Stretch-blow molding machine

Abstract

A stretch-blow molding machine having at least one blow molding station, in which a split blow mold, an adjustable blow nozzle with a valve section, a stretching rod with a stretching rod drive system, and an electronic control unit are provided, the electronic control unit arranged in the blow molding station is equipped with hardware and software for selectively operating the blow molding station with a combination of a cam drive and a pneumatic drive, or a combination of an electric servo drive and a pneumatic drive, or only an electric servo drive in the stretching rod drive system. The movement of the stretching rod is initiated in the stretch-blow molding machine in the production process of a container by means of an electric servomotor with the beginning of or during the locking phase of the blow mold and before the blow nozzle is placed, and the stretching rod is already displaced to a position in which the stretching rod is either very closely approached to the preform bottom or contacts the preform bottom, or has even already pre-stretched the preform, until the blow nozzle is placed.

1 . Stretch-blow molding machine, comprising: at least one blow molding station having at least one split blow mold, an adjustable blow nozzle with a clock-controlled valve section, an adjustable stretching rod with a clock-controlled stretching rod drive system, and an electronic control unit at least for controlling the stretching rod drive system, the stretching rod drive system comprising one of a combination of a cam drive and a pneumatic drive, a combination of an electric servo drive and a pneumatic drive, or only an electric servo drive, the electronic control unit arranged in the blow molding station is equipped with hardware and software for selectively operating a blow molding station with the combination of the cam drive and the pneumatic drive, or the combination of the electric servo drive and a pneumatic drive, or only the electric servo drive. 
     
     
         2 . Stretch-blow molding machine according to  claim 1 , wherein the control unit is equipped with hardware and software for controlling the blow nozzle and/or the valve section. 
     
     
         3 . Stretch-blow molding machine according to  claim 1 , wherein the blow molding station is arranged in a part rotating relative to a stationary part of the stretch-blow molding machine. 
     
     
         4 . Stretch-blow molding machine according to  claim 1 , wherein the control unit is installed in the blow molding station separately from the electric servo drive. 
     
     
         5 . Stretch-blow molding machine according to  claim 4 , and wherein a frequency converter of the electric servo drive, comprising a servomotor in the form of a rotary motor or a linear motor, is separated from the servomotor. 
     
     
         6 . Stretch-blow molding machine according to  claim 5 , and wherein a frequency converter of an electric servo drive comprises at least one controlled set-up switched-mode power supply by means of which an intermediate circuit voltage set up to between about 600 to 900 Volt for supplying the electric servomotor adapted to the set-up intermediate circuit voltage can be generated and maintained independent of the mains voltage applied to the frequency converter. 
     
     
         7 . Stretch-blow molding machine according to  claim 5 , and the use of two-phase or multi-phase current for the servomotor. 
     
     
         8 . Stretch-blow molding machine according to  claim 3 , and wherein intermediate circuits of frequency converters for electric servomotors in the rotating part are electrically coupled with intermediate circuits of frequency converters for electric servomotors in the stationary part, and that at least one energy storage for supplying at least the electric servomotors in the rotating part in case of a power outage are provided in the stationary part. 
     
     
         9 . Stretch-blow molding machine according to  claim 6 , and wherein at least one energy storage for supplying at least the electric servomotors in the rotating part in case of a power outage are provided in the rotating part. 
     
     
         10 . Stretch-blow molding machine according to  claim 3 , and drive axles of the stationary part are electrically coupled drive axles in the rotating part. 
     
     
         11 . Stretch-blow molding machine according to  claim 3 , and at least one transmitter for controlling at least one electric servomotor in the rotating part is provided in the rotating part. 
     
     
         12 . Stretch-blow molding machine according to  claim 8 , and wherein the frequency converter is designed in STO and/or SLS technology and/or that the stretching rod drive system comprises at least one electronic type label for storing at least motor-specific parameters that can be read out. 
     
     
         13 . Stretch-blow molding machine according to  claim 3 , and wherein a central lubrication device for all blow molding stations for supplying mechanical sections of drive systems with lubricant is provided in the rotating part. 
     
     
         14 . Stretch-blow molding machine according to  claim 1 , wherein the servomotor of the stretching rod drive system designed as rotary motor is connected with a stretching slide coupled with the stretching rod either via a threaded spindle or via a cable chain, and that the servomotor and the control unit are mounted on a bearing support which comprises at least one linear guidance for the stretching slide. 
     
     
         15 . Stretch-blow molding machine according to  claim 14 , wherein the bearing support comprises a U-profile open at one longitudinal side, inside of which the threaded spindle and the linear guidance are arranged, the stretching rod is arranged at the rear side of the U-profile facing away from the open longitudinal side of the U-profile, and the stretching slide grips around the U-profile from outside and engages from the open longitudinal side to the linear guidance to the inside of the U-profile with a coupling with the threaded spindle and the linear guidance. 
     
     
         16 . Stretch-blow molding machine according to  claim 14 , wherein at least one driver rod for a blow molding slide arranged at a distance to the stretching slide and comprising the blow nozzle is arranged at the stretching slide and can be coupled with the stretching slide via a driver coupling acting only in one moving direction of the stretching slide. 
     
     
         17 . Stretch-blow molding machine according to  claim 1 , wherein the servomotor of the stretching rod drive system designed as linear motor has a tubular design with respect to its rotor and forms one of a coaxial or essentially coaxial direct drive of the stretching rod with the rotor. 
     
     
         18 . Stretch-blow molding machine according to  claim 17 , wherein the rotor of the linear motor is arranged with respect to the stretching rod laterally offset by no more than 100 mm. 
     
     
         19 . Stretch-blow molding machine according to  claim 17 , wherein the rotor is guided with respect to a stator of the linear motor by one of guide rings in the stator or at both ends of the stator, or at least one guide sleeve continuously or partially continuously integrated in the stator, or at least one guidance arranged outside the stator. 
     
     
         20 . Stretch-blow molding machine according to  claim 17 , wherein the linear motor is embodied for a temporary generator-based operation with energy recovery. 
     
     
         21 . Stretch-blow molding machine according to  claim 1 , wherein with the electric servomotor, the stretching rod can be selectively one of force-controlled or path-controlled by the control unit in one and the same cycle in the production process. 
     
     
         22 . Stretch-blow molding machine according to  claim 17 , wherein the rotor is coupled with an energy storage mechanism, at least for partially compensating forces acting from the blow pressure in the blow mold on the stretching rod. 
     
     
         23 . Stretch-blow molding machine according to  claim 17 , wherein the linear motor and the control unit are mounted on a bearing support, and that the bearing support comprises a linear guide for the stretching slide at which the stretching rod, which penetrates a stretching slide linearly adjustable to the stretching rod, is coupled with the rotor. 
     
     
         24 . Stretch-blow molding machine according to  claim 14 , wherein one of an adjustable stop, a spring-mounted stop, or a combination thereof, for the stretching slide is arranged at the bearing support. 
     
     
         25 . Stretch-blow molding machine according to  claim 14 , wherein in the rotating part of the stretch-blow molding machine, a lifting member is arranged at the blow molding slide which is associated to a catch cam. 
     
     
         26 . Method of stretch blow molding containers from preforms in a blow molding station of a stretch-blow molding machine, wherein in the blow molding station, at least one split blow mold, an adjustable blow nozzle with a clock-controlled valve section, an adjustable stretching rod with a clock-controlled stretching rod drive system, and an electronic control least or controlling the stretching rod drive system are provided, comprising lifting the blow nozzle from the opened blow mold, retracting the stretching rod, inserting a preform into the blow mold, closing and locking the blow mold, placing the blow nozzle onto the preform in a sealing manner, inserting the stretching rod until the stretching rod approaches and/or contacts the preform bottom and is displaced, under pressure application of the preform via the blow nozzle, close to the bottom of the mold cavity of the blow mold, and, in the production process of a container, initiating the movement of the stretching rod by means of an electric stretching rod servomotor at the latest with the beginning of or during the locking phase of the blow mold and/or before the blow nozzle is placed onto the preform and the stretching rod is displaced into a position in which the free end of the stretching rod is either very closely approached to the preform bottom or contacts the preform bottom, or the preform is already prestretched until the blow nozzle is placed. 
     
     
         27 . Method according to  claim 26 , and changing at least twice the speed of the stretching rod movement in a cycle in the production process of a container to the position of the free stretching rod end in the mold cavity bottom, without return of movement. 
     
     
         28 . Method according to  claim 27 , and changing and/or adjusting the speed of the stretching rod movement depending on one of the blow pressure or the mass flow rate of the blow air. 
     
     
         29 . Method according to  claim 26 , and wherein the stretching rod displaced in the cycle by means of the linear motor is displaced in the return stroke with the blow pressure in the blow mold, and that the servomotor in the return stroke is either de-energized or driven by the stretching rod as a generator. 
     
     
         30 . Method according to  claim 26 , and wherein the blow molding slide is taken along at least over a portion of the return stroke of the stretching rod by the stretching rod or the stretching slide, or the stretching slide is terminated at the locked blow molding slide. 
     
     
         31 . Method of stretch-blow molding containers from preforms in a blow molding station of a stretch-blow molding machine, wherein in the blow molding station, at least one split blow mold, an adjustable blow nozzle with a clock-controlled valve section, an adjustable stretching rod with a clock-controlled stretching rod drive system, and an electronic control unit at least for controlling the stretching rod drive system are provided, comprising lifting the blow nozzle from the opened blow, retracting the stretching rod, inserting a preform into the blow mold, closing and locking the blow mold, placing the blow nozzle onto the perform in a sealing manner, inserting the stretching rod until the stretching rod approaches and/or contacts the preform bottom and is displaced, under pressure application of the preform via the blow nozzle, close to the bottom of the mold cavity of the blow mold, and motor-specific parameters stored in an electronic type label of the stretching rod drive system are read out by a frequency converter allocated to an electric stretching rod servomotor for a preferably optimized adjustment of the motor and/or closed-loop control parameters. 
     
     
         32 . Stretch-blow molding machine according to  claim 3 , wherein the rotating part comprising a blow-molding unit comprising several blow molding stations. 
     
     
         33 . Stretch-blow molding machine according to  claim 5 , wherein the frequency converter is separated from the servomotor at a distance excluding heat coupling from the servomotor to the frequency converter, or at a central installation point containing several to all frequency converters for several blow molding stations of the stretch-blow molding machine. 
     
     
         34 . Stretch-blow molding machine according to  claim 33 , wherein the central installation point is a cooled switch cabinet. 
     
     
         35 . Stretch-blow molding machine according to  claim 6 , wherein the frequency converter of an electric servo drive is in an immediate circuit. 
     
     
         36 . Stretch-blow molding machine according to  claim 6 , wherein the intermediate voltage set up is between about 750 to 800 volt. 
     
     
         37 . Stretch-blow molding machine according to  claim 9 , wherein the at least one energy storage comprises a flywheel, a capacitor bank, or a battery. 
     
     
         38 . Stretch-blow molding machine according to  claim 10 , wherein the drive axles of the rotating part are electric drive systems. 
     
     
         39 . Stretch-blow molding machine according to  claim 12 , wherein the at least motor-specific parameters are read out by a frequency converter of the electric stretch rod servomotor. 
     
     
         40 . Stretch-blow molding machine according to  claim 14 , wherein the threaded spindle is a ball threaded spindle. 
     
     
         41 . Stretch-blow molding machine according to  claim 14 , wherein the bearing support is a heat sink. 
     
     
         42 . Stretch-blow molding machine according to  claim 16 , wherein the one moving direction of the stretching slide is in the direction of the return stroke. 
     
     
         43 . Stretch-blow molding machine according to  claim 19 , wherein the at least one guidance arranged outside the stator comprises two spaced guide members and a linear guide. 
     
     
         44 . Stretch-blow molding machine according to  claim 22 , wherein the energy storage mechanism comprises one of a spring or a pneumatic cylinder. 
     
     
         45 . Stretch-blow molding machine according to  claim 23 , wherein the linear motor and the control unit are mounted via a heat sink. 
     
     
         46 . Stretch-blow molding machine according to  claim 23 , wherein the bearing support also supports the valve section. 
     
     
         47 . Stretch-blow molding machine according to  claim 23 , wherein the stretching rod is coupled with the rotor in a releasable manner. 
     
     
         48 . Stretch-blow molding machine according to  claim 25 , wherein the lifting member comprises a drive roller. 
     
     
         49 . Method according to  claim 27 , wherein changing at least twice the speed of the stretching rod movement is one of path-depending, force-depending, time-depending, or a combination thereof.