Method for producing decorated molded parts

Abstract

A method for producing decorated molded parts from thermoplastic film, characterized in that, in a decoration unit comprising at least two magazines, each magazine containing the number of label holders corresponding to the number of cavities of the mold, the at least two magazines are used such that a first magazine supplies the decoration unit with labels and the at least second magazine is ready loaded with labels or is loaded with labels and subsequently made available, and that when the first magazine is recognizably empty or when a desired number of machine cycles have been produced, the decoration unit is switched off for at least one cycle while the thermoforming machine is running, undecorated molded parts are produced, and the second magazine is engaged for the decoration unit.whereupon the decoration unit is supplied with labels from the second magazine and produces decorated molded parts again.

Description

[0001] The invention relates to a method for producing decorated molded parts. State of the art

[0002] The publication DE 10 2012 005 915 B4 describes a device and a method for decorating molded parts made of heated thermoplastic film with labels. In this and comparable decoration processes for molded parts made of thermoplastic film with labels, the state-of-the-art decoration units each have a magazine that is continuously refilled by the operator visually or by machine signal. During a batch change, the magazine is emptied and the label holders are filled with new, differently designed labels. For this purpose, the thermoforming line is shut down for an extended period.

[0003] EP 0 525 614 A1 discloses a method and apparatus for producing a plastic container, and a plastic container produced in this way. Suction cups remove labels from label holders and feed them to a turnstile. The turnstile rotates counterclockwise by 90° each time, feeding the picked-up labels to a molding tool, where the labels are bonded to the hot plastic film. The suction cups of the turnstile then remove the labeled molded parts from the molding tool and, after a further 90° rotation, place the molded parts on an outfeed conveyor.

[0004] The document DE 41 37 982 A1 describes a method for inserting labels into the deep-drawing mold of a thermoforming machine and a device for carrying out the method. Large-format labels are removed from label holders and bent into a curved shape by guide plates in the holders. The erected labels are then moved to the cavities of a molding tool of a thermoforming machine and transferred to the cavities. During the transfer process, the labels are bent again and thus fold once around an axis, so that they are placed in the cavity in a bent state. There, they are then bonded to the heated plastic film.

[0005] The document DE 42 32 963 C1 shows a device for applying printed labels to the side walls of a plastic container. Suction cups remove labels from label holders and feed them to a rotating device. The rotating device rotates 180° each time, feeding the picked-up labels to a forming tool, where the labels are bonded to the hot plastic film. The suction cups of the rotating device then remove the labeled molded parts from the mold and, after another rotation, place them on stacking trays.

[0006] The document DE 100 23 658 C1 discloses a method for producing empty or filled thermoplastic containers whose walls are provided with a ring-shaped label. Ring-shaped labels are formed, transferred to a conveyor, and guided underneath the containers, which are still connected with the film strip. The labels are removed and placed on the container wall. The connection is made by adhesive, form-fitting, or shrink-fitting. The method is applicable to containers with conical or cylindrical side walls. The invention further relates to an apparatus for carrying out the method. Task

[0007] The invention is based on the object of improving and simplifying the setting up and operation of devices for labelling moulded parts made of thermoplastic film.

[0008] This object is achieved according to the invention by the measures specified in claim 1. Further preferred embodiments of the invention emerge from the remaining features mentioned in the respective subclaims. Example

[0009] The decoration technique that is always meant here is the process known as in-mould decoration, in which flat label blanks are taken from magazines, these are pre-formed three-dimensionally in at least one erection step and are transferred into the moulding tool of a thermoforming machine via at least one transfer step using at least one transfer tool.

[0010] It is proposed to use at least two magazines, each of which holds all the labels required for one machine cycle.

[0011] The advantages of equipping the decoration unit with at least two magazines are numerous. The operator can reload labels safely and comfortably, a major advantage, especially with tightly arranged magazines containing smaller-format labels. If the label holders are also removable, the labels can be refilled conveniently and precisely on a workbench. This completely eliminates the otherwise unavoidable disruptions caused by improperly inserted labels.

[0012] Furthermore, differently designed labels can be loaded into the other magazines, so that a label change with the same molded parts can be carried out quickly, safely and without mixing in just a few cycles with undecorated molded parts.

[0013] It is inventively provided that the method for producing decorated molded parts from thermoplastic film is designed such that, in a decoration unit having at least two magazines, wherein the magazines each contain the number of label holders corresponding to the number of cavities of the mold, the at least two magazines are used such that a first magazine supplies the decoration unit with labels and the at least second magazine is ready loaded with labels or is loaded with labels and then made ready, and that when the first magazine is noticeably running empty or when a desired number of machine cycles is reached, the decoration unit is switched off for at least one cycle while the thermoforming machine is running and undecorated molded parts are produced and the second magazine is brought into engagement for the decoration unit,whereupon the decoration unit is supplied with labels from the second magazine and again produces decorated molded parts.

[0014] Sensors of the thermoforming machine or the magazines should detect when the first magazine is running empty or when a desired batch size of molded parts has reached its end, and the control system of the thermoforming machine should take over the process steps of switching off the decoration unit, moving the magazines so that the second magazine engages with the decoration unit, and starting the decoration unit after the movement.

[0015] Sensors of the thermoforming machine or the magazines should detect the emptying of the first magazine or the end of a desired batch size of molded parts and the control should issue a visual and / or acoustic signal to the operator, prompting him to switch off the decoration unit, move the magazines so that the second magazine engages with the decoration unit and start the decoration unit after moving.

[0016] The control system of the thermoforming machine should detect the machine cycle with the undecorated molded parts and automatically eject them.

Claims

[1] Process for producing decorated molded parts from thermoplastic film, characterized byin that in a decoration unit which has at least two magazines, wherein the magazines each contain the number of label holders which corresponds to the number of cavities of the moulding tool, the at least two magazines are used in such a way that a first magazine supplies the decoration unit with labels and the at least second magazine is ready loaded with labels or is loaded with labels and then made ready and that when the first magazine is noticeably running empty or when a desired number of machine cycles has been reached, the decoration unit is switched off for at least one cycle while the thermoforming machine is running and produces undecorated moulded parts and the second magazine is brought into engagement for the decoration unit, whereupon the decoration unit is supplied with labels from the second magazine and produces decorated moulded parts again. [2] Method according to claim 1, characterized bythat sensors of the thermoforming machine or the magazines detect when the first magazine is running empty or when a desired batch size of molded parts has ended, and the control of the thermoforming machine carries out the process steps of switching off the decoration unit, moving the magazines so that the second magazine engages with the decoration unit, and starting the decoration unit after the movement. [3] Method according to claim 1, characterized by that sensors of the thermoforming machine or the magazines detect the emptying of the first magazine or the end of a desired batch size of molded parts and the control system issues a visual and / or acoustic signal to the operator, prompting him to switch off the decoration unit, move the magazines so that the second magazine engages with the decoration unit and start the decoration unit after moving. [4] Method according to claim 1, characterized bythat the control of the thermoforming machine recognizes the machine cycle with the undecorated molded parts and automatically ejects them.