The FEDRAT option allows you to define how the machine tool determines the cutting feed rates. For Rapid moves see the Motion Control section.
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Description: |
This command establishes a modal feed rate for all following motion commands. feed rate indicates the desired rate of tool movement in units per minute or units per revolution.
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Parameter Definitions: |
1. "f" specifies a new feed rate. The previous type of input (units per minute or per revolution) will stay in effect. If the type of input has not been programmed previously, the postprocessor will assume either IPM or MMPM depending upon the type of input specified by the MDF or the units switch at execution. 2. "IPM,f" and "MMPM,f" specify the desired feed rate in inches per minute and millimeters per minute, respectively. "IPR,f" and "MMPR,f" specify the desired feed rate in inches per revolution and millimeters per revolution, respectively. If IPR or MMPR is specified, the feed rate in IPM or MMPM will be calculated on the basis of the current spindle speed in revolutions per minute (uPM = uPR * RPM).
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Considerations: |
1. A new spindle speed will cause recalculation of the feed rate when in the IPR or MMPR mode. 2. Feed rate codes will be output in the next non rapid motion block. |
Parameter Definitions:
1. "PERMIN,f" and "PERREV,f" specify the desired feedrate mode depending upon the UNITS/ command (i.e., MMPM, MMPR, IPM, or IPR.)
When you select FEDRAT, you must specify whether the feed rate is controlled by the NC tape.
Are Feedrates Tape Controlled - If your machine tool uses only operator controlled feed rates, then you should select NO.
If you use feed rates supplied by the NC program, then you should select YES and indicate whether to output feed rates (with GOTO commands) as IPM, IPR, or FRN.
Feedrate G Codes - You are prompted to specify whether or not the feed rate output is controlled by a G Code.
Feedrate Output Mode(s) - If the machine control has more than one output mode (for example, IPR and IPM) and the feed rate output mode is not controlled by a G Code, a different Word Address character (such as an F code for IPM and an E code for IPR) is usually used to determine the output mode.
Your options are:
If you select this option you are prompted to define the G Code value (e.g. 94 if you want the GPM to output G94), the format of the Word Address character for the feed rate itself (e.g. F10), and the valid feed rate range. The Minor Words define the feed rates as follows:
IPM - Inches Per Minute
IPR - Inches Per Revolution
FRN - Feedrate Number
FRN - Inverse Time Mode
DPM - Degrees Per Minute
You will be prompted for the Validity, G code, format for the feed rate code, the Minimum and Maximum values for each output mode.
Rotary Axis Contouring Mode -
IPM
IPR
FRN (INVERSE TIME)
DEGREES PER MINUTE
Rotary Axis Rapid Mode -
IPM
IPR
FRN (INVERSE TIME)
DEGREES PER MINUTE
X&Y RAPID FEEDRATE MODE
This option follows basically the same interactive procedure as G Code Does Determine The Output Code except that you do not define G Code values for each output mode.
You can specify how many feed rate output modes the GPM can output. These are IPM (MMPM), IPR (MMPR), or Inverse Time (FRN.) If your machine tool supports only one feed rate mode (e.g. IPM), the GPM converts any feed rate in the CLSF to that mode.
If G Codes do not determine output mode, you will probably define different Word Address characters for the different units. The GPM then changes Word Address characters when you use the SET/MODE command in the CLSF.
For example, you might use F for Inches Per Minute and E for Inches Per Revolution.
You are then prompted for the valid feed rate mode(s.)
When you select one of the options, the system prompts you to define the Word Address format, and the valid feed rate range. Since you can define only one output mode, the system does not prompt you to select Valid or Not Valid. The system automatically makes the option you select Valid and makes the others Not Valid.
Finally, you are prompted for the minimum and maximum machine travel feed rates, a feed rate FRN factor, and a distance calculation method for Inverse Time feed rates (FRN.)
After selecting Entry Complete you are given the following Miscellaneous Feedrate Data options:
Default Feedrate Output Mode -This option allows you to select the default feed rate unit. You can define a default unit which causes the GPM to convert any feed rate in the CLSF into this unit until a SET/MODE. command changes the default unit for a program.
The SET/MODE command changes the default output mode for the program being postprocessed. It has no effect on the default mode of the MDF being used.
You should use this option if your machine tool can accept only a certain unit (e.g. IPR.) Then, no matter what units are in the CLSF, the GPM outputs only the selected unit.
The options toggle between:
OFF (OUTPUT MODE = INPUT) - causes the GPM to output the feed rate in the unit specified in each FEDRAT command. For example, FEDRAT/IPM,10 causes the GPM to output a feed rate of ten inches per minute.
IPM - causes the GPM to output all feed rates in Inches Per Minute until a SET/MODE command changes the default feed rate mode.
IPR - causes the GPM to output all feed rates in Inches Per Revolution until a SET/MODE command changes the default feed rate mode.
FRN - causes the GPM to output all feed rates as a Feedrate Number until a SET/MODE command changes the default feed rate mode.
Default Feedrate Expressed In Units Per Minute - Enter a numerical value which represents the default feed rate, in Inches Per Minute, that the GPM uses if it encounters machine tool motion statements in the CLSF before a FEDRAT command.
IPM/MMPM Output Frequency - This option allows you to define how often the GPM outputs the feed rate code (e.g. F10.)
Modal, Only When Changes Or Alignment Blocks - causes the GPM to output a feed rate code only when the feed rate changes or in a machine tool alignment block (using the postprocessor command LOAD/TOOL usually forces an alignment block.)
An alignment block is a block where all current information is output, even if it is modal. For example, the feed rate might be modal, and not change during a tool change, however, since the controller might have used the F code buffer during the tool change, you need to make sure that the feed rate get output again. Alignment blocks allow the GPM to take care of this task for you.
Every Motion Block - causes the GPM to output the feed rate code in every block which causes machine tool motion.
EVERY OUTPUT BLOCK - causes the GPM to output the feed rate code in every block in the postprocessed output.
IPR/MMPR Output Frequency - This option is similar to the IPM/MMPM output frequency.
FRN Output Frequency - This option is similar to the IPM/MMPM output frequency.
Canned Cycle Feedrate Word Address Characters - This option allows you to define a different Word Address character for feed rates output within canned machine cycles.
If you select NO, the system returns with a Current Status of Same As Non Cycle. This causes the GPM to output feed rates within canned cycles with the same Word Address character as is used when no cycle is in effect.
If you select YES, enter the new Word Address character for feed rates within canned machine cycles.
Output Current Feedrate With The Feedrate Mode - This will force out the feed rate code whenever the Feedrate output Mode code is output (e.g., g94 is output with the F code.)
Distance Calculation Method - This allows you to specify the method used to calculate the distance that is used to determine a feed rate number. The feed rate number (FRN) formula used in the GPM is FRN=K*(IPM)/Distance. Note that K represents an adjustment factor, initially set to one.
After you choose this option, you have the following selections:
X,Y,Z Delta Distance Is - a distance measured in either Machine Coordinates or Part Coordinates. The Machine Coordinates are the X,Y,Z motion including rotary motion. The rotary motion is derived from translating tool axis into rotational components. The Part Coordinate deltas are X,Y,Z motion without including the tool axis motion.
Rotary Deltas Are - measured in Degrees or Arc Length. Degrees is the distance in degrees that the rotary axis travels. Arc Length is the arc distance that the tool tip travels in rotary motion.
Rotary Deltas Are Combined With Linear -allows three choices for adding the rotary delta distance to the X,Y,Z delta (linear) distance for the total distance.
Always - which adds the rotary and linear distances.
Only Use Linear - ignores rotary motion.
Greater Of The Forth Or Fifth - uses the greater arc distance.
4th Axis Conversion Factor Degrees To Inch - this should usually be set to one. If you have a Fanuc control you might need to set this to 25.4.
Tracking Point For Rotary Distance - allows tracking tilting rotary heads at either the Tool
K Factor To Apply To FRN - This is the adjustment factor that is usually set to one.
Extended FRN - is used for Sundstrand controls capable of extended precision for FRN numbers. After you select this option you are prompted: Is FRN With Negative F Code and Increased Resolution Required For Small FRN Values? If you answer Yes, you have the following choices. These options having the correct default settings for a Sundstrand control:
Total Number of Digits - 7
Number of Decimal Places - 4
Maximum Rounding Error Before Extended FRN - .0240
Maximum Extended FRN - 999.9999
Minimum Extended FRN - .0001