Chapter 21 Flashcards
Define: Rortational vs Prismatic Part
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)
Define: Lathe
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.
Define: Facing
(Operation related to: Turning) The tool is fed radially into the rotating work on one end to create a flat surface on the end.
Define: Taper Turning
(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.
Define: Contour Turning
(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.
Define: Chamfering
(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
Define: Cutoff
(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”
Define: Boring
(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.
Define: Drilling
(Operation related to: Turning) Can be performed on a lathe y feeding the drill into the rotating work along its axis
Define: Reaming
(Operation related to: Turning) Similar to drilling, process of using a multi-point tool to smooth the interior surface of a hole.
Define: Between Centers
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.
Define: Chuck
Has 3-4 jaws to grasp the cylindrical work part about it’s outside diameter or the inside diameter of a tubular part.
Define: Collet
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.
Define: Tapping
Drilling operation in which a tap is used to provide internal screw threads on an existing hole.
Define: Peripheral vs. Face Milling
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)
Define: Up vs. Down Milling
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”
Define: Slab Milling
The basic form of peripheral milling in which the cutter width extends beyond the work-piece on both sides.
Define: Slotting
(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.
Define: End Milling
Form of face milling in which the cutter diameter is less than the work with so a slot is cut into the part.
Define: Pocket Milling
Form of end milling in which the cutter mills shallow pockets into flat parts. (Inside workpiece; not perimeter)
Define: Chip Load
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.
Define: Feed Rate
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
Define: Shaping
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
Define: Planing
In which the worktable moves, not the cutter. Allows for larger parts to be machined then on a shaper. (Single-Column or Double-Column)
Define: Broaching
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.
Define: Gear Hobbing
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.
Define: High-Speed vs. Conventional Machining
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
