MACHINING OPERATIONS AND MACHINE TOOLS
What is meant by the designation 30cm x 90cm (12in x 36in) in a lathe?
12 in swing (largest diameter a work piece can hold in the lathe) and 36 in is distance between centers
What does a mill turn center do?
A CNC milling machine, cylindrical job fixed to specified angle to machine outside surface of job by milling cutter
What is face milling?
Axis of cutter is perpendicular to surface being milled, machining is performed by cutting edges on both end and outside periphery of cutter
What is peripheral milling?
Axis of tool is parallel to surface being machined, operation performed by cutting edges on outside periphery of cutter.
Name the various ways in which a work part can be held in the lathe.
Between centers, chuck, collet, faceplate
What are prismatic parts?
Block or flat shape, geometry involves linear or rotating tool motion to remove material from linear motion of work part, EX. milling, shaping and sawing.
What does a conventional turning center do?
CNC lathe machine capable of cutting rotated work pieces by means of turning tool, don't have capacity to stop work part at angular position
What are rotational parts?
Cylindrical or disc like shape, Geometry involves cutting tool to remove material from rotating part, EX. Turning & Boring
What is down milling?
Direction of cutter motion is the same as the feed direction when the teeth cut the work
What is up milling?
Direction of motion of cutter teeth is opposite feed direction when teeth cut into work.
True or False: Broaching is performed using a rotating multi tooth cutting tool?
False, rotation of multiple tooth is not taking place during broaching process
What is a dead center and when is the term used in the context of work holding in a lathe?
Fixed w/ tailstock, Relative motion between work and dead center so friction develops, used at lower speeds
What is pocket milling?
Form of end milling to cut shallow pockets into flat parts
Describe profile milling?
Form of end milling where outside periphery of flat part is cut
What are the three basic forms of sawing operation?
Hacksawing (lowest material removal rate), bandsawing, circular sawing
What is a blind hole?
Hole doesn't go through the work piece
What is tapping?
Internal threads made, feed is non-linear across inside surface of work part, done on drilling machine
What is an engine lathe?
Lower range of speed, tailstock carries only one tool, longer time to complete work part, only one cutting tool handled per time
What is a turret lathe?
More range of speed, Tailstock carries six sided-big nut for turning job, time required to complete work part is less, multiple tools can be carried
What is boring operation?
Produce enlarged and finished hole w/ single point cutting tool to existing hole, tool not set at angle, done on lathe or milling machine
What is turning operation?
Producing external cylindrical shape using single point cutting tool, TOOL ANGLE VERY IMPORTANT for high degree of accuracy, Only done on lathe
What is the distinguishing feature of a radial drill press?
Radial arm for drilling head to be moved and clamped, radial arms can swing, large radial drill can produce cylindrical holes in large parts
What is a live center and when is the term used in the context of work holding in a lathe?
Rotates in bearing of tailstock, no relative motion between work and live center so no friction, used at higher speeds
Describe the turning process.
Single-point tool removes material from the surface of rotating workpiece, linear in motion, parallel to axis of rotation, EX. straight turning, taper turning, external grooving, facing, chamfering, cutoff, boring, knurling, and profiling
What is a universal milling machine?
Table can be swiveled horizontally about vertical axis at any angle, used for cutting angular shapes and helixes
What is a conventional knee-and-column machine?
Table can be swiveled horizontally in x, y, and z directions, used for forming keyways, cutting gears, milling cutters, and cutting dovetail.
What is internal broaching?
Used as pull type, produce holes, internal gears, and splines, external spur gear tooth used, initially cost is high
What is external broaching
Used as push or pull type, produces gear teeth and splicer jobs, internal spur gear tooth is used, cost is low initially
What is generating?
Work part is determined by feed trajectory of cutting tool, material removed by speed motion, shape determined by feed motion, feed trajectory involves variation in depth or width of cut during operation
What is forming?
Work part shaped geometrically by cutting tool, material removed by speed motion, shape determined by cutting edge of tool, feed trajectory involves depth of cut to final penetration after completion of feed motion
What is planing?
Work piece moves linearly is clamped on table and tool fixed, heavy duty, large cutting force transferred to table, multi-point cutting tool.
What is a turning center?
Work piece rotates and tool is fixed, used for cutting rotated work pieces with turning tool
What is a machining center?
Work piece stationary and tool moves, used to machine surface of work parts with milling cutter tool.
What is shaping?
Work piece stationary clamped on table, tool moves linearly, light duty, large cutting force transferred to tool, single point cutting tool
What is threading?
external threads are made by use of single point cutting tool, linear in motion across outside surface of work part, done on lathe