DE3215588A1 - Process and apparatus for producing moulded parts or articles from plastic - Google Patents

Abstract

The invention relates to a further development of the process and the apparatus for producing moulded parts or articles from plastic, according to Patent Application P 3133872. In this case, a preform is injection-moulded via a nozzle and, at the same time, a second, already injection-moulded preform is shaped under the effect of pressure by a pressing-stretching ram in the mould cavity insert for the finished part. After opening the apparatus, moving back the nozzle and moving out the mould cores and turning the mould plates on the moving mould half, the finished article is ejected. After ending the turning movement and by closing the apparatus, the core of the one pressing-stretching ram with the injection-moulded preform engages in the mould cavity insert for the finished part and the free core of the other pressing-stretching ram engages in the mould cavity insert for the preform. According to Fig. 1, the apparatus according to the invention has, on the fixed mould half, a platen with a mould cavity insert for the preform and a mould cavity insert for the finished part and, on the moving mould half, mould plates or mould plate assemblies which can turn about fixed turning bolts and receive two pressing-stretching rams which can move in guide bushes and align with the assigned mould cavity inserts in the platen on the fixed mould half. The mould plate on the moving mould half, firmly connected to the turning bolts, has a bore for receiving the head of one of the two pressing-stretching rams. <IMAGE>

Description

"Method and Apparatus for Manufacture

of molded parts or objects made of plastic " "Get lost and device for animal parking? from molded parts or objects to plastic " the Invention according to the main patent / patent application P 31 33 872.0) relates to a method for the production of molded parts or objects made of plastic, whereby the to be processed Plastic using a device for plasticizing, preferably one Injection molding machine, introduced into a tool with one or more parting lines or is injected, wherein the injection molded part or the preform during the Cooling phase in the tool using new or partially new mold cavities at least is subjected to compression molding (compression stretching) and / or pressure treatment. she further relates to a device for performing the method, consisting of an injection molding machine and a shaping tool with one or more Parting lines, with the injection molding machine as a press for one or more reshaping or press stretching of the preform and / or as a press for exercising holding pressure is formed on the molded part.

Starting from the objective of the main patent outlined above is the task of the present invention training in the procedure and to improve the apparatus so as to reduce the time lapse for the production of the press-stretched or pressure-formed molded parts or objects made of plastic and significantly reduced for the implementation of the method required force build-up, for example the pressure pad, in its previously required Number can be reduced.

According to the invention, this object is thereby achieved on the method side solved by placing a preform through a nozzle, preferably an immersion nozzle, which is attached to the The nozzle-side mold cavity insert for the preform has reached the stop and at the same time or almost at the same time a second, already injected preform in the mold cavity insert for the finished part under the action of pressure by a press-stretching die reshaped and the sprue is separated after opening the tool and moving back the immersion nozzle as well as moving the tool cores out of the corresponding nozzle-side Preform or finished part mold nest blocks and rotation of the corresponding mold plates or form plate packets on the closing side of the tool, the finished object ejected or demolded ir and preferably after the end of the rotary movement by 180 ° and while closing the tool, the core of one pore.

with the shrunk-on, injection-molded preform in the mold cavity insert for the finished part and the free core of the other press-stretching punch snaps into the cavity insert for the preform.

Device side. ' the object according to the invention is achieved by that the shaping tool on the nozzle side consists of a fixed, preferably circular clamping plate or clamping plate package with one each Mold cavity insert for the preform and the finished part and on the closing side from around a fixed pivot pin with a mold plate and a clamping plate is firmly connected to the pivot pin rotatable, preferably circular Form plate packs, which ewel receive movable press-stretching punches in guide bushes, consists, wherein the press-stretching punches are arranged such that they are associated with the The mold cavity inserts in the nozzle-side clamping plate are aligned and those with the pivot pin firmly connected, non-rotating mold plate on the closing side a hole or Recess for receiving the head of one of the two press-stretching dies when closing of the shaping tool.

Further advantages result from the claims 2 to 4 and 6 to 11 mentioned features.

On the basis of the exemplary embodiments shown schematically in FIGS the invention is explained in more detail below. It shows Fig. 1 according to the invention Device in section in the open state; Fig. 2 is a plan view of the mold plate of Fig. 1; 3 shows a plan view of a further advantageous embodiment with clamping plate on the nozzle side with four mold cavity inserts; Fig. 4 is a plan view onto the closing-side mold plate associated with the embodiment according to FIG for holding four press stretching punches.

The device according to the invention has the presence of a Parting line C-D has a two-part structure, which is divided into a nozzle-side and a is divided on the closing-side part. The nozzle side consists of a preferred one circular clamping plate or clamping plate package 1 for the inclusion of each one Mold cavity insert for the Vorrormlfntt 9, which has a cavity 15 for the Immersion nozzle is in connection, and the prefabricated part 10, which are arranged symmetrically to each other are. The clamping plate or the clamping plate package 1 is normally solid, but can, according to one embodiment, be designed to be rotatable or movable up and down be.

The closing side of the device consists of the mold plate or the FormnlattennMceten 2, the intermediate mold plate 3 and the rotary plate 4, which are preferably Are circular, in which the closing-side mold cavities 14 and the Preßreckstempel 7 with the guide bushes 8 and the pivot pin 11, which with the Form plate 5 and the closing-side clamping plate 6 is firmly connected, added are. Each press-stretching die 7 can be designed separately as a core and sleeve and allows a relative movement to the Ejection of the molded part on the closing side. The specified distance between the vormolatten 3 and lt is kept constant by the disk spring assemblies 13. the also preferably circular shaped plate 5 is with a bore or recess 16 for receiving the head of one of the two press-stretching dies 7 provided. The spring package 12 drc: Ct len press stretching die 7 with the unrrichtung open in the starting position.

In the open state of the device according to the invention are the Mold plates or Form plate packs 2 to 4 around the pivot pin 11 on the plane of rotation A-3 can be rotated, preferably by 180 °. The rotary movement can be mechanical or hydraulic take place.

How it works When the device is closed, the following processes take place from (except for the first injection cycle): First, the preform is fed through a nozzle, preferably an immersion nozzle, injected in the cavity 15, which also with time Delay during the pressure holding time after the forming can take place. Simultaneously or almost at the same time an already injected preform is placed in the mold cavity 10 immersed and by the action of pressure, for example pressure pad of a fully hydraulic Injection molding machine, and the resulting reduction in the distance between the Form plates or form plate packs 4 to 6 and 2 to 3 via the press-stretching die 7 reshaped. In this case, the sprue is automatically cut off. Acts on the closing side the movement of the mold plate 4-6 due to the recess or

Bore 16 in the mold plate 5 does not appear, i.e. there is no deformation.

After opening the device, a rotary movement finally takes place of the mold plates 2-4 on the pivot pin 11 by preferably 130 °, # the cut Preform closes on the core of the press-stretching die 7 by shrinking it on remains. At the same time, the ejector movement takes place on the nozzle side (mold cavity 10) or on the closing side (not shown) The finished part is demolded and the preform, which has already been molded on, fixes the device in the pressing or reshaping position closes again and the cycle starts all over again.

with the aid of the method according to the invention and the method according to the invention Device, a cycle time reduction of approx. 40 7 can be achieved, since the spraying of a preform and the press stretching of an already molded preform in parallel take place. In addition, the build-up of force, for example of the pressure pad, is here a fully hydraulic injection molding machine, only required once, resulting in a Energy savings result. Likewise, the elimination of the usual required spacer strips on the press stretching tool, as well as the embossing circuit on the Injection molding machine a simplification of the structure of the device.

The injection time of the preform is advantageously shorter than the press stretching time for the preform, start and end of the "preform cut" process are from depending on the respective optimization conditions by increasing the number the pressing die and the corresponding number of Formnesteinsi.'tze in the The device according to the invention It increases the output even further. So show Figures 3 and 4 an advantageous embodiment of such a device, in which, according to FIG. 3, the nozzle-side clamping plate 1 with two preform cavity inserts each 9 and two precast mold cavity inserts 10, offset by 90 °, provided and accordingly. According to FIG. h on the closing side, offset by 90 °, four press-stretching dies are provided.

1. Support plate on the nozzle side 2. Form plate 3. Intermediate form plate 4. Rotary plate 5. Form plate 6. Clamping plate on the closing side 7. Press stretching bar 8. Guide bushing 9. Mold cavity insert for the preform 10. Mold cavity insert for the prefabricated part 11. Pivot bolts 12. Return springs 13. Disc spring assemblies 14. Closing side Mold cavity 15. Cavity for immersion nozzle 16. Bore or recess for press-stretching die head A-B = plane of rotation C-D = parting plane

Claims (11)

Claims: Process for the production of molded parts or objects made of plastic, the plastic to be processed using a device for plasticizing, preferably an injection molding machine, in a tool with a or several parting lines is introduced or injected, wherein the injection molded part or the preform during the cooling phase in the tool using new ones or partially new mold cavities of at least one pressure forming (press stretching) and / or pressure treatment is exposed, according to patent application P 31 33 872.0, thereby characterized in that a preform fever a nozzle, preferably immersion nozzle, the has moved to the stop on the mold cavity insert for the preform on the nozzle side, injected and at the same time or almost at the same time a second already carved one A preform in a mold cavity insert for the finished part under the action of diuron The press-straightening die is reshaped and the sprue is cut off after the tool has been opened and retraction of the immersion nozzle and removal of the tool cores from the corresponding Nozzle-side preform or precast mold nest inserts and rotation of the corresponding Mold plates or mold plate packages on the closing side of the mold the finished object is ejected or removed from the mold and, after specifying the rotational movement, preferably by 1 '> and with closing of the tool the core of a press-stretching die with the shrunk, injection-molded preform in the mold nest insert for the Finished part and the free core of the other press-stretching punch in the mold cavity insert to lock the preform into place. 2. The method according to claim 1, characterized in that the pressure forming of the preform by the Preßreckstemnel after closing the mold during the compression of the disk spring assemblies between the mold plate assemblies on the closing side are arranged using the force of the clamping unit of an injection molding machine or using one or more hydraulic or pneumatic cylinders. 3. The method according to claim 2, characterized in that the disc springs and / or mechanical and / or hydraulic locks alone the parting plane during the injection molding process of the preform, the press stretching process and the subsequent ones Keep the pressure hold time closed. 4. The method according to any one of claims 1 to 3, characterized by that the injection molding of a preform within the duration of the deformation the other preform is carried out by pre-stretching. 5. Device for the production of molded parts or objects Plastic for carrying out the method according to claims 1 to 4, consisting of an injection molding machine and a shaping tool with one or more Parting lines, with the injection molding machine as a press for one or more reshaping (Press stretching) of the preform and / or as a press for applying pressure is formed on the molded part, according to patent application P 31 33 872.0, characterized in that that the shaping tool on the nozzle side consists of a fixed, preferably circular clamping plate or clamping plate package with one each Mold cavity insert for the preform and the finished part and on the closing side from around a fixed pivot pin with a mold plate and a clamping plate is firmly connected to the pivot pin rotatable, preferably circular Form plate packs, which receive two press-stretching punches movable in guide bushes, exists, the press-straightening punches are arranged in such a way that they are connected to the assigned arranged Foflrnesteins; lasts in the nozzle-side clamping plate are aligned and with the Pivot bolt firmly connected, non-rotating mold plate on the closing side Bore or recess for receiving the head of one of the two press stretching tools having when closing the forming tool. 6. Apparatus according to claim 5, characterized in that the nozzle-side Mold cavity insert for the finished part with an ejector for the ferticr formed Object is provided. 7. Apparatus according to claim 5, characterized in that the press-stretching die are designed in two parts as a core and sleeve. 8. Device according to one of claims 5 or 7, characterized in that that the compression ram in the guide bushes by spring assemblies in their starting position being held. 9. Device according to claims 5 to 8, characterized in that Disk spring assemblies are arranged between the closing-side shaped assemblies, which when reducing the distance between the mold plates from each other the parting plane of the tool, closed by pressure build-up of the disc springs on the parting line keep. 10. Apparatus according to claim q, characterized in that the disk spring assemblies completely or partially replaced by mechanical and / or hydraulic locks are. 11. Device according to claims 5 to 10, characterized in that that they have several mold cavity sets on the nozzle side for both the preforms and for the finished parts and closing side one of these mold cavity inserts Number of press-straightening dies and holes or recesses in the mold plate fiir the inclusion of the heads of the press-stretching punches that are not used for pressure forming aufeist, whereby the mold cavity and the press-straightening die are symmetrically underneath- and / or are arranged to one another.