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Adaptive Control machining - PowerPoint by swenthomasovelil

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									ADAPTIVE CONTROL
   MACHINING
INTRODUCTION
• ADAPTIVE CONTROL MACHINING(AC)
 ORGINATED OUT OF RESEARCH IN EARLY
 1960’S SPONSERED BY THE US AIRFORCE.



• AC USES MICROPROCESSER BASED CONTROLS
 AND IS TYPICALLY INTEGRATED WITH A
 EXISTING CNC SYSTEM.
• IN AC MACHINING THERE IS IMPROVEMENT IN
  THE PRODUCTION RATE AND REDUCTION IN
            MACHINING COSTS.



• THIS OCCURS AS A RESULT OF CALCULATING
    AND SETTING OF OPTIMAL PARAMETERS
            DURING MACHINING.
ADAPTIVE CONTROL
• AC POSSESSES ATTRIBUTES OF BOTH FEED-
 BACK CONTROL AND OPTIMAL CONTROL



• FEATURE THAT DISTINGUISHES AC CONTROL
 FROM OTHER TWO TYPES IS THAT AN AC
 SYSTEM IS DESIGNED TO WORK IN A TIME
 VARYING ENVIORNMENT
• AN AC SYSTEM IS DESIGNED TO OPERATE FOR
 THE CHANGING ENVIORNMENT BY
 MONITORING ITS PERFOMANCE AND
 ACCORDINGLY SOME ASPECTS OF ITS
 CONTROL MECHANISM TO ACHIEVE OPTIMAL
 OR NEAR OPTIMAL PERFOMANCE


• AN AC EVALUATES ITS PERFOMANCE WITHIN
 THE ENVIORNMENT AND MAKES NECESSARY
 CHANGES IN ITS CONTROL CHARACTERISTICS
 TO IMPROVE OR IF POSSIBLE TO OPTIMIZE ITS
 PERFOMANCE
FUNCTIONS OF AC
• IDENTIFICATION FUNCTION


• DECISION FUNCTION


• MODIFICATION FUNCTION
ADAPTIVE CONTROL SYSTEM
• AC OF METAL WORKING PROCESS IS A
   LOGICAL EXTENSION OF THE NUMERICAL
   CONTROL AND COMPUTER CONTROL



• IN NC PROCESS THE CUTTING SPEED AND
   FEEDS ARE PRESCRIBED BY THE PART
   PROGRAMMERS
IN PRACTICE THE AC SYSTEMS OF MACHINE
TOOLS CAN BE CLASSIFIED INTO TWO TYPES




     • AC WITH OPTIMISATION(ACO).



     • AC WITH CONSTRAINTS(ACC).
DEFINITION
• THE TERM AC DENOTES A CONTROL SYSTEM
 THAT MEASURES CERTAIN O/P VARIABLES AND
 USES THESE TO CONTROL SPEED AND/OR
 FEED

• THE TYPICAL MEASURES OF PERFOMANCE IN
 MACHINING HAVE BEEN METAL REMOVEL RATE
 AND COST PER VOLUME OF METAL REMOVEL
WHERE TO USE AC

 • ONE OF THE PRINCIPLE REASONS FOR USING
  NC IS THAT IT REDUCES THE
  NONPRODUCTIVE TIME IN A MACHINING
  OPERATION.

 • AC DETERMIES THE PROPER SPEEDS AND
  FEEDS DURING MACHINING AS A FUNCTION
  OF VARIABLES IN SUCH FACTORS AS WORK
  MATERIAL HARDNESS,WIDTH OR DEPTH OF
  CUT,AIR GAPS IN THE PART GEOMETRY AND
  SO ON
• THE FOLLOWING CHARACTERISTICS CAN BE
     USED TO IDENTIFY SITUATIONS WHERE AC
     CAN BE BENEFICIALLY APPLIED

1. IN-PROCESS TIME CONSUMES A SIGNIFICANT
     PORTION OF THE MACHINING CYCLE TIME
2.   THERE ARE SIGNIFICANT SOURCES OF
     VARIABILITY IN JOB FOR WHICH AC CAN
     COMPENSATE
3.   COST OF OPERATING MACHINING TOOL IS
     HIGH
4.   THE TYPICAL JOB INVOLVES STEEL & HIGH
     STRENGTH ALLOYS
SOURCES OF VARIABILITY
1. VARIABLE GEOMETRY OF CUT
2. VARIABLE WORKPIECE HARDNESS &
   VARIABLE MACHINABILITY
3. VARIABLE WORKPIECE RIGIDITY
4. TOOL WEAR
5. AIR GAPS DURING CUTTING
BENEFITS OF AC
• INCREASED PRODUCTION RATES

• INCREASED TOOL LIFE

• GREATER PART PROTECTION

• LESS OPERATOR NTERVENTION

• EASIER PART PROGRAMMING
CONCLUSION
• FOR A MACHINING OPERATION AC IS THE BEST
 METHOD FOR CONTROLLING THE PROCESS

• IT HAS BEEN ESTABLISHED THAT IT WAS
 POSSIBLE TO INCREASE THE METAL REMOVING
 RATE BY 35% TO 45% BY USING AC
 TECHNIQUES
THANK YOU

								
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