Mold with gate cutter

Abstract

The invention relates to a mold (200) for producing a foam coating (120) made of plastic on a flat component (100) or for producing a foamed plastic part (120), the mold (200) comprising a mixing head (300) for producing liquid plastic from at least two components, at least one first cavity (240) for receiving plastic for forming the foam coating (120) or producing the foamed plastic part (120), a gate channel (210) for connecting the mixing head (300) to the at least one first cavity (240), and a further cavity (220) formed at the transition from the gate channel (210) to the first cavity (240) and widening the gate channel (210). In order to automatically cut a label-like gate which is otherwise adhered to a foam covering, the invention provides a gate cutter (400) having at least one slide (410) which is movably mounted on a mold (200), the slide being movable in the direction of the gate channel (210) towards a first cavity (240) by means of at least one actuating cylinder (450) and, in the final position of the movement of the slide, closing the first cavity (240) from the gate channel (210) and / or from a further cavity (220) by means of at least one edge (414) and / or a contour (412).

Description

Technical Field

[0001] The invention relates to a mould according to the preamble of claim 1 . Background Art

[0002] This type of mold has long been known from the production of polyurethane (PU) foam-coated glass covers for vehicle sliding roofs. Until now, after the polyurethane had cured, the tag-like gate, which remained at the transition from the gate channel to the cavity for the foam covering, had to be neatly separated from the foam covering by a worker using a sharp knife. Besides the extra effort, there was also the risk of irreparably damaging the foam covering with the knife, resulting in the entire foam-coated glass cover having to be disposed of as scrap.

[0003] A tool for producing plastic parts is known from CN 206386338 U, in which a scraper is mounted on the tool so as to be movable by means of a hydraulic cylinder. JP 60089322 discloses a tool for producing plastic parts, in which a slide is movable transversely to the gate and extends a gate channel with a hole, the slide closing the gate channel after the mold cavity has been filled. Summary of the Invention

[0004] The object of the present invention is to provide a mold with the help of which a flat component with a foam coating can be removed from the mold in the finished condition without reworking.

[0005] This object is achieved by a mould having the features of claim 1. Advantageous embodiments of the invention are indicated in the dependent claims.

[0006] According to the present invention, a mold for producing a foam coating on a plate-like component or for producing a foam-coated plastic part has a mixing head for producing a liquid plastic made of at least two components. The mold has at least one first cavity for receiving the plastic for forming the foam coating or the plastic part. A gate channel is used to connect the mixing head to the at least one first cavity. At the transition from the gate channel to the first cavity, a further cavity is formed that widens the gate channel. According to the present invention, a gate cutter, which is also called a gate trimmer, is movably mounted on the mold by at least one slide that can be moved in the direction of the gate channel toward the first cavity by means of at least one actuating cylinder. In its final position of displacement, the slide closes the first cavity with at least one edge and / or contour relative to the gate channel and / or relative to another cavity.

[0007] It is particularly advantageous if the actuating cylinder is hydraulically connected by means of a branch line to the main line of the cleaning cylinder, which is used to actuate the cleaning piston for cleaning the mixing head. As a result, the slide does not require any further control; instead, this is achieved by the hydraulic system of the mold simultaneously with or with the aid of an additional valve, so as to be slightly offset in time before the cleaning stroke, which in any case needs to be triggered after each foaming operation.

[0008] Advantageously, the control is carried out so that the actuating cylinder of the cleaning piston and the slide can only be actuated when the first chamber is completely filled, ie after the foam coating is completely produced. Preferably, this is done by a defined amount of plastic generated in the mixing head and delivered to the first chamber.

[0009] According to an advantageous embodiment, provision is made for the slide to be connected to the actuating cylinder by means of a guide element which is displaceably mounted in a vertical guide groove.

[0010] Particularly advantageous is a mold in which the slide can be moved vertically by means of at least one further actuating cylinder using guide grooves arranged on the guide element. This allows the slide to be raised to a cleaning position for the cleaning operation and then lowered back to its use position in a simple manner.

[0011] When the slide is in its final position, the gap for receiving excess plastic material is unobstructed between the slide and the mixing head near the gate channel. This gap serves to systematically remove excess liquid plastic material remaining in the mixing head's outlet pipe during the subsequent cleaning stroke of the mixing head. The excess plastic material forms a thin, tab-like structure in the gap provided for this purpose, which is neatly separated from the plastic frame or component by the edge of the gate cutter.

[0012] In a preferred embodiment, the slide has, on its front edge facing the first cavity, a profile adapted to the profile of the foam covering. This profile delimits and shapes the foam covering according to the profile intended for the foam covering.

[0013] The slide is advantageously provided with at least one seal which at least partially surrounds the gate channel and the further cavity at a distance. The seal prevents excess plastic material from travelling too far and supports its orderly return to the gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Exemplary embodiments of the tool according to the invention are explained in more detail below with reference to the accompanying drawings, in which:

[0015] Figure 1 Shows an overall perspective view of the lower mold according to the present invention;

[0016] Figure 2shows a plan view of the front part of the tool with the mixing head and the sprue cutter, with its slide in the home position, which allows the injection of plastic material,

[0017] Figure 3 A perspective detail view of the front tool area is shown with the gate cutter and slide in position to complete the introduction of the plastic material and trim the gate.

[0018] Figure 4 A perspective section through the slide of a gate cutter in the region of its actuating cylinder is shown in order to clarify its vertical guidance,

[0019] Figure 5 shows a perspective sectional view through the slide of the gate cutter in the region of the gate channel and in the position in which the introduction of the plastic material is completed and the gate is trimmed,

[0020] Figure 6 shows a perspective section through the slide which has been raised into its cleaning position in the region of the gate channel,

[0021] Figure 7 shows an enlarged perspective sectional view through the front area of ​​the slide in the filling position for the first cavity,

[0022] Figure 8 shows an enlarged perspective sectional view through a front area of ​​the slide in a position in which the slide closes the first cavity and separates the first cavity from the gate,

[0023] Figure 9 Shown Figure 2 A variant having an additional seal on the slide;

[0024] Figure 10 Shown Figure 3 A variant of having an additional seal on the slide; and

[0025] Figure 11 A variant of the lower mold is shown in which the gate cutter is rotatably articulated to the lower mold in its rotational cleaning position. DETAILED DESCRIPTION

[0026] exist Figure 1 , a mold 200 is shown in an overall view. The mold 200 is composed of a lower mold shown in the figure and an upper mold (not shown) that can be lowered onto the lower mold from above. In this example, the plate-like component 100 ( Figure 1 Not shown; see Figure 8) is placed into the lower mold 200. The glass cover 100 is enclosed in the mold 200 at its edge by a foam coating 120 made of plastic.

[0027] The mixing head 300 is used to introduce liquid plastic, and is provided with a plate 310 adjacent to the mold 200, and a mixing channel 320 is discharged into the plate 310. When the mixing channel 320 formed in the mixing head 300 appears on the front side of the plate 310, it merges into the gate channel 210 of the mold 200.

[0028] The front portion of the gate passage 210 directed toward the plate-like member 100 is formed on a slide 410 (at the Figure 1 shown in the following figures).

[0029] like Figure 2 As can be seen, a first injection channel 330 for the first component and a second injection channel 340 for the second component lead to the mixing channel 320. The plastic produced in the mixing channel 320 is preferably polyurethane (PU). The two mixed components, in a static liquid state, are introduced into a first cavity 240 in the mold 200 via the mixing channel 320 and the gate channel 210. This first cavity 240 is a negative representation of the contour of the foam coating 120 for the glass cover 100. When the lower mold 200 and the upper mold (not shown) are closely abutted together by the molding machine, the first cavity 240 is formed between them.

[0030] At the transition between the gate channel 210 and the first cavity 240, a second cavity 220 for the gate 130 is formed, which serves as a widening area to introduce the liquid plastic material flowing from the gate channel 210 to the first cavity 240 into the first cavity 240 in a wider front. In conventional molds, the gate 130 remains adhered to the foam cover 120 as a tab-like attachment after the foam cover 120 is completed (i.e., after the plastic material is cured) and must be manually separated therefrom.

[0031] The slide 410 consists of a central portion reaching into the second cavity 220 and two retainers 420 arranged to the sides of the central portion, whose front edges extend only to about half the distance between the plate 310 and the foam cover 120 when viewed from the plate 310.

[0032] In each of the two holders 420, a T-shaped undercut vertical guide groove 430 is formed, into which a corresponding guide element 440 embodied as a mushroom-shaped T-nut engages. Figure 4It can be seen that the guide element 440 is in turn connected to a piston 454 via a guide rod 452. The piston 454 is displaceably mounted in a horizontal actuating cylinder 450. To this end, the horizontal actuating cylinder 450 is connected to a hydraulic branch line 460 ( Figure 2 ).

[0033] The hydraulic main line 370 leads to a cleaning cylinder 355, which is arranged in the mixing head 300, and a cleaning piston 365 is installed in the cleaning cylinder 355 in a hydraulically displaceable manner. The cleaning piston 365 is connected to a cleaning plunger 360, which extends into the cleaning channel 350. The cleaning channel 350 is connected to the mixing channel 320 as a rear extension of the mixing channel 320 and closes the mixing channel 320 with its rear end facing the rear behind the two injection channels 330 and 340. The cleaning piston 365 and the cleaning plunger 360 can be moved from Figure 2 The indicated operating position is shifted from Figure 2 The position shown starts from the left side to the cleaning position, where the components for producing the plastic material are injected or sprayed from the two injection channels 330 and 340 into the mixing channel 320. In the cleaning position, the end face of the cleaning plunger 360 is pushed to the end face of the plate 310 by the cleaning piston 365. In this case, the mixing channel 310 is completely cleared of the plastic material by the cleaning plunger 360 pushed forward out of the mixing channel.

[0034] By virtue of the direct coupling of the hydraulic branch line 460 to the main line 370, when the cleaning piston 365 is activated, the piston 454 in the actuator cylinder 450 is also pushed forward (i.e., to the Figure 2 As a result, the slide 410 of the gate cutoff machine 400 is also shifted to the left.

[0035] When the sliding member 410 is in Figure 7 [and] when the liquid plastic used to create the foam coating 120 flows through the cavity 220 and the vertical feed channel 225 into the cavity 240 in order to completely fill it, when in the operating position shown Figure 8 In the position shown, the slide 410 closes the feed channel 225 with its front edge 414. The profile 412 of the slide 410 has a cross section in the shape of a quarter circle, which rests exactly on the rounded end profile of the upwardly directed rounded ribs of the foam coating 120 and helps to shape the plastic material during its curing.

[0036] By including a hydraulic delay element 380 in the main line 470 (e.g. a valve or a throttle downstream of the branch line 460) or by means of a surge by means of a separate valve and a separate hydraulic line, the actuating cylinder 450 is particularly advantageously actuated slightly before the cleaning piston 365, so that even before the residual plastic material is pushed out of the mixing channel 320 by the gate cut-off machine 400, the connection to the chamber 240 is interrupted and a detrimental pressure increase in the chamber 240 can no longer occur.

[0037] Because when in Figure 8 In the closed position shown, the front edge 414 of the slide 410 closes the entire feed channel 225, so that excess liquid plastic is forced to flow back from the cavity 220 of the gate 130 into the gap 230. Figure 7 The position shown moves forward to Figure 8 In the position shown, the slider 410 does not block the gap 230 on its rear side.

[0038] In a preferred variant, as from Figure 4 and Figure 6 As can be clearly seen, the slide 410 can be moved not only horizontally (i.e. parallel to the gate channel 210) but also vertically. For this purpose, an additional actuating cylinder 470 is arranged below the holder 420 of the slide 410. A piston 472 displaceable in the actuating cylinder 470 is in driving engagement with the holder 420 via a joint 474. When the slide 410 is moved from Figure 4 The situation shown moves vertically to Figure 6 In the position shown, the holder 420 is guided by the vertical guide groove 430 along the guide element 440 . Figure 6 The shown raised position of the slide 410 serves the purpose of thoroughly cleaning the mould 200 , during which clean plastic material which has flowed back into the gap 230 can also be removed.

[0039] exist Figure 9 and Figure 10 In the embodiment shown, as Figure 2 and Figure 3 In addition to the above, an additional seal 416 is arranged on the upper side of the slide 410. This seal 416 extends forward on both sides of the gate channel 210, expands in the area of ​​the second cavity 220, more specifically in the area of ​​the gate 130, and closes it on both sides. This seal 416 effectively prevents the liquid plastic from flowing to the side in the direction of the holder 420.

[0040] Figure 11 An alternative embodiment of the mold 200 is shown in which the gate cutter 400 is mounted for rotation relative to the mold 200 about a pivot axis 480 by being secured to a rotating bracket 490 after the slide 410 has been linearly advanced to its cutting or trimming position. Figure 11In the embodiment, the foam coating of the plate-like component 100 produces the foam coating 120. The sliding member 410 seals the cavity 240 from the cavity 220 and although Figure 11 Although not shown, the cleaning piston 365 has cleaned the mixing channel 320 by pushing out the remaining plastic material. Excess plastic material hardens in the vertical gap 230 to form a label-like structure. Figure 11 When rotated upward as shown, the gap 230 becomes more accessible for cleaning and introduction of release agent.

[0041] In contrast to known molds, the glass cover 100 with the finished foam covering 120 can be removed from the mold 200 according to the invention after the plastic material has solidified, without the need to still remove the gate 130 on the foam covering 120. Thus, costly manual reworking is completely eliminated, as is the risk of damaging the foam covering 120 during manual reworking.

[0042] By means of the present invention, the size of the gate in the tool can be made smaller. For example, the length / thickness ratio can also be changed from the previous 100 mm length×1 mm thickness (i.e. 100 mm 2 cross section) is changed to 50mm length × 2mm thickness (ie 100mm 2 This means that the mold is better filled from the center, there is less turbulence in the material, and therefore fewer sources of error during the foaming process. The parting line is then only visible in an area of ​​50 mm and not over a length of 100 mm as before.

[0043] The invention makes it possible to avoid the pressure buildup in the tool that usually occurs when the cleaning piston pushes residual plastic material out of the mixing head outlet pipe after the chamber has been completely filled. This residual material (in the case of a plastic frame of a foam-coated glass cover for a sunroof, this residual material is only about 8 grams) is usually caused by plastic material pressing through the seal, foaming of the sheet metal tab inserted there, for example on the front side, foaming of the glass corners, usually during the foam coating of the glass cover, or collapse of the foam insert.

[0044] The invention effectively prevents the formation of surface defects in the form of slight undulations or depression marks, since the still liquid plastic is first compressed and flows away, so to speak, by gravity until it hardens.

[0045] The present invention also allows for the preservation of slides, as the gate is not permitted in the visible area. In this case, the gate is not located on the outer edge of the component, but rather somewhere within the geometry. This also results in a better quality of the finished component, as a visible parting line is avoided.

[0046] Finally, the invention also offers significant economic advantages through significant time savings: the invention eliminates the need for cutting and grinding the radius on the contour, which takes approximately 10 seconds. In three-shift operation, this results in approximately 5,300 additional parts being manufactured per year.

[0047] The invention is not only effective in tools for producing plastic frames on glass covers, but also in all parts produced in the same or similar manner in a mold using such a mixing head system from at least two-component plastics. Suitable materials for the plastic frames or plastic parts therefore include not only polyurethane (PU), but also other materials such as epoxy resins using a resin infusion process (RTM or resin transfer molding), or other plastics or using other processes.

[0048] In the figures, the mold 200 is shown as a lower mold, on which a mixing head 300 and a gate channel 210 are arranged. This lower mold is supplemented by an upper mold, which is not shown in the figures but is shown, for example, in application DE 10 2019112 763.7 by the same applicant and on which a mixing head 300 and a gate channel 210 can also be arranged alternatively.

[0049] Reference Signs List

[0050] 100 (Plate-shaped) components (glass cover)

[0051] 120 Foam Covering

[0052] 130 Gate

[0053] 200 mold

[0054] 210 Gate channel

[0055] 220 cavities (for gate)

[0056] 225 Feed Channel

[0057] 230 gap

[0058] 240 cavity (for 120)

[0059] 300 Mixing Head

[0060] 310 panels

[0061] 320 mixed channels

[0062] 330 injection channel (component 1)

[0063] 340 injection channel (component 2)

[0064] 350 Cleaning Channel

[0065] 355 Cleaning Tank

[0066] 360 Cleaning Plunger

[0067] 365 Cleaning Piston

[0068] 370 Main Line

[0069] 380 (Hydraulic) Delay Element

[0070] 400 Gate Cutting Machine

[0071] 410 Slide

[0072] 412 Profile

[0073] 414 front edge

[0074] 416 seals

[0075] 420 retainer (on 410)

[0076] 430 (vertical) guide groove

[0077] 440 Guide element (T-nut)

[0078] 450 Actuating Cylinder (Horizontal)

[0079] 452 guide rod

[0080] 454 Piston

[0081] 460 branch line

[0082] 470 Actuating Cylinder (Vertical)

[0083] 472 Piston

[0084] 474 connections

[0085] 480 pivot axis

[0086] 490 bracket

Claims

1. A mold (200) for producing a foam coating (120) made of plastic on a flat component (100) or for producing a foamed plastic part, the mold (200) comprising a mixing head (300) for producing liquid plastic from at least two components, at least one first cavity (240) for receiving the plastic in order to form the foam coating (120) or produce the foamed plastic part, a gate channel (210) for connecting the mixing head (300) to the at least one first cavity (240), and a further cavity (220) formed between the gate channel (210) and the at least one first cavity (240). the transition from the first cavity (240) to the first cavity (240) and widening the gate channel (210), wherein a gate cutter (400) having at least one slide (410) is movably mounted on the mold (200), wherein the slide (410) can be moved in the direction of the gate channel (210) towards the first cavity (240) by means of at least one actuating cylinder (450) and, in the final position of the movement of the slide, the first cavity (240) is closed off from the gate channel (210) and / or from the further cavity (220) by means of at least one edge (414) and / or contour (412), Wherein when the slide (410) is in its final position, the gap (230) for receiving excess plastic material is not blocked between the slide (410) and the mixing head (300) near the gate channel (210).

2. The mold according to claim 1, characterized in that The actuating cylinder (450) is hydraulically connected to the main line (370) of the cleaning cylinder (355) by means of a branch line (460), which is used to actuate a cleaning piston (365) in order to clean the mixing head (300).

3. The mold according to claim 2, characterized in that The actuating cylinder (450) and the cleaning piston (365) can only be actuated when the first chamber (240) is completely filled.

4. The mold according to claim 1, characterized in that The slide (410) is connected to the actuating cylinder (450) by means of a guide element (440) which is displaceably mounted in a vertical guide slot (430).

5. The mold according to claim 4, characterized in that The slide (410) can be moved vertically by means of at least one further actuating cylinder (470) by means of the guide groove (430) arranged on the guide element (440).

6. The mold according to any one of claims 1 to 5, characterized in that The sliding element (410) has a profile (412) on its front edge (414) facing the first cavity (240) that is adapted to the profile of the foam coating (120).

7. The mold according to any one of claims 1 to 5, characterized in that The sliding member (410) is provided with at least one sealing member (416), and the sealing member (416) at least partially surrounds the gate channel (210) and the further cavity (220) at a certain distance.

8. The mold according to claim 2 or 3, characterized in that: After the branch line (460), an additional valve or hydraulic delay element (380) is provided in the main line (370) of the cleaning cylinder (355), which causes a time delay between the hydraulic impact of the actuating cylinder (450) and the hydraulic impact of the cleaning cylinder (355).

9. The mold according to any one of claims 1 to 5, characterized in that The gate cutter (400) is mounted on the mold (200) so as to be rotatable about a pivot axis (480).

10. The mold according to claim 9, characterized in that The rotation of the gate cutter (400) about the pivot axis (480) occurs only after the slide (410) has been moved to its final position in order to close the first cavity (240) from the gate channel (210) and / or from the further cavity (220).

11. The mold according to claim 2 or 3, characterized in that: The slide (410) is connected to the actuating cylinder (450) by means of a guide element (440) which is displaceably mounted in a vertical guide slot (430).

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