GB2247638A

GB2247638A - Providing an aperture using a laser

Info

Publication number: GB2247638A
Application number: GB9018455A
Authority: GB
Inventors: Robert John Godfrey; John Anthony Butler; Mark Anthony Morris
Original assignee: MCLENNON J L Ltd
Current assignee: MCLENNON J L Ltd
Priority date: 1990-08-22
Filing date: 1990-08-22
Publication date: 1992-03-11
Also published as: GB9018455D0

Abstract

A method of providing an aperture in an article (10) using a laser (47) comprises feeding the article (10) into a chamber through an inlet (35) thereof, retaining the article (10) in a selected position within the chamber (25). The laser (47) is operated to direct a beam produced thereby to impinge upon a predetermined part of the article (10) to make the aperture. The article (10) is then caused to move towards and from an outlet (36) of the chamber. <IMAGE>

Description

Title: "Providing an aperture using a laser" Description of Invention This invention relates to a method of providing an aperture in an article using a laser, and to an apparatus for performing the method.

According to a first aspect of the invention we provide a method of providing an aperture in an article using a laser, the method comprising feeding the article into a chamber through an inlet thereof, retaining the article in a selected position within the chamber, operating the laser to direct a laser beam produced thereby to impinge upon a predetermined part of the article to make the aperture, causing the article to move towards and from an outlet of the chamber.

The article may be fed towards the inlet of the chamber along a linear feed means such as a chute, under gravity or preferably with the aid of a propulsion means which may be a second article in which an aperture is to be provided subsequently to the aperture being provided in the first mentioned article.

Thus the article may comprise one of a batch of articles which are fed towards the chamber, and into the chamber severally.

The article may be retained in the selected position by a gripping means provided in the chamber. The article may be positioned in engagement with the gripping means by a positioning means which may conveniently comprise a member movable in the chamber from a first position in which the article can be fed through the inlet into the chamber, to a second position when the member acts both to close the inlet opening into the chamber to prevent any further article entering the chamber, and to move the article into the selected position in which it is in engagement with the gripping means.

The movable member may be movable by means of a pneumatically actuated piston, although the movable member may otherwise be moved within the chamber.

The gripping means may comprise a loop of resilient material received in a corresponding groove in a side wall of the chamber so as to project inwardly of the chamber from the groove thus resiliently to grip the article.

In one embodiment, the article may be circular, in which case the loop may comprise an 0 ring.

The predetermined part of the article on which the laser beam impinges may, when the article is in the selected position, correspond with a focus of the laser beam thus to enable a laser beam of minimum power to be used.

Where the article is circular, preferably the predetermined part of the article is the centre of the circle in which case, the article does not require correctly orientating at the selected position.

However, when the predetermined part is not the centre of a circular article, the method may include orientating the article to ensure that the predetermined part is correctly aligned with the laser beam which is directed to impinge upon the article.

To cause the article to move towards the outlet, the gripping means where provided, may be made to release its grip. Conveniently this may be achieved by a further operation of the movable member to urge the article past the gripping means in the chamber, where the gripping means resiliently grips the article. Where the gripping means otherwise grips the article, the gripping means may be actuated to release the article and permit it to move towards the outlet.

Preferably the method includes, subsequently to making the aperture, moving the movable member from its second position to its first position thereby permitting a further article to be fed through the inlet into the chamber, and then moving the movable member back to its second position when the movement of the movable member will be transmitted through the further article to the first mentioned article to cause the first mentioned article to be moved from the selected position towards the outlet of the chamber, the movement of the movable member also positioning the further article in the selected position within the chamber so that an aperture may be provided therein by the laser.

The method may include urging the article through the outlet of the chamber, for example, using a stream of air.

The invention is particularly but not exclusively useful for producing small through apertures through articles. By "small" we mean apertures having a maximum dimension of less than 1 mm, preferably less than .5 mm, and yet more preferably of .3 mm or less.

It will be appreciated that where the article is made of a plastic material, it is very difficult accurately to mould an aperture of such small dimension therein, and that methods which involve the provision of an aperture subsequent to moulding using for example a hot wire, are slow and unreliable. The method of the present invention is particularly suitable for mass production purposes because the articles of a batch of articles can be fed towards and into the chamber, severally positioned accurately at the selected position, and the aperture accurately provided by operation of the laser, whilst removal of the articles from the chamber can be achieved very speedily.

Furthermore, because movement of each article is arrested when in the selected position, when the laser is operated, an accurately sized and positioned aperture can be provided.

According to a second aspect of the invention we provide a method of providing an aperture in each article of a batch of generally similar articles comprising performing the method of the first aspect of the invention on each of the articles of the batch in turn.

Each article but the last article, may be urged by the next article towards the inlet and fed into the chamber and may be moved from the selected position by the positioning means acting through the next article.

The laser may repeatedly be operated to produce an aperture in each of the articles. Preferably a shutter or the like is opened and closed so that the laser beam is not directed onto an article whilst any article is being moved into the selected position or is moving towards the outlet of the chamber, but only when a single article is in the chamber in the selected position.

According to a third aspect of the invention we provide an apparatus for performing the method of the first and/or second aspects of the invention, comprising, means to feed an article through an inlet into a chamber, means to retain the article within the chamber in a selected position, a laser to produce a laser beam and means to direct the laser beam to impinge upon a predetermined part of the article, means to cause the article to move towards an outlet from the chamber from where the article may be removed from the chamber.

The feed means may comprise a linear means such as a chute along which the article moves towards the chamber, and the inlet of the chamber may comprise an opening through the chamber wall which preferably is just big enough to permit the article to pass therethrough when in a predetermined orientation. For example, where the article is generally flat, the opening into the chamber comprising the inlet may be in the form of a slot positioned at the end of the chute or other linear feed means where provided.

The means to retain the article in the selected position may comprise a resilient loop of a configuration generally corresponding generally to the outer periphery of the article, the loop being received in, and projecting inwardly of the chamber, from a groove in the chamber wall whereby the article can be resiliently gripped by the loop.

Preferably the loop is positioned below the inlet, the article falling under gravity towards the selected position. Positioning of the article is preferably achieved by a movable member which has a measured stroke, so that the article is moved accurately to the selected position.

The movable member may move downwardly from a first position in the chamber where the article can pass through the inlet thereof into the chamber, downwardly to a second position to position the article in the selected position.

As the movable member moves from the first position, preferably the movable member blocks the inlet to the chamber to prevent any further article entering the chamber.

Preferably the movable member is configured to correspond to the shape of the article so that the article does not become misorientated during positioning.

The chamber may comprise, beneath the loop and groove, an end wall adjacent which a transversely extending outlet may be provided. The outlet may comprise an opening through the chamber wall and in an opposite position of the chamber wall, another, preferably smaller, opening may be provided. Means may be provided to provide an airstream into the chamber from the further opening opposite the outlet opening, which airstream in use, helps remove an article from the chamber through the outlet. The air inlet is preferably smaller than the outlet for the article, so that a venturi effect is produced by the streaming air.

The end wall of the chamber may have a yet further opening provided therein, and the laser may be located such that the laser beam produced thereby passes upwardly through the yet further opening in the end wall to impinge upon the predetermined part of the article, located above in the selected position.

The invention will now be described with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of an article in which an aperture has been made by a method in accordance with the invention, FIGURE la is a cross sectional view taken on the lines 1-1 of Figure 1, FIGURE 2 is a partially exploded perspective view of an apparatus for use in performing the method of the invention, FIGURE 3a is a cross sectional view taken on the lines 3-3 of Figure 2, but showing the apparatus in an assembled condition with a movable member thereof in a first position, FIGURE 3b is a view similar to that of Figure 3a, but showing the movable member in a second position.

Referring to the drawings, an article in which an aperture is to be provided comprises a component 10 of an insert as described in our co-pending patent application No. 9004731.7. The component 10 comprises a disc 11 having an upstanding circumferential lip 12, and a central turret 13, all integrally moulded in a plastics material.

An aperture 15 is provided at the centre of the component 10, the aperture 15 comprising a through passage through the turret 13.

An apparatus 20 to provide the aperture 15 in the component 10 comprises a base 21 on which a linear feed means comprising a chute 22 is secured, the chute 22 comprising a channel 23, the width W of which is just slightly greater than the diameter d of the component 10.

In use, the chute 22 is inclined downwardly slightly so that the component 10 can move towards a chamber 25 at least partially under gravity.

The apparatus 20 is however adapted to mass production purposes and so a component 10 such as indicated in dotted lines in figure 2, is urged along the chute 22 by further downstream components 10 on the chute 22. The chute 22 may be lubricated as necessary and/or if desired, a stream of air or other gas may be directed along the channel 23 in the direction of arrow A to facilitate feeding the components 10 severally towards the chamber 25.

Also mounted on the base 21, is a first chamber containing part 26 which is secured to the base 21 by fasteners 27 and locating pegs 28 which are received in respective holes 29 and 30 of the base 21. The part 26 contains a hollow 31 which together with a hollow 32 provided in a second chamber containing part 33, provides the chamber 25 towards and into which the components 10 are severally fed.

The second chamber containing part 33 is secured to the first chamber part by fasteners 34 and locating pegs 34a which are received in respective apertures 34b,34c.

The first chamber containing part 26 has a cut out portion 35 which is aligned with the chute 22 to provide a slot through which the components 10 can severally be fed from the chute 22 into the chamber 15.

The first chamber containing part 26 has a further cut-out portion 36 adjacent the base 21, i.e. beneath the cut-out portion 35, to enable components 10 to pass out of the chamber 25, the cut-out portion 36 being arranged oppositely to an opening 37 which is provided for a purpose hereinafter explained.

Part of the base 21 provides a lower end wall 38 of the chamber 25, and there is provided a further opening 39 in the end wall 38 for a purpose hereinafter explained.

The second chamber containing part 33 contains a piston 40 which is adapted to reciprocate in a cylinder 41.

The piston 40 carries a positioning member 42 which is movable from a first position as seen in figure 3a when fluid e.g. compressed air, is introduced into the cylinder 41 via a first inlet 43 above the piston 40, downwardly to a second position as seen in figure 3b.

The movable positioning member 32 can be moved backwards to the first position by introducing fluid into the cylinder 41 via a further inlet 44 positioned below the piston 40.

Within the chamber 15 there is provided a circumferential groove 45 in which is received an 0 ring 46. Mounted on the base 21 beneath the chamber 15 is a laser assembly 47 (shown illustratively only in figures 3a and 3#b) which laser 47 assembly is adapted to provide a laser beam and direct it through the opening 39 in the end wall 38 into the chamber 25.

Operation of the method and apparatus will now be described.

A plurality of components similar to component 10 are fed along the chute 22 either under the influence of gravity alone, or preferably with the aid of an urging means such as a stream of air. Each component 10 will therefore be pushed by the next component 10 on the chute 22, towards the chamber 25.

It will be appreciated that when the movable positioning member 42 is in the first position shown in figure 3a, a component 10 can enter the chamber 25 through the slot provided by the cut-out portion 35 in the first chamber containing part 26. The component 10 will fall a short way under gravity downwardly until its movement is arrested by the 0 ring 46 received in the groove 45. During the falling movement of the component 10, the positioning member 42 is moved downwardly by introducing air into the cylinder 41 through the inlet 43. Thus no further component can enter the chamber 25 because the movable member 42 will block the slot provided by the cut-out portion 35.

The downwards movement of the member 42 is a measured stroke and is arranged to move the component downwardly in the chamber 25 to a selected position where the 0 ring 46 will be approximately half way up the upstanding wall 12 of the component 10. Thus the component 10 will be retained in the selected position within the chamber 25. With the movement of the component 10 arrested, the laser 46 will produce a laser beam and direct it through the opening 39 in the end wall 38 of the chamber 25, and the laser beam will impinge upon the component 10.

Because the component 10 is round and the opening 39 is provided along a centre axis of the chamber 25, it will be appreciated that the laser beam will be directed to the centre of the component 10 to form the aperture 15 through the turret 13 as illustrated in figure la.

The laser beam is then either deflected or switched off so as no longer to pass through the opening 39 to impinge upon the component 10. The movable member 42 is moved back from the second position of figure 3b to the figure 3a position by introducing air into the inlet 44 to the cylinder 41 and allowing air to escape from the cylinder 41 via the first inlet (now outlet) 43.

When the member 42 reaches its figure 3a first position, it will be appreciated that the next or second component 10 of the plurality of components on the chute 22 will then be permitted to enter the chamber 25 through the slot afforded by the cut-out portion 35.

This second component will move downwardly in the chamber, and the movable member 42 will be moved downwardly again to block the entrance of any further components 10 into the chamber 75, until the second component engages the first component which is still at the selected position held by 0 ring 46. The movement of the movable member 42 will thus be transmitted through the second component to the first component to urge the first component past the 0 ring 46 to fall to the lower part of the chamber 25. At the same time, a stream of air is introduced into the chamber 25 through the opening 37.

Because the cut-out portion 36 is larger than the opening 37, a venturi effect is produced, and the first component will move downwardly towards the outlet afforded by the cut-out portion 36, and be removed from the chamber 25. It will be appreciated that the second component will then occupy the selected position held by the 0 ring 36, and the laser 46 can be operated again to direct a laser beam through the opening 39 onto the centre of the second component to provide an aperture 15 in the turret 13 thereof.

It will be appreciated that the method described can be performed repeatedly to provide an aperture in each of a plurality of components.

Various modifications are possible without departing from the scope of the invention. For example, the retaining means within the chamber to hold a component in the selected position need not comprise a# O -~ns , but any other retaining means could be provided to maintain a component in that position. For example, where a component is not circular as is the component 10 described, a loop of a non-annular configuration preferably having a configuration corresponding to the periphery of the component to be retained, may be provided in a groove in the chamber 25. Alternatively, the retaining means may comprise one or more movable parts which is movable to a position to retain the component in a selected position within the chamber.

Where the component 10 is not circular, means to orientate the component within the chamber may need to be provided to ensure that the aperture is provided by the laser 47 in a selected part of the component.

The movable member 42 need not be movable by means of a piston in a compressed air cylinder as described, but any other means for reciprocating a movable member 42 within the chamber could be provided. In the present example, the movable member 42 is generally circular and is arranged to engage with the component 10 within the boundary of the upstanding wall 12 so that as the movable member 42 moves downwardly, misorientation of the component 10 is unlikely to occur. Other arrangements for components of different configurations are no doubt possible.

Although a linear feed means is preferred, such as is provided by the chute 22, any other suitable feed means may be provided to enable components to be fed severally into a chamber where the components are retained in a selected position whilst an aperture is made therein by a laser beam.

Rather than actuating the laser 46 repeatedly, it is preferred for some obscuring means to be provided which can be moved to permit a laser beam to pass through the aperture 3 in the end wall 38 of the chamber 25 only when a component 10 is in the selected position.

Because the components 10 are each held in a selected position, the invention enables a laser beam which produces a diverging beam to be provided, provided that the selected position is at a plane of focus of the laser beam.

Thus a laser of minimum power only is required.

It is envisaged that a single laser may be used to provide a laser beam to each of a plurality of chambers of a bank of apparatus which are provided for making apertures in components. Thus the laser 47 need not be mounted directly on the base 21 but could be mounted separately therefrom, with some means being provided to direct the laser beam through the opening 39 when required.

It has been found in trials that using the apparatus described an aperture may be made in up to 250 components per minute because location of the components at the selected position is fast and simple, and there is no need to focus the laser because such focus can be prearranged to be at a plane comprising the selected position with the chamber.

Although the invention has been described in relation to making an aperture in a plastic component, it will be appreciated that such an arrangement can be provided to make an aperture in components of other configuration and other materials as desired.

The features disclosed in the foregoing description or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A method of providing an aperture in an article using a laser, the method comprising feeding the article into a chamber through an inlet thereof, retaining the article in a selected position within the chamber, operating the laser to direct a laser beam produced thereby to impinge upon a predetermined part of the article to make the aperture, causing the article to move towards and from an outlet of the chamber.

2. A method according to claim 1 wherein the article is fed towards the inlet of the chamber along a linear feed means under gravity or with the aid of a propulsion means.

3. A method according to claim 2 wherein the propulsion means is a second article in which an aperture is to be provided subsequently to the aperture being provided in the first mentioned article.

4. A method according to any one of claims 1 to 3 wherein the article is retained in the selected position by a gripping means provided in the chamber.

5. A method according to claim 4 wherein the article is positioned in engagement with the gripping means by a positioning means comprising a member movable in the chamber from a first position in which the article can be fed through the inlet into the chamber, to a second position when the member acts both to close the inlet opening into the chamber to prevent any further article entering the chamber, and to move the article into the selected position in which it is in engagement with the gripping means.

6. A method according to claim 5 wherein the movable member is movable by means of a pneumatically actuated piston.

7. A method according to any one of claims 4 to 6 wherein the gripping means comprises a loop of resilient material received in a corresponding groove in a side wall of the chamber so as to project inwardly of the chamber from the groove thus resiliently to grip the article.

8. A method according to claim 7 wherein the article is circular and the loop comprises an O ring.

9. A method according to any one of the preceding claims wherein the predetermined part of the article on which the laser beam impinges when the article is in the selected position, corresponds with a focus of the laser beam.

10. A method according to any one of the preceding claims wherein the article is circular, and the predetermined part of the article on which the laser beam impinges, is the centre of the circle.

11. A method according to any one of claims 1 to 9 wherein the method includes orientating the article to ensure that the predetermined part is correctly aligned with the laser beam which is directed to impinge upon the article.

12. A method according to any one of claims 4 to 11 where appendant to claim 4 wherein to cause the article to move towards the outlet, the gripping means is made to release its grip.

13. A method according to claim 12 where appendant to claim 5 wherein the gripping means is made to release its grip by a further operation of the movable member to urge the article past the gripping means in the chamber.

14. A method according to any one of claims 5 to 13 where appendant to claim 5 wherein subsequently to making the aperture, the movable member is moved from its second position to its first position thereby permitting a further article to be fed through the inlet into the chamber, and then the movable member is moved back to its second position when the movement of the movable member will be transmitted through the further article to the first mentioned article to cause the first mentioned article to be moved from the selected position towards the outlet of the chamber, the movement of the movable member also positioning the further article in the selected position within the chamber so that an aperture may be provided therein by the laser.

15. A method according to any one of the preceding claims which includes urging the article through the outlet of the chamber using a stream of air.

16. A method according to any one of claims 1 to 15 in which a small through aperture is provided in an article.

17. A method according to claim 16 wherein the aperture has a maximum dimension of less than 1 mm.

18. A method according to claim 17 wherein the aperture has a maximum dimension of less than 0.5 mm.

19. A method according to claim 18 wherein the aperture has a maximum dimension of less than 0.3 mm.

20. A method of providing an aperture in an article substantially as hereinbefore described with reference to the accompanying drawings.

21. A method of providing an aperture in each article of a batch of generally similar articles comprising performing the method of any one of claims 1 to 20 on each of the articles of the batch in turn.

22. A method according to claim 21 where appendant to claim 5 wherein each article but the last article, is urged by the next article towards the inlet and is fed into the chamber and is moved from the selected position by the positioning means acting through the next article.

23. A method according to claim 21 or claim 22 wherein the laser is repeatedly operated to produce an aperture in each of the articles.

24. A method according to any one of claims 21 to 23 wherein a shutter or the like is opened and closed so that the laser beam is not directed onto an article whilst any article is being moved int- the selected position or is moving towards the outlet of the chamber, but only when a single article is in the chamber in the selected position.

25. A method of providing an aperture in each article of a batch substantially as hereinbefore described with reference to the accompanying drawings.

26. An apparatus for performing the method of any one of claims 1 to 20, or 21 to 25, comprising, means to feed an article through an inlet into a chamber, means to retain the article within the chamber in a selected position, a laser to produce a laser beam and means to direct the laser beam to impinge upon a predetermined part of the article, means to cause the article to move towards an outlet from the chamber from where the article may be removed from the chamber.

27. An apparatus according to claim 26 wherein the feed means comprises a linear means along which the article moves towards the chamber, and the inlet of the chamber comprises an opening through the chamber wall which is just big enough to permit the article to pass therethrough when in a predetermined orientation.

28. An apparatus according to claim 26 or claim 27 wherein the means to retain the article in the selected position comprises a resilient loop of a configuration corresponding generally to the outer periphery of the article, the loop being received in, and projecting inwardly of the chamber, from a groove in the chamber wall whereby the article can be resiliently gripped by the loop.

29. An apparatus according to claim 28 wherein the loop is positioned below the inlet, the article falling under gravity towards the selected position.

30. An apparatus according to any one of claims 26 to 29 wherein the article is positioned in the selected position by a movable member which has a measured stroke.

31. An apparatus according to claim 30 wherein the movable member moves downwardly from a first position in the chamber where the article can pass through the inlet thereof into the chamber, to a second position to position the article in the selected position, the movable member when moving from the first position, blocking the inlet to the chamber to prevent any further article entering the chamber.

32. An apparatus according to claim 30 or claim 31 wherein the movable member is configured to correspond to the shape of the article so that the article does not become misorientated during positioning.

33. An apparatus according to any one of claims 28 to 32 where appendant to claim 28 wherein the chamber comprises, beneath the loop and groove, an end wall adjacent which a transversely extending outlet is provided, the outlet comprising an opening through the chamber wall and in an opposite position of the chamber wall, another, preferably smaller, opening provided.

34. An apparatus according to claim 33 wherein means are provided to provide an airstream into the chamber from the further opening opposite the outlet opening, which airstream in use, helps remove an article from the chamber through the outlet.

35. An apparatus arrnr%in9 to claim 33 or claim 34 wherein the end wall of the chamber has a yet further opening provided therein, and the laser is located such that the laser beam produced thereby passes upwardly through the yet further opening in the end wall to impinge upon the predetermined part of the article, located above in the selected position.

36. An apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

37. Any novel feature or novel combination of features herein disclosed and/or shown in the accompanying drawings.