FEATURES OF SINUMERIK CNC SYSTEM

It is a microprocessor CNC, continuous path control with integrated programmable logic controller ( PLC ). The system has linear axes control with simultaneous interpolation of two axes .

Variable programming concept. Around 500 variables are available.

Graphic Simulation ie display of tool path to check the program errors.

Background editing of programs i.e. while executing one program another program can be entered without interrupting the machining.

Various built in machining cycles, for easy programming. Block search facility. Memory capacity about 128 KB. Blue print programming. Conditional jump ( @ functions ) etc

Meaning of alphabetical, Numerical and Special characters used in SINUMERIK system

Alphabetical characters

A - Angle 0-3590

B - Radius / ChamferD - Tool offsetF - Feed rateG - Preparatory functionH - Auxiliary functionI - Arc center offset in X- axisK - Arc center offset in Z- axisL - Sub program / Machining cycleM - Miscellaneous functionN - Block NumberP - Number of passesR - Assignable Parameters / VariablesS - Spindle speed in RPM or CCS in mts / minT - Tool number

X - Transversal axisZ - Longitudinal axis

Numerical characters

0 – 9

Special characters

+ Addition- Subtraction* Multiplication/ Division= Equal to% Main Program fileLF End of Block@ Jump functions / Slash ( For skipping blocks )

SYSTEM DIRECTORY

The CNC system directory consists of three ( 3 ) types of programs in memory

-Main programs ( % )-Sub programs ( L )-Machining cycles ( L )

MAIN PROGRAMS / PART PROGRAMS (%)

A part program comprises a complete string of blocks which define the sequence of a machining process on a numerically controlled machine tool. Subroutines and cycles may be components of the program

A part program comprises:

- The character for program start ( % )- A number of blocks with end of block character ( LF )- The character for program end ( M02 / M30 )SUB PROGRAMS / SUBROUTINES ( L )

When a component has repetitive pattern machining at different places, subroutines programming can be used to reduce the effort of writing a detailed program. The program for repetitive machining can be stored in the memory as a separate program and can be called in the main program whenever needed. When the last block in the subroutine is executed, control will automatically return to the main program. Loop identification will be there for start of the subprogram and end of the sub program and calling of a sub program.

Subroutines can be called not only from a part program, but also from other subroutines. This process is referred to as subroutine nesting. Different controls allow nesting of subprograms up to different levels depending on the software capability. Usually nesting will be possible up to three levels. The sub programs either in absolute co-ordinates or incremental depends upon their usage.

STRUCTURE OF A PART PROGRAM

The part program is a set of instructions proposed to get the machined part from the desired blank and the machine tool. A part program defines a sequence of NC machining operations. The information contained in the program can be dimensional or non – dimensional like speed, feed, auxiliary functions, etc. The basic unit of a part program input to the control is called a block. Each block contains adequate information for the machine to perform a movement and functions. Blocks in turn are made up of words and each word consists of a number of characters. All blocks are terminated by the block end character. The maximum block length for each CNC is fixed.

BLOCK FORMATS :

Format is the sequence of words in which information appears in a program. Types of formats used in NC programming.

Word address format:

In word address format each word is identified by a letter eg: Letter N identifies the sequence number, word T identifies tool function etcTab sequential format :

In tab sequential format, each word is separated from the other by a tab character. The words are identified by their respective positions in the block.

Word address format is used widely in CNC programming.

A block may contain any or all the following:

Optional block skip ( / ) Sequence or block number ( N ) Preparatory functions ( G ) Dimensional information (X, Y, Z, etc ) Dwell Decimal point ( . ) Feed rate ( F ) Spindle speed ( S ) Tool number ( T ) Tool offset function ( D ) Miscellaneous functions ( M ) Auxiliary function ( H ) Sub program number ( L ) Repetitive count ( P ) End of block ( LF )

Optional Block Skip character ( / ) :

A programmer may program all the operations of a particular family of components. The operator can omit certain operations in a program for a particular component. A particular operation may be required for a particular component and may not be required for another component. These blocks are programmed with the character / (Slash) as the first character. Whenever a program is read by the control unit, the blocks preceded by the / character are omitted (not executed) when a switch on the system is activated.

Block and Sequence Number ( N ) :

A part program is constructed with a number of blocks. Block number represents the operation number in a program and is usually the first character.

The number of digits in a block number depends upon the control manufacturer (usually it is four digits). Block numbers are mainly used for the convenience of an operator in identifying the different operations. (block numbers need not be consecutive and in most of the cases it is not must to have the block numbers ). Many times it is useful to give a single block number to a set of operations when they are related to each other. It is convenient for the block numbers within the original program to be in multiples of five so that additional blocks could be inserted during any editing that may needed.

The blocks in the program can be explained by means of remarks. A remark permits instructions for the operator to be displayed on the screen. The text of a remark is enclosed between the start- of- remark character “ ( “ and the end-of-remark character “ ) “.

The maximum number of characters allowed in a block is 120.

BLOCK NUMBERING :

The block number is used to identify each of the blocks that make up a program. The block number consists of the letter N followed by a figure between 0and 9999. Number must be written at the start of each block. It is advisable to avoid giving blocks consecutive numbers, so that new blocks can be interposed where required.

Preparatory function (G):

These are the codes which prepare the machine to perform a particular function like positioning, contouring, thread cutting and canning cycling. In general the following preparatory functions can be identified. Some of the preparatory functions (G - codes) exits in the system in machine switch on condition. These codes need not mention in the main program unless the other code is required.

LIST OF PREPARATORY FUNCTIONS (G - CODES )

Group G00 - Linear interpolation, at traverse rate / Rapid G01 - Linear interpolation, at defined feed rateG02 - Circular interpolation, clockwiseG03 - Circular interpolation, counter clockwiseG33 - Thread cutting with constant lead

Group

G04 - Dwell time under address X

Group

G17 - Plane selection XY - planeG18 - Plane selection XZ - planeG19 - Plane selection YZ - plane

Group

G40 - Tool nose radius compensation - CancelG41 - Tool nose radius compensation, leftG42 - Tool nose radius compensation, right

Group

G53 - Suppress the zero offsets

Group

G54 - Fixing zero offset for component - 1G55 - Fixing zero offset for component - 2G56 - Fixing zero offset for component - 3G57 - Fixing zero offset for component - 4

Group

G70 - Input system in inchG71 - Input system in metric

Group

G90 - Absolute dimension programmingG91 - Incremental dimension programming

Group

G92 - Limitation of spindle speed S when using with G96

Group

G94 - Feed rate under address F mm/minG95 - Feed rate under address F mm/rev

G96 - Constant cutting speedG97 - Constant RPM

Some of the G-codes exists in the switch on condition. These codes need not program in the beginning unless they are to be replaced. They are G00,G40,G71,G90,G95 etc

Model G functions:

The G function is effective until another G function of the same group is specified.

Non-Model G functions ( one shot G functions ):

The G function is effective only in he block in which it is specified.

TYPES OF INTERPOLATION :

a) Linear interpolationb) Circular interpolation

Linear interpolation (G01):

The tool must travel at a set feed rate along a straight line to the target position whilst machining the work piece at the same time. The controller calculates the tool path by means of linear interpolation.

Linear interpolation - Paraxial- In two axes- In three axes- At the programmed feed rate- At the programmed spindle speed- To the target position programmed using absolute or incremental position data

Circular interpolation (G02 / G03 ) :

The tool must traverse between two points on the contour in a circular arc, whilst simultaneously machining work piece. The controller calculates the tool path by means of circular interpolation. The action of preparatory function G02 and G03 is modal.

The center point of the circle is defined in one of the following ways.

a) By the interpolation parameters ( I,K )b) Directly using the radius ( B )

G02X +

G03

Z +Circular interpolation

- Along a circular arc in a clockwise direction with G02- Along a circular arc in a counter clock wise direction with G03- About the programmed center point of the circle

- From the starting position on a circular path to the programmed end position

Dimensional Information (X, Y, Z etc ):

These give the coordinate positions of the tool. Movement of machine tool slides in one or more axes is determined by the dimensional data entered in the program.

Feed rate word (F)

The rate at which the cutter travels through the material, is specified in mm/min or mm/rev.

Spindle Speed (S)

This may indicate either the spindle rpm or the constant cutting speed in m/min.

Tool number (T)

For machines having automatic tool changers or turrets, the T-word calls out a particular tool that has to be used for cutting.

D - Word

This word activates the tool and cutter radius and length compensations. Tool compensation is a very useful feature in a control system and ensures that programming is independent of tool dimensions. The control system contains a memory in which both tool length and tool radius compensations are stored.

Miscellaneous functions ( M )

These are the operations associated with the machine for functions other than positioning or contouring, e.g. coolant on or off, spindle rotation, etc.The following are the various miscellaneous functions in general.LIST OF MISCELLANEOUS FUNCTION ( M-CODES)

M00 - Unconditional program stopM01 - Conditional program stop

M02 - End of program with return to program startM30 - End of program

M03 - Spindle rotation, clockwiseM04 - Spindle rotation, counter clockwiseM05 - Spindle stop

M08 - Coolant ONM09 - Coolant OFF

M13 - Coolant ON with Spindle ONM15 - Coolant OFF with Spindle OFF

M16 - Tool clamping

M17 - End of subroutine (written in the last block of the subroutine)

M19 - Spindle orientation (Used in machining centre)

M24 - NeutralM25 - Speed range 1M26 - Speed range 2M27 - Speed range 3

Auxiliary functions ( H ):

One auxiliary function per block can be entered under address H for machine switching functions or movements not covered by numerical control.

End of block character ( LF ):

Each programmed block ends with End of block character i.e. LF.

PREPARATION OF PART PROGRAM

While preparing the part program for a component the programmer first studies the drawing and decides upon the sequence of operations, cutting tools, speeds and feeds at various points, other necessary information like starting and stopping of machine tool etc.

The below shown system features or the combination of different features, which were discussed in earlier pages, can be used advantageously while preparing the program depending upon the amount of material to be removed, machining sequence, machine and the programmers convenience.

System features used in manual programming.

1. Work piece dimensioning, input system 2. Diameter programming3. Absolute coordinate system 4. Incremental coordinate system 5. Combination of Absolute and incremental ( Not possible with Sinumerik system )6. Polar coordinate system (Useful in machining Centers)7. Programming with Constant RPM or Constant Cutting Speed8. Tool nose radius compensation (TNRC)9. Parametric programming (Also called Variable programming)10. Blue print programming (Also called Contour definition Programming)11. System built in machining cycles for stock removal in rough and finish cuts ( In Turning, Drilling and Threading ) 12. Developed, user sub programs (Also called macros in Fanuc system)13. Subroutine nesting14. Mirroring one of the axis ( Z Axis only in lathes )15. Programming with Conditional jump ( @ ) functions

Some of the basic features exits readily in the machine switch on condition

WORK PIECE DIMENSIONING, INPUT SYSTEM

As a standard metric dimensioning input is being used in CNC system. This can be changed to FPS ie inches co-ordinate system by assigning G70 code.

DIAMETER PROGRAMMING

All lathe centers allow diameter programming system for programmers convenience. Diameter value is assigned against X- axis command.

ACTIVITY FLOW CHART FOR CNC MACHINES

RAW MATERIAL & ENGINEERING DRGS FOR THE COMPONENTTO BE MACHINED

SELECTION OF MACHINE TOOL / CNC SYSTEM

SELECTION OF CUTTING TOOLS & PREPARATION OFMACHINING PLAN

DEVELOPMENT OF PART PROGRAMS

PROGRAM INPUT CNC SYSTEM

MACHINE TOOL CUTTING TOOLS SETTING AND LOADING INTO THE MAGAZINE

PROGRAM VERIFICATION AND MACHINING OFFIRST PIECE

OPTIMISATION OF PROGRAM

REGULAR PRODUCTION

FRONT TURNING LATHE( MACHINING BEFORE TURNING CENTER )

X -

Z - Z +

X +

OPERATOR PLATFORM

REAR TURNING LATHE( MACHINING AFTER TURNING CENER )

X +

Z - Z +

X -

OPERATOR PLATFORM

CNC M/C WORK PIECE, TOOL REF CONCEPT ( REAR TURNING LATHE )

M/C REF / SLIDE REF

M/C REF VALUE ( ZM )

TOOL OFFSET ( X )

M/C REF VALUE ( XM )

TOOL REF

MACHINE ZERO TOOL OFFSET ( ZT )

WORK PIECE ZERO

ZERO OFFSET ( Z )/ G54 / G55 ETC

ABSOLUTE CO-ORDINATE SYSTEM

X+ P2 ( 65 , 90 )

P1 ( 45 , 50 )

45 65

Z - Z+

50

90

X -

INCREMENTAL CO-ORDINATE SYSTEM

X + P2 ( 20 , 40 ) W.R.T P1

P1 ( 45 , 50 ) 20 W.R.T P0

45 Z - P0 ( 0 , 0 ) Z+

50 40

X –

TOOL NOSE RADIUS COMPENSATION ( TNRC)

MAGNIFIED VIEW OF CUTTING TOOL RADIUS

THEORITICAL TOOL TIP

EFFECT OF CUTTING TOOL RADIUS WHILE TURNING INCLIND AND RADIUS PORTIONS

TOOL LOCATION FOR TNRC

( AFTER TURNING CENTRE M/CS)

X +

4 8 3

5 7

Z +

1 6 2

VARIABLE / PARAMETRIC PROGRAMMING WITH - R VARIABLES

Modern CNC systems offer the manual programmer increased computing power. Parametric programming allows the programmer to use canned cycles to save time. The cycles are uniquely written for the programmer and allows the programmer to design his own canned cycles.

Parameters, with address R, are used in a program to represent the numeric value of an address, and can be assigned to all functions except N. They are subdivided into transfer parameters, computing parameters. The number of R – parameters depends on the CNC system version used. The values are assigned to the parameters in the main program.

Parameter definition :

Parameter definition is used to assign certain numeric values with signs to the various parameters. They can be defined either in part programs or in subroutines

Example : R1 = 10 LF

Parameter calculation :

Parameter linkingAll four basic arithmetic operations are possible with parameters. The

linking sequence is however crucial to the result of the calculation.

Arithmetic operation Programmed arithmetic operation

Definition R1 = 100 Assignment R1 = R2 Negation R1 = - R2 Addition R1 = R2 + R3 Subtraction R1 = R2 – R3 Multiplication R1 = R2 * R3 Division R1 = R2 / R3

Value assignment amongst parameters :

The value of one parameter can be assigned to another parameter.

Example : R1 = R3 LF

Calculations using numbers and parameters :

It is possible to add parameter to the value of an address or to subtract it from it. No sign signifies a positive number.

Example : X = 10 + R100 LF

It is possible to multiply, divide, add and subtract absolute numbers and R parameters.

Example : R10 = 15 + R11 LF

Parameter string :

All 4 basic arithmetic operations are permissible in any sequence. It is possible to link up to 10 parameters together in a parameter string. A parameter string is limited by the block length of 120 characters maximum.

Example : R1 = R2 + R3 - R4 * R5/R6

BLUE PRINT PROGRAMMING / CONTOUR DEFINITION PROGRAMMING:

Multi-point cycles for direct programming in accordance with the work piece drawing are provided for blueprint programming. The points of intersection of the straight lines are entered as coordinate values or via angles. The various straight lines may be joined together directly in the form of a corner, rounded via radii or chamfered. The geometrical calculation is performed by the controller. The end position coordinates may be programmed using either absolute or incremental position data.Angle ( A ) :

Counter Clock wise system for REAR TURNING CENTER

+ X

+ Z

Clock wise system for operating for BEFORE TURNING CENTER

+ Z

+ X

PROGRAMMING WITH CONDITIONAL JUMP FUNCTIONS FUNTIONS :

By using @ functions CNC programs and machining cycles can be generated manually without the help of computer. The elements used in with @ functions are

K ConstantR R Parameter

Conditional jump functions :

A ) Absolute Jump

@ 100 K_________LF

Example : @ 100 K – 150 LF Absolute jump to the block 150 towards the beginning of the program

@ 100 K 200 LF Absolute jump to the block 200 towards the end of the program

B ) @ 121 R_______ R_______ K LF ( Equal )

C ) @ 122 R________R________K LF ( Not equal )

D ) @ 123 R________R________K LF ( Greater than )

E ) @ 124 R________R________K LF (Greater than or equal )

F ) @ 125 R________R________K LF ( Less than )

G ) @ 126 R________R________K LF ( Less than or equal )

While loops :

@ 131 to @ 136

Repeat loops :

@ 141 to @ 146

Data transfer :

@ 200 R________LF ( Delete variable )

@ 201 R________K______LF ( Load variable with value )

Mathematical functions :

@ 610 R_______R_______LF ( Absolute value generation )

Example : R12 = - 34 LF

@ 610 R76 R12 LF ( R76 = 34 )

@ 613 R_______K_______LF ( Square root )

@ 614 R_______R_______R_______LF ( Square root from sum of squares )

@ 620 R LF ( Increment )

Example : If R70 = 1 Then @ 620 R70 LF ( R70 = 2 )

@ 621 R LF ( Decrement )

Example : If R60 = 1 Then @ 621 R60 LF ( R60 = 0 )

@ 622 R LF ( Integer component )

Example : If R80 = 2.9 LF @ 622 R80 LF ( R80 = 2 )

TRIGONOMETRIC FUNCTIONS :

@ 630 R_______R_______LF ( Sine function )

Example : If R27 = 30 LF @ 630 R15 R27 LF ( R15 = 0.5 )

@ 631 R_______R_______LF ( Cosine function )

@ 632 R_______R_______LF ( Tangent function )

@ 634 R_______R_______LF (Arc Sine )

Example : If R17 = 0.866 LF @ 634 R16 R17 LF ( R16 = 60 )

@637 R_______R_______R_______LF ( Angle from two vectorcomponents )

R35

R36Example : If R35 = 20 R36 = 30 @ 637 R17 R35 R36 LF (R17=146.31 0 )

@ 640 R______K_______LF ( Natural logarithm )

Example : If @ 640 R80 K 10 LF ( Natural logarithm value of 10 is

Stored in R80 )

@ 641 R80 K2.5 LF ( Exponential of 2.5 = 12.182 is stored in R80 )

MACHINING CYCLES / CANNED CYCLES ( L )

Machining Cycles are permanently stored sub programs for use as standard machining process which have been created either by the machine manufacturer or by ourselves. They can be specially protected against misuse. These machining cycles can be adapted to any particular machining by writing in the parameters. A canned cycle (fixed cycle) defines a series of machining sequences for Turning, boring, Threading etc. The canned cycles are stored as subroutines in L93 to L97.

Various machining cycles available areL93 - Grooving cycleL95 - Stock removal cycle (With undercuts)L96 - Stock removal cycle (Without undercuts)L97 - Threading cycle etc

Details of one of the stock removal cycle, L96 cycle is given below.

PROGRAMMING DETAILS OF PARAMETERS IN MACHINING CYCLE L96

Values to be assigned only to the parameters given below. No other parameters to be used for programming. R20 = Sub program number, where the profile details to be machined are

storedR21 = Starting point of the profile - X co-ordinateR22 = Starting point of the profile - Z co-ordinateR24 = Allowance for finishing, required in X axisR25 = Allowance for finishing, required in Z axisR26 = Depth of cut R27 = Tool nose radius compensation ( TNRC )R29 = Type of machiningL96 Machining cycleP = Number of times the machining cycle to be called

Type of machining

R29 = 31 External TurningR29 = 32 External FacingR29 = 33 Internal Turning R29 = 34 Internal FacingR29 = 21 External Turning, finishing cut ( Tool moves w.r.t to final contour )R29 = 22 External Facing, finishing cut ( Tool moves w.r.t to final contour )R29 = 23 Internal Turning, finishing cut ( Tool moves w.r.t to final contour )R29 = 24 Internal Turning, finishing cut ( Tool moves w.r.t to final contour )

GENERAL DIFFERENCE BETWEEN SINUMERIK AND FANUC SYSTEM CODES

COMMENT SINUMERIK FANUC

MAIN PROGRAM % OSUB PROGRAM L PMACHINING CYCLE L GVARIABLES CALL L G65VARIABLE R1, R2 …. #1, #2 …RADIUS VALUE B / CR RSUB PROGRAM CALL L M98SUB PROGRAM END M17 M99NO OF REPETITIONS P LPROGRAM END M2 / M30TOOL WITH OFFSET T01 D1 T0101CONDITIONAL JUMPS @121,@122 ….. GOTO, IF, LT,GT

….PROGRAM SEARCH BY BLOCK

SEARCHBY CURSOR

G - CODES

FEED RATE MM/MIN G94 G98FEED RATE MM/REV G95 G99INCREMENTAL IN X- AXIS

G91 X U

INCREMENTAL IN Z - AXIS

G91 Z W