WO2010100023A1

WO2010100023A1 - Method and device for separating retained samples

Info

Publication number: WO2010100023A1
Application number: PCT/EP2010/051910
Authority: WO
Inventors: Gerd Fuhrmann
Original assignee: Intravis Gmbh
Priority date: 2009-03-05
Filing date: 2010-02-16
Publication date: 2010-09-10
Also published as: DE102009011269B3

Abstract

The invention relates to a method and to a device for separating retained samples from a production process of corresponding molded parts by means of a plurality of cavities arranged in at least one permanent mold. Individual cavity identifications are associated with the cavities and are transferred to the surface of each molded part during molding. In the transport stream of the molded parts, images comprising the cavity identifications on the molded parts are at times taken by means of at least one digital camera. Depending on the cavity identification contained in the image, means for separating the molded part depicted in the image are activated as retained samples from the transport stream.

Description

Method and device for rejecting return patterns

The invention relates to a method and a device for separating out restoring patterns from a manufacturing process of matching moldings with the aid of a plurality of cavities arranged in at least one permanent mold, each of which is assigned an individual cavity identification, which is transferred to the surface of each mold during casting, wherein the manufactured Moldings are removed in at least one flow.

A typical manufacturing process of matching moldings by means of several arranged in at least one permanent cavity forms the injection molding. It is mainly used in plastics processing. With such manufacturing processes, it is possible to economically produce molded parts in large numbers. For this purpose, the material, usually plastic, is plasticized with an injection molding machine in an injection unit and injected into a permanent mold, called a tool during injection molding. In a tool, there are usually several cavities. In addition, there are manufacturing processes in which several permanent molds, each containing a cavity, simultaneously or in immediate time sequence produced several matching moldings and then transported by a conveyor in a flow. The molded parts produced at the same time or in the immediate temporal sequence of several cavities are also referred to as shot during injection molding.

The high speed of operation of current injection molding machines, the regular large number of cavities in a tool as well as the largely unmanned operation has the consequence of manufacturing errors often noticed late, so that a large amount of rejects is produced.

Defects in the moldings are often caused by individual cavities of the tool, for example, problems in the gate area. In order to be able to detect such problems promptly, it is necessary to remove restoring patterns from the current production of the molded parts. In order to completely monitor the quality of the molded parts produced, it is preferable to remove restoring patterns from all the cavities.

According to the state of the art, devices for discharging a molded part from each of the cavities are installed directly between the production machine and the conveyor for the removal of the molded parts produced. If several injection molding machines are operated, such a device must be arranged immediately behind each production machine. The devices have, for example, a flap in a short transfer chute of the

Injection molding machine for conveyor, which is manually operated to eliminate a shot of an injection molding machine. The discharged sample samples are collected in a container and examined for errors in the manufacturing process using methods known per se.

Based on this prior art, the invention is based on the object to propose a method that allows a targeted rejection of restoring patterns and without changes to existing manufacturing machines, especially injection molding machines, are required. In addition, a device for carrying out the method is to be created.

The solution to this task is based on the idea of separating the restitution patterns away from the problem Making machine, in particular the injection molding machine to make in the flow of the moldings. In detail, the object is achieved in a method of the type mentioned above in that in the flow of the moldings at least temporarily Kavitätenkennungen on the

Forms comprehensive images can be made using at least one digital camera, the images are processed in a data processing unit, wherein a control unit connected to the data processing unit depending on the image contained in the image

Cavity detection means for rejecting the molded part shown in the image are activated as a return pattern from the flow.

An advantageous device for carrying out the method results from the features of claim 6.

The invention uses the individual cavity identification transmitted on the surface of each molded part during casting, in particular an individual associated with each cavity

Number. In the flow, the cavity identifications on the molded parts comprehensive pictures are at least temporarily made with the help of a digital camera, the images can be made in the continuous flow molding or at intermittent flow with a stationary mold part. The image signals recorded by each digital camera are evaluated in the data processing unit. A control unit connected to the data processing unit activates the means for rejecting the molded part shown in the image as a return pattern from the delivery flow as a function of the cavity detection contained in the respective image.

The data processing unit preferably cooperates with the control unit such that the control unit At least one molded part with each individual Kavitätenkennung is selected as a restoring pattern from the flow. This ensures that problems in all cavities can be detected promptly by the restoring patterns separated out in a time interval. However, depending on the manufacturing process, it may also be sufficient to separate out restoring patterns from individual cavities, that is to say moldings having selected cavity identifications. The corresponding program for rejection is stored in the data processing unit and processed.

In principle, it is possible to sequentially collect recovery patterns from the flow. In practice, however, it is often sufficient for the rejection to take place at regular time intervals, the time interval for the rejection being to be determined so long that statistically the rejection of a restoring pattern is ensured with each cavity identifier predetermined by the data processing unit. It should be noted that the moldings do not always come in the same order from the injection molding machine in the flow. In that regard, it may take some time, especially when merging the flow rates of several injection molding machines, until a set of return pattern with the of the

Data processing unit predetermined cavity identifiers is compiled.

In the manufacturing processes of matching moldings, especially in the injection molding of plastic parts, moldings are often discharged from the flow and fed to a quality assurance system that inspects using digital cameras surfaces of the molding to determine errors in the label or the material. For this purpose, usually from a first flow of the molded parts away from the injection molding machine, a second Branch flow diverted to the quality assurance system. In this quality assurance system, the inventive method can be implemented particularly advantageous in that the already existing digital cameras at least temporarily customize the cavity identities on the molded parts, which are processed in the data processing unit of the quality assurance system, with the

Data processing unit connected control unit activates the means for rejecting the restoring pattern.

If the molded parts are held by a gripper in the second delivery stream at least during the production of the images, this can at the same time serve as a means for rejecting the return pattern. If the cavity identification on the image produced by the digital camera coincides with the cavity identification prescribed by the data processing unit, the gripper can eject the molded part by opening the gripper and thus separate it from the second delivery flow.

With the method according to the invention, restoring patterns from the production processes of different production machines, in particular injection molding machines, can be discarded if the delivery streams of the cavities arranged remotely are first combined and the production of the images with the help of at least one digital camera and the rejection of the moldings as a restoring pattern in the merged Flow rate. It is of crucial importance that all cavities are assigned individual cavity identifications. Therefore, a cavity of a first production machine may not have an identifier matching a cavity of a second production machine, since otherwise there will be no clear assignment of the Set of return patterns to one of the injection molding machines is possible.

The conveyor is preferably designed as a continuous conveyor. The pictures are made of the continuously moving moldings. However, the apparatus for carrying out the method may also comprise a conveyor with an intermittently operating drive which is stopped for the production of the image. However, the conveyor, for example, a pocket conveyor whose pockets each receive a molded part should, however, be such that slipping of the molded part on the conveyor is reliably prevented when stopping or accelerating the conveyor.

Since the orientation of the molded part on the conveyor is often random in such processes, an all-round detection of the surface of the molded part in the region in which the cavity detection is arranged must be ensured. This is ensured either by a plurality of digital cameras arranged around the molded part or by an optical system, for example a concave mirror optics, which images the cavity detection on the image produced by the camera independently of the position of the molded part on the conveyor.

The invention will be explained in more detail with reference to the figures. Show it:

1 shows a schematic representation of an apparatus for carrying out the method according to the invention,

FIG. 2 shows a permanent mold with six cavities

Production machine for the production of matching molded parts as well FIG. 3 a schematic representation of the integration of the method according to the invention into a quality assurance system,

Figure 4 is an illustration of a

Quality assurance system in which the method according to the invention is carried out,

FIG. 5 detailed representations of various stations of the quality assurance system according to FIG. 4 for carrying out the method according to the invention as well as FIG

FIG. 6 shows an enlarged partial representation of a quality assurance system according to FIG. 4.

An unillustrated conveyor promotes molded parts (1), for example, preforms for the production of beverage bottles or beverage bottles, in a first flow (2) whose conveying direction is symbolized by the arrows, from an injection molding machine, not shown, with a six cavities (3) permanent ( 4) from the injection molding machine to a further processing process or a collection container. Each cavity (3) of the permanent mold (4) is associated with a cavity detection (A-F), which is transferred to the casting of each mold part (1) on its surface, as can be seen in Figure 1.

The specially designed as a continuous conveyor conveyor for the moldings (1) is arranged in the emission of a light source (5). At least one digital camera (7) aligned with its lens (6) on one of the molded parts (1) is connected to a data processing unit (8) for processing the electronic image signals recorded by it. In the direction of the flow (2) is located behind the digital camera (7) a device (9) for the separation of individual moldings (1), which comprises, for example, a gripper or ejector, with the aid of which individual moldings are rejected as restoring patterns (10). The return pattern (10), which is rejected by the device (9) in FIG. 1, has the cavity identifier B.

With the permanent mold (4) are at each stroke of the injection molding machine simultaneously six matching

Molded parts (1) produced, on the surface of each an individual Kavitätenkennung (A-F)) is located. The moldings (1) are pressed by an ejector from the permanent mold (4) of the injection molding machine and fall on a conveyor, such as a conveyor belt, go through a setup station, in which the moldings (1) in the form of beverage bottles, placed, and are in any order in the continuous flow (2) transported away from the injection molding machine.

Preferably, the cavity identifications (A-F) on the molded parts (1) comprising images are produced at regular time intervals of about 5 minutes using the digital camera (7), which are then processed in the data processing unit (8). It will continue to produce images until a set of return patterns is discarded. The control unit (11) which communicates with the data processing unit (8) activates the device (9) for the function of the cavity detection contained in the image

Separation of the molding shown in the image (1) as a return pattern (10) from the flow (2).

If the means for rejecting the molded part shown in the image are activated with a time offset to the production of the image, must be by an object tracking in the Flow arranged behind one another moldings be ensured that the means for rejection time-shifted actually discard the molded part shown in the image. If the flow rate is isolated, the speed of the flow (eg of the conveyor belt) is continuously measured. Furthermore, the position of the molded part is stored in the image recording relative to the conveyor belt. The position of the device (9) for the separation, eg an ejector, is known. It can therefore be determined when the molding is located immediately in front of the ejector. Alternatively, in the case of an occasional delivery flow, it is possible to separate out the shaped parts immediately with sufficiently fast image processing and a high operating speed of the means for separating out the shaped parts.

FIG. 3 shows an alternative possibility for implementing the method according to the invention in a production process of matching molded parts. A production machine (12), in particular a

Injection molding machine, produces with a cycle time of seven seconds each 96 moldings, which corresponds to a production capacity and a first flow rate (13) of about 50,000 molded parts / h. With a per se known unit for discharging (14) is from the first

Flow (13) a second flow (15) branched off, which has about 1,200 molded parts / h. This second flow (15) is fed to a quality assurance system (16). The remaining parts of the first flow (13) are fed from the conveyor, not shown, a storage container (17).

For example, the unit (14) may divert moldings from the first flow (13) every five minutes during the continuous operation of the production machine 96 and feed them to the quality assurance system (16). Alternatively it is it is possible for the unit (14) to branch off a molding every three seconds. In the quality assurance system (16), in both cases the images of cavities (AF) of the branched moldings (1) are continuously recorded by means of a digital camera (7) of the

Quality assurance system (16) are processed, which are processed in the data processing unit of the quality assurance system, wherein the means for rejecting the return pattern (10) are activated by a control unit connected to the data processing unit depending on the cavity identifier contained in the image (A-F). Usually, as long as molded parts are discarded until a molded part with each individual Kavitätenkennung (A-F) is discarded.

Figures 4, 5 and 6 show an embodiment of a quality assurance system (16) for implementing the method described above:

The second flow (15) with molded parts (1) passes via a feeding device, not shown, on an inclined guide rail (18) of the quality assurance system (16). The molded parts (1) accumulate in front of a pocket wheel (19) rotating about an axis. As soon as the pocket wheel (19) rotates, slides in the direction of the flow (15) front

Molded part (1) in one of the empty, evenly over the circumference of the pocket wheel (19) distributed pockets (21). The pocket wheel (19) is further rotated about the axis by means of a rotary drive from pocket (21) to pocket (21), so that, for example, every three seconds a molded part (1) is received by the pocket wheel (19). The moldings (1) are stable in the pockets (21) of the pocket wheel (19).

The pocket wheel (19) is rotated by the rotary drive counterclockwise, so that the molded parts (1) to a station (22) for taking pictures with the aid of digital camera (7) arrive. The station (22) also comprises an inner hook (23), which can be lowered from above, vertically to the surface of the pocket wheel (19) in the molded part (1). The inner hook (23) holds the molding (1) by means of expansion and lifts it slightly out of the pocket (21). Subsequently, the inner gripper (23) by means of a rotary drive (24) performs at least one complete revolution. The digital camera (7) takes several pictures of the neck and thread area (25) of the molded part (1) from the side, for example 36 pictures. The lighting of the molding is also done from the side.

The neck and thread area (25) of the molded parts (1) has the cavity identifications (A-F), so that the recorded images comprise this information. The images are processed in the data processing unit (8), whereby the device (9) controlled by the data processing unit (8) rejects the reset patterns as a function of the cavity identifier (A-F) contained in the image.

Furthermore, the position of the molded part (1) in relation to the camera (7) is known to the data processing unit (8) through the detection of the cavity identifications (AF), so that the molded part, after completion of the recordings, by means of the rotary drive (24) of the inner hook (23) in a particular, the

Data processing unit (8) known rotational position in the pocket wheel (19) can be lowered, so that the molded part (1) for subsequent tests in the quality assurance system (16) is optimally positioned.

The following station (26) for examining the nature of the molded parts (1) comprises a vertically movable with respect to the surface of the pocket wheel (19) probe (27), which from a laterally on the station (26) arranged lighting (28) radiated and passing through the transparent wall of the molding (1) passing light receives. This light is supplied in particular by a fiber to a spectrometer.

In order to define on the surface of the molding (1) a defined area (14), which is used for the investigation of

Constitution is suitable by means of the spectrometer, the prior alignment of the molded part (1) by the station (22) on the basis of the cavity detection (A-F) or another unique identifiable feature is required. Without the prior alignment of the molded part (1) in the station (22) by means of the rotatable inner gripper (23) there would be the risk that the examination of the condition would take place, for example, through a parting seam of the molded part (1) and thereby be falsified. Furthermore, there would be no guarantee that the investigation of the

Texture of the moldings (1) would take place in all parts in a matching area.

In the device for rejection (9) discernible in FIGS. 4 and 6, a suction plate (31), which is arranged on an arm (32), is moved over the upward-pointing opening of the molded part (1). Then, the suction cup (31) is lowered to the mouth of the molding (1) and the air sucked out of the molding (1). By moving the arm (32), the molded part (1) held by the suction cup (31) is moved by the pocket (21) in the pocket wheel (19) via a discharge point (33) in the base plate (34) of the quality assurance system (16) and thrown off there. Below the discharge point (33) there is a distributor (35) which can be seen in detail in FIG. 5 and which comprises two flaps (36, 37) which, depending on the flap position, place the dropped molded part (1) on different chutes (38a, b) and therewith Distribute boxes (39 a, b). The flaps (36, 37) of the distributor (35) of the device (9) are controlled by the data processing unit (8) and the control unit (11) in such a way that after some time a complete Set of moldings (1) with the Kavitätenkennungen (AF) on the chute (38 a) in the associated box (39 a) passes. The remaining chutes and boxes are used for the separation of moldings (1) according to other criteria, which is not the subject of the present invention.

If the method according to the invention, as described above, is integrated into an already existing quality assurance system (16), there are cost advantages. Furthermore, it is advantageous to combine the production streams of several production machines, which can also be set up far from each other. The return patterns are discarded from the combined flow, so that only one device for carrying out the method is required.

A significant advantage of the method according to the invention is that the separation of return patterns (10) in the delivery stream (2, 15) is possible almost anywhere, without requiring modifications to the production machine.

LIST OF REFERENCE NUMBERS

Claims

Claims:

Anspruch [en] A process for separating back patterns from a manufacturing process of matching moldings by means of a plurality of cavities arranged in at least one permanent mold, each of which is assigned an individual cavity identification, which is transferred to the surface of each mold part during molding, wherein the moldings produced in at least one flow be removed, characterized in that in the flow (2,15) of the molded parts (1) at least temporarily the Kavitätenkennungen (AF) on the molded parts (1) comprising images using at least one digital camera (7) are made, the images in a data processing unit (8) are processed, wherein from a to the data processing unit (8) connected to the control unit (AF) means for separating out (9) of the molded part (1) shown in the image as a function of Return pattern (10) from the flow ( 2,15) are activated.

2. The method according to claim 1, characterized in that from the control unit (11) at least one molded part (1) with each individual Kavitätenkennung (A-F) as a restoring pattern (10) from the flow (2,15) is discarded.

3. The method according to claim 1 or 2, characterized in that the separation takes place at regular time intervals.

4. The method according to any one of claims 1 to 3, characterized in that from a first flow (13) of the molded parts (1) of the at least one permanent mold (4) at least temporarily a second flow (15) which is fed to a quality assurance system (16) which at least temporarily produces the cavity identifications (AF) on the mold parts (1) comprising images by means of at least one digital camera (7) in the data processing unit

(8) of the quality assurance system (16) are processed by means of a data processing unit connected to the control unit (11) depending on the cavity identifier contained in the image (A-F) means for the separation (9) of the molding shown in the image

(1) as a return pattern (10) from the second flow

(15) are activated.

5. The method according to any one of claims 1 to 4, characterized in that the conveying streams (2) of mutually distant cavities (3) are merged and the production of images using at least one digital camera (7) and the separation of the moldings ( 1) as a return pattern (10) in the merged flow.

6. Apparatus for carrying out the method according to one of claims 1 to 5, characterized in that

a conveyor for shaped parts (1) is arranged in the emission area of at least one light source (5),

- The device at least one with its lens

(6) on one of the molded parts (1) aligned digital camera (7), which is connected for processing the electronic image signals of the camera (7) with a data processing unit (8), in the direction of the flow (2) behind the digital camera ( 7) or the digital cameras (7) means for sorting (9) of molded parts (1) as a return pattern (10) from the flow (2) are arranged and the data processing unit (8) is connected to a controller (11) for activating the means for rejecting (9) molded parts (1).

7. Apparatus according to claim 6, characterized in that the conveyor is a climbing conveyor.

8. Apparatus according to claim 6 or 7, characterized in that for all-round detection a plurality of digital cameras (7) are arranged around the molded part (1) around.

9. Device according to one of claims 6 to 8, characterized in that the means for rejection (9) comprise a gripper.