JP7640221B2 - Laser engraving device and laser engraving method - Google Patents

Description

The present invention relates to a laser marking device and a laser marking method for laser marking coil material fed to a press machine that forms a portion of a can.

By adding information or a pattern to a part of a can, it is possible to enhance the decorativeness of the can, provide information about the individual product, or advertise the individual product. The opening tab on the can lid is a part that is particularly noticeable when a person holding the can opens it, and in the case of a stay-on tab type, it does not separate from the main body of the can lid even after opening, so by adding information or a pattern to that part, it is possible to effectively enhance the decorativeness of the can, or provide information about the individual product.

To add information or pictures to cans, laser engraving (laser marking) is used, in which a laser beam is applied to the coating applied to the surface of the can or directly to the surface of the can to engrave the information. By using laser engraving for the engraving on the tab mentioned above, highly precise engraving can be performed in a relatively small space. A device (laser engraving device) that performs laser engraving on the coil material that forms part of the can has a laser head between a roll of coil material in which a strip-shaped plate material is wound into a roll and a press machine to which the coil material pulled out from the roll is supplied, and laser engraves a predetermined position on the coil material supplied to the press machine before it is formed by the press machine (see Patent Document 1 below).

Special Publication No. 2015-531684

Such laser marking devices are required to perform variable marking, which marks different content for each molding object. To perform variable marking, it is necessary to communicate marking data for each molding object and switch the operating program of the laser head. In this case, it takes time to switch the marking data, and the time per press stroke to send the coil material to the press is limited by the total time taken for the laser head to actually mark the content of one marking data and the time required to switch the marking data for each molding object. This limitation has been an obstacle to molding objects with markings with high productivity.

The present invention aims to address these problems. In other words, the objective of the present invention is to enable highly productive molding of objects with markings when applying variable markings for each object to be molded on coil material supplied to a press machine that molds a portion of a can.

In order to solve such problems, the present invention has the following configuration.
An apparatus for laser engraving a coil material fed to a press machine for forming a portion of a can, the apparatus comprising: a feed mechanism for feeding the coil material at a set speed; a laser head for irradiating the coil material fed at the set speed with laser light to continuously engrave engraving data for a plurality of molding objects at predetermined positions on the coil material for each molding object; and a data communication unit for switching the engraving data of the laser head , the data communication unit collectively switching the engraving data for a plurality of objects to be engraved on the plurality of molding objects, and keeping the communication time such that the combined time of a single communication required to collectively switch the engraving data and the time to continuously engrave each of the plurality of molding objects is shorter than the time required for multiple strokes of the press machine, the number of times being the same as the number of the plurality of molding objects.

A method for laser engraving coil material supplied to a press machine which forms part of a can, the method comprising: a laser engraving step in which a laser head irradiates laser light onto the coil material which is fed to the press machine at a set speed, and continuously engraves engraving data for a plurality of molding objects at predetermined positions on the coil material for each molding object ; and a data communication step in which the engraving data of the laser head is switched collectively , the plurality of engraving data to be engraved on the plurality of molding objects being switched collectively, the data communication step being characterized in that the combined time required for one communication cycle to collectively switch the engraving data and the time required for continuously engraving each of the plurality of molding objects is kept to be shorter than the time required for multiple strokes of the press machine which are the same number of times as the number of the plurality of molding objects.

The laser marking device of the present invention, which has these characteristics, can switch between multiple markings for each molding object at once, so even when performing variable marking for each molding object, the time per press stroke can be set to a short time, making it possible to mold the molded object with markings with high productivity.

FIG. 1 is an explanatory diagram showing a schematic configuration of a system for forming a can end with a tab. FIG. 2 is an explanatory diagram showing the configuration of a laser marking device. 1A and 1B are explanatory diagrams for explaining engraving data switching methods ((a) individual communication method and (b) collective communication method). FIG. 1 is an explanatory diagram showing an example of a laser engraving method. FIG. 5 is an explanatory diagram showing movement of the marking position in FIG. 4 . 11A and 11B are explanatory diagrams showing another example of a laser engraving method and an operation chart thereof;

Below, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different figures indicate parts with the same function, and duplicated explanations in each figure will be omitted as appropriate. In the following description, the tab of a can lid will be used as an example of the object to be molded, but the present invention is not limited to this, and can be applied to parts of a can, such as the can lid itself, the can body, and the metal cap, which are molded from coil material.

First, in FIG. 1, the schematic configuration of a system for forming can lids with tabs is described. In this example, a press (conversion press) 1 is used to form the tabs, process the lids, and attach the lids to the tabs. The coil material T from which the tabs are formed is a strip of aluminum sheet material, which is pulled out from a roll R wound in a roll shape and fed to the press 1 at a set speed. In the press 1, the tabs are formed on the coil material, and a can lid panel P fed on a separate conveyor 2 is processed, and a can lid product W with the formed tab attached to the processed can lid is sent out from the exit of the press 1.

In the illustrated example, the press 1 is used for conversion pressing, but the present invention is not limited to this. The press 1 may be used to form only the tabs, and another press may be used to form the can lids and join the tabs formed by the press 1 (which are not separated from the coil material).

The laser engraving device 10 that engraves the tabs is placed on the coil material T that is pulled out from the roll R and supplied to the press machine 1. The laser engraving device 10 performs laser engraving on the coil material T before the tabs are formed at a predetermined position that corresponds to the stroke of the press machine 1.

As shown in FIG. 2, the laser marking device 10 includes a feed mechanism 11 (feed roll 11A and tension roll 11B) that feeds the coil material T in the direction of the arrow at a set speed, a laser head 12 (first laser head L1, second laser head L2, and third laser head L3) that irradiates the coil material T fed at the set speed with laser light to mark each tab to be formed, a control unit 13 that controls the laser head 12, and a data communication unit 14 that switches the marking data for the laser head 12.

In the illustrated example, the laser marking device 10 has a base 10A, on which a feed mechanism 11 or a laser irradiation unit 15 equipped with a laser head 12 is provided. The control unit 13 and data communication unit 14 are provided on a control panel (not shown) or the like that is provided on the base 10A.

The laser marking device 10 is equipped with a speed sensor 16 that measures the feed speed of the coil material T. The speed sensor 16 can be a laser Doppler velocimeter that measures the feed speed of the coil material T in a non-contact manner by irradiating the coil material T with laser light. The output of the speed sensor 16 is sent to the control unit 13, and the feed amount (distance) is calculated from the measured feed speed. The control unit 13 controls the marking timing of the laser head 12 according to the output of the speed sensor 16 (feed amount of the coil material T) so that marking is performed at a predetermined position on the coil material T.

The laser head 12 performs engraving for each individual tab using engraving data that is switched by the data communication unit 14. In the illustrated example, multiple laser heads 12 (three laser heads L1, L2, and L3) are provided, and the data communication unit 14 switches the engraving data for each laser head 12 individually.

The data communication unit 14 of the laser marking device 10 switches the marking data of the laser head 12 using a collective communication method as shown in Fig. 3(b) rather than an individual communication method as shown in Fig. 3(a). In the case of the individual communication method shown in Fig. 3(a), the time ts1 between press-molding strokes must be longer than the combined time (tc1+tw1) of the communication time tc1 required to switch the marking data required to perform the next marking (e.g., "marking 2") and the time tw1 required to actually perform one marking (i.e., tc1+tw1<ts1). Therefore, there is a limit to how short the time ts1 between strokes can be, and it is not possible to mold a tab with a marking with high productivity.

In contrast, when the batch communication method shown in Figure 3(b) is used, multiple pieces of engraving data (six pieces in the illustrated example) can be switched in one communication time tc2, so the combined time (tc2+tw2) of one communication time tc2 and the time tw2 required to perform multiple engravings (stamp 1 to stamp 6) in succession needs to fit within the time required for multiple strokes (stroke 1 to stroke 6), and the time between strokes (ts2) can be set short. This makes it possible to mold engraved tabs with high productivity.

The multiple engraving data communicated using the combined communication method can contain different engraving contents to correspond to each tab. In this case, if the multiple engraving contents include complex engraving that requires a relatively long engraving time, by combining it with engraving contents that require a short engraving time, it becomes possible to include the complex engraving content without lengthening the stroke time.

Figure 4 shows a laser marking method for forming a tab with markings with high productivity using three laser heads 12 (L1, L2, L3). In this example, the marking positions (F1, F2, F3) assigned to each of the multiple laser heads 12 (L1, L2, L3) are sequentially divided along the feed direction of the coil material T. In the illustrated example, a position where multiple marks (six marks) are made in succession is considered as one section, and the section (F1) assigned to laser head L1, the section (F2) assigned to laser head L2, and the section (F3) assigned to laser head L3 are sequentially lined up along the feed direction of the coil material T. That is, on the opposite side of the feed direction of the coil material T, the section F2 is set next to the section F1, and the section F3 is set next to the section F2.

To set the marking positions on the coil material T in this way, multiple laser heads 12 (L1, L2, L3) are arranged along the longitudinal direction of the coil material T, and the marking areas E1, E2, E3 of each laser head L1, L2, L3 are set in a fixed state along the longitudinal direction of the coil material T. The marking area here refers to the range that can be marked with one laser head.

Here, each laser head L1, L2, L3 switches multiple pieces (six pieces) of engraving data at once, and when the section (F1, F2, F3) of the engraving position that it is responsible for reaches a predetermined position in its own engraving area (E1, E2, E3), it performs multiple (six) engravings in succession at the predetermined position within that section.

Explaining the operation of laser head L1 individually, the coil material T is fed in the direction of the arrow in the figure, section F1 enters marking area E1, and immediately after multiple marks are made in succession by laser head L1, section F2 handled by laser head L2 and section F3 handled by laser head L3 enter marking area E1 in sequence (sections F2 and F3 have already been marked in the previous stage). The operation of laser heads L2 and L3 is similar.

Figure 5 shows the movement of the marking position in the example shown in Figure 4. The movement distance of the coil material T depends on the press stroke, and the movement distance of the coil material T in one stroke is set to S1 in the example shown. As shown, the number of strokes until one marking position section (F1) enters and exits one marking area (E1) is six strokes, and this number of strokes and the number of marking data within one marking position section (F1) are set to be the same.

For one laser head 12, while the section F1 of the marking position that it is responsible for passes through the marking area E1 of its own laser head, it engraves the marking data for multiple pieces (six pieces) to be engraved in each section, and switches the marking data before the section of the next marking position that it is responsible for enters the marking area of its own laser head.

With this marking method, multiple laser heads are arranged along the feed direction of the coil material, and the marking positions assigned to each laser head on the coil material T are divided sequentially along the feed direction of the coil material T, making it possible to smoothly perform variable marking for each tab even if the press stroke time is set short.

Figure 6 shows another marking method in which three laser heads 12 (L1, L2, L3) are used to form tabs with markings with high productivity. In this example, multiple laser heads 12 (L1, L2, L3) are arranged for each row of tabs to be formed on the coil material T, and the marking positions assigned to each laser head are divided for each row of tabs to be formed. Specifically, the marking area E1 of laser head L1, the marking area E2 of laser head L2, and the marking area E3 of laser head L3 are aligned in parallel with the three rows of tabs to be formed, respectively.

According to this, in order for each laser head (L1, L2, L3) to continuously engrave multiple pieces of engraving data (for example, six pieces) at a predetermined position, it is necessary to fit the time tw for multiple engravings (stamp 1 to stamp 6) and the communication time tc for switching multiple pieces of engraving data for the next engraving all at once within the time for multiple strokes (six strokes), as shown in the operation chart in Figure 6.

This means that one laser head is assigned to each row of tabs being molded, so the marking position for each row can be corrected for each laser head. It also makes it easier to identify the laser head that needs to be corrected if an engraving error occurs, providing advantages in terms of control and management.

As described above, the tab marking device and method according to the embodiment of the present invention can smoothly mark variable data on coil material even when the time between strokes of the tab forming press machine is shortened to increase productivity. This makes it possible to mark coil material with various patterns and information while changing them at any time without reducing productivity.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention includes design changes and the like that do not deviate from the gist of the present invention. In addition, the above-mentioned embodiments can be combined by reusing each other's technologies, as long as there are no particular contradictions or problems in the purpose, configuration, etc.

1: Press machine, 2: Conveyor,
10: laser engraving device, 10A: base, 11: feed mechanism,
12 (L1, L2, L3): Laser head,
13: control unit, 14: data communication unit, 15: laser irradiation unit,
16: Speed sensor, T: Coil material, R: Roll

Claims (8)

An apparatus for laser marking a coil material fed to a press machine for forming a part of a can, comprising:
A feed mechanism that feeds the coil material at a set speed;
a laser head that irradiates a laser beam onto the coil material fed at a set speed, and continuously marks marking data for a plurality of molding objects at predetermined positions on the coil material for each molding object;
A data communication unit for switching the marking data of the laser head,
The data communication unit collectively switches marking data for a plurality of pieces to be marked on the plurality of molding objects , and limits the communication time for one communication so that the total time required for collectively switching the marking data and the time for continuously marking each of the plurality of molding objects is shorter than the time required for multiple strokes of the press machine, the number of which is the same as the number of the plurality of molding objects.
A laser engraving device characterized by:

2. The laser marking device according to claim 1, wherein the plurality of pieces of marking data include different marking contents.
3. The laser marking device according to claim 1, further comprising a plurality of said laser heads, said data communication section switching a plurality of pieces of marking data for each of said plurality of laser heads.
4. The laser marking device according to claim 3, wherein the marking positions assigned to each of the multiple laser heads are divided sequentially along the feed direction of the coil material, and for each laser head, marking data for multiple pieces to be marked in each division while the division of the marking position assigned to that laser head passes through the marking area of that laser head, and the marking data is switched before the division of the next marking position assigned to that laser head enters the marking area of that laser head.
5. The laser marking device according to claim 4, wherein a plurality of said laser heads are arranged along the longitudinal direction of said coil material.
4. The laser marking device according to claim 3, wherein the marking positions assigned to each of the plurality of laser heads are divided for each row of forming objects to be formed on the coil material.
7. The laser marking device according to claim 1, wherein the object to be molded is a tab for a can lid.
A method for laser engraving a coil material supplied to a press machine for forming a part of a can, comprising the steps of:
a laser engraving process in which a laser head irradiates a laser beam onto the coil material fed to the press at a set speed, and engraves engraving data for a plurality of molding objects in succession at predetermined positions on the coil material for each molding object;
A data communication step for switching the marking data of the laser head,
In the data communication step , a plurality of marking data to be marked on the plurality of molding objects are collectively switched,
The time required for one communication to switch the marking data collectively and the time required for consecutively marking each of the plurality of molding objects is set so as to be shorter than the time required for multiple strokes of the press machine, the number of which is the same as the number of the plurality of molding objects.
A laser engraving method characterized by:

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