 The basic milling machine is which one of the following: (a) bed type, (b) knee-and-column, (c) profiling mill, (d) ram mill, or (e) universal milling machine?

22.13 A planing operation is best described by which one of the following: (a) a single-point tool moves linearly past a stationary workpart, (b) a tool with multiple teeth moves linearly past a stationary workpart, (c) a workpart is fed linearly past a rotating cutting tool, or (d) a workpart moves linearly past a single-point tool?

22.14 A broaching operation is best described by which one of the following: (a) a rotating tool moves past a stationary workpart, (b) a tool with multiple teeth moves linearly past a stationary workpart, (c) a workpart is fed past a rotating cutting tool, or (d) a workpart moves linearly past a stationary single-point tool?

22.15 The three basic types of sawing, according to type of blade motion involved, are (a) abrasive cutoff, (b) bandsawing, (c) circular sawing, (d) contouring, (e) friction sawing, (f) hacksawing, and (g) slotting?

22.16 Gear hobbing is a special form of which one of the following machining operations: (a) grinding, (b) milling, (c) planing, (d) shaping, or (e) turning?

What is a gang-drilling machine?

List the three parts of a common twist drill. List the three parts of a common twist drill.

What is the purpose of a tombstone that is used with a horizontal machining center (HMC)? What is the purpose of a tombstone that is used with a horizontal machining center (HMC)?

The four axes are the three linear axes: X, Y, and Z; and the rotational axis:

For what types of parts are VTLs (vertical turret lathes) used?

Identify the three basic forms of sawing operation?

What is the difference between internal broaching and external broaching?

How do shaping and planing differ?

What can a mill-turn center do that a conventional turning center cannot do?

What is the difference between a machining center and a turning center?

What is a machining center?

How does a universal milling machine differ from a conventional knee-and-column machine?

Describe the difference between up milling and down milling?

What is pocket milling?

Describe profile milling.