Method and device for blow moulding containers

Technical Field

The invention relates to a container used for blow molding method, in this method, a prefabricated blanks made of thermoplastic material along the conveying path in the region of the heating section after processing by the thermal conditions in a blow molding die is formed by blow-molding pressure into the container.

Furthermore, the invention also relates to a container used for blow molding apparatus, the apparatus is configured to blow mould, the blow molding is provided with a die adapted to the outline of the container on the contour.

Background Art

The role by blow-molding pressure to the forming of the container, the prefabricated blanks made of thermoplastic material, such as PET (polyethylene terephthalate) is made inside the prefabricated blanks in the blow molding machine is supplied to the different processing station. Typically, such blow-molding machine is provided with a heating device and a blow-molding device, in which in the area of the blow moulding device, processing by the temperature in advance of the prefabricated blanks through the double axial directional expansion into container. The expansion by means of the guide to treats the inflation prefabricated blanks of the air pressure in the. In DE-OS4340291 prefabricated blanks elaborated on in the process of expansion of the. This text is referred to at the beginning of the introduction of gas under pressure is also included in the compressed gas bubble in the container of compressed gas and in the blow molding process to the prefabricated blanks in the beginning of the introduction.

In DE-OS4212583 for forming has described the basic structure of the blowing of the container. In DE-OS2352926 on a prefabricated blank for the possibility of temperature.

Used for blow molding the inner of the device, and a prefabricated blank is blow molded container can be by means of different operating device. In particular for conveying the application of the core rod is proved to be favourable, prefabricated blanks inserted in the conveying of the core rod. However, prefabricated blanks can also be used other supports device operation. Prefabricated blanks for the operation of the application of the clamp to and grasped and can be introduced into a prefabricated blanks the mouth portion of the opening in the area of the core can be used for the application of the structure of the same.

For example, in DE-OS19906438 described in the use of transfer wheel operated under the condition of the container, wherein the transfer wheel is set at between blow molding wheel and output sections.

Prefabricated blanks has already been explained the operation of the so-called on the one hand in the two-stage method, in this method, the prefabricated blanks first manufacturing process of injection molding, and after the intermediate storage is immediately when its temperature conditions in processing and is blow molded container. On the other hand in so-called single-stage method to realize application, in this method, prefabricated blanks directly in the injection molding of the manufacture and fully solid after hardening treatment temperature is appropriate and is immediately blow molding.

Blowing in use in the implementation of the disclosed the different forms. In is disposed on the rotating conveying wheel in the associated, often meet die may turn the nature the book type of the bearing member. However, it is also possible that, using movable relative to each other or to other ways of the mould is being directed to the load member. In the blowing of the fixed position (these blowing in particular is suitable for receiving a plurality of for forming the cavity of the container), typically are arranged parallel to each other is the use of a plate as a mold-bearing member.

Before the implementation of the heating, will usually prefabricated blanks inserted in the transport rod, the transport rod the prefabricated blank or transmission through the entire blow molding machine, either only in the area of the heating device for rotary. Such prefabricated blank is erected to heating, i.e. the prefabricated blanks of the elevation orientation downward in the vertical direction, when in this heating, prefabricated blanks is usually inserted in the conveying of the mandrel on the sleeve-like clamping element. The heating of the prefabricated blanks, prefabricated blanks of the bottle mouth oriented upwards in the vertical direction, when in this heating, will usually increase the core rod is inserted in the mouth of the prefabricated blanks, the expanding core-rod fixed and clamp the prefabricated blanks.

In the implementation of blow-molding techniques when forming the container, is an important task of: implementing in the container wall material distribution of the input. Similarly, in an application requirements: pre-given container volume is ensured. When the container in the blow mould during the blow molding, although accurately realize the pre-given a given volume, but the container of the pressure reducing and taken out from the blow molding mold after the shrinkage material usually, so as to complete the blow molding of the actual volume of the container than in the blow mould before pressure is reduced, and in small volume of the container.

In order to reduce shrinkage effect, discloses different measures, the measures relates to appropriate material is distributed, advantageous given the outline of a structured container wall and in the manufacture of blow-molding techniques. However, only the measures the extent of the contraction is reduced, but not completely prevent reduced volume of the container.

Content of the invention

The purpose of this invention lies in, of the type mentioned at the beginning in such a way that the method of the improvement, as small as possible so as to comply with the deviation of the input of the final product of a given volume.

According to the present invention, the stated purpose is realized through the following manner, in other words the container during the blow-molding pressure in a practical contour blow molding, the actual contour and the container different in such a way that the given profile, the actual contour of the container and during the demoulding after shrinking is conducted substantially having a given profile.

Another purpose of this invention is that, in this way to design a device of the type mentioned at the beginning, so that the deviation is input to only the volume of the final product is very small to manufacture.

According to the present invention, the stated purpose is realized through the following manner, in other words, the blowing mould with the inner outline of the container is constructed to make the outer contour of at least a given value of the different area of the distribution curve.

Therefore, according to the present invention, the container during the blow-moulding process in a contour and a volume manufacturing, the profile and volume and at the time of the final product is pre-given set value. Associated in considering the deviation of the characteristic of the known container material to be calculated or determined on the basis of experience. Therefore, in consideration of the well known the container material under the condition of the physical characteristic is variably controlled in such a way that the contraction, the contraction a container after the container has a given contour and predefines the given volume of the input.

Consider and contraction through the following manner particularly relevant to the area of the container, that is, of the real profile during the blow-molding pressure in the bottom of the container in the area different from the given profile.

A preferred application of:a plurality of foot blow molding of the container.

Description of drawings

Shown schematically in the Figure embodiment of the invention. Wherein:

Figure 1 is a perspective view of a manufacturing blank for the blowing of the container;

Figure 2 is longitudinal a cross-sectional view of a blow molding mold, a prefabricated blanks in the blow molding mold is stretched and expansion;

Figure 3 is plan of a is used for showing a used for blow-molded container of the basic structure of the device;

Figure 4 is a modified, the heating sections of the heating capacity is increased;

Figure 5 a illustrated in part with supporting legs of a side view of the bottle;

Figure 6 shows in accordance with Figure 5 of the video in the bottom of the bottle to the VI;

Figure 7 shows in accordance with Figure 5 of the video in the bottom of the bottle to VII;

Figure 8 shown in accordance with Figure 7 of a perspective view of the bottom of the bottle;

Figure 9 for manufacturing is shown in accordance with Figure 5 of the mould of the bottom of the bottle, with the size of the mark;

Fig. 10 a is shown in accordance with Figure 9 the die making the bottom of the bottom of the bottle, with a marking the final size.

Mode of execution

In fig. 1 and 2 shown in a is used for making the prefabricated blanks 1 is formed into the container 2 the principle structure of the device.

For making container 2 forming apparatus basically comprises a station 3, which is provided with a blow mould blowing 4, prefabricated blanks 1 can be put in to the blow mould. Prefabricated blanks 1 can be composed of polyethylene terephthalate is made of injection-molded piece. In order to allow the prefabricated blanks 1 are put into the blow molding die 4 and in order to allow the finished product container 2 is taken out of the, blow molding die 4 by a number of mold halves 5, 6 and a bottom part 7 a, the bottom part can be formed by the one lifting device 8 positioning. Prefabricated blanks 1 can be formed by a conveying core rod 9 is kept at a blowing station 3 in the area of, the conveying the core rod and the prefabricated blanks 1 through the together with a plurality of processing stations inside the device. However, it is also possible that, for example, by pliers or other operating mechanism will be prefabricated blanks 1 directly inserted into the blow molding die 4 in.

In order to allow the introduced pressure air, in the conveying core rod 9 a is arranged at the lower part is connected with the piston 10, which is connected to the plug of the prefabricated blanks 1 supply pressure to the air and at the same time conveying the mandrel 9 sealing. However, the configuration of the conversion, it is also possible, in principle, is on, the use of fixed pressure air input pipeline.

In this embodiment, the prefabricated blank 1 of the drawing by means of a tension rod 11 to, the tension rod is composed of a cylinder 12 positioning. According to another embodiment, (curve) of the cam (Kurvensegment) for the tension rod 11 of the mechanical positioning, these cam segment is some-loading (Abgriffrolle). When a rotation is provided with a plurality of blowing blow-molded wheel 3 is, with the cam section of the the purpose of using in particular.

In the Figure 1 embodiment shown, stretching system is constructed, so as to provide two cylinder 12 a series arrangement. The tension rod 11 by a primary cylinder 13 first at the beginning of the real stretching process has been moved to the prefabricated blank before 1 the bottom 14 in the area of the. During the real stretching process, the primary cylinder 13, together with the tension rod and a plurality of bearing the primary cylinder 13 of the slide 15 by the sub-cylinder a 16 or through a cam control device positioning. In particular, sub-cylinder 16 is cam is controlled in the following manner, so that by a guide roller 17 actual stretching location of the pre-given, during the implementation of the process of drawing, the guide rollers sliding along a cam track. The guide roller 17 by the secondary cylinder 16 pressure to the rail. The slide seat 15 along two guiding element 18 sliding.

When mounted on a carrier 19, 20 in the area of the mold halves 5, 6 closes, by means of a locking device 20 to carry out these carrier 19, 20 the lock relative to each other.

In order to adapt the prefabricated blanks 1 a mouth of the section 21 with different shapes, according to fig. 2, in the blow molding die 4 in the region of the thread of the insert 22.

Figure 2 in addition to the blow molding of the container 2 is shown with dotted lines and prefabricated blanks 1 and shown schematically for the ongoing container 23.

Figure 3 shows the basic structure of a blow molding machine, which is provided with a heating section of a rotating blow molding wheel 24 and 25. From the prefabricated blank inlet 26 a, prefabricated blanks 1 by the transfer wheel 27, 28, 29 is delivered to the heating section 24 in the area of the. Along the heating section 24 is provided with the heating element 30 and the fan 31, so that the prefabricated blanks 1 temperature processing. The prefabricated blank 1 after processing the full temperature, the prefabricated blanks is forwarded to the blow molding wheel 25, in the blow molding wheel some is set in the area of station 3. Complete the blow molding of the container 2 by the additional transfer wheel is supplied to the one output section 32.

In order to be able to make the prefabricated blanks 1 is formed in such a way that the container 2, the container 2 has the following the material characteristics, the characteristics of the material filled in the container 2 in the food, in particular of the possibility of the beverage application, in the heating and directional prefabricated blanks 1 needed to comply with special steps of the method. Furthermore, the size of the can through abide by the specific design requirements and obtain advantageous effects.

Can be made from different plastic as the thermoplastic material. For example, can be made of PET, or PEN PP.

Prefabricated blanks 1 during the orientation process by the expansion of the supplied to the pressure air. The supply of pressure air is divided into a pre-blow molding phase and an immediately following main blow moulding stage, the stage pre-blow molding having a low pressure level is supplied to the gas, such as pressure air, is supplied to the stage main blow molding with higher pressure level of gas. During the stage pre-blow molding , typically in the pressure range of 10 bar to 25 of the pressure air, supplied to the pressure during phase main blow molding section to 25 bar to 40 of the pressure air.

Similarly by fig. 3 can be seen, in the illustrated embodiment, heating section 24 is composed of a plurality of surrounding the transport element 33 form, these conveying elements are arranged sequentially along the chain and some steering wheel 34 by the guide. Particularly, through the chain is arranged to form a substantially rectangular basic outline. In the illustrated embodiment, the heating section 24 to the transfer wheel 29 and an input wheel 35 in the extension region using a single size larger steering wheel 34 and in the region of the adjacent potion is provided with two relatively small size of the steering wheel 36. However, in principle, may also take into account any other guide device.

In order to allow the transfer wheel 29 and input wheel 35 relative to each other the arrangement of as close as possible, the arrangement shown has proved to be particularly advantageous, because the heating section 24 in the area of the corresponding extended position the three steering wheel 34, 36, to be precise that is small, respectively, positioned in the heating sections 24 a linear path in the transition region of the steering wheel 36 and a relatively large, positioning in the direction of the transfer wheel 29 and input wheel 35 in the direct transition region of the steering wheel 34. Substituted application chain transport element 33 to, for example, possible is, adopts a rotating heating wheel.

In the container 2 after the completion of blow molding, the container is composed of a wheel 37 from the station 3 and in the area of the derived through the transfer wheel 28 and output wheel 38 is transmitted to the output section 32.

In Figure 4 is shown the heating section of the modification of the 24 in, through the comparatively large amount of heating element 30 in the unit time can be in a greater amount of prefabricated blanks 1 temperature processing. In this, fan 31 the cooling air into the cooling air passage 39 in the area of the, these cooling air passages are respectively located at the corresponding heating element 30 and through the flow-out opening opposite the output cooling air. The arrangement of the through flowing-off direction, for the cooling air substantially transverse to a prefabricated blanks 1 the direction of flow of the conveying direction. These cooling air passages 39 can be located in the heating element 30 in the area of the opposite side to the surface of the used for heating the radiation reflector, is equally possible, through the output of the cooling air also realize heating element 30 of the cooling.

Figure 5 shows the container 2 of the area of bottom 41 of a side view. The bottom area is provided with a plurality of feet 42, these foot through some recess 43 spaced apart from each other. The center of the bottom 44 is arranged in the area of an inner arch structure 45.

Figure 6 shows the area of bottom 41 in accordance with Figure of 5 to the VI in the view of the video. The Figure 5 and Figure 6 it can be seen the combination in particular, these foot 42 and recesses 43 inverted rounded transition contour forming with each other.

By fig. 7 and fig. 8 can be seen from the view of the, illustrated embodiment is provided with five foot 42 of the container 2, these feet in the circumferential direction around the center of the bottom of the the 44 are relative to each other. Each foot 42 of the size is selected to be substantially equal. Similarly, all the recess 43 the size of the relative to each other is substantially selected to be approximately equal. The states the foot department 42 and recesses 43 relative to the the center of the bottom of the center line of 44 substantially radially oriented.

Figure 9 is shown for producing the area of bottom 41 of the bottom mould of 46. The bottom die 46 can be used as the blow mould 4 bottom part of 7. In Figure 9 is shown in a variety of different size parameter, in particular the radius of curvature, in the combination of Figure 10 will also be detailed is the curvature radius. The bottom mould 46 for the size of the large Letters said parameter.

Figure 10 shows the use of the bottom mould 46 of the produced under the situation, after the material of the region of the bottom of the slack 41, its has the same corresponding, small Letters for the size of the said parameter.

In manufacturing the area of bottom 41 of the objective is, accurate possible to comply with Figure 10 of the size shown in the set value of the parameter. Because the container 3 after the material of the shrinkage characteristic during the demoulding, the stated goal is realized by the following ways, in other words the blow molding mold 46 of fig. 10 shown in the parameter is chosen to be the size of the Figure 10 the bottom area 41 determines the size of the different parameters.

Found in accordance with the present invention in particular: the best container production is not uniform through all size parameter of the increased or decreased, but taking into account the contour of the container 10 a given aforesaid shown in 9 the size of the blow mould in the parameter must be chosen to be larger than the part of smaller than that of the corresponding or in part, and in accordance with the given value of the different parameters of the different correction factor are respectively taken into account.

Furthermore, through the following manner can support the area of bottom 41 the reliability of the profile, i.e. the pre-set value the size of the generally determined.

According to one experiment in particular of the following favourable embodiment of the requirement.

Radius R1 and radius R2 should be in the proportion of 0.5 <R2/R1 <0.7 range. In this, the radius R1 corresponding to the radius of the largest bottle and radius R2 corresponding to the stated foot 42 and the center of the bottom of the supporting area 44 of the distance.

Radius R3 determines the radius R1 and R4 between connected region, to the radius R3 speaking, 100 mm <R3 <150 mm interval to be proved that the size of the stone. In this, radius R4 corresponding to the recess 43 to the bottom 44 of the transition in the area.

Radius R4 the radius R3 and the recess 43 a radius of R5 and in an advantageous manner, is in 5 mm <R4 <10 mm range.

Bottom-center 44 of the radius R5 in an advantageous manner, in a 25 mm <R5 <75 mm range.

On the area of bottom 41 of Figure 10 the size of the recorded in a parameter, the center of the bottom 44 the height of the feet a and 42 b in the height of the, for the bottom mould 46 and A>a B>b the size selection. In the radius R4 aspects, R4 less than r4.

Figure 10 the radius of the shown in r6 and r7 size is determined in such a way, that the radius r6 apply 10 mm <r6 <50 mm interval, in the radius r7 regard, 5 mm <r7 <30 mm interval proved to be favourable.

In the radius R5 aspects, R5 <r5, in the radius R2 regard, R2> r2. Radius r2 is variable.

In particular, the following special relationship to be blow-molded bottle is adapted to the specific size of the bottom mould 46 of the profile. Generally speaking, R1> r1, wherein typically, R1 is selected to be less than r1 large 0.1% to 1.0%. The R2 side, the R2 value for r2 of 99% to 101%. In R3 hand, to the radius value r3 of 95% to 99%. In the radius R4 hand, this radius R4 value for r4 of 20% to 100%, in the radius R5 regard, the radius R5 for the value r5 of 10% to 50%.

Advantageously, R2/R1 is selected to be 0.6 <R2/R1 <0.7.

Advantageously, R2/R1 is selected to be 0.65 <R2/R1 <0.7.

Advantageously, R3 is selected to be 50 mm <R3 <100 mm.

Advantageously, R3 is selected to 60 mm <R3 <100 mm.

Advantageously, R3 is selected to 78 mm <R3 <100 mm.

Advantageously, R4 is selected to be 5 mm <R4 <100 mm.

Advantageously, R4 is selected to be 17.5 mm <R4 <22.5 mm.

Advantageously, R4 is selected to be 18.0 mm <R4 <20.5 mm.

Advantageously, R5 is selected to be 5 mm <R5 <10 mm.

Advantageously, R5 is selected to 7.5 mm <R5 <12.5 mm.

Advantageously, R5 is selected to be 8 mm <R5 <10.5 mm.

Advantageously, R6 is chosen as 5 mm <R6 <10 mm.

Advantageously, R6 is chosen as 6 mm <R6 <9 mm.

Advantageously, R6 is selected to be 6.5 mm <R6 <7.5 mm.