• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Method for controlling a method of manufacturing a container by stretching a plastic preform (2) in a machine (1) comprising a mold (26), the preform (2) having a body (3) a neck (4) which opens at one end of the body (3) and a bottom (5) which closes the body (3) at another end thereof, the manufacturing method comprising the steps of: - heating the preform to a predetermined temperature in a furnace (10) of thermal conditioning; introducing the preform (2) into the mold (26); - moving an elongation rod (28) to stretch the preform (2); this control method comprising a step of determining the impact position (P0r) of the elongation rod (28), that is to say its position at the moment when it reaches the bottom (5) of the preform (2) during its displacement.
    公开号:FR3024071A1
    申请号:FR1457220
    申请日:2014-07-25
    公开日:2016-01-29
    发明作者:Mikael Derrien
    申请人:Sidel Participations SAS；
    IPC主号:
    专利说明:

    [0001] The invention relates to the manufacture of containers, such as bottles or jars, obtained by stretch blow molding thermoplastic preforms, such as polyethylene terephthalate (PET). ), high density polyethylene (HDPE) or any other known material. The invention more particularly relates to a method for manufacturing containers made of plastic material, such as PET, by stretching preforms in a mold with a pressurized fluid, in particular air, of the type in which the machine for its implementation comprises a control system, a thermal conditioning furnace and a blowing unit comprising at least one blowing station, said station comprising a mold, into which the preforms are introduced, coming from the furnace, each in order to undergo a container-forming operation, the operation including a drawing step (also called an elongation step) of the preform, using an elongation rod which is associated with the mold and is controlled sliding towards the bottom of the mold. The stretching and blowing of the body of a preform requires that it be heated to a temperature above the glass transition temperature of the material. It is thus first of all carried out a thermal conditioning of the preform by circulating it inside an oven. The furnace comprises heating means which are for example formed by infrared lamps. The preform is moved into the furnace by a conveying system. The heated preform is then introduced into the mold and then stretched by means of a sliding rod (called a drawing rod or elongation rod) and pressurized gas is introduced into the preform to transform it into a container. blowing. The introduction of the gas under pressure comprises in all cases a blowing step proper, which consists in introducing into the preform a gas, generally air under high pressure (typically between 18 and 40 bar). The blowing step is usually preceded by a first step, called pre-blowing, which consists in introducing a gas at a lower pressure (between 8 and 15 bar) while the elongation rod, having reached the bottom of the preform, causes the longitudinal stretching thereof. The stretching, pre-blowing and blowing steps (alternatively stretching and blowing) take place according to a pre-established sequencing during the parameterization of the machine, which sequencing takes into account the preforms used and the shape of the container. to obtain. The stretching and blowing (or pre-blowing and blowing) allow the constituent material of the preform to undergo a molecular bi-orientation, which gives the final container special mechanical properties. Pre-blowing initiates the deformation of the preform to turn it into a container and blowing allows an optimal impression in the mold, so that the details of the container are well marked. In the remainder of the description, unless further clarifications are made, the expression "blowing process" will be used indiscriminately to designate a sequence comprising a pre-blowing step followed by a blowing step or to designate a process comprising only a blowing step. Consequently, "to start the blowing process" will mean either starting the pre-blowing step by injecting the pre-blowing gas in the case where such a step exists, or starting the blowing step directly by injecting the blast gas. blowing.
    [0002] After a certain time of contact of the plastic material against the mold, during a degassing step, the pressure is brought back into the vessel at atmospheric pressure before discharging the final container from the mold. In other processes, the degassing step is preceded by a step of recycling a portion of the fluid contained in the container, in order to reinject it to other uses (in the machine itself or in the factory where the machine is installed). There may still exist a so-called scavenging step for hot fillable bottles, during which a flow of air ensures the cooling of the container which is in contact with a hot mold.
    [0003] The preforms are generally obtained by injecting the material into dedicated injection molds. They have a tubular cylindrical body closed at one of its axial ends, which is extended at its other end by a collar, also tubular. The neck of the preform is generally injected so as to already have the shape of the neck of the final container, while the body of the preform is called to undergo a relatively large deformation to form the body of the final container, following the blowing operations. The neck of the preforms often has a support collar intended to hold them on the upper edge of the molds, during the formation of the containers. A container has a side wall (also referred to as a body), a neck that extends from an upper end of the body, and a bottom that extends from a lower end of the body, to the opposite of the collar. The bottom of the container defines a seat, usually at the junction with the body, and through which the container can rest on a flat surface (such as a table).
    [0004] The mold comprises a wall defining a cavity for imparting its shape to the body of the container. This cavity is closed at a lower end by a mold bottom to give its shape to the bottom of the container. Today, in order to parameterize a machine to produce a given type of container, an injection preform is placed in a mold of the machine, while the machine is stopped, (thus cold and not which has not been reheated) corresponding to those which will be used for this type of container, then the position of the elongation rod is determined when it reaches the bottom of the preform. The position at which the end of the extension rod reaches the bottom of the preform is conventionally called by the Applicant Zero Point ("Point 0") of the elongation. From point 0, the continuation of the movement of the elongation rod causes the elongation of the preform. In parameterization, a position of the elongation rod is also established at which the blowing process, which may correspond to or be located beyond point 0, must begin. In other words, a theoretical stretching length is determined between the point 0 and the beginning of the blowing process. Indeed, since the preform begins to be stretched, if nothing else is done, the constituent material of the preform is tightened on the rod. A first consequence is a risk of excessive cooling of the areas of the preform in contact with the elongation rod (it is usually cold) leading to a poor quality container, because it then becomes impossible to properly deform these areas because of their cooling. Another consequence is a risk of deterioration, in particular by drilling, of the bottom of the preform by the elongation rod.
    [0005] Other operations are further parameterized between the moment when the elongation rod reaches the bottom of the preform and that where the bottom of the preform, driven by the rod, reaches the bottom of the mold (called Point 10). Still other operations take place after the achievement of Point 10.
    [0006] This procedure has various disadvantages. Indeed, the determination of the Point 0 is carried out machine stopped, on a cold preform, output of injection press. However, it has been found that apparently identical preforms may behave differently after passing through the thermal conditioning oven of the blowing machines. In particular, it was found that after heating in the oven, the length of some preforms could vary, the difference of up to 5 to 10 mm from one preform to another. In particular, it has been found that for thin preforms used to produce small format bottles, for example 0.5 liter bottles, and low wall thicknesses, the length of such preforms at the furnace outlet could be more than 10 mm lower than their length at the entrance of the oven, in other words compared to their length at the outlet of the injection press. In the case of 20 preforms intended to be transformed into small-size bottles (typically light 0.5-liter bottles of water), such a reduction in length, also called withdrawal or "shrinkage" by the person skilled in the art, corresponds to a longitudinal variation of about 15%. This reduction is also accompanied by an increase in the diameter of the preform. For the same type of bottles, diameter increases of about 7% were noted. On the other hand, there may also exist, for the same production of preforms, gaps of a few mm between the maximum withdrawal and the minimum shrinkage. The existence of a shrinkage during the heating of the preforms results from the generation of stresses in the preforms during their manufacture. These constraints appear because of the pressures or the temperature to which the material is subjected during the injection. During heating, some of the stresses are released with the result that the length and the diameter of the preforms are reduced. Relaxation of stress is sometimes called relaxation.
    [0007] 3024071 5 Shrinkage differences were noticeable not only for the same production of preforms or preforms of the same type, but also from one type of preform to another. These phenomena are accentuated by the current tendency to reduce the weight of the containers 5 and therefore that of the preforms and their thickness. For the same type of preforms, the various shrinkage phenomena and the differences can be explained in the following way: when the preforms are obtained using the same press that can contain several tens of cavities (presses with a hundred or so cavities 10 are known), it can happen that, from one cavity to another, there is not exactly the same amount of material that is injected, or that a cavity is less well cooled than 'other. In addition, a single container manufacturing machine must be fed with hundreds of thousands of preforms (some exceed 15 million) per day of production and it is conceivable that the preforms for such a machine do not come out of the same press injection. In this case, there may be variations from one press to another, due to possible differences in setting parameters between two presses. Finally, other parameters may influence, such as the intrinsic quality of the injected material. The differences in shrinkage from one type of preform to the other may have one or more origins, among which in particular the different parameters of the preform designs, the thicknesses of the preforms, the resin specifications and / or the parameters of the preform processes. injection, especially the injection pressure, even if the weights of the preforms would be identical. Consequently, the containers produced may have different material distributions, insofar as certain preforms will not have shrunk, while others will have undergone 30, which, moreover, may be different from a preform to the other. Moreover, insofar as some preforms will have become shorter than others before their introduction into the mold, effective stretching will begin before reaching the Point 0 determined during parameterization. However, the stretched length of the preform 35 before the start of pre-blowing has a considerable influence on the distribution of the material of the package (for some containers, the stretching must be zero). Also, if the drawing starts too early with respect to pre-blowing, or if stretching takes place when it should not have been, and if the shrinkage is different from one preform to another, Different material distributions will appear on the containers, with a risk of tightening of the material on the stem, a risk all the greater as the containers are manufactured with a high rate of elongation. Current machines are more and more automated, making it possible to correct various time drifts of the blowing process. It is known (see document W02008 / 081107 in the name of the applicant) to correlate singular points of an actual blowing curve with machine parameters (in particular the flow rate or the pre-blowing pressure), and of apply corrections of the parameters according to divergences observed in these singular points. However, the automation does not correct defects such as those mentioned above. Indeed, one or more fins 15 caused by the modification of the physical characteristics of a preform can not be corrected by the control method described in WO2008 / 081107 previously cited. A first object is to overcome these disadvantages, by proposing a method for improving the forming of the containers produced, while limiting the scrap, and maintaining - or increasing - the production rates. Another object is a method which can, if necessary, be implemented in an automated machine such as that mentioned in the document WO 2008/081107 mentioned above.
    [0008] By "forming" in the rest of the description is meant more particularly a distribution of the material. For these purposes, it is proposed, according to a first aspect, a method of controlling a method of manufacturing a container by stretching blow molding of a plastic preform in a machine 30 comprising a mold, the preform comprising a body a neck that opens at one end of the body and a bottom closing the body at another end thereof, the method of manufacture comprising the steps of: - heating the preform to a predetermined temperature in a furnace; thermal conditioning; - introduce the preform into the mold; moving an elongation rod to stretch the preform, the control method comprising a step of determining the impact position of the elongation rod, i.e., its position at the moment when it reaches the bottom of the preform during its displacement. Thus, by determining the impact position, in other words the effective Point 0 (point of impact of the elongation rod) and no longer a theoretical Point 0, it becomes possible to optimize the manufacture of the containers. , taking into account the behavior of the preforms during their reheating. Moreover, the determination of the effective Point 0 makes it possible to deduce the longitudinal shrinkage undergone by the preform, which is constituted by the difference between the impact position as determined and that which it would have reached in the absence of withdrawal. The control method has, according to various implementations, the following characters, if necessary combined: the determination of the impact position of the elongation rod is carried out by detecting an increase in the driving torque of the elongation rod; the drive of the elongation rod being carried out by means of an electric motor, the determination of the impact position of the elongation rod is carried out by detecting the instant when the training current the electric motor increases, reflecting the resistance to training undergone by the elongation rod due to its contact with the bottom of the preform; is calculated the difference between the impact position and a standard position of impact of the elongation rod, predetermined during the setting of the machine, a start order of the blowing process being given only if the difference calculated does not exceed a predetermined allowable value; the order of commencement of the blowing process is given when the elongation rod reaches its impact position; The order of commencement of the blowing process is given after the elongation rod has reached its impact position and has caused the preform to stretch; is calculated the difference between the impact position and the standard position of impact of the elongation rod, predetermined during the setting of the machine, a fault signal being emitted when the difference reaches or exceeds a value pre-determined eligible amount; The difference between the impact position and the standard impact position of the elongation rod is calculated, the preform being ejected after the reopening of the mold when the value of the difference exceeds a predetermined admissible value; 5 - is calculated the difference between the impact position and the standard position of impact of the elongation rod, is checked if the difference is recurrent and, if so, is modified at least one parameter of the machine; the standard impact position of the elongation rod is the theoretical impact position that would be obtained with a cold preform 10 leaving the injection machine; the standard position of impact of the elongation rod is an average real impact position calculated during the parameterization of the machine from a sample of several preforms which have been reheated and, consequently, a withdrawal, in conditions that will be implemented during production. It is proposed, secondly, a machine for manufacturing containers from preforms which comprises at least one mold in which can be driven in sliding an extension rod, the drive means of the elongation rod being associated means for detecting the impact position of the elongation rod as it contacts the bottom of the preform. Other objects and advantages of the invention will be apparent from the description given hereinafter with reference to the accompanying drawings in which: FIG. 1 is a schematic view of a container making machine; FIG. 2 is a diagrammatic sectional view of a blowing station within the machine of FIG. 1. In the remainder of the description, the terms "high", "low" and the terms "high" , "bass", are used for the sake of clarity with reference to the orientation of the figures without this having any limiting scope. In Figure 1 is schematically illustrated a machine 1 for the manufacture of containers from preforms 2 of thermoplastic material and more particularly PET (polyethylene terephthalate).
    [0009] Each preform 2 comprises a cylindrical body 3, a neck 4 in the definitive shape of that of the container to be obtained (which generally does not undergo any deformation during the manufacture of the container) and which opens at one end of the body. 3, and a bottom 5 whose shape is generally hemispherical and which closes the body 3 at another end thereof. The machine 1 of manufacture comprises an oven 10 and a blowing unit 12. The function of the oven 10 is to heat the preforms 2 to a temperature greater than or equal to the glass transition of the constituent material, for example greater than 80 ° C. when this material is PET. The oven 10 comprises a conveyor (schematically illustrated) for conveying the preforms 2 by rotating them on themselves, and heating means 16, such as infrared lamps facing reflectors or laser sources, for heating the Preforms 2. The preforms 2 enter the furnace 10, mounted on the U-shaped conveyor. They are heated by the scroll by the heating means 16, which, if present, is placed on one side. or on either side of the preforms 2 with respect to their direction of travel. The hot preforms 2 are extracted from the furnace 10 and transferred into molds of the blowing unit 12 by a first transfer device 18, such as a transfer wheel, interposed between the furnace 10 and the blowing unit 12. . The transfer wheel comprises arms (not shown, because known per se) which successively enter the preforms 2, after their exit from the furnace 10, at their neck, to introduce them each turn in a mold 26 of the unit 12 of blowing. The blowing unit 12 comprises a carousel 20 rotating on the periphery of which are arranged several blowing stations 22. Each blowing station 22 comprises at least one mold 26 which usually consists of three parts, namely two half-molds 26A, 26B and a mold bottom 26C, which define the manufacturing cavity of the container.
    [0010] Each hot preform 2 leaving the oven 10 is introduced into a mold 26 of the blowing station 22 to be blown into it and converted into a container 23. Once completed, the container 23 is extracted from the blowing station 22 by a second device 24. transfer, similar to the first transfer device 18, and well known to those skilled in the art. In Figure 2 is detailed a station 22 blowing. It comprises: a mold 26, made of steel or aluminum alloy, consisting of two half-molds 26A, 26B and a bottom 26C of mold, defining a cavity whose periphery has the shape of the final container 23 produced. The mold 26 is intended to successively receive hot preforms 2 from the furnace 10, a rod 28 of elongation mounted movably along the main axis X of the mold 26, between a high position allowing the introduction of a preform 2 in the mold 26 when the latter is open and a low position where the end of the elongation rod 28 is in contact with the mold bottom 26C. The passage from the high position to the low position of the elongation rod 28 is carried out to stretch the material axially along the X axis, a blowing nozzle 30 mounted movably between a high position during the introduction of the preform 2 and a low position where the lower end of this nozzle 30 caps the preform 2 in a sealed manner in order to bring the blowing air into the preform 2 to come to press the plastic against the walls of the mold 26 The rod 28 of elongation slides in the nozzle 30, a pressure sensor 32, opening into the nozzle 30 to make a measurement of the pressure in the closed volume constituted by the nozzle 30 and the preform 2 during the blowing operation of the container 23, - a circuit 34 of low-pressure pre-blast air between 3 and 15 bar. This circuit 34 comprises a source 36 of low pressure and a pipe 38 for conveying air from the low pressure source 36 to the nozzle 30 to form the future container 23 and a solenoid valve EV1, called the pre-blow solenoid valve. allowing the low-pressure source 36 to communicate with the interior of the preform 2 via the nozzle 30.
    [0011] The solenoid valve EV1 is placed on the pipe 38 between the source 36 of low pressure and the nozzle 30. The pre-blowing air circuit 34 further comprises an anti-return valve 39 preventing fluid coming from another source or content in the preform (respectively the container) is introduced therein, - a circuit 40 of high pressure blowing air, between 15 and 40 bar, which comprises a source 42 of high pressure and a pipe 44 allowing the fluid to be conveyed from the source 42 of high pressure to the nozzle 30 to form the future container and a solenoid valve EV2, called the blow-off solenoid valve, controlling the communication of the source 42 of high pressure with the preform 2. The solenoid valve EV2 is placed on the pipe 44 between the source 42 of high pressure and the nozzle 30. The blower air circuit 40 further comprises a nonreturn valve 45 preventing fluid from another source or content in the pref elm (respectively the container) is introduced therein, - a circuit 46 for recovering the blowing air, which comprises a pipe 50 for conveying the air contained in the container after its manufacture to recovery means 48 , such as a recovery circuit or tank, and a solenoid valve EV3, said recovery solenoid valve, controlling the communication between the container and the recovery means. The solenoid valve EV3 is placed on the line 50 of the recovery circuit 46, 25 - a degassing circuit 52 for putting the inside of the container into communication with the outside, for the return to atmospheric pressure, before the recovery of the nozzle 30 in the high position, the degassing circuit 52 comprising a venting loop, one end of which is connected to a silencer 54 to avoid any noise nuisance, and the other to a connected pipe 56 at the nozzle 30, and a solenoid valve EV4, called degassing solenoid valve, controlling the communication of the air contained in the container 23 with the atmosphere, - an electronic control unit 58, in particular in the form of a controller industrial programmable circuit (PLC), electrically connected to the pressure sensor 32, solenoid valves EV1, EV2, EV3, EV4 via respective actuators R1, R2, R3, R4 whose function 3024071 12 is to ensure the opening and / or the top closure EV1, EV2, EV3, EV4 solenoid valves. Advantageously, the control unit 58 comprises: a processor 60, an analog input module 62 connected to the pressure sensor 32 to collect the measurements and convert them into a digital signal for processing by the processor, a memory 64 connected to the processor for storing data from the pressure sensor 32 (after conversion), an analog output module 66 controlled by the processor 60, and controlling the solenoid valves EV1, EV2, EV3, EV4 via the actuators R1, R2, R3, R4 so as to modulate the opening and closing to vary the flow of fluid supplied to the nozzle 30, and the axial displacement control device of the rod 28 a communication interface 68 for the implementation in the control unit 58 of the program controlling its operation, a sensor 70 for detecting the torque applied by means 72 for driving the rod 28. 60, in one embodiment, the drive means 72 is constituted by an electric motor, and the torque detection sensor 70 is a current sensor. The analog output module 66 also receives the position data of the elongation rod 28 from the electric motor. The operation of the machine is similar to that of the known machines, with the difference that the machine uses a method according to which the displacement of the rod 28 of elongation is controlled, so as to determine the impact position (POr) of the rod 28 of elongation at the moment when it reaches the bottom 5 of the preform 2 during its displacement and to order the beginning of the blowing process taking into account this actual position. In Fig. 2, where the preform 2 is shown in phantom, the impact position (POr) of the stretching rod 28, while the stretching has not yet begun, is indicated. Assuming that the preform 2 has shrunk when it is heated in the furnace 10 by the heating means 16, the theoretical Point 0 (POth) used in the prior processes 3024071 13 would be a little further in the race of the rod 28 of elongation, as shown in Figure 2. The determination of the impact position (POr) of the rod 28 of elongation can be performed by detecting the driving torque 5 of the rod, thanks to the sensor 70 which can be a current sensor. The arrival of the rod 28 of elongation in contact with the bottom of the preform 2 results in an increase in the torque required for driving, causing a greater current draw at the motor 72. The position of the rod 28 This elongation at this instant can be easily measured using means within the reach of those skilled in the art, for example means for measuring the number of revolutions made by the motor 72 since its departure from its position. initial and send the corresponding data to the analog output module 66. The measurement of the position of the elongation rod 28 is permanent so that, after the impact position (POr) has been reached, the processor 60 is able to give a start order of the blowing process (order from the beginning of the pre-blowing step or order of the direct start of the blowing step) at a time that was determined during the parameterization of the machine 1.
    [0012] In one implementation, the machine 1 is set so that the start order of the blowing process is given at the very moment when the extension rod 28 comes into contact with the bottom 5 of the preform 2. In other words, the drawing starts in synchronism with the blowing process. In a variant, the machine 1 is set so that the start order of the blowing process is given after the stretching rod 28 has reached its impact position (POr) and has caused a beginning of stretching, In fact, concretely, it is the actual stretching length which is checked in order to give the start order of the blowing process at the appropriate time. In a preferred implementation, during parameterization, it is determined a standard position (Pe) of impact of the rod 28 of elongation. In a variant of this implementation, the reference position (Pe) corresponds to the theoretical impact position or Point 0 (POth) that would be obtained by placing in the mold 26 preforms that have not been heated in the oven 10.
    [0013] In a second variant of this embodiment, the impact standard position (Pe) is determined using measurements made from several preforms 2 corresponding to those that will be used in production. The preforms of the sample are subjected to heating in the furnace 10 identical to that which they will undergo in production, the impact position (POr) of each is measured, which makes it possible to estimate an average position of impact (in other words an average withdrawal), which constitutes the standard position (Pe). Of course, the number of preforms in the sample must be significant so that the impact standard position (Pe) is correct. Whatever the type of preform used to determine the standard position, it can be entered manually in the control unit by an operator or automatically acquired during its determination.
    [0014] For each type of preform, a permissible deviation value between the impact standard position (Pe) and the impact position (POr) is entered in the control unit 58. The value of the allowable deviation is a value beyond which it becomes difficult or impossible to envisage proper forming of the container, since the automatic adjustment of the blowing steps becomes difficult. In production, the value of the difference between the impact position (POr) of each preform and the standard position (Pe) of impact is calculated and, if for a preform it exceeds that of the allowable difference, then in a fault signal is transmitted by means of the control unit 58. As a variant or in addition, the preform (or the malformed container) considered can be ejected when the mold is reopened at the end of the cycle. The appearance of a fault signal can be used to launch additional investigations. Thus, a recurrence of a permissible deviation can occur after the loading of a new batch of preforms, the quality of the injection of which would have varied with respect to the qualified preforms. Also, in one implementation, it is checked whether the deviation is recurrent and, if so, it is tempted to automatically modify at least one parameter of the machine to obtain a heating profile allowing a shrinkage compatible with the machine. obtaining a correct forming of the container.
    [0015] It is therefore conceivable that the invention can be exploited in different ways. A first way is to perform a simple quality check of the preforms 2, the determination of the impact position (POr) 5 not being systematic but performed only on one or some of the blowing stations 22 at every turn of the wheel, to verify by correlating preform temperature and preform length that the preforms introduced into the machine have a stable quality. Indeed, if, after identical heating of preforms 2 having the same radiation absorption characteristics and the same material, a variation in the length is noted, this signifies variations in the injection qualities of the batches of preforms 2 successively loaded. . The result of the measurements can be compared, for example, with a length of heated preform deemed to be compliant and acquired automatically or manually during the parameterization of the process (with a range more or less defined by the user). In the case of recurring overruns, meaning withdrawals outside the defined specifications, the user may only be informed or the production stopped. A second way is to perform, in addition to the quality control of the preforms according to the first way, an additional regulation of the beginning of the blowing process: in this case an acquisition is performed for each blowing station 22 at each turn 25 . The quality control part mentioned above can be integrated and, in addition, the beginning of the blowing process (usually the beginning of the pre-blowing stage, as long as it is requested after the beginning of the drawing (at Actual point 0, which corresponds to the majority of cases), can be adjusted according to the length of the preform after heating and shrinking, to start automatically after the preform 2 has been stretched a length This makes it possible to perfectly control this essential parameter, which is the length of preform 2 stretched before the beginning of the blowing process to ensure a good material distribution of the containers.
    [0016] The invention is particularly suitable for lightened thin preforms for which the orientation rates are high and therefore the applied heat, high. Indeed, the small thicknesses of preforms, of the order of 1.5 mm, which are found more and more pl us are particularly conducive to the presence of many constraints during injection. When heating the preform, the bi-orientation rates of the material are high, and the heating applied in the oven 10 must be at high temperature (125 ° C - 135 ° C). The combination of this high temperature with the stresses present in the preforms will have the effect of generating a shrinkage of the preforms along their length and a slight expansion on their diameter. The large shrinkage essentially concerns thin preforms for making small volume (typically less than 0.5 I) still water bottles. The lengths of these preforms are less than 90mm (typically between 60 and 70mm). The shrinkage after heating on this type of preform can easily reach 10mm, which corresponds to nearly 15% shrinkage on a preform of 70mm for a diameter expansion of about 7%. The same preform 20 with the same resin, but with a reduced level of stress, will after heating a shrinkage of about 5mm (about 7% recessed and 3% diameter expansion). The additional regulation of the beginning of the blowing process can be associated with any type of machine, including so-called smart machines, that is to say which also have other control systems (container control systems by vision, or others), such as those described in document W02008 / 081107 previously cited. It is conceivable for all types of preforms and bottles because even if the most significant withdrawals are more observed on the flat water in small volume, they are present on all the preforms.
    权利要求:
    Claims (12)
    [0001]
    REVENDICATIONS1. Method for controlling a method of manufacturing a container by stretching a plastic preform (2) in a machine (1) comprising a mold (26), the preform (2) having a body (3) a neck (4) which opens at one end of the body (3) and a bottom (5) which closes the body (3) at another end thereof, the manufacturing method comprising the steps of: - heating the preform to a predetermined temperature in a furnace (10) of thermal conditioning; introducing the preform (2) into the mold (26); - moving an elongation rod (28) to stretch the preform (2); this control method being characterized in that it comprises a step of determining the impact position (POr) of the elongation rod (28), that is to say its position at the moment when it reaches the bottom (5) of the preform (2) during its displacement.
    [0002]
    2. Method according to claim 1, characterized in that the determination of the impact position (POr) of the rod (28) of elongation is performed by detecting an increase in the driving torque of the rod (28) d 'elongation.
    [0003]
    3. Method according to claim 1, characterized in that the driving of the rod (28) of elongation being carried out using an electric motor (72), the determination of the impact position (POr) of the elongation rod (28) is performed by detecting the moment when the drive current of the electric motor (72) increases, reflecting the resistance to the drive undergone by the elongation rod (28) due to its contact with the bottom (5) of the preform (2).
    [0004]
    4. Method according to one of claims 1 to 3, characterized in that is calculated the difference between the impact position (POr) and a standard position (Pe) impact of the rod (28) of elongation, predetermined during the setting of the machine (1), a start order of the blowing process given only if the calculated difference does not exceed a predetermined permissible value.
    [0005]
    5. Method according to any one of claims 1 to 4, characterized in that the order of commencement of the blowing process is given when the rod (28) of elongation reaches its impact position (POr). 3024071 18
    [0006]
    6. Method according to any one of claims 1 to 4, characterized in that the order of commencement of the blowing process is given after the rod (28) of elongation has reached its impact position (POr) and caused a beginning of stretching of the preform (2).
    [0007]
    7. Method according to one of claims 1 to 3, characterized in that is calculated the difference between the impact position (POr) and the standard position (Pe) impact of the rod (28) of elongation, predetermined during the setting of the machine (1), a fault signal being emitted when the difference reaches or exceeds a predetermined permissible value.
    [0008]
    8. Method according to one of claims 1 to 3, characterized in that is calculated the difference between the impact position (POr) and the standard position (Pe) impact of the rod (28) of elongation, the preform (2) being ejected after the reopening of the mold (26) when the value of the gap exceeds a predetermined allowable value.
    [0009]
    9. Method according to one of claims 1 to 3, characterized in that is calculated the difference between the impact position (POr) and the standard position (Pe) impact of the rod (28) of elongation, is checked if the deviation is recurrent and, if so, is modified at least one parameter of the machine.
    [0010]
    10. Method according to one of claims 4 to 9, characterized in that the standard position (Pe) impact of the rod (28) of elongation is the theoretical impact position (POth) that would be obtained with a preform (2) cold output of the injection machine. 25
    [0011]
    11. Method according to one of claims 4 to 9, characterized in that the standard position (Pe) impact of the rod (28) of elongation is an average real impact position calculated during the parameterization of the machine (1) from a sample of several preforms (2) that have been reheated and consequently shrunk, under conditions that will be implemented during production.
    [0012]
    12. Machine (1) for carrying out the method according to one of the preceding claims, for the manufacture of containers from preforms (2), which comprises at least one mold (26) in which can be driven in sliding a rod (28) for elongation 28, characterized in that the means (72) for driving the rod (28) for elongation are associated with means for detecting (71) the 3024071 19 position of impact (POr) of the elongation rod (28) when it comes into contact with the bottom of a preform (2).
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    同族专利:
    公开号 | 公开日
    CN106573407B|2019-04-19|
    US20170203495A1|2017-07-20|
    WO2016012706A1|2016-01-28|
    JP2017524572A|2017-08-31|
    FR3024071B1|2016-08-19|
    EP3172033B1|2018-05-23|
    JP6712259B2|2020-06-17|
    EP3172033A1|2017-05-31|
    CN106573407A|2017-04-19|
    US10751927B2|2020-08-25|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JPH06254955A|1993-03-02|1994-09-13|Nissei Asb Mach Co Ltd|Biaxially stretched blow molding device|
    US20140079839A1|2010-04-27|2014-03-20|Krones Ag|Stretch-blow molding machine|
    EP2460638A2|2010-12-03|2012-06-06|Krones AG|Method for stretch blowing and stretch blowing machine|
    US20140145378A1|2011-05-19|2014-05-29|Sidel Participations|Method for manufacturing containers, including an anticipated boxing operation|
    US5169705A|1991-02-14|1992-12-08|Husky Injection Molding Systems Ltd.|Servo electric driven stretch rods for blow molding machine|
    JP3468815B2|1994-02-21|2003-11-17|株式会社タハラ|Method and apparatus for automatically adjusting the driving height of a blow molding machine|
    JPH09272147A|1996-04-05|1997-10-21|Mitsubishi Plastics Ind Ltd|Stretching apparatus of blow molding machine|
    CH692492A5|1998-03-25|2002-07-15|Tetra Pak Plastics Ltd Tetra P|molding machine stretch blow.|
    JP4097319B2|1998-06-10|2008-06-11|株式会社タハラ|Method and apparatus for automatic setting of drawing rod position|
    FR2909304B1|2006-12-05|2009-03-27|Sidel Participations|PROCESS FOR MANUFACTURING CONTAINERS WITH FEEDBACK BASED ON THE POINT OF BEGINNING|
    DE102008012757A1|2008-03-05|2009-09-10|Krones Ag|Device for producing plastic containers|
    EP2279070A2|2008-05-28|2011-02-02|Sacmi Cooperativa Meccanici Imola Societa' Cooperative|System for blowing plastic containers, specifically bottles.|
    DE102009006508A1|2009-01-21|2010-07-22|Khs Corpoplast Gmbh & Co. Kg|Method and apparatus for blow molding containers|
    FR2964902B1|2010-09-16|2012-10-12|Sidel Participations|PROCESS FOR MANUFACTURING A CONTAINER FROM A BLANK, WITH FEEDBACK BASED ON A MINIMUM PRESSURE DETECTOR|
    WO2012112474A2|2011-02-15|2012-08-23|Amcor Limited|Reverse stretch rod for machine hygiene and processing|
    FR2975331B1|2011-05-19|2014-03-07|Sidel Participations|METHOD OF STRETCH BLOWING A CONTAINER, COMPRISING RETRACTION OF THE STRETCH ROD DURING A BOXING OPERATION|
    US9833939B2|2011-11-15|2017-12-05|Amcor Limited|Plural blow molding with servo controls|
    US20150042022A1|2012-03-14|2015-02-12|Norgren Ag|Stretch blow molding system with a proportional pre-blowing valve|
    JP6028521B2|2012-10-25|2016-11-16|東洋製罐株式会社|Blow molding apparatus and blow molding method|
    TW201429671A|2012-11-01|2014-08-01|Norgren Gmbh|Stretch blow molding system with simultaneous preblowing valve actuation|
    FR3024071B1|2014-07-25|2016-08-19|Sidel Participations|METHOD FOR CONTROLLING A PROCESS FOR BLOWING PLASTIC CONTAINERS|FR3024071B1|2014-07-25|2016-08-19|Sidel Participations|METHOD FOR CONTROLLING A PROCESS FOR BLOWING PLASTIC CONTAINERS|
    JP6838202B2|2018-02-01|2021-03-03|エイジーアール インターナショナル，インコーポレイテッド|Energy efficient blow molding machine control|
    WO2021054403A1|2019-09-20|2021-03-25|日精エー・エス・ビー機械株式会社|Blow molding device and blow molding method for resin container|
    JP6864164B1|2019-09-25|2021-04-28|日精エー・エス・ビー機械株式会社|Blow molding equipment and blow molding method|
    法律状态:
    2015-06-25| PLFP| Fee payment|Year of fee payment: 2 |
    2016-01-29| PLSC| Search report ready|Effective date: 20160129 |
    2016-06-22| PLFP| Fee payment|Year of fee payment: 3 |
    2017-06-21| PLFP| Fee payment|Year of fee payment: 4 |
    2018-06-21| PLFP| Fee payment|Year of fee payment: 5 |
    2020-06-23| PLFP| Fee payment|Year of fee payment: 7 |
    2021-06-23| PLFP| Fee payment|Year of fee payment: 8 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1457220A|FR3024071B1|2014-07-25|2014-07-25|METHOD FOR CONTROLLING A PROCESS FOR BLOWING PLASTIC CONTAINERS|FR1457220A| FR3024071B1|2014-07-25|2014-07-25|METHOD FOR CONTROLLING A PROCESS FOR BLOWING PLASTIC CONTAINERS|
    PCT/FR2015/051976| WO2016012706A1|2014-07-25|2015-07-17|Method for controlling a method for the blow-moulding of plastic containers|
    JP2017504061A| JP6712259B2|2014-07-25|2015-07-17|Control method of blow molding method for container made of plastic material|
    US15/329,114| US10751927B2|2014-07-25|2015-07-17|Method for controlling a process for the blow-molding of plastic containers|
    CN201580040189.XA| CN106573407B|2014-07-25|2015-07-17|For controlling the control method for being used for the method for container of blowing plastic material|
    EP15754266.3A| EP3172033B1|2014-07-25|2015-07-17|Method for controlling a method for the blow-moulding of plastic containers|
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