Canned Cycles for the Mill 322

block

A single line of a part program. A block is composed of words and is written in code.

boring

The process of enlarging an existing hole with a single-point tool. Boring can be performed on a mill using either the canned cycle G85 or G86.

canned cycles

A predetermined machining sequence used to simplify programming. A canned cycle sequence is initiated by a single G code.

chips

An unwanted piece of metal that is removed from a workpiece. Chips are formed when a tool cuts or grinds metal.

circular pocket

An interior recess shaped like a circle that is cut into the surface of a workpiece. Pockets generally are created using an end mill.

clearance plane

The distance specified by the R level. A clearance plane indicates the safe distance for rapid tool movement from one operation to the next.

CNC mill

A machine tool that uses computer numerical data to control cutting operations on flat, square, or rectangular workpieces. On a CNC mill, the cutting tool rotates against a workpiece that is fixed to a worktable.

computer numerical control

CNC. A self-contained system of computers and precision motors that executes program instructions to guide machine tool components and manufacture parts. CNC machines use part programs to control the cutting operations required to create a part.

concentricity

A geometric tolerance that creates a tolerance zone for the median points of a cylindrical feature. Concentricity of a hole improves when the hole is reamed or bored with the G85 canned cycle.

conversational programming

A programming method that allows an operator to machine a part by responding to a series of prompts. Conversational programming does not reveal the actual program codes.

coordinates

A series of numerical positions that describe any point of an object in three-dimensional space. Coordinates are usually described on CNC mills using the X, Y, and Z axes of the Cartesian coordinate system.

counterboring

A holemaking operation that enlarges one end of a previously drilled hole to a certain depth. Counterboring allows the enlarged end to provide room for the head of a screw or nut.

cutting fluid

Any fluid used to cool, lubricate, and clear chips during metal cutting. Cutting fluid can be made of oil, water, synthetic fluids, or a combination of these.

cycle time

The full time it takes to manufacture a part. Lower cycle time can be achieved when using a peck drilling canned cycle with the G73 rapid peck drilling cycle.

depth

The distance of an object from top to bottom. Depth in a hole or pocket is measured from the surface of the part to the bottom of the hole or pocket.

depth of cut

The depth to which the cutting tool penetrates the surface of the workpiece. On a mill, depth of cut is dictated by the movement of either the spindle or the worktable.

diameter

The distance from one edge of a circle to the opposite edge through the center. A drill's diameter indicates its width or thickness.

drag line

A mark left along the length of a hole at the end of a G86 rough boring operation. Drag lines are the result of a boring tool retracting rapidly out of a hole.

drilling

The use of a multipoint tool to machine a new round hole into the surface of a workpiece. Drilling is a type of holemaking operation.

dwell

A pause built into the execution of a program in which the cutting tool remains in contact with the workpiece. A dwell can be used to improve the finish of a hole.

end mill

A type of milling cutter that performs a mix of peripheral and face milling with its bottom and side cutting edges. End mills can be used to machine grooves, slots, circular slots, pockets, and contours.

F code

A word in a part program that determines the feed rate during a cutting operation. F codes are usually given in inches per minute or inches per revolution.

face mill

A type of mill cutter that contains multiple teeth surrounding its large body diameter. The face mill uses the bottom as a cutting surface to mill large flat surfaces.

features

A physical part attribute that naturally contains variation and imperfections. Features include corners, edges, flat surfaces, and holes.

feed

The rate at which the cutting tool and the workpiece move in relation to one another. Feed is typically a linear movement but can also be angular and circular.

feed rate

The rate at which the cutting tool and the workpiece move in relation to one another. Feed rate is typically a linear movement.

G code

A word in a part program that determines the type of operation performed on the CNC machine. G codes apply to all blocks following their occurrence until a new G code occurs in the part program.

G code programming

A method of programming that pairs address letters with numerical values to form words. G code programming is used to write a part program.

G73

A code in G code programming that generally activates the rapid peck drilling canned cycle. During the G73 canned cycle, the cutting tool backs up between pecks without fully exiting the hole.

G74

A code in G code programming that generally activates the left-hand tapping canned cycle. During the G74 canned cycle, the cutting tool rotates counterclockwise as it enters a hole to cut a thread.

G75

A code in G code programming that generally actives the clockwise rectangular pocket milling canned cycle. The G75 canned cycle begins machining over the pocket's center point and cuts outward in a clockwise direction.

G76

A code in G code programming that generally actives the counterclockwise rectangular pocket milling canned cycle. The G76 canned cycle begins machining over the pocket's center point and cuts outward in a counterclockwise direction.

G77

A code in G code programming that generally actives the clockwise internal circular milling canned cycle. The G77 canned cycle begins machining over the pocket's center point and cuts outward in a clockwise direction.

G78

A code in G code programming that generally actives the counterclockwise internal circular milling canned cycle. The G78 canned cycle begins machining over the pocket's center point and cuts outward in a counterclockwise direction.

G80

A code in G code programming that cancels a mode. G80 is used to end a canned cycle.

G81

A code in G code programming that generally activates the general drilling canned cycle. During the G81 canned cycle, the cutting tool positions to a hole location, drills a hole, and then exits out of the hole.

G82

A code in G code programming that generally activates the drilling with dwell canned cycle. During the G82 canned cycle, the cutting tool remains in position at the bottom of a hole before retracting out of it.

G83

A code in G code programming that generally activates the standard peck drilling canned cycle. During the G83 canned cycle, the cutting tool moves rapidly out of the hole between pecks.

G84

A code in G code programming that generally activates the right-hand tapping canned cycle. During the G84 canned cycle, the cutting tool rotates clockwise as it enters a hole to cut a thread.

G85

A code in G code programming that generally activates the boring/reaming canned cycle. The G85 canned cycle feeds a cutting tool into and then back out of a hole at the same feed rate without stopping at the bottom of the hole.

G86

A code in G code programming that generally activates the rough boring canned cycle. In the G86 canned cycle, a cutting tool feeds into a hole, stops at the bottom, and then moves rapidly back out of the hole.

G98

A code in G code programming that instructs the cutting tool to return to the initial level. G98 codes are often used at the end of canned cycles.

G99

A code in G code programming that instructs the cutting tool to return to the R level or clearance plane. G99 codes are often used at the end of canned cycles.

holemaking

The act of machining a hole into the interior surface of a workpiece. Holemaking can be accomplished by drilling, boring, reaming, and tapping.

initial level

The imaginary plane that indicates the tool position when a canned cycle is initiated. The initial level is typically located above the R level.

initial level return

A movement that positions the cutting tool at the initial level at the end of a canned cycle. Initial level return occurs when a G98 code is used in a part program.

internal circular milling

A milling operation during which a round interior recess, called a pocket, is cut into the surface of a workpiece. Internal circular milling operations are usually machined using an end mill.

left-hand tap

A cutting tool that rotates counterclockwise as it enters a hole to cut a thread. Left-hand taps require the use of the tapping canned cycle G74.

machine control units

MCU. A small, powerful computer that controls and operates a CNC machine. Machine control units offer standard canned cycles as well as special canned cycles.

MCU

Machine control unit. A small, powerful computer that controls and operates a CNC machine. MCUs offer standard canned cycles as well as special canned cycles.

mode

A programmed function that stays in effect until it is either cancelled or substituted with another function. Most canned cycles function as modes on a CNC machine.

override

A control that adjusts a programmed element of part machining during operation of the part program. Speed and feed overrides allow an operator to adjust speed or feed rates.

P code

A word in the drilling with dwell G82 canned cycle that indicates how long the tool should dwell inside the hole. P codes are also used in multiple repetitive canned cycles to indicate the starting block number of the final toolpath.

part program

A series of alphanumeric instructions used by a CNC machine to perform the necessary sequence of operations to machine a specific workpiece. Multiple part programs can be stored in a CNC at one time.

peck drilling

A drilling operation that periodically retracts the tool to clear chips or flood the hole with coolant. Peck drilling is often used for holes that are deeper than the drill diameter.

pecks

A single pass of a peck drilling cycle. A complete peck drilling cycle is composed of a number of pecks.

pocket

An interior recess that is cut into the surface of a workpiece. Pockets may be round or rectangular.

pocket milling

A milling operation during which an interior recess, called a pocket, is cut into the surface of a workpiece. Pockets can be either rectangular or round and generally are created using an end mill.

Q code

A word in peck drilling and multiple repetitive canned cycles. Q codes indicate peck distance for peck drilling cycles and the ending block number of the final toolpath in a multiple repetitive cycle.

R code

A word in a canned cycle that describes the location of the R level or clearance plane. R codes are required for holemaking canned cycles to function.

R level

The imaginary plane parallel to the X axis or Z axis indicating the cutting tool clearance plane. An R level indicates the safe distance for rapid tool movement from one operation to the next.

R level return

A movement that positions the cutting tool at the R level or clearance plane. R level return occurs when a G99 code is used in a part program.

radius

The linear distance between a point on the periphery of a circle and its center point. The radius of a circular pocket determines its dimensions in the X and Y axes.

rapid positions

The quick movement of a machine component to a certain location. Rapid positioning occurs when the cutting tool is a safe distance from the workpiece.

reaming

The process of enlarging or smoothing an existing hole with a multipoint tool. Reaming can be performed on a mill using the canned cycle G85.

rectangular pocket

An interior recess shaped like a rectangle that is cut into the surface of a workpiece. Pockets generally are created using an end mill.

right-hand tap

A cutting tool that rotates clockwise as it enters a hole to cut a thread. Right-hand taps require the use of the tapping canned cycle G84.

rough boring

A holemaking operation that enlarges an existing hole with a single-point tool that rapidly retracts from the hole after machining. Rough boring often leaves a mark, known as a drag line, along the length of the hole.

speed

The rate at which the machine spindle rotates. The spindle speed affects how fast the cutting tool moves at the point of contact.

spindle

The part of the machine tool that rotates. On the mill, the spindle holds the cutting tool.

spot drilling

A drilling operation that uses a shorter, sturdier drill to create a small hole that prevents the next drill from wandering off center. Spot drilling often uses a drill size slightly larger than the hole diameter to leave a chamfer after the hole is drilled.

stress

A force that attempts to deform an object. The effects of stress are called strain.

surface finish

The degree of roughness and variation on the surface of a part after it has been manufactured. Surface finish on a part is never perfectly smooth, due to irregularities created during machining.

synchronizing

To operate at the same time or rate. Synchronizing allows feed and speed to work together to create tool movements.

tap

A cylindrical cutting tool used to produce internal threads in a preexisting hole. A tap has thread forms on its outer surface that match the internal threads it is designed to produce.

tapping

The process of cutting internal threads in a hole with a rotating multipoint tool. Tapping can be performed on a mill using the canned cycle G84 or G74.

threads

A long, spiral ridge around the exterior or interior of a cylindrically shaped object. Threads can be machined in a hole using the tapping canned cycle.

tolerance

An unwanted but acceptable deviation from a given dimension. Tolerances indicate the allowable difference between a physical feature and its intended design.

toolpath

A series of program blocks that describes the movement of a single cutting tool. Toolpaths are typically generated using conversational programming.

workpiece

A part that is in the process of being manufactured. A workpiece may be a complete product in itself or one component of a product consisting of many parts.

X axis

The linear axis representing coordinate positions along a line parallel to the longest edge of the worktable. The X axis usually runs left to right.

X code

A word in a part program that describes a specific position along the X axis. X codes are usually used in conjunction with Y codes on a CNC mill.

Y axis

The linear axis representing coordinate positions along a line parallel to the shortest edge of the worktable. The Y axis usually runs toward and away from the operator.

Y code

A word in a part program that describes a specific position along the Y axis. Y codes are usually used for CNC mills but not for CNC lathes.

Z axis

The linear axis representing coordinate positions along a line parallel to the spindle and perpendicular to the worktable. The Z axis usually runs up and down.

Z code

A word in a part program that describes a specific position along the Z axis. Z codes are usually used for both CNC mills and CNC lathes.

Z depth

The Z axis position that marks the depth of a hole in a holemaking canned cycle. The Z depth is indicated by the Z code.