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NCCNC machines
Prepared by
RDMakwana
Requirement leads to invention
bull Many things in world require variations
For example aero planes are to be made of different design
bull ldquoThe manufacturing technology available during late 40rsquos and early 50rsquos could not meet the design and manufacturing challenges arising out of the need to develop sophisticated aircraft and satellite launch vehicles
bull John parsons of parsons corporation was subcontractors to USAF was thinking about using digital computers to reduce computation
bull Machining of complex curvature which is highly skilled job
bull He at that time proposed that coordinate points of three dimensional profile can be used to control milling machine table to produce accurate jobs
bull USAF accepted his proposal and awarded a contract
bull Later on project went to servomechanism laboratory of Massachusetts Institute of Technology in 1951 who demonstrated working milling machine in 1952
bull Bendix corporation produced first commercial NC unit in 1954
Introduction to Numerical Control Machines
bull NC machines are machines controlled by programs automation of small and medium volume production is done
bull Definition of NC
ldquoThe control of a machine tool by means of recorded information on punched tape or cards is known as Numerical Controlrdquo
OR
ldquoNumerical Control is defined as a form of software controlled automation in which the process is controlled by alphanumeric characters or symbolsrdquo
NC machine
bull In initial stages the NC machine tools had NC systems added to machine to only control the position of work piece relative to the cutting tool
bull The operator had to select the cutting tools speed and feed etc
bull In next stage material removal was also controlled by the NC system
bull The instructions to the NC machines are fed through an external medium ie paper tape or magnetic tape
bull The information is stored into the memory of control system called lsquobuffer storagersquo and is processed by the machine step by step
bull When the machine is working on one block the next block is read from the tape
bull Tape has to be run repeatedly depending on the number of components to be produced
bull If there is minor change in component the tape has to be discarded and new tape with changed programme has to be produced
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
Requirement leads to invention
bull Many things in world require variations
For example aero planes are to be made of different design
bull ldquoThe manufacturing technology available during late 40rsquos and early 50rsquos could not meet the design and manufacturing challenges arising out of the need to develop sophisticated aircraft and satellite launch vehicles
bull John parsons of parsons corporation was subcontractors to USAF was thinking about using digital computers to reduce computation
bull Machining of complex curvature which is highly skilled job
bull He at that time proposed that coordinate points of three dimensional profile can be used to control milling machine table to produce accurate jobs
bull USAF accepted his proposal and awarded a contract
bull Later on project went to servomechanism laboratory of Massachusetts Institute of Technology in 1951 who demonstrated working milling machine in 1952
bull Bendix corporation produced first commercial NC unit in 1954
Introduction to Numerical Control Machines
bull NC machines are machines controlled by programs automation of small and medium volume production is done
bull Definition of NC
ldquoThe control of a machine tool by means of recorded information on punched tape or cards is known as Numerical Controlrdquo
OR
ldquoNumerical Control is defined as a form of software controlled automation in which the process is controlled by alphanumeric characters or symbolsrdquo
NC machine
bull In initial stages the NC machine tools had NC systems added to machine to only control the position of work piece relative to the cutting tool
bull The operator had to select the cutting tools speed and feed etc
bull In next stage material removal was also controlled by the NC system
bull The instructions to the NC machines are fed through an external medium ie paper tape or magnetic tape
bull The information is stored into the memory of control system called lsquobuffer storagersquo and is processed by the machine step by step
bull When the machine is working on one block the next block is read from the tape
bull Tape has to be run repeatedly depending on the number of components to be produced
bull If there is minor change in component the tape has to be discarded and new tape with changed programme has to be produced
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull John parsons of parsons corporation was subcontractors to USAF was thinking about using digital computers to reduce computation
bull Machining of complex curvature which is highly skilled job
bull He at that time proposed that coordinate points of three dimensional profile can be used to control milling machine table to produce accurate jobs
bull USAF accepted his proposal and awarded a contract
bull Later on project went to servomechanism laboratory of Massachusetts Institute of Technology in 1951 who demonstrated working milling machine in 1952
bull Bendix corporation produced first commercial NC unit in 1954
Introduction to Numerical Control Machines
bull NC machines are machines controlled by programs automation of small and medium volume production is done
bull Definition of NC
ldquoThe control of a machine tool by means of recorded information on punched tape or cards is known as Numerical Controlrdquo
OR
ldquoNumerical Control is defined as a form of software controlled automation in which the process is controlled by alphanumeric characters or symbolsrdquo
NC machine
bull In initial stages the NC machine tools had NC systems added to machine to only control the position of work piece relative to the cutting tool
bull The operator had to select the cutting tools speed and feed etc
bull In next stage material removal was also controlled by the NC system
bull The instructions to the NC machines are fed through an external medium ie paper tape or magnetic tape
bull The information is stored into the memory of control system called lsquobuffer storagersquo and is processed by the machine step by step
bull When the machine is working on one block the next block is read from the tape
bull Tape has to be run repeatedly depending on the number of components to be produced
bull If there is minor change in component the tape has to be discarded and new tape with changed programme has to be produced
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull USAF accepted his proposal and awarded a contract
bull Later on project went to servomechanism laboratory of Massachusetts Institute of Technology in 1951 who demonstrated working milling machine in 1952
bull Bendix corporation produced first commercial NC unit in 1954
Introduction to Numerical Control Machines
bull NC machines are machines controlled by programs automation of small and medium volume production is done
bull Definition of NC
ldquoThe control of a machine tool by means of recorded information on punched tape or cards is known as Numerical Controlrdquo
OR
ldquoNumerical Control is defined as a form of software controlled automation in which the process is controlled by alphanumeric characters or symbolsrdquo
NC machine
bull In initial stages the NC machine tools had NC systems added to machine to only control the position of work piece relative to the cutting tool
bull The operator had to select the cutting tools speed and feed etc
bull In next stage material removal was also controlled by the NC system
bull The instructions to the NC machines are fed through an external medium ie paper tape or magnetic tape
bull The information is stored into the memory of control system called lsquobuffer storagersquo and is processed by the machine step by step
bull When the machine is working on one block the next block is read from the tape
bull Tape has to be run repeatedly depending on the number of components to be produced
bull If there is minor change in component the tape has to be discarded and new tape with changed programme has to be produced
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
Introduction to Numerical Control Machines
bull NC machines are machines controlled by programs automation of small and medium volume production is done
bull Definition of NC
ldquoThe control of a machine tool by means of recorded information on punched tape or cards is known as Numerical Controlrdquo
OR
ldquoNumerical Control is defined as a form of software controlled automation in which the process is controlled by alphanumeric characters or symbolsrdquo
NC machine
bull In initial stages the NC machine tools had NC systems added to machine to only control the position of work piece relative to the cutting tool
bull The operator had to select the cutting tools speed and feed etc
bull In next stage material removal was also controlled by the NC system
bull The instructions to the NC machines are fed through an external medium ie paper tape or magnetic tape
bull The information is stored into the memory of control system called lsquobuffer storagersquo and is processed by the machine step by step
bull When the machine is working on one block the next block is read from the tape
bull Tape has to be run repeatedly depending on the number of components to be produced
bull If there is minor change in component the tape has to be discarded and new tape with changed programme has to be produced
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
NC machine
bull In initial stages the NC machine tools had NC systems added to machine to only control the position of work piece relative to the cutting tool
bull The operator had to select the cutting tools speed and feed etc
bull In next stage material removal was also controlled by the NC system
bull The instructions to the NC machines are fed through an external medium ie paper tape or magnetic tape
bull The information is stored into the memory of control system called lsquobuffer storagersquo and is processed by the machine step by step
bull When the machine is working on one block the next block is read from the tape
bull Tape has to be run repeatedly depending on the number of components to be produced
bull If there is minor change in component the tape has to be discarded and new tape with changed programme has to be produced
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull The information is stored into the memory of control system called lsquobuffer storagersquo and is processed by the machine step by step
bull When the machine is working on one block the next block is read from the tape
bull Tape has to be run repeatedly depending on the number of components to be produced
bull If there is minor change in component the tape has to be discarded and new tape with changed programme has to be produced
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
CNC machines-Computer Numerical Control
bull A dedicated computer is used to perform all the basic NC functions
bull Part program is input and stored in computer memory
bull Programs can be used in future
bull CNC machine tools are widely used today due to many control features available on these machines
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
CNC machines-Computer Numerical Control
bull The CNC machines have the facility for proving the part programme without actually running it on the machine tool
bull This is called simulation-in which the control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
Direct Numerical Control
bull DNC is a manufacturing system in which a large number of machines are controlled by a computer through direct connections
bull All machines are linked to a main frame computer which sends information to individual machines as and when required
bull All part programs are stored in the computer
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Two configurations
1 The main computer is directly linked to the machine In this configuration there could be delays at the main computer in providing details to the machine tool
2 The main computer is connected to machine tool through a mini computer called satellite computer Satellite computer receives part program form main computer and controls the machine tool operation
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
Advantages of CNC machines
bull Reduced lead time Lead time time between the receipt of a design
drawing by the production engineer and manufacturer getting ready to start production planning time load-unload time
bull Elimination of operator errors Program is checked before actual operation by
simulation Fatigue boredom or inattention by an operator will not
affect the quality or duration of the machining
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Lower labour cost
One operator can run two or more machines
bull Longer tool life
Tools can be used at optimum speeds and feeds
Speed and feed can be changed by editing program
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
Disadvantages of CNC machines
bull High machine cost
bull Complicated maintenance
bull Skill amp training are required for programming and maintenance
bull High tooling cost
bull Temperature humidity amp dust must be controlled
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
Evolution of Controllers
bull Vacuum tube
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull In 1952 MIT servo mechanism laboratories used vacuum tubes for controller hardware
bull Very large- control unit bigger than machine tool
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Electronic relays
bull The first NC machines were sold to the commercial market in about 1955
bull Electro mechanical relays were used
bull Same problem as vacuum tubes ndash large size
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Discrete semi conductors
Transistors were used in around 1960
Electromechanical relays were replaced by transistors
Increased reliability because use of transistors avoided wear problem
Size smaller than others
They were sensitive to heat fans or air conditioners were required
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Integrated circuits
In 1965 IC were introduced
Significant improvement in size and reliability
Reduced cost of NC system
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Programmable Logic Controllers
PLC acts as a sequencer
It responds to various sensors connected to its inputs makes logical decisions according to programmed instructions into its memory and sets output as per program
First PLC was conceived in 1968 by Bedford Associates
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Microprocessors and microcomputers
bull Most compact digital control devices have developed with greater working speeds and capacity at lower costs around 1975
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
bull Computer Numerical Control
The first commercial CNC was introduced in 1970
Computer was smaller in size and less expensive
Easily programmable through their own softwares
