Plasticizing unit

Abstract

The invention relates to a plasticizing unit for a molding machine, comprising: a plasticizing screw which is arranged in a material cylinder in a rotationally drivable manner and is designed to plasticize a material to be plasticized; and at least one supply device which is arranged on the circumferential surface of the material cylinder and is designed to supply the material to be plasticized into the material cylinder; according to the invention, a dividing device is provided which divides the supply device into two sub-regions, the first sub-region being designed to supply the material to be plasticized into the material cylinder and the second sub-region being fluidically connected to the degassing device, and / or is fluidically connected to a degassing device along a longitudinal axis of the mass cylinder at one end of the mass cylinder, via which opening the at least one plasticizing screw is pushed into the mass cylinder, the degassing device being designed to discharge gas generated during plasticizing of the material to be plasticized from the mass cylinder.

Description

Technical Field

[0001] The invention relates to a plasticizing unit for a molding machine and to a molding machine having such a plasticizing unit having the features of the preamble of claim 1 . Background Art

[0002] A molding machine may be understood to mean an injection molding machine, an injection press, a press, etc. Of course, a molding machine is also conceivable which supplies the plasticized material to an open molding die.

[0003] The following shall briefly introduce the prior art based on injection molding machines. Generally, similar contents apply to molding machines.

[0004] Plasticizing units of the same type include:

[0005] at least one plasticizing screw arranged in a rotationally drivable manner in the material cylinder, the plasticizing screw being designed to plasticize the material to be plasticized, and

[0006] - At least one supply device arranged on the circumference of the material cylinder, which is designed to supply the material to be plasticized into the material cylinder.

[0007] Corresponding plasticizing units are used in injection molding machines to plasticize the material to be plasticized by means of a rotational movement of a plasticizing screw, wherein the material to be plasticized is plasticized by shear energy, shear heat and, if appropriate, externally supplied thermal energy.

[0008] The corresponding plasticizing units are usually embodied as single-screw or multi-screw extruders (also called “single-shaft or multi-shaft extruders”).

[0009] After plasticization, the plasticized material is supplied to a separate injection unit of the injection molding machine so that the plasticized material is injected into the mold cavity, where it hardens to form a molded part; or the plasticizing screw itself is designed to be axially movable and can itself be used to inject the plasticized material (combined plasticizing and injection unit).

[0010] It is known from the prior art to use contaminated plastics as materials to be plasticized. For example, these plastics can be regrinds, grounds and / or agglomerates, which are used, for example, in recycling or compounding applications.

[0011] This topic is becoming increasingly important, as recycling of plasticized materials (such as thermoplastics) can make them available for new uses or new areas of application and thus create significant advantages in terms of environmental friendliness.

[0012] Of course, other further processing possibilities are also feasible. Therefore, for example, the plasticized material can be supplied to a continuous casting machine, an injection press, a press, a semi-finished product production plant or the like and further processed by means of it.

[0013] However, the problem in composite or recycling applications is that the plasticized material still carries unwanted gases and gaseous inclusions after or during plasticization, which lead to poor component quality during further processing. These unwanted gases can be foreign substances, such as residues of cleaning solutions or additives.

[0014] It is known from the prior art to degas plasticized materials in order to homogenize the melt and / or to prevent the formation of pores during further processing.

[0015] Therefore, it is known from the prior art to provide corresponding degassing devices on the material cylinder of the plasticizing unit, which are to be connected to the plasticizing zone in the material cylinder so that the degassing devices can extract the gas released during plasticizing.

[0016] For this purpose, it is necessary to adapt the material cylinder accordingly, wherein additional openings are produced in the material cylinder for these applications, which in turn have to be sealed accordingly and care has to be taken to ensure that no plasticized material escapes via these degassing openings.

[0017] Furthermore, corresponding plasticizing units can only be used in combination with a degassing device, whereby not only the production complexity for producing the corresponding plasticizing unit must be increased, but the plasticizing unit is then also restricted in its field of application by the degassing device.

[0018] A further disadvantage of the prior art is that already existing plasticizing units cannot be retrofitted with a degassing device without difficulty, since the material cylinder of the plasticizing unit has to be processed in a correspondingly complex manner in order to be able to provide the degassing device. Summary of the invention

[0019] The object of the present invention is to at least partially improve the aforementioned disadvantages of the prior art and / or to provide a plasticizing unit which can also be used for applications with plasticized material to be degassed and which is nevertheless associated with lower production costs and / or greater variability in terms of application areas.

[0020] This object is achieved by a plasticizing unit for a molding machine and a molding machine having such a plasticizing unit having the features of claim 1 .

[0021] According to the present invention, the plasticizing unit for the molding machine comprises the following:

[0022] at least one plasticizing screw which is arranged in a rotationally drivable manner in the material cylinder and is configured to plasticize the material to be plasticized, and

[0023] at least one supply device arranged on the circumference of the material cylinder, the supply device being configured to supply the material to be plasticized into the material cylinder,

[0024] in,

[0025] A dividing device is provided, which divides the supply device into two sub-areas, the first sub-area being designed for supplying the material to be plasticized into the material cylinder and the second sub-area being fluidically connected to the degassing device, and / or

[0026] An opening at one end of the material cylinder along the longitudinal axis of the material cylinder is fluidically connected to the degassing device, and the at least one plasticizing screw is pushed into the material cylinder through the opening.

[0027] The degassing device is designed to discharge gas generated during the plasticization of the material to be plasticized from the material cylinder.

[0028] In the process according to the first aspect, already existing supply devices can be used for degassing the material to be plasticized during plasticization.

[0029] In the process of the second aspect of the invention, the existing opening at the end of the material cylinder (which is used to position the at least one plasticizing screw in the material cylinder) can be used to discharge the gas generated during the plasticization of the material to be plasticized from the material cylinder via the degassing device.

[0030] The common point of the above-mentioned aspects of the present invention is that a plasticizing unit can be created, which does not require separate, complex manufacturing measures on the material cylinder in order to still be able to degas during the plasticization of the material to be plasticized, thereby creating the following possibility, that is, not only existing plasticizing unit systems but also new plasticizing unit systems are given the ability to still realize this application, and these systems are not only for degassing in one application field.

[0031] In this way, the corresponding plasticizing unit can also be removed from the degassing device again later and plasticized without degassing.

[0032] Furthermore, it is possible to use a corresponding degassing device for a plurality of molding machines, in particular injection molding machines, since the degassing device can be switched between the individual plasticizing units depending on the production situation.

[0033] Due to the low production outlay for producing the plasticizing unit according to the invention, the economic and ecological efficiency of the molding machine can also be increased.

[0034] The present invention makes use of the surprising insight gained through experiments by the applicant that it is not absolutely necessary to extract the gases generated during plasticization in the area of ​​the plasticizing zone of the material cylinder, but that the goal can also be achieved by degassing through the supply opening / supply device and / or through the material cylinder opening (which is used to arrange the plasticizing screw in the material cylinder).

[0035] Furthermore, the provided plasticizing unit and the simple possibility for supplementing a degassing device can increase interest in compounding and / or recycling applications, since corresponding plasticizing units for these applications can now be realized more easily or can even be retrofitted, thus naturally improving the ecological advantages by increasing the recycling of material.

[0036] The device according to the invention can also find application by being used in already known embodiment variants of the prior art (as described, for example, in the introduction) and can be installed subsequently.

[0037] Molding machine can be understood as injection molding machine, injection molding press, press, etc. It also refers to a molding machine that supplies plasticized material to the opened molding mold.

[0038] For example, the material to be plasticized can be a polymer plastic, preferably a thermoplastic.

[0039] Advantageous embodiments of the invention are defined in the dependent claims.

[0040] Preferably, an open-loop control or closed-loop control device can be provided, which is designed for open-loop control or closed-loop control:

[0041] at least one feeding device for feeding the material to be plasticized into the material cylinder via the supply device, and

[0042] A drive unit for the at least one plasticizing screw.

[0043] It can be provided that the at least one feed device comprises a material conveying device and / or a further plasticizing device and / or at least one metering device.

[0044] For example, it can be provided that the material to be plasticized in a hardened state is supplied to a material cylinder via a supply device through a feeding device (if the material to be plasticized is preferably present as granules), or the material to be plasticized has also been plasticized by another plasticizing device and has been supplied to the material cylinder in a plasticized state via a supply device, and the material to be plasticized is further plasticized in the material cylinder (such an application is also generally referred to as a multi-stage plasticizing process).

[0045] Preferably, it can be provided that the open-loop control or the closed-loop control unit is designed for underfeeding the plasticizing screw.

[0046] Underfeeding is a known method and means that the plasticizing screw is supplied, for example via a feeding device, preferably a doser, with less material to be plasticized than the plasticizing screw can convey in the feed zone.

[0047] As a result, the screw path is only completely filled from a certain distance from the feed opening or the supply device. The pressure build-up in the plasticizing unit also starts from this point.

[0048] When the effective screw length is extended accordingly by reducing the degree of underfeeding, the location where the pressure is built up moves toward the discharge opening of the material cylinder (ie away from the supply device).

[0049] Thus, by underfeeding, the feed zone of the at least one plasticizing screw can remain partially filled and thus ensure improved possibilities for back degassing via the supply device or opening.

[0050] By means of improved degassing, volatile components can be extracted.

[0051] In this way, polymers can be processed particularly carefully, in particular when plastic granules are used as the material to be plasticized.

[0052] Preferably, it can be provided that the dividing device has a dividing plate, preferably a perforated plate, which divides the supply device into the two sub-areas.

[0053] It can be provided that the supply device has a filling hopper.

[0054] Preferably, it can be provided that the fluid connection has an intake pipe, which particularly preferably projects into the second partial region.

[0055] It can be provided that the fluid connection covers, preferably gas-tightly covers, an opening through which the at least one plasticizing screw is pushed into the material cylinder.

[0056] Furthermore, it can be provided that the degassing device comprises at least one conveying device for generating a negative pressure for degassing the material cylinder, preferably the at least one conveying device comprises a fan, a compressor and / or a compactor.

[0057] Preferably, it can be provided that the degassing device has at least one filter device.

[0058] It can be provided that the degassing device has at least one separation device for separating liquid components from the gas discharged from the plasticizing section, preferably the at least one separation device comprising a cyclone separator and / or a condensate collector.

[0059] Preferably, it can be provided that the degassing device comprises at least one cooling device which is designed to cool the gas discharged from the plasticizing section.

[0060] The cooling of the gas discharged from the plasticizing section can be used to condense liquids dissolved in the gas in order to be able to release them from the gas and thus separate them from the gas.

[0061] It can be provided that the at least one plasticizing screw is mounted and / or driven so as to be linearly displaceable in the material cylinder.

[0062] It can be provided that the material cylinder has a discharge opening, preferably a nozzle, along the longitudinal axis at one end (second end) which forms the end facing away from the opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Further examples, advantages and details of the invention are shown in the drawings and in the following description of the drawings.

[0064] Figure 1 A first embodiment of a plasticizing unit according to the invention is shown,

[0065] Figure 2 A second embodiment of a plasticizing unit according to the invention is shown, and

[0066] Figure 3 A molding machine with a plasticizing unit is shown. DETAILED DESCRIPTION

[0067] Figure 1 A first embodiment of a plasticizing unit 1 according to the invention is shown.

[0068] The plasticizing unit 1 comprises a material cylinder 3 , into which a plasticizing screw 4 is pushed through an opening 11 .

[0069] The opening 11 is located at the rear end of the material cylinder 3 in terms of its longitudinal extension 10 .

[0070] As can be seen, the plasticizing screw 4 is mounted rotatably and displaceably along a longitudinal axis 10 and can be driven via a drive device 14 .

[0071] The material to be plasticized can be supplied to the material cylinder 3 via a supply device 5 .

[0072] The supply device 5 comprises a filling hopper 16 , through which the material to be plasticized is supplied from the feeding device 13 to the material cylinder 3 to the plasticizing screw 4 .

[0073] The supply device 5 also comprises corresponding openings in the material cylinder 3 so that the material to be plasticized can be supplied to the plasticizing screw 4 inside the material cylinder 3 .

[0074] The material to be plasticized is supplied in an open-loop or closed-loop controlled manner via a feed device 13 which is designed as an external metering unit in the present exemplary embodiment.

[0075] The open-loop or closed-loop control device 12 can open-loop or closed-loop control the amount and / or mass flow of the material to be plasticized supplied via the supply device 5 through the feed device 13 , and is connected to the feed device 13 in a signal-conducting manner.

[0076] The open-loop or closed-loop control device 12 is also connected in a signal-conducting manner to a drive 14 of the plasticizing screw 4 and is designed for open-loop or closed-loop control of the movement and rotation of the plasticizing screw 4 via the drive 14 .

[0077] Furthermore, the plasticizing unit 1 comprises a dividing device 6 which divides the supply device 5 , or more precisely the filling hopper 16 in the present exemplary embodiment, into two sub-areas 7 , 8 .

[0078] The first subregion 7 is designed here for feeding the material to be plasticized into the material cylinder 3 .

[0079] The second subregion 8 in the present exemplary embodiment is designed for establishing a fluidic connection to a degassing device 9 .

[0080] For this division, the dividing device 6 has a partition 15 so that the material to be plasticized is not accidentally sucked out via the degassing device 9 .

[0081] The degassing device 9 is designed to discharge gas generated during the plasticization of the material to be plasticized from the material cylinder 3 .

[0082] For this purpose, the degassing device 9 comprises a suction line 17 which projects into the second sub-region 8 for suction purposes.

[0083] Furthermore, the degassing device 9 comprises a conveying device 18 for establishing a negative pressure in order to suck out the gases generated during the plasticization of the material to be plasticized.

[0084] In the present exemplary embodiment, the conveying device 18 is only schematically indicated by arrows.

[0085] Furthermore, the degassing device 9 comprises a separation device 20 for separating liquid components from the gas discharged from the plasticizing section, and a filter device 19 for filtering suspended matter and / or particles from the gas discharged from the plasticizing section.

[0086] The separation device 20 of the present exemplary embodiment of the degassing device 9 is realized as a condensate trap 21 .

[0087] As from Figure 1 It can also be seen that the open-loop or closed-loop control device 12 is designed with the aid of the conveying device 18 and the drive device 14 for underfeeding the plasticizing screw 4 , wherein the plasticizing screw 4 is supplied with a smaller amount of material to be plasticized than it can receive in the feed zone.

[0088] If through Figure 1 As shown, it can be seen that only in the later region of the screw flight of the plasticizing screw 4 is the screw flight completely filled with the material to be plasticized or plasticized and pressure is built up.

[0089] A corresponding process (underfeeding of the plasticizing screw 4 ) has shown that reverse degassing can be carried out in a particularly advantageous manner via the degassing device 9 and that good results can be achieved in the end product (plasticized mass).

[0090] Figure 2 A further embodiment of the plasticizing unit 1 according to the invention is shown.

[0091] and Figure 1 Compared with the embodiment of Figure 2 The degassing device 9 in the exemplary embodiment is fluidically connected to the material cylinder 3 at the opening 11 .

[0092] The opening 11 of the material cylinder 3 is used to position and drive the plasticizing screw 4 in the material cylinder 3 .

[0093] In addition, the plasticizing unit 1 Figure 2 According to an embodiment of the present invention, the opening 11 is used to suck the gas generated during plasticization out of the material cylinder 3 via the degassing device 9 .

[0094] For this purpose, the opening 11 of the material cylinder 3 is closed by the degassing device 9 in a sealing manner, preferably in a gas-tight manner.

[0095] Figure 2 The remaining features of the embodiment of (and thus of the plasticizing unit 1, of the degassing device 9 and of the feeding device 13) are substantially the same as Figure 1 The embodiments are equivalent.

[0096] Figure 3 An exemplary molding machine with a plasticizing unit 1 according to an embodiment of the present invention is shown.

[0097] exist Figure 3 The molding machine 2 shown by way of example in FIG. 1 is an injection molding machine and has a plasticizing unit 1 and a closing unit 23, which are arranged together on a machine frame 24. Alternatively, the machine frame 24 can also be designed in multiple parts.

[0098] The closing unit 23 has a fixed mold clamping plate 25 , a movable mold clamping plate 26 and an end plate 27 .

[0099] The movable mold platen 26 can be moved relative to the machine frame 24 via a toggle mechanism 28 , which is shown symbolically.

[0100] The mold halves of the molding mold 29 can be clamped or mounted on a fixed mold clamping plate 25 and a movable mold clamping plate 26 (as shown by the dotted lines).

[0101] The fixed mold clamping plate 25 , the movable mold clamping plate 26 and the end plate 27 are supported and guided relative to one another via a beam 30 .

[0102] exist Figure 3 The closed forming mold 29 shown in FIG. 1 has at least one cavity. An injection channel leads to the cavity, and the plasticized material can be supplied to the plasticizing unit 1 via the injection channel.

[0103] The injection unit 1 of the present embodiment has a material cylinder 3 and a plasticizing screw 4 arranged in the material cylinder 3 .

[0104] The plasticizing screw 4 can rotate about its longitudinal axis and can move axially along the longitudinal axis in the conveying direction to not only plasticize the material to be plasticized but also inject it from the material cylinder 3 into the cavity of the molding die 29. The corresponding embodiment of the plasticizing screw 4 is usually also called an injection screw.

[0105] These movements are driven via a schematically shown drive unit 14. The drive unit 14 preferably comprises a rotary drive for the rotary movement and a linear drive for the axial injection movement.

[0106] Figure 3 The molding machine 2 is shown with an injection unit 22 , wherein the injection unit 22 shown in the present exemplary embodiment has an injection screw which also serves to plasticize the material to be plasticized.

[0107] The plasticizing unit 1 (and therefore also the injection unit 22 ) is connected in terms of signaling to an open-loop control or closed-loop control unit 12 .

[0108] For example, the open-loop control or closed-loop control unit 12 outputs control instructions to the plasticizing unit 1 and / or the driving unit 14 .

[0109] The open-loop control or closed-loop control unit 12 can be connected to an operating unit and / or a display device 31 or can be an integral component of such an operating unit.

[0110] In addition, the plasticizing unit 1 comprises a degassing device, which is schematically shown in the figure and can be used according to Figure 1 or Figure 2 The embodiment is connected to the plasticizing unit 1.

[0111] List of reference numerals:

[0112] 1 Plasticizing unit

[0113] 2 Molding Machine

[0114] 3 Material cylinder

[0115] 4Plasticizing screw

[0116] 5 Supply device

[0117] 6 Division device

[0118] 7 The first sub-area

[0119] 8 Second sub-area

[0120] 9Degassing device

[0121] 10 Vertical axis

[0122] 11 Opening

[0123] 12Open-loop control or closed-loop control device

[0124] 13 Feeding device

[0125] 14 Drive device

[0126] 15 Partition

[0127] 16 Filling hopper

[0128] 17 Suction tube

[0129] 18Conveying device

[0130] 19 Filter device

[0131] 20Separation device

[0132] 21 Condensate trap

[0133] 22 injection units

[0134] 23 closed units

[0135] 24 racks

[0136] 25 Fixed mold clamping plate

[0137] 26 Movable mold clamping plate

[0138] 27 End plate

[0139] 28 elbow mechanism

[0140] 29 Molding mold

[0141] 30 beams

[0142] 31 Display device

Claims

1. A plasticizing unit for a molding machine (2), comprising: at least one plasticizing screw (4) which is arranged in a rotationally drivable manner in the material cylinder (3), and is configured to plasticize the material to be plasticized, and At least one supply device (5) is arranged on the circumference of the material cylinder (3), and the supply device is configured to supply the material to be plasticized into the material cylinder (3). It is characterized in that A dividing device (6) is provided, which divides the supply device (5) into two sub-areas (7, 8), wherein the first sub-area (7) is designed for supplying material to be plasticized into the material cylinder (3), and the second sub-area (8) is fluidically connected to the degassing device (9), and / or An opening (11) is fluidically connected to the degassing device (9) at one end of the material cylinder (3) along the longitudinal axis (10) of the material cylinder (3), and the at least one plasticizing screw (4) is pushed into the material cylinder (4) via the opening (11). The degassing device (9) is designed to discharge gas generated during plasticizing of the material to be plasticized from the material cylinder (3).

2. The plasticizing unit according to claim 1, wherein: At least one open-loop control or closed-loop control device (12) is provided, which is designed for open-loop control or closed-loop control: at least one feeding device (13) for supplying the material to be plasticized into the material cylinder (3) via the supply device (5), and A drive unit (14) of the at least one plasticizing screw (4).

3. Plasticizing unit according to the preceding claim, wherein: The open-loop control or closed-loop control unit (12) is designed to underfeed the plasticizing screw (4).

4. The plasticizing unit according to at least one of the preceding claims, wherein: The dividing device (6) comprises a partition (15), preferably a perforated plate, which divides the supply device (5) into the two sub-areas (7, 8).

5. The plasticizing unit according to at least one of the preceding claims, wherein: The supply device (5) comprises a filling hopper (16).

6. The plasticizing unit according to at least one of the preceding claims, wherein: The fluid connection has an intake pipe (17) which preferably projects into the second partial region (8).

7. The plasticizing unit according to at least one of the preceding claims, wherein: The fluid connection covers, preferably gas-tightly, an opening (11) through which the at least one plasticizing screw (4) is pushed into the material cylinder (3).

8. The plasticizing unit according to at least one of the preceding claims, wherein: The degassing device (9) comprises at least one conveying device (18) in order to generate negative pressure to degas the material cylinder (3). Preferably, the at least one conveying device (18) comprises a fan, a compressor and / or a compactor.

9. The plasticizing unit according to at least one of the preceding claims, wherein: The degassing device (9) has at least one filter device (19).

10. The plasticizing unit according to at least one of the preceding claims, wherein The degassing device (9) has at least one separation device (20) for separating liquid components from the gas discharged from the plasticizing section. Preferably, the at least one separation device (20) comprises a cyclone separator and / or a condensate collector (21).

11. The plasticizing unit according to at least one of the preceding claims, wherein The degassing device (9) comprises at least one cooling device which is designed to cool the gas discharged from the plasticizing section.

12. The plasticizing unit according to at least one of the preceding claims, wherein The at least one plasticizing screw (4) is supported and / or driven so as to be linearly displaceable in the material cylinder (3). 13 . A molding machine, in particular an injection molding machine, comprising a plasticizing unit ( 1 ) according to at least one of the preceding claims.

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