METHOD FOR PRODUCING A THERMOFORMED PRODUCT, AND INSTALLATION AND MACHINE THEREFORE

Abstract

A method for producing a thermoformed product on a single machine with several stations and with different tools includes the following steps: (a) melting and homogenizing plastic granules and providing the plastic melt at a preform station; (b) producing a preform at the preform station in a preform cavity; (c) transferring the preform by a transfer carrier to a thermoforming station at the same machine, the thermoforming station having a thermoforming tool having a thermoforming cavity; (d) preferably heating the preform during the transfer; (e) thermoforming of the thermoformed product in the thermoforming cavity. Advantageously, the final thermoformed product is produced directly from the plastic granules using only a single machine, and in particular without any waste, when the preform is dimensioned in such a way that it does not present any excess with respect to the final shape of the product to be produced.

Claims

1. A method for producing a thermoformed product on a single machine with several stations and with different tools, comprising the following steps: a. melting and homogenizing plastic granules and providing the plastic melt at a preform station; b. producing a preform at the preform station in a preform cavity, injection compression molding or compression molding; c. transferring the preform by means of a transfer carrier to a thermoforming station at the same machine, the thermoforming station comprising a thermoforming tool having a thermoforming cavity; d. preferably heating the preform during the transfer with a radiation heater; e. thermoforming the thermoformed product in the thermoforming cavity.

2. A method for producing a thermoformed product on one or more machines, with several stations and with different tools, comprising the following steps: a. providing a plastic mass at a preform station, either by melting and homogenizing plastic granules and providing the plastic melt at the preform station or by providing a solid plastic element, for instance a film portion, at the preform station; b. producing a preform at the preform station in a preform cavity; c. transferring the preform by means of a transfer carrier to a thermoforming station, the thermoforming station comprising a thermoforming tool having a thermoforming cavity and the transfer carrier holding the preform only on one side; d. preferably heating the preform during the transfer, with a radiation heater; e. fixing the preform to the thermoforming cavity by means of a tenter of the thermoforming station; f. thermoforming the thermoformed product in the thermoforming cavity.

3. A method for producing a thermoformed product on one or more machines with several stations and with different tools, comprising the following steps: a. providing a plastic mass at a preform station, either by melting and homogenizing plastic granules and providing the plastic melt at the preform station or by providing a solid plastic element, for instance a film portion, at the preform station; b. producing a preform at the preform station in a preform cavity; c. transferring the preform by means of a transfer carrier to a thermoforming station, the thermoforming station comprising a thermoforming tool having a thermoforming cavity; d. preferably heating the preform during the transfer with a radiation heater; e. thermoforming the cup-shaped product in the thermoforming cavity; f. as well as an additional step altering the provided plastic mass, the preform and/or the thermoformed product, mechanically, optically or sensor technically.

4. A method for producing a thermoformed product on one or more machines, with several stations and with different tools, comprising the following steps: a. melting and homogenizing plastic granules and providing the plastic melt at a preform station; b. producing a preform at the preform station in a preform cavity by means of compression molding; c. transferring the preform by means of a transfer carrier to a thermoforming station at the same machine, the thermoforming station comprising a thermoforming tool having a thermoforming cavity; d. preferably heating the preform during the transfer, with a radiation heater; e. thermoforming the thermoformed product in the thermoforming cavity.

5. The method according to claim 1 for producing a thermoformed product.

6. The method according to claim 1, wherein the preform is produced with a thickness profile deviating from a uniform thickness.

7. The method according to claim 1, with the following additional step: printing of the preform and/or of the thermoformed product by means of a printer, by means of a 3D printing process, by means of a liquid-jet printer; during rotation of the preform, the product and/or of the printer.

8. The method according to claim 1, with the following additional step: positioning an element in the thermoforming cavity, a label, a smart tag or an RFID chip, for connecting the element to the product.

9. The method according to claim 1, with the following additional step: positioning a multi-component preform in the preform cavity, by means of a two-component injection process, with one or two of the at least two components being injected and, in case of the injection of only one component, a second component being injected or introduced in some other manner.

10. The method according to claim 1, where a multi-layer film is provided for thermoforming.

11. The method according to claim 1 for producing a food capsule, a coffee capsule, with the additional steps: filling and/or sealing.

12. The method according to claim 1, the provision of the plastic mass at the preform station or of the plastic granules taking place with at least partial usage of a biologically degradable plastic according to the classification of the brochure Wolfgang Beier: “Hintergrund: Biologisch abbaubare Kunststoffe” of the Umweltbundesamt, August 2009.

13. The method according to claim 1, the provision of the plastic mass at the preform station or of the plastic granules taking place with at least partial usage of a polylactide (PLA).

14. The method according to claim 1, with the following additional step: applying a barrier layer, comprising an oxide.

15. The method according to claim 1, where a rim of the preform has already got its shape, in which it is clamped by the tenter, during the transfer.

16. The method according to claim 1, with the following additional step: Treating a rim of the preform, by applying a second plastic or a caoutchouc.

17. The method according to claim 1, wherein before thermoforming, a rim is formed to be an energy director.

18. The method according to claim 1, with the following additional step: Printing an electric oscillating or electronic circuit.

19. The method according to claim 1, with the following additional step: Printing a hologram on the thermoformed product.

20. The method according to claim 1, with the following additional step: Use of a combined IML embossing die, a label being employed which has a paint edge and an embossing having a mechanical edge, the contour of the paint edge being aligned with the one of the mechanical edge.

21. The method according to claim 1, wherein the production process for the preform uses precisely the amount of plastic required for the thermoformed product so that production takes place without waste.

22. An installation with more than one machine for performing the method according to claim 1.

23. Machine for performing a method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0083] In the following, the disclosure will be described in more detail using an example of embodiment with reference to the drawing wherein

[0084] FIG. 1 shows schematically, in perspective view, a machine with a turntable and four tray-shaped carriers for workpieces, and with several stations.

DETAILED DESCRIPTION OF THE DRAWING

[0085] Machine 1 in FIG. 1 substantially comprises different stations which are arranged on one common bed 2 and connected in one machine direction 4 via a turntable 3.

[0086] The turntable 3 has a vertical switch shaft 5.

[0087] The turntable 3 has four workpiece trays 6 which are numbered by way of example.

[0088] A machine controller (not shown in detail) drives the turntable 3 with motors (not shown in detail) so that it can actuate the turntable 3 forward by a shifting angle of 90° each. In this way, a workpiece tray 6 can be shifted to precisely four positions.

[0089] Thus, the machine 1 with the workpiece trays 6 can move to exactly four stations.

[0090] It is explicitly pointed out that in other examples of embodiment, other numbers of trays, other carriers, other numbers of stations or other switching angles can be provided.

[0091] The machine 1 introduced here, however, is extremely compact, inexpensive and very precise as well as quick for a production.

[0092] In one of the positions that can be reached, a preform station 7 (shown only in a very rudimentary manner) is arranged. The preform station 7 has a compression molding die and, at its rear, a plastic melt (not shown) from an extruder (not shown).

[0093] The station subsequent to the preform station 7 in the machine direction 4 is a thermoforming station 8.

[0094] The thermoforming station 8 has an upper table 10 which can be moved vertically by means of a toggle lever drive 9 and has an upper die 11 attached to it which substantially contains a pre-stretching die (not shown) and a tenter 12.

[0095] The thermoforming station 8 additionally has a lower die (not shown) which has, as is known in the state of the art, a cavity for molding the thermoformed products (not shown) to be produced.

[0096] In the present example of embodiment, the workpiece trays 6 each have ten product bearing frames 13, 14 (numbered by way of example). Each workpiece tray 6 can therefore carry ten preforms and, one station further, also ten thermoformed products. Thus, with each switching cycle ten products or ten semi-finished products, respectively, per workpiece tray 6 are further moved.

[0097] The tenter 12 is so large that it encompasses the workpiece tray 6 with ten bearing frames, in any case the ten product bearing frames 13, 14.

[0098] Smaller tenters can be provided within the outer tenter 12, which can again clamp one or more workpieces so as to avoid slippage of rims of the thermoformed products through the product bearing frames 13, 14 while the form punch is pressed in or during thermoforming.

[0099] In another station, for instance in the third station, a removal station 15 can be provided. The fourth station of the example of embodiment introduced here is a free station 16 which can, however, also be used for cleaning or inspection purposes, for example.

[0100] In operation, the machine 1 produces thermoformed products in the following manner:

[0101] In a first step, a plastic produced with the compression-molding method, for instance by means of an extruder, is deposited at the preform station 7 and during the course of operation, a preform (not shown) is manufactured.

[0102] An additional step can already be performed here, for instance, provision with materials, printing, rim finishing, bottom finishing, a second component can be added etc.

[0103] The preforms produced are then removed from the preform cavities, for instance by lowering the preform cavities and indexing the turntable 3. In this manner, the preforms are moved into the thermoforming station 8. The preforms can still be deformed easily because they still retain their first heat.

[0104] The thermoforming station then performs the thermoforming in the manner known from the state of the art, preferably by means of a pre-stretching die.

[0105] For this purpose, the machine 1 will first fix the tenter 12 on the preforms and operate with the pre-stretching dies, but, in any case, with overpressure negative pressure, only afterwards.

[0106] Subsequently the thermoforming station 8 reopens again, the turntable 3 indexes to the next position, and the finished thermoformed products can be removed.

[0107] As mentioned above, other functions and additional stations can be provided as well.

[0108] Maybe it may be useful to apply barrier layers, sealing layers, color layers or prints.

[0109] For molding, compressed-air molding, vacuum molding, a pre-stretching die and a pressure can be used.

[0110] Secondary treatment can provide, for instance, a barrier layer, it can include printing, filling or sealing.

[0111] In any case, the machine makes it possible to arrive at the thermoformed product starting directly from the granules, with minimum space occupation, high working precision and high output. In spite of thin walls, high stability can be achieved by orienting of the macromolecules. In addition, the wall thickness distribution in the finished thermoformed product can be controlled by preform shaping.

[0112] The preform geometry preferably corresponds to the perpendicular projection of the final product, that is, production can be waste-free.

[0113] Functional elements such as a sealing lip, an energy director etc., can be introduced already during production of the preform.