Abstract:
An injection blow molding machine having an injection molding rotor including a plurality of injection molding units with individual split mold cavities for preforms, a transfer rotor, a blow molding rotor including a plurality of blow molds, and a removal rotor, essentially within a shared operating plane, and split mobile neck molding parts which fit into each blow mold and each mold cavity and which are transferred with a preform and removed with a stretch-blown bottle from the blow mold. In the process, each preform is transferred in the neck molding part into the blow mold.

Description:
The present application claims the benefit of priority of International Patent Application No. PCT/EP2007/007048, filed Aug. 9, 2007 which application claims priority of German Patent Application No. 10 2006 037 683.8, filed Aug. 11, 2006. The entire text of the priority application is incorporated herein by reference in its entirety. 
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to an injection blow molding machine of the type used for molding containers, such as plastic bottles, in bottling operations. 
     BACKGROUND 
     In an injection blow molding machine known from DE 197 37 697 A, two injection molding rotors are associated with the transfer rotor, said injection molding rotors being supplied with plasticized plastic material by a common extruder and comprising each a plurality of individual mold cavities. The total number of mold cavities in the two injection molding rotors corresponds to the number of blow molds on the blow molding rotor. One of the injection molding rotors is rotatingly driven, whereas the other is stationary. In the stationary injection molding rotor, the preforms are injection molded, whereas the rotating other injection molding rotor transfers the finished preforms one by one via the transfer rotor to the blow molding rotor. Prior to being transferred, the preforms are cooled in the injection molding rotor. The temperature or temperature distribution in each preform can be conditioned by tempering prior to the blow molding process. In the one-stage process carried out in the injection blow molding machine, the blow molding cycle time is substantially shorter than the cycle time required for producing and tempering the preform. Since the total number of mold cavities corresponds to the number of injection molds, it is difficult to optimally use the capacity of the blow molding rotor. In addition, a high amount of energy is required for the subsequent conditioning of the preforms. 
     In an injection blow molding machine known from DE 31 24 523 C, a central injection molding rotor, which comprises a plurality of mold cavity groups and which is supplied by a single extruder, has peripherally associated therewith a total number of four blow molding rotors for stretch blow molding the containers in groups. 
     U.S. Pat. No. 3,357,046 A discloses that stationary blow molds have associated therewith a rotating extruder arrangement, that the preforms are formed by severing them from a tube portion, and that they are filled immediately with the future container content and formed into containers. 
     In the injection blow molding machine known from DE 195 28 695 A, two injection molding units, which each comprise a plurality of mold cavities, are movable relative to injection molding cylinders in an injection molding station. The preform groups are removed from the mold cavities in the direction of their longitudinal axes and are then transferred in a direction transversely to the blow mold groups. The preform group can be transferred to and introduced in the blow mold group with a transfer tool comprising a plurality of neck molding parts, or the transfer tool is replaced, between the injection molding unit and the blow mold groups, by another blow-mold neck molding tool for dealing with a plurality of preforms simultaneously. The finished containers are removed from the neck molding tools and transported away. 
     SUMMARY OF THE DISCLOSURE 
     One aspect of the present disclosure to provide an injection blow molding machine and a process for stretch blow molding plastic containers, in particular bottles, by means of which a high output of high-quality plastic containers can be achieved continuously and in a single-stage process. Part of the object to be achieved is that the potential output capacity of the blow molding rotor should be optimally utilized in spite of the fact that the injection molding cycle time exceeds the blow molding cycle time. 
     The artifice of producing each preform in the neck molding part, transferring it in the neck molding part, forming the plastic container in the same neck molding part, and removing it also with the neck molding part as well as executing the motion steps substantially parallel to the operating plane, reduces the amount of technical equipment required and guarantees that neither the possibly sensitive preforms nor the plastic containers will be damaged when they are being manipulated. The neck molding parts are in addition to functional molding components also individual components of the transfer and removal system. 
     The process can take place continuously, since the neck molding parts have not only a forming function during the injection molding and stretch blow molding processes but also a transfer and removal function. This will substantially simplify the handling after the production of the preforms and after the stretch blow molding of the plastic containers and result in a high quality of the preforms and of the future plastic containers. 
     Although the rotors rotate continuously and synchronously in the injection blow molding machine, the output of containers from the blow molding rotor will not be limited by the longer injection molding cycle times, but the potential output capacity of the blow molding rotor can be optimally utilized, since, thanks to the excessive number of mold cavities according to an expedient embodiment, a number of preforms will continuously be produced which is large enough for allowing the blow molding rotor to operate with an optimum output capacity. In addition, each preform will be transferred to the blow mold comparatively quickly and has therefore an optimum temperature and/or temperature distribution for stretch blow molding. Furthermore, the period of time between production and stretch blow molding will be identical for each preform. 
     In spite of the continuous production of individual preforms with an injection molding cycle time which is longer than the blow molding cycle time for each individual preform, the blow molding rotor can, according to an expedient process variant, be operated with full output capacity, since the excessive number of preforms produced will compensate the difference between the blow molding cycle time and the injection molding cycle time. 
     According to an expedient embodiment, the number of injection molding units corresponds to the number of blow molds on the blow molding rotor, but each injection molding unit comprises more than only one mold cavity so as to obtain, in spite of the continuous operation, an excessive number of preforms, which is expedient for optimally utilizing the output capacity of the blow molding rotor. The control of each injection molding unit is structurally simple and is able to utilize the rotary movement of the injection molding rotor. At the transfer position, the mold cavity is open so that the finished preform is removed and transferred with the neck molding part; in the course of this process, the preform can consolidate or relax still further, since it is only in contact with the still warmed-up neck molding part and does not come into contact with any other manipulation element. 
     According to an expedient embodiment, each injection molding unit comprises three split injection molds provided in a star-shaped mode of arrangement on a shaft which is adapted to be intermittently rotated relative to the injection molding rotor. Each injection mold defines a mold cavity for producing a preform. During each full rotation of the injection molding rotor, the shaft executes only part of a rotation so as to offer a finished preform for transfer. Simultaneously, a holding pressure phase, which is important to the quality of the preform, is given for a further preform, and an injection molding process, which is not specially limited in time, can be carried out for still another preform. In this way, the injection molding cycle times and the blow molding cycle times are adjusted to one another in such a way that, in spite of the shorter injection molding cycle time, the full output capacity of the blow molding rotor can be utilized even in a continuous mode of operation. 
     In the injection molding rotor, each injection molding unit has associated therewith a separate plasticizing screw which rotates together with the injection molding rotor. In addition, at least one injection molding cylinder, which is adapted to be supplied by the plasticizing screw, is preferably provided. It is here possible to use an injection molding cylinder for each mold cavity, or to use a common injection molding cylinder for the mold cavities of the injection molding unit, said common injection molding cylinder being filled with plastic material from the plasticizing screw and used for introducing an exactly predetermined amount of material under high pressure into the mold cavity. An expedient separation of functions is here given, since the plasticizing screw guarantees the supply and the optimum plasticizing degree, whereas the injection molding cylinder guarantees the correct amount of material and the correct injection pressure. 
     With respect to a compact, low structural design, the plasticizing screws are arranged substantially parallel to the operating plane and radially to the axis of the injection molding rotor. They are centrally supplied with the plastic material by means of a common material distributor. 
     According to an expedient embodiment, each mold cavity is defined by an injection mold with two mold halves, the split, openable neck molding part and a mandrel. One of the mold halves and, preferably, the mandrel can be fixed relative to the shaft of the injection molding unit, whereas the other mold half is pivotably supported on said first mold half or in a mold carrier half. As is normally the case, means can be used for fixing or arresting the injection mold during the injection molding process. 
     It will be expedient when the neck molding part, which has to fulfil the injection molding and the blow molding function as well as the transfer and the removal function, is provided with a female thread so as to form a threaded neck, and, preferably, with at least one annular groove for forming a container neck holding ring, as is common practice e.g. in the case of PET bottles. Neck molding parts having a different shape can, however, be used as well, depending on the type of plastic container produced. Neck molding parts having a smooth inner wall and/or bead forming parts for other closure means can, for example, be used as well. 
     According to an expedient embodiment, the neck molding part carries two guide cones which are arranged one on top of the other on the outer side of said neck molding part. An upper guide cone is provided for applying thereto the transfer and removal elements, whereas a lower guide cone serves to position and fix the neck molding part in the mold cavity and in the blow mold, respectively. 
     According to a particularly expedient embodiment of the injection blow molding machine, the transfer rotor and the removal rotor are coaxially combined in a single rotor such that they are positioned one on top of the other. This will reduce the amount of space required in the injection blow molding machine. An important aspect is here that cam control means are provided for the transfer and removal elements, said cam control means controlling an alternate overtaking function for the transfer and removal elements. It will be expedient when the transfer and removal elements consist of pairs of clamps that are extendable and retractable as well as possibly pivotable; each of said clamps is either spring biased and opens and closes automatically when applied to the respective element, or the clamps are adapted to be opened and closed in a controlled mode. 
     In an expedient embodiment of the injection blow molding machine having an optimum output capacity, the blow molding rotor has provided thereon eight blow molds, the injection molding rotor has provided thereon eight injection molding units comprising each three injection molds, the transfer rotor has provided thereon four transfer elements, and the removal rotor has provided thereon four removal elements. The rotors are driven such that the mold cavity located at the transfer position, each clamp and each blow mold move essentially at the same circumferential speed. 
     In addition, it will be expedient to provide control means, preferably cam control means on the transfer and removal rotor, for opening or closing each neck molding part. Each neck molding part will not be opened until the finished plastic container can be removed, and after this removal it will be closed immediately for insertion into the mold cavity. It is even possible to introduce the neck molding part into the open mold cavity in the open condition and to close it only when the mold cavity is being closed. 
     For guaranteeing a neat transfer of the finished plastic containers to a discharge conveyor, it will be expedient to provide a mandrel for temporarily securing and transporting away each plastic container, said mandrel being insertable, at least to a certain degree, into the container neck and expandable in said container neck, when the neck molding part delivering the plastic container is opened. It would, however, also be possible to take hold of the bottom of the container, or to grasp the container in some other way as soon as the neck molding part is opened. 
     According to an advantageous process variant, each mold cavity is first transferred, during a full rotation of the injection molding rotor, from an injection position by a third of a turn to a holding pressure position. This is followed by a holding pressure and consolidation phase of the plastic material in the mold cavity so as to optimally form the preform. The mold cavity can, but need not, temporarily stop at the holding pressure position. During the next full rotation of the injection molding rotor, the mold cavity is moved by a third of a turn to a transfer position and opened in such a way that, when meeting a transfer element, the preform, with the closed neck molding part, will be removed from the mold cavity and rapidly transferred to the blow mold. During the next full rotation of the injection molding rotor, the mold cavity will be closed again and transferred to the injection position. In the injection position, the closed and locked mold cavity can temporarily be stopped at the rotating injection molding rotor while the latter continues to rotate. 
     According to another process variant the respective neck molding part is transferred from the mold cavity and removed from the blow mold by a clamp of a combined transfer and removal rotor. The combined rotor has provided thereon a respective pair of clamps, said pair of clamps being controlled in the direction of rotation of the rotor in such a way that a clamp constituting the rear clamp in the direction of circulation will overtake the other, front clamp of the pair once during the transfer process and also once during the removal process, said overtaking taking place between the positions of the injection molding and blow molding rotors. By means of this overtaking step, the initially leading clamp with the neck molding part and the preform held therein is, during the transfer process, overtaken by the empty clamp, which introduced the neck molding part into the mold cavity, so that the empty clamp will then constitute the leading clamp and remove the closed neck molding part with the finished plastic container from the blow mold, before the then trailing clamp with the preform will introduce the preform with the neck molding part. In a similar way, the initially leading clamp with the neck molding part and the plastic container is overtaken by the empty clamp, which transferred the preform into the blow mold, between the blow molding rotor and the injection molding rotor so that the then leading empty clamp will, in turn, remove the neck molding part with the preform from the mold cavity, before the clamp with the neck molding part, which then no longer contains the plastic container, will introduce said neck molding part into the mold cavity. The overtaking processes can be controlled easily, but they allow the use of a combined transfer and removal rotor instead of two separate and separately driven and controlled transfer and removal rotors. 
     Finally, the process according to the present disclosure is so conceived that, at least at the injection and transfer positions of each mold cavity, the rotation of the injection molding unit is temporarily interrupted at the injection molding rotor which continues to rotate, so that the injection process and the transfer process take place in a neatly controlled manner. It is, however, also imaginable that the rotation of the injection molding unit is only slowed down temporarily or even continued continuously. 
     It will be expedient to assign still another function to the neck molding part in the blow mold insofar as said neck molding part is used for attaching thereto the blowing nozzle. This means that the blowing nozzle is brought into sealing engagement with the neck molding part; to this end, appropriate sealing measures are taken at the blowing nozzle and/or at the neck molding part, without any necessity of using the preform for this purpose and possibly damaging it in so doing. This results in an increased flexibility of the blow molding process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the subject matter of the present disclosure and of the process are explained on the basis of the drawings, in which: 
         FIG. 1  shows a schematic top view of rotor components of an injection blow molding machine (first embodiment), 
         FIG. 2  shows a schematic top view of an injection molding unit of an injection molding rotor of the injection blow molding machine according to  FIG. 1  (and  FIG. 6 ), 
         FIG. 3  shows an axial section of a view, part of which is a top view, of an injection mold of the injection molding units according to  FIG. 1 , 
         FIG. 4  shows a schematic side view of a process step during the removal of plastic containers from the blow molding rotor according to  FIG. 1 , 
         FIG. 5  shows a schematic side view of a detail of the injection molding rotor in  FIG. 1  and  FIG. 6 , respectively, 
         FIG. 6  shows a schematic top view of a second embodiment of the injection blow molding machine, 
         FIG. 7  shows a schematic side view, part of which is a sectional view, of a blow mold of the blow molding rotor in  FIG. 1  and  FIG. 6 , respectively, and 
         FIG. 8  shows an axial section of an injection mold with an injection molding cylinder and a plasticizing screw of the injection molding rotor in  FIG. 1  and  FIG. 6 , respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows, without specifying in detail drive units and auxiliary equipment, an injection molding rotor S, a blow molding rotor B spaced apart from said injection molding rotor S, and transfer and removal rotors T, E cooperating with the rotors S, B, of an injection blow molding machine M used for producing from preforms R plastic containers F, in particular PET bottles. The rotors S, B, T, E operate essentially in a shared operating plane, the axes of the rotors extending essentially at right angles to said plane. The injection molding rotor S has provided thereon e.g. eight injection molding units  1  which are arranged at uniform, circumferentially spaced intervals. Also the blow molding rotor B is provided with eight blow molds  11 . Each transfer and removal rotor T, E comprises four transfer and removal elements  8 ,  9 ,  15 ,  16 ,  18 , respectively. 
     In the embodiment shown in  FIG. 1 , each injection molding unit  1  comprises three injection molds  1   a ,  1   b  and  1   c  which are arranged in a star-shaped mode of arrangement on a shaft  6  on the injection molding rotor S and which each define a mold cavity  2  for producing a preform R. Each injection molding unit  1  has associated therewith a plasticizing screw P in the injection molding rotor S. The plasticizing screws P rotate together with the injection molding rotor, they are arranged in a horizontal and substantially radial mode of arrangement and they are supplied by a central material distributor  7 . Each injection mold  1   a ,  1   b ,  1   c  is divided in a plane that extends parallel to the axis of the injection molding rotor S so that two mold halves  4 ,  5  are formed, which are adapted to be pivoted relative to one another, possibly in a mold carrier. An important part of the mold cavity  2  is a neck molding part  3 , which is divided as well. 
     The transfer elements  8 ,  9  on the transfer rotor T are clamps used for gripping only the respective neck molding part  3  and adapted to be extended and retracted at least in the direction of a double arrow  10 . The clamps can be spring biased and open or close automatically when applied to the neck molding part  3 , or they are opened or closed in a controlled mode. 
     Also each blow mold  11  on the blow molding rotor B is divided and comprises two mold halves  12 ,  13  as well as a bottom mold  14  which is only indicated by a broken line. Each blow mold  11  cooperates with a blowing nozzle which is not outlined in  FIG. 1 . 
     Also the removal elements  15 ,  16  on the removal rotor E are clamps, which are adapted to be moved to an fro at least in the direction of a double arrow  17  and which are similar to the clamps provided on the transfer rotor T. In addition, mandrels  18  are provided whose purpose and function will be explained hereinbelow. The removal rotor E cooperates with a discharge unit  19  (e.g. a removal belt or an air conveyor) for the finished plastic containers F. The directions of rotation of the rotors are marked by arrows. 
     The three injection molds  1   a ,  1   b ,  1   c  are adapted to be rotated by means of the shaft  6  in  FIGS. 1 and 2  by a third of a turn relative to the injection molding rotor S while said injection molding rotor rotates one full turn. In this way, each injection mold  1   a ,  1   b ,  1   c  is advanced during three full rotations of the injection molding rotor S between an injection position I, a holding pressure position II and a transfer position III. This rotation can take place continuously or intermittently. 
     While the rotors rotate continuously and while, making use of the full output capacity, the individual plastic containers F are stretch blow molded and formed in the blow molding rotor B, e.g. a number of preforms R exceeding the number of blow molds  11  on the blow molding rotor B is produced in the injection molding rotor S. Each preform R dwells at the injection molding rotor S for e.g. more than one full rotation, viz. e.g. for three full rotations, so that, in spite of the fact that the cycle time for the stretch blow molding of the plastic containers F is, as is usually the case, shorter than the cycle time for the injection molding of the preform, the output capacity of the blow molding rotor B will not be limited by the longer cycle time for the injection molding of the preform. 
       FIG. 2  illustrates the arrangement of the three injection molds  1   a ,  1   b ,  1   c  on the shaft  6 . In  FIG. 2 , it is additionally indicated that each of the injection molds, which are approximately square when seen from above, could be divided diametrically into the mold halves  4 ,  5 . The shaft  6  is anchored in the injection molding rotor S and is driven through a control  21  stepwise or continuously in a ratio of 1:3 to the rotation of the injection molding rotor S, i.e. during three full rotations of the injection molding rotor S, the injection molding unit  1  executes a 360° rotation over three thirds of a rotation. In the course of this process, each mold cavity  2  is opened at the transfer position III so that the preform R with the closed neck molding part  3  is ready for removal from the mold cavity  2 . At least one of the mold halves  4 ,  5  can be fixedly attached to the shaft  6 , whereas the other mold half can be pivotably supported on said first-mentioned mold half or on a mold carrier which is not shown, The rotation control means  21  of the shaft  6  can also be implemented such that it controls the opening and closing movements of the injection molds  1   a ,  1   b ,  1   c.    
       FIG. 3  shows a section through the injection mold  1   a  at right angles to the mold parting plane  24 . The mold cavity  2  in the mold halves  4 ,  5 , is implemented in the shape of the preform and has an injection opening  25  at the bottom. In an upper area of the mold cavity  2 , a circumferentially extending conical reception means  26  is formed, which serves to position and fix the neck molding part  3 . Also the neck molding part  3  is adapted to be opened in the mold parting plane  24  and comprises two shells  25  provided with a female thread  30  and e.g. a circumferentially extending annular groove  27  (for the holding ring of the container neck). On the outer circumference of the shells, an upper guide cone  28  for applying the transfer and removal elements, and a lower guide cone  29  for insertion in the groove  26  (and a corresponding groove in the respective blow mold  11  or in a blow mold carrier) are formed one on top of the other. 
     The neck molding part  3  serves, on the one hand, for forming the outlet area of the preform R and, on the other hand, for forming the plastic container F, and in addition for transferring the preform and for removing the plastic container. Another function of the neck molding part  3  can be that it cooperates with the blowing nozzle of the blow mold, said blowing nozzle being attached directly to the neck molding part  3 . 
       FIG. 4  shows the course of action for removing the finished plastic containers F from the blow molding rotor R. Each plastic container F is removed with the closed neck molding part  3  from the blow mold and moved along the removal rotor E to the discharge conveyor  19 . In the course of this movement, the removal element  16  holds the closed neck molding part  3  until the plastic container F has been aligned with a mandrel  18 , which moves as well and which has arranged thereon an expandable head  33  at the lower end of its shaft  32 . The head  33  is introduced by means of a cam control  34  into the neck of the plastic container F and expanded until the plastic container F is suspended from the mandrel  18 . Via cam control means which are not specified in detail, the neck molding part  3  is simultaneously opened, e.g. by the removal element  16 , until also the holding ring  31  of the plastic container F is released and the plastic container can be transported away. The neck molding part  3  is then advanced still further in its open condition, or it is closed again and then reintroduced into a mold cavity  2  of an injection mold  1   a ,  1   b ,  1   c.    
       FIG. 5  illustrates a detail of the injection molding rotor S with the shaft  6 , which is rotatably supported in a portal  38  and which is adapted to be rotatingly driven via a control gear  35 . The shaft  6  carries mold carriers  36  for the injection molds  1   a ,  1   b ,  1   c  of the injection molding unit  1 .  FIG. 5  shows of each injection mold the neck molding part  3  in the mold cavity  2  and the injection opening  25  of the mold cavity, the injection opening of the injection mold  1   a  being in alignment with an injection element  37  of the plasticizing screw P. Furthermore, a mandrel  20  is inserted into the neck molding part  3  from above. For producing the preform R, the plasticized plastic material is injected into the mold cavity  2  either from the plasticizing screw or by making use of an injection molding cylinder  42  which will be explained on the basis of  FIG. 8 . The rotation of the shaft  6  can temporarily be interrupted during this injection process, whereas the injection molding rotor S continues to rotate. The injection molding cylinder, which is not shown, could then rotate together with the injection mold  1   a  about the axis of the shaft  6  until the injection mold  1   a  has reached the holding pressure position II. Then, the shaft  6  starts rotating again until the injection mold  1   a  has finally reached the transfer position III in  FIG. 2  where it will be opened. 
       FIG. 6  illustrates analogously to  FIG. 1  a top view of a second embodiment of the injection blow molding machine, which is characterized in that the transfer and removal rotors T, E of  FIG. 1  are combined, one on top of the other, in a rotor T, E provided with a total of eight pairs of transfer and removal elements  8 ,  9 ,  15 ,  16  and the mandrels  18  (not shown); the transfer and removal elements can not only be extended and retracted, but they may also be pivotable. In the combined transfer and removal rotor, cam control means K 1 , K 2  are provided, with the aid of which a respective overtaking function can be executed, when the elements move from the injection molding rotor S to the blow molding rotor B and vice versa. 
     The transfer and removal elements  9 ,  16  are e.g. a respective pair of clamps. When the overtaking function is executed, e.g. during the transfer from the injection molding rotor S to the blow molding rotor B, the clamp  16 , which is first the trailing clamp in the direction of circulation, overtakes the leading clamp  9  once due to the function of the cam control means K 1 , so that the clamp  16  will finally arrive before the clamp  9  at the open blow mold  11  in the direction of circulation and remove the finished plastic container F with its neck molding part  3 , before the then trailing clamp  9  transfers a neck molding part  3  and a preform R to the blow mold  11 . 
     In a similar way, the cam control means K 2  controls an overtaking function once on the removal path between the blow molding rotor B and the injection molding rotor S. The clamp  9 , which first constitutes the trailing clamp in the direction of circulation, overtakes the other clamp  16  belonging to the pair of clamps and holding the neck molding part  3  with the plastic container F, so that the empty clamp  9  will arrive at the open mold cavity  2  as the leading clamp for removing the neck molding part  3  with the preform R, before the clamp  16 , which then no longer carries the plastic container F, arrives, with the neck molding part  3 , at the mold cavity  2 . Each plastic container F is in this case removed by the mandrel  18  (not shown) when the neck molding part  3  has been opened, and is then supplied to the discharge conveyor  19 . The neck molding part  3  is closed, e.g. by the clamp  16 , before it is introduced into the open injection mold  1   a ,  1   b ,  1   c  of the injection molding unit  1 , said injection mold occupying the transfer position III. 
       FIG. 7  illustrates schematically a blow mold  11  with a blow mold carrier  39  and the blow mold halves  12 ,  13  in the open condition. Also the bottom mold  14  is positioned in the blow mold carrier  39 , and so is the neck molding part  3  with the guide cone  29 . The blowing nozzle  40  is attached directly to the neck molding part  3  as soon as said neck molding part  3  has been closed and locked. For this purpose, suitable connection and sealing means, which are not emphasized in detail, can be provided on the blowing nozzle  40  and/or on the neck molding part  3 . 
     Finally,  FIG. 8  illustrates once more the closed injection mold  1   a  of the injection molding unit  1  in the injection molding rotor S during cooperation with the plasticizing screw P and the injection molding cylinder  42  for filling the mold cavity  2  through the injection opening  25  with plasticized plastic material and producing the preform R. The mold halves (only the mold half  5  is indicated) of the injection mold  1   a  are contained in a mold carrier  41 ; in this embodiment, the guide cone  29  of the neck molding part  3  cooperates with this mold carrier  41 . For securing the guide cone  29  in position, an appropriate reception groove  26 ′ is formed in the mold carrier  41 . The upper guide cone  28  for the transfer and removal elements is exposed. The mandrel  20  is introduced into the mold cavity  2  until an annular flange  20   a  of the mandrel  20  rests on the upper side of the neck molding part  3 . 
     The injection molding cylinder  42  contains an e.g. hydraulically operable dosing piston  45  in a cylinder tube  43  which is introduced in the mold carrier  41  and which is in sealing engagement with the lower surface of the injection mold  1   a . The dosing piston  45  is retracted to a lower charging position before the plasticizing screw P introduces plasticized plastic material into a dosing chamber  44  through an inlet  46 . Subsequently, the piston  45  is displaced upwards until it closes the inlet  46  and presses a preset amount of plastic material into the mold cavity  2 . In the course of this process, the inlet  46  is temporarily sealed off until the piston  45  is moved downwards later on. The injection molding cylinder  42  can remain attached until the holding pressure position II of the injection mold  1   a  has been reached. Then, the mold carrier  41  is either slightly raised, or the injection molding cylinder  42  is slightly lowered, before the rotary movement of the injection mold  1   a  about the shaft  6  is continued. 
     Due to the continuous process flow, the period of time required for each preform until the respective preform is introduced in the blow mold after its production is equal. The dwell time of the preform in the injection molding rotor S is sufficiently long for allowing optimum forming, holding of the pressure and stress relieving and for achieving an optimum temperature or temperature distribution in the preform. If necessary, cooling or thermal conditioning is executed in this phase or in a later phase. Such thermal conditioning of the preform may also be executed while the preform moves along the transfer rotor T and into the blow mold. The preform R does not come into contact with other manipulating elements at any time, since the neck molding part  3  has to fulfil not only forming functions during the injection and stretch blow molding processes but also transfer and removal functions and possibly even the connection function for the blowing nozzle  40  and the attachment function for the mandrel  20 . During each blow molding process, stretching and pre-blowing is executed, as usual, when the process has begun, whereas final blowing is carried out subsequently while the blow molding rotor rotates. Cam guides or other aids can be provided for opening and closing the clamps. Since the blow molding rotor and the injection molding rotor are capable of rotating at essentially the same speed, also the movement of the transfer and removal rotors is uniform and quiet. At least theoretically, eight different blow molds could be installed, which allow the production of differently dimensioned plastic containers, since each blow mold is so to speak supplied from a separate injection molding unit  1  which produces the preform in the blow mold according to the requirements in question. 
     Broader variations are additionally possible when not only eight different blow molds but also different thread inserts (neck molding parts) are used. Taking all this into account, a much more flexible production is possible, since also particular (peculiar) shapes can be produced (e.g. angular containers from angular preforms).