Hybrid injection molding machine
First Claim
1. An energy conserving hybrid injection molding machine comprising:
- an injection unit for injecting molding material into the mold cavity of a mold, said injection unit including a screw member rotatably and translatably carried in a tubular barrel, said barrel having an end in fluid communication with said mold cavity;
a first drive unit coupled to said injection unit for rotating said screw in said barrel;
said first drive unit including a first AC induction motor, a mechanical coupling connecting said first AC induction motor with said screw and a vector control drive for controlling the operation of said first AC motor pursuant to a variable rotate command signal;
a second drive unit coupled to said injection unit for translating said screw in said barrel;
said second drive unit including a second AC induction motor, a hydraulic constant delivery pump driven by said second AC induction motor, a first hydraulic coupling between said pump and said screw for translatably moving said screw within said barrel and a second vector control drive for variably controlling the speed of said second AC induction motor pursuant to a variable injection command signal;
a machine controller for generating said command signals to cause said molding machine to perform a given molding cycle, said machine controller including motor speed sensors measuring the speed of said first and second AC motors; and
,said vector control drive for each motor including means for calculating maximum torque and flux current components passing through stator windings only from a speed signal comparing a motor speed signal with a set command speed signal whereby the torque produced by the AC motors is not used to control the motors.
5 Assignments
0 Petitions
Accused Products
Abstract
An energy efficient general purpose injection molding employs a hydraulic drive for injection and clamp machine functions and an electric drive for screw recovery. Both drives use AC "squirrel cage" induction motors under vector control. Speed command signals for the vector controls are generated by the machine'"'"'s controller utilizing state transition and predictive signal techniques to account for motor and motor/pump response latencies. Hydraulic drive efficiency is improved by varying motor speed/pump output to match cycle requirements to retain hydraulic drive advantages for mold clamp and injection functions while improving the electric drive performance for screw recovery.
32 Citations
21 Claims
-
1. An energy conserving hybrid injection molding machine comprising:
-
an injection unit for injecting molding material into the mold cavity of a mold, said injection unit including a screw member rotatably and translatably carried in a tubular barrel, said barrel having an end in fluid communication with said mold cavity; a first drive unit coupled to said injection unit for rotating said screw in said barrel;
said first drive unit including a first AC induction motor, a mechanical coupling connecting said first AC induction motor with said screw and a vector control drive for controlling the operation of said first AC motor pursuant to a variable rotate command signal;a second drive unit coupled to said injection unit for translating said screw in said barrel;
said second drive unit including a second AC induction motor, a hydraulic constant delivery pump driven by said second AC induction motor, a first hydraulic coupling between said pump and said screw for translatably moving said screw within said barrel and a second vector control drive for variably controlling the speed of said second AC induction motor pursuant to a variable injection command signal;a machine controller for generating said command signals to cause said molding machine to perform a given molding cycle, said machine controller including motor speed sensors measuring the speed of said first and second AC motors; and
,said vector control drive for each motor including means for calculating maximum torque and flux current components passing through stator windings only from a speed signal comparing a motor speed signal with a set command speed signal whereby the torque produced by the AC motors is not used to control the motors. - View Dependent Claims (2, 3, 4)
-
-
5. An energy conserving hybrid injection molding machine comprising:
-
an injection unit for injecting molding material into the mold cavity of a mold, said injection unit including a screw member rotatably and translatably carried in a tubular barrel, said barrel having an end in fluid communication with said mold cavity; a first drive unit coupled to said injection unit for rotating said screw in said barrel;
said first drive unit including a first AC induction motor, a mechanical coupling connecting said first AC induction motor with said screw and a vector control drive for controlling the operation of said first AC motor pursuant to a variable rotate command signal;a second drive unit coupled to said injection unit for translating said screw in said barrel;
said second drive unit including a second AC induction motor, a hydraulic pump driven by said second AC induction motor, a first hydraulic coupling between said pump and said screw for translatably moving said screw within said barrel and a second vector control drive for variably controlling the speed of said second AC induction motor pursuant to a variable injection command signal;a clamp unit for supporting first and second sections of a mold selectively movable from a first parted position in which said mold sections are closed to define said mold cavity therebetween; said second drive unit further including a second hydraulic coupling operable to move said clamp between said first and second positions and maintaining said clamp in said second position at a set force;
said second vector control drive further effective to vary the speed of said second AC motor pursuant to a variable pump command signal;said second drive unit includes a third AC motor, a second pump driven by said third motor, and a third vector control drive for driving said third AC motor; and
,machine controller means for generating said command signals to cause said molding machine to perform a given molding cycle. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. An injection molding machine comprising:
-
a) an injection unit for injecting molding material into the mold cavity of a mold by causing a screw to linearly move within a tubular barrel;
said injection unit including a first AC induction motor, a constant delivery pump connected to said first AC motor, a first hydraulic coupling directing pump fluid at a set pressure and flow to control movement of said screw in said barrel and a first vector drive for variably controlling the speed of said first motor in accordance with a first inject command signal;b) a clamp unit for opening and closing said mold;
said clamp unit including a second AC induction motor, a second constant delivery pump connected to said second motor, a second hydraulic coupling directing pump fluid at a set pressure and flow to control opening, closing and clamping of said mold; and
a second vector control drive controlling the speed of said second AC induction motor in accordance with a second clamp command signal;c) an ejector unit for ejecting the finished molded part from said mold and for setting cores into said mold cavity;
said ejector unit including a third AC induction motor, a third constant delivery pump connected to said third motor, a third hydraulic coupling directing pump fluid at a set pressure and flow to cause ejection of said part and thereafter setting of said core; and
a third vector control means for variably controlling the speed of said third AC motor in accordance with a third eject command signal;d) a screw recover unit for rotating said screw, said screw recover unit including a fourth AC induction motor, a mechanical coupling causing rotation of said screw; and
a fourth vector control for variably controlling the speed of said fourth in accordance with a fourth AC induction motor rotate command signal; and
,e) a controller for generating said first, second, third, and fourth command signals. - View Dependent Claims (18, 19, 20, 21)
-
Specification