Chapter 21

Question 1

Define: Rortational vs Prismatic Part

Answer 1

Rotational: Work part that has a cylindrical or disk-like shape and is created by rotating the work part (turning or boring)

Prismatic: or Non-rotational, work part is block-like or plate-like and formed by linear motions of the part or tool (milling, shaping, planing, and sawing)

Question 2

Define: Lathe

Answer 2

The machine tool that carries out “turning.” This machine tool provides power to turn the part at a given rotational speed and to feed the tool at a specified rate and depth of cut.

Question 3

Define: Facing

Answer 3

(Operation related to: Turning) The tool is fed radially into the rotating work on one end to create a flat surface on the end.

Question 4

Define: Taper Turning

Answer 4

(Operation related to: Turning) Instead of feeding the tool parallel to the axis of rotation of the work, the tool is fed at an angle, thus creating a tapered cylindrical or conical shape.

Question 5

Define: Contour Turning

Answer 5

(Operation related to: Turning) Instead of feeding the tool along a straight line parallel to the axis of rotation as in turning, the tool follows a contour that is other than straight, thus creating a contoured form in the turned part.

Question 6

Define: Chamfering

Answer 6

(Operation related to: Turning) The cutting edge of the tool is used to cut an angle on the corner of the cylinder forming a chamfer

Question 7

Define: Cutoff

Answer 7

(Operation related to: Turning) The tool is fed radially into the rotating work at some location along its length to cut off the end of the part. Sometimes called “parting”

Question 8

Define: Boring

Answer 8

(Operation related to: Turning) A single-point tool is fed linearly, parallel to the axis of rotation, on the inside diameter of an existing hole in the part.

Question 9

Define: Drilling

Answer 9

(Operation related to: Turning) Can be performed on a lathe y feeding the drill into the rotating work along its axis

Question 10

Define: Reaming

Answer 10

(Operation related to: Turning) Similar to drilling, process of using a multi-point tool to smooth the interior surface of a hole.

Question 11

Define: Between Centers

Answer 11

The use of two centers, one in the head-stock and the other in the tailstock. This method is appropriate for parts with large length-to-diameter ratios. Consists of a dog and center.

Question 12

Define: Chuck

Answer 12

Has 3-4 jaws to grasp the cylindrical work part about it’s outside diameter or the inside diameter of a tubular part.

Question 13

Define: Collet

Answer 13

A tubular bushing with longitudinal slits running over half its length and equally spaced around its circumference to apply a secure grasping pressure against the work.

Question 14

Define: Tapping

Answer 14

Drilling operation in which a tap is used to provide internal screw threads on an existing hole.

Question 15

Define: Peripheral vs. Face Milling

Answer 15

Peripheral Milling: (or Plain Milling) is an operation where cutting edges on the outside periphery of the cutter cut into the surface being machined. This surface is parallel with the cutter. (slab, slot, saw, side, straddle, form milling)

Face Milling: Similar to peripheral milling except that the axis of the cutter is perpendicular to the surface being milled. (conventional, partial, end, profile, and pocket milling)

Question 16

Define: Up vs. Down Milling

Answer 16

Up Milling: (Conventional Milling) Peripheral milling in which the direction of motion of the cutter teeth is opposite the feed direction when the teeth cut into the work. It is milling “against the feed”

Down Milling: (Climb Milling) Peripheral milling in which the direction of cutter motion is the same as the feed direction when the teeth cut the work. It is milling “with the feed”

Question 17

Define: Slab Milling

Answer 17

The basic form of peripheral milling in which the cutter width extends beyond the work-piece on both sides.

Question 18

Define: Slotting

Answer 18

(or Slot Milling) is a form of peripheral milling in which the cutter is less than the workpiece width, creating a slot in the work.

Question 19

Define: End Milling

Answer 19

Form of face milling in which the cutter diameter is less than the work with so a slot is cut into the part.

Question 20

Define: Pocket Milling

Answer 20

Form of end milling in which the cutter mills shallow pockets into flat parts. (Inside workpiece; not perimeter)

Question 21

Define: Chip Load

Answer 21

In milling, the chip load (f) refers to the feed rate given as a feed per cutter tooth. Represents the size of the chip formed by each cutting edge.

Question 22

Define: Feed Rate

Answer 22

Feed rate is the the product of the spindle speed, number of teeth on the cutter, and chip load

Feed Rate = N * n_teeth * f

Question 23

Define: Shaping

Answer 23

A machining operation performed by a machine called a “shaper” where a ram pushes a cutter laterally across piece and then is automatically reset on completion of each stroke

Question 24

Define: Planing

Answer 24

In which the worktable moves, not the cutter. Allows for larger parts to be machined then on a shaper. (Single-Column or Double-Column)

Question 25

Define: Broaching

Answer 25

Machining process in which multiple teeth are used by a moving tool linearly to achieve work in the direction of the tool axis. Work is performed on a stationary workpiece.

Question 26

Define: Gear Hobbing

Answer 26

A Milling operation using a complex “hob” to create the fins or teeth of a gear. The hob has a slight helix and its rotation must be coordinated with the much slower rotation of the gear blank in order for the hob’s cutting teeth to mesh with the blank’s teeth.

Question 27

Define: High-Speed vs. Conventional Machining

Answer 27

High Speed: Using cutting speeds that are significanly higher than those usid in conventional machining operations. DN ratio, bearing bore dimeter multiplied by max spindle speed, of between 500,000 and 1,000,000.

Conventional Machining: Much slower cutting speeds on the order of 300-600x slower