WO2019077368A1

WO2019077368A1 - Improvements relating to masking

Info

Publication number: WO2019077368A1
Application number: PCT/GB2018/053036
Authority: WO
Inventors: Stephen James DYMOND; Ze Feng ZHOU; Hai Ming LV; Andrew Douglas Pearson Green; Ciaran Joseph WILSON
Original assignee: P2i Ltd
Current assignee: P2i Ltd
Priority date: 2017-10-19
Filing date: 2018-10-19
Publication date: 2019-04-25
Anticipated expiration: 2020-04-19
Also published as: TW201928092A; CN209778978U

Abstract

La présente invention concerne une languette facilitant le retrait d'un matériau de masquage appliqué sur un substrat, la languette comprenant: un pied sur lequel la languette peut reposer; et une patte s'étendant transversalement à partir du pied. L'invention concerne également un procédé de masquage d'un substrat, le procédé comprenant: l'application d'un matériau de masquage et d'une languette sur le substrat, le matériau de masquage recouvrant un pied de la languette et une patte de la languette faisant saillie au-delà du matériau de masquage, ainsi qu'un appareil associé.The present invention relates to a tongue facilitating the removal of a masking material applied to a substrate, the tongue comprising: a foot on which the tongue can rest; and a tab extending transversely from the foot. The invention also relates to a method of masking a substrate, the method comprising: applying a masking material and a tongue to the substrate, the masking material covering a foot of the tongue and a tab of the tongue protruding beyond the masking material, as well as an associated apparatus.

Description

IMPROVEMENTS RELATING TO MASKING

TECHNICAL FIELD

This invention relates to the masking of substrates. In particular, though not exclusively, it relates to methods and apparatus for masking and/or de-masking substrates, to masked substrates, and to tabs of use in masking.

BACKGROUND

When surface modifying an item, e.g. by applying a coating to an item by vapour deposition, there is often a need to mask the item such that part of the item's surface is not modified. Masking may be of importance, for example, where part of the item would lose its desired functionality or aesthetic were a coating to be applied to it.

A technical field in which there are specific concerns around masking is that of coating electronic devices or components using a vapour deposition process. Whilst applying coatings to such devices or components can bring great benefits, such as liquid repellence (see for example the Applicant's WO 2007/083122), parts of the device or component may benefit from remaining uncoated. Such parts may include, without limitation, electrical contacts, exterior surfaces and screens. The functionality or aesthetic of such parts may be affected if they are not effectively masked during coating.

However, vapour deposition brings with it particular challenges in the context of masking. For example, plasma assisted vapour deposition, e.g. plasma polymerisation, offers exceptional penetration, such that even relatively inaccessible surfaces are effectively coated. While this represents an advantage in many situations, it means that highly effective masking is required to seal off part of an item that is not to be coated.

Suitably conformal and adherent masks, particularly masks that are cured in-situ, often suffer from the drawback of being difficult to remove. This applies particularly where only small areas, such as electric contacts, are to be masked.

There remains a need in the art for effective and convenient masking of substrates, for example prior to surface modification processes.

It is an object of the invention to facilitate masking and de-masking of items. SUMMARY OF THE INVENTION

From a first aspect, the invention provides a method of masking a substrate, the method comprising: applying a masking material and a tab to the substrate with the masking material overlying a foot of the tab and a leg of the tab protruding beyond the masking material.

In this manner, removal of the masking material is facilitated because the protruding tab can be gripped to pull off the overlying masking material.

Suitably, the method may comprise applying the tab with the foot locating the tab with respect to the substrate. Conveniently, the foot may rest on or against the substrate or the masking material when applied.

The masking material may advantageously be applied to overlie substantially the entirety of the foot. Advantageously, the masking material may be applied to underlie the foot, i.e.

between the substrate and the foot.

The leg of the tab may extend from the foot to protrude beyond the masking material.

Suitably, the foot may be the sole part of the tab that protrudes beyond the masking material.

The leg may extend from the foot at any suitable angle. Advantageously, the leg may extend transversely from the foot. In various embodiments, the leg may extend at an angle in the range of from 5 to 185 degrees to the foot, for example in the range of from 20 to 160 degrees, or even in the range of from 30 to 150 degrees to the foot. Advantageously, the leg may extend substantially orthogonally from the foot. This can facilitate resting of the tab on the foot.

The tab may advantageously comprise an engagement formation to aid attachment of the masking material to the tab. In particular, the tab may be applied with the engagement formation extending from the foot into the masking material. Conveniently, the foot may terminate in the engagement formation for enhancing engagement with overlying masking material. Suitably, the engagement formation may comprise a transversely extending element, such as a hook or the like. Conveniently, the leg may extend from a first end of the foot and the engagement formation may extend from an opposed second end of the foot.

The tab may conveniently be unitary, i.e. formed as one piece. Conveniently, the tab may comprise a sheet or web of material, for example a strip that has been bent or moulded.

Advantageously, the tab may comprise one or more bends defining a boundary between the foot and leg, and between the foot and the engagement formation where present.

The tab may comprise any suitable material consistent with its function of being gripped. Advantageously, the tab may comprise a flexible material. This can facilitate peeling removal of the masking material, as discussed below. Advantageously, the flexible material may permit flexing of the leg with respect to the foot.

To provide a degree of flexibility and aid gripping, the tab may suitably have a thickness in the range of from about 0.05 to 1 mm, for example in the range of from about 0.1 to 0.5 mm. The tab may suitably comprise or consist of a sheet or web of material with such a thickness.

Advantageously, the tab may have a width in the range of from 1 mm to 10 mm, for example in the range of from 2 to 5 mm. The tab may suitably be formed from a sheet or web of material with such a width.

The foot of the tab may define a footprint upon which the tab may rest. Suitably, the footprint of the tab may have an area in the range of from 1 to 25 mm², for example in the range of from 2 to 12 mm², or suitably in the range of from 3 to 9 mm².

Optionally, the tab may have a height, suitably measured transversely from the foot to a projecting end of the leg of the tab, of in the range of from 1 to 10 mm, for example in the range of from 3 to 7 mm.

Advantageously, the centre of gravity of the tab may lie within the footprint of the tab, such that the tab can be freestanding.

To aid durability and withstand gripping forces, the tab may comprise a material with a suitable hardness. In various embodiments, the tab comprises a material with a Shore A hardness of at least 75 and/or a material with a Shore D hardness of at least 50. Such hardness may be measured according to ISO 7619-1. Suitable materials for the tab include plastics and metals. Those skilled in the art will be aware of a range of suitable plastics. Suitable metals include alloys, such as, for example, steel. Other suitable metals will be apparent to those skilled in the art.

In various embodiments, the tab comprises a strip of steel having a thickness of at most 0.5 mm, bent to define the foot, the leg and optionally the engagement formation if present.

The substrate may, for example, comprise an electronic device or component. Suitably, the substrate may comprise a semiconductor material. In various embodiments, the substrate comprises a printed circuit board. Optionally, the masking material may be applied to mask an electrical contact on the substrate.

The masking material may take any desired form, consistent with achieving a desired masking performance or effect.

In various embodiments, the masking material comprises a curable resin. In particular, the masking material may be fluid in an uncured state and solid in a cured state. The method may comprise curing the resin after application.

Advantageously, the resin may be radiation curable, for example UV curable. Such masking materials are known in the art. They may typically comprise a polymerizable monomer or oligomer, a photoinitiator and optionally various other additives, for example such as antioxidants, fillers and thickening agents. Examples of suitable polymerizable monomers include substituted vinyl compounds, in particular such as acrylates.

The UV curable resin used in the present invention may advantageously comprise an acrylated urethane, for example a substituted or unsubstituted urethane methacrylate or urethane acrylate. Such compositions are sold by Dymax^R™ under the trade names Dymax^RTM 9-20479-B, Dymax^R™ 9-20318-F, and Dymax^R™ 9-318-F.

However, the method may also make use of other types of masking material.

The masking material may comprise a plurality of units of masking material. For example, the masking material may comprise a plurality of dots or other regions of masking material. The method may comprise applying a plurality of discrete units of masking material. In an embodiment, the method comprises applying a first amount of masking material, applying the tab onto the first amount of masking material and applying a second amount of masking material to overlie the tab and the first amount of masking material. In this manner a cushion or blanket of masking material may be provided for the tab, providing for more effective masking of the substrate.

Advantageously, the method may comprise at least partially curing the first amount of masking material before applying the tab. The second amount of masking material may be applied to contact the first amount of masking material. Optionally, the method may comprise fusing or adhering together the first and second amounts of masking material. In this manner the tab can be more securely attached to the underlying first amount of masking material.

The first and second amounts of masking material may together make up a unit of masking material. In various embodiments, the first amount of masking material may represent at least 30% by weight of the unit, or even at least 50% by weight of the unit. Optionally the unit of masking material may comprise one or more further amounts of masking material applied subsequently to the second amount of masking material.

The method may advantageously comprise applying the masking material in an uncured state and curing the masking material, e.g. after the masking material and the tab are applied to the substrate. In various embodiments, the method comprises applying masking material to the substrate in uncured form and applying the tab by pushing the tab into the masking material.

Conveniently, applying the tab may comprise placing the tab on or atop the substrate. In various embodiments, applying the tab comprises placing the tab on masking material borne by the substrate. Thus the tab need not contact the substrate.

One or more steps of the method may be automated. Suitably, the tab may be applied to the substrate by a robotic apparatus. In an embodiment, the tab may be applied to the substrate by a robotic gripping arm.

Additionally, or alternatively, the masking material may be applied to the substrate by a robotic apparatus. Suitably, the masking material may be applied to the substrate by a robotic dispensing arm. To reap the benefits of deploying the tab, the method may advantageously comprise removing the masking material from the substrate by gripping the tab where it protrudes from the masking material and removing the tab from the substrate with the masking material attached to the tab.

Optionally, the tab may be gripped and removed by a robotic apparatus, for example a robotic gripping arm.

In various embodiments, the method comprises masking the substrate during a surface modification process. The method may thus comprise a surface modification process carried out while the substrate is masked by the masking material. Advantageously, the surface modification process may comprise plasma polymerisation. Suitably, the surface

modification process may be conducted at sub-atmospheric pressure.

Conditions during surface modification may optionally comprise: an excitation medium; and a monomer that is at least partly activated by the excitation medium to form a liquid repellent coating on the substrate. The excitation medium may in particular comprise a plasma, optionally a pulsed plasma.

The monomer may suitably be a compound of formula (I):

where R¹ , R² and R³ are independently selected from hydrogen, alkyl, haloalkyl or aryl optionally substituted by halo; and R⁴ is a group X-R⁵ where R⁵ is an alkyl or haloalkyl group and X is a bond; X is a group of formula -C(0)0(CH2)_nY, where n is an integer of from 1 to 10 and Y is a bond or a sulphonamide group; or X is a group

-(0)pR⁶(0)q(CH2)t, where R⁶ is aryl optionally substituted by halo, p is 0 or 1 , q is 0 or 1 and t is 0 or an integer of from 1 to 10, provided that where q is 1 , t is other than 0.

Suitably, the substrate may be exposed to a plasma comprising a monomer compound for a period of time sufficient to allow a protective polymeric coating to form on the substrate; wherein the monomer compound has the following formula (II):

where Ri , R2 and R₄ are each independently selected from hydrogen, optionally substituted branched or straight chain C1-C6 alkyl or halo alkyl or aryl optionally substituted by halo, and R3 is selected from:

where each X is independently selected from hydrogen, optionally substituted branched or straight chain C1-C6 alkyl, halo alkyl or aryl optionally substituted by halo; and rii is an integer from 1 to 27.

In some embodiments, the monomer may be as identified in the claims of WO 2007/083122, which is incorporated herein by reference.

Suitably, the monomer may be selected from 1 H, 1 H,2H,2H-perfluorohexyl acrylate (PFAC4), 1 H,1 H,2H,2H-perfluorooctyl acrylate (PFAC6), 1 H, 1 H,2H,2H-perfluorodecyl acrylate

(PFAC8) and 1 H,1 H,2H,2H-perfluorododecyl acrylate (PFAC10).

Suitably, the masked substrate may be exposed to the monomer compound in combination with a crosslinking agent comprising two or more unsaturated bonds attached by means of one or more linker moieties and has a boiling point at standard pressure of less than 500 °C. The crosslinking reagent may be selected, for example from 1 ,4-butanediol divinyl ether (BDVE), 1 ,4-cyclohexanedimethanol divinyl ether (CDDE), 1 ,7-octadiene (170D), 1 ,2,4 - trivinylcyclohexane (TVCH), divinyl adipate (DVA), 1 ,3-divinyltetramethyldisiloxane

(DVTMDS), diallyl 1 ,4-cyclohexanedicarboxylate (DCHD), 1 ,6-divinylperfluorohexane (DVPFH), 1 H,1 H,6H,6H-perfluorohexanediol diacrylate (PFHDA) and glyoxal bis(diallyl acetal) (GBDA).

The coating may advantageously be liquid repelling, e.g. water and/or oil repelling. It has been found that applying masking material and a tab member in accordance with the method can address the particular challenges associated with masking in such processes.

Of course the method may comprise applying a plurality of units of masking material and a plurality of tabs to one or more substrates, with each unit of masking material overlying an associated one of the tabs and each tab protruding beyond its associated masking material. Each of the plurality of units of masking material and tabs may be applied, and optionally removed, as generally described or defined herein. The plurality of units and tabs may be applied simultaneously and/or sequentially.

Advantageously, the plurality of units and tabs may be applied and optionally removed in a production line. Suitably, the production line may comprise a plurality of automated stations arranged to perform the method on substrates travelling on a conveyor.

A second aspect of the invention provides an apparatus or production line for masking substrates, the apparatus or production line comprising: a feed of substrates; a supply of tabs; a supply of masking material; and a masking mechanism for applying the masking material and tabs to the substrates in the feed, with the masking material overlying the tabs and the tabs protruding beyond the masking material.

The tabs, masking material and substrates may be as described or defined in respect of the first aspect of the invention.

The feed of substrates may optionally comprise a conveyor bearing the substrates.

The supply of tabs may optionally comprise a tab feeder. In various embodiments, the tab feeder comprises a bowl feeder providing a feed of tabs.

The supply of tabs may suitably comprise a conveyor bearing the tabs.

The supply of masking material may optionally comprise a reservoir of curable resin.

Advantageously, the resin may be UV curable.

The masking mechanism may optionally comprise a mask application station for applying the masking material to the substrates in the feed. In various embodiments, the mask application station comprises a robotic applicator configured to obtain masking material from the supply of masking material and apply units of masking material to the substrates. The applicator may, for example, comprise a nozzle for applying units of uncured, resinous masking material.

The masking mechanism may comprise a curing station for curing units of masking material applied to the substrates. The curing station may suitably comprise one or more UV sources for UV curing masking material applied to the substrates.

The masking mechanism may optionally comprise a tab placement station for applying the tabs to the substrates in the feed. Suitably, the tab placement station may comprise a robot configured to pick tabs from the supply of tabs and apply them to the substrate.

Advantageously, the robot may comprise a plurality of arms for picking and placing tabs. The robot may, for example, make use of optical sensing to locate the tabs.

In various embodiments, the masking mechanism may comprise sequential mask application, tab placement and curing stations such that: uncured masking material is applied to the substrates; the tabs are applied to the masking material; and the masking material is cured after the tabs are applied.

Optionally, the masking mechanism may comprise a preliminary curing station for at least partially curing the masking material before the tabs are applied. The masking mechanism may advantageously comprise a supplementary mask application station for applying further masking material to overlie the tabs after the tabs are applied.

A third aspect of the invention provides an apparatus or production line for de-masking substrates, the apparatus or production line comprising: a feed of masked substrates comprising a masking material and a tab applied thereto, with the masking material overlying the tab and the tab protruding beyond the masking material; and a de-masking mechanism for removing the masking material from the substrates by gripping the tabs where they protrude from the masking material and removing the tabs from the substrate with the masking material attached to the tabs.

Suitably, the de-masking mechanism may comprise a robot configured to pick tabs from the supply and remove them together with the overlying masking material. Optionally, the de- masking mechanism may comprise a robot comprising a plurality of robotic arms. In various embodiments, the de-masking mechanism makes use of optical sensing to locate the tabs.

A fourth aspect of the invention provides a production line comprising an apparatus or production line according to the second aspect of the invention in combination with an apparatus or production line according to the third aspect of the invention. Optionally the production line according to the fourth aspect of the invention may comprise a surface modification station between the masking and de-masking apparatus or lines.

A fifth aspect of the invention provides a masked substrate comprising a masking material and a tab applied thereto, with the masking material overlying the tab and the tab protruding beyond the masking material.

Optional features of the masked substrate may be such as are obtainable by the first aspect of the invention.

A further aspect of the invention provides a tab for facilitating the removal of masking material applied to a substrate, the tab comprising: a foot upon which the tab can rest; and a leg extending transversely from the foot.

Optional features of the tab may be as described in respect of the first aspect of the invention.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", mean "including but not limited to", and do not exclude other components, integers or steps. Moreover the singular encompasses the plural unless the context otherwise requires: in particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Optional features of each aspect of the invention may be as described in connection with any of the other aspects. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1A is a side view of a tab;

Figure 1 B is a rear view of the tab of Figure 1 A;

Figure 1C is a bottom view of the tab of Figure 1A;

Figure 1 D is a front perspective view of the tab of Figure 1A;

Figure 1 E is a side view of a first tab variant;

Figure 1 F is a rear perspective view of second tab variant;

Figure 1G is a front perspective view of third tab variant;

Figure 1 H is a rear perspective view of fourth tab variant;

Figure 11 is a side view of fifth tab variant;

Figure 2 is an illustration of a first production line for masking substrates;

Figure 3A is a cross sectional view of a first variant of a masked substrate obtained from the production line of Figure 2;

Figure 3B is a plan view of the masked substrate in Figure 3A;

Figure 4A is a cross sectional view of a second variant of a masked substrate obtained from the production line of Figure 2;

Figure 4B is a plan view of the masked substrate in Figure 4A;

Figure 5A is a cross sectional view of a third variant of a masked substrate obtained from the production line of Figure 2;

Figure 5B is a plan view of the masked substrate in Figure 5A;

Figure 6 is an illustration of a second production line for masking substrates;

Figure 7A is a cross sectional view of a first variant of a masked substrate obtained from the production line of Figure 6;

Figure 7B is a plan view of the masked substrate in Figure 7A;

Figure 8A is a cross sectional view of a second variant of a masked substrate obtained from the production line of Figure 6;

Figure 8B is a plan view of the masked substrate in Figure 8A;

Figure 9 is an illustration of a production line for de-masking substrates.

DETAILED DESCRIPTION

Referring to Figures 1A to 1 D, in an embodiment of the invention, there is provided a tab 1 for facilitating the removal of masking material applied to a substrate. Masking material and substrate are not shown in Figures 1A to 1 D for clarity. The tab 1 comprises a foot 1a upon which the tab 1 can rest and a leg 1 b extending transversely, in particular substantially orthogonally, from the foot 1a. The transversely extending leg 1 b of the tab 1 facilitates gripping of the tab 1 during placement and removal from a substrate.

In use, as will be described below, masking material may be applied to overlie the tab 1 , for example over the foot 1a, such that removal of the tab 1 from a substrate with the help of the leg 1 b also removes the masking material. In this manner the leg 1 b can also faciliate the removal of masking material.

The foot 1 a of the tab 1 terminates in a hook 1c, extending transversely, in particular substantially orthogonally from the foot 1 a. The hook 1 c acts as an engagement formation, to aid attachment of masking material to the tab 1 in use. The leg 1 b extends from a first end of the foot 1 a and the hook 1 c extends from an opposed, second end of the foot 1 a.

Advantageously, this helps the centre of gravity of the tab 1 to lie more centrally within a footprint of the tab, such that the tab 1 is more stable when freestanding on the foot 1 a.

The tab 1 is unitary, comprising an oblong strip of steel having a thickness of about 0.2 mm, bent at right angles to define the foot 1 a, the leg 1 b and the hook 1 c. On account of its thickness, the steel strip retains a degree of flexibility, permitting flexing of the leg 1 b with respect to the foot 1 a. The tab 1 has a width of about 2 mm and a height of about 5 mm. The foot 1a of the tab 1 defines a footprint of about 5 mm².

It will be appreciated by those skilled in the art that a wide range of modifications can be made to the tab 1 without departing from the scope of the invention as defined in the appended claims.

For example, the tab 1 could alternatively be formed of a plastics material instead of steel.

The tab can of course also have a different size or shape. Referring to Figures 1 E to 11, in which like reference numerals are used for like parts, a first tab variant (Figure 1 E) has an inwardly angled foot, a second tab variant (Figure 1 F) has a tongue-shaped leg 1 b

(broadening as it extends from the foot 1a), a third tab variant (Figure 1G) has additional lateral hooks 1d to aid engagement with masking material, a fourth variant (Figure 1 H) has no engagement formation at all, and a fifth variant (Figure 11) comprises a dimple 1e on the foot to aid optical recognition. These variants are only a few non-limiting examples of possible modifications. The tab 1 may be applied to a substrate manually, or using an automated apparatus or production line.

Referring now to Figure 2, in one embodiment of the invention, a production line 2 for masking substrates 4 comprises: a feed of substrates 4; a supply of tabs 1 ; a supply of masking material 8; and a masking mechanism 10.

The feed of substrates 4 comprises a primary conveyor 12 bearing the substrates 4. The conveyor 12 carries the substrates 4 through the production line 2 from a supply of substrates 4 in the form of a stack 14.

The supply of tabs 1 comprises a bowl feeder 16, which provides a feed of tabs 1 onto a secondary conveyor 18, which carries the tabs 1 from the bowl feeder 16 to the masking mechanism 10. The tabs 1 are as described in respect of any of Figures 1A to 11, or as generally defined anywhere herein, comprising a foot 1 a, a leg 1 b and optionally a hook 1 c.

The supply of masking material 8 comprises a reservoir 20 of UV curable resin in fluid communication with the masking mechanism 10.

The masking mechanism 10 comprises a tab application station in the form of a robot 22 with multiple arms 24 configured to apply tabs 1 to the substrates 4 in the feed. Only one arm is shown in Figure 2 for simplicity and of course any suitable number of arms 24 could be used. The robot 22 picks tabs 1 from the secondary conveyor 18, gripping their legs 1 b, and applies a tab 1 to each of the substrates 4 travelling on the primary conveyor 12. The tabs 1 are applied to rest with their foot 1a on the substrates 4 in or near a region of the substrates 4 to be masked. Of course, the number of tabs 1 per substrate 4 can vary depending on masking requirements.

The robot 22 also acts as a mask application station for applying masking material 8 to the substrates 4 travelling on the primary conveyer 12, after the tabs 1 are applied. The mask application station 26 comprises a robotic applicator 28 on each arm 24 of the robot 22, configured to draw masking material 8 from the reservoir 20 and apply units 30 of masking material 8 to the substrates 4 as they travel along the primary conveyor 12. In particular, the units of masking material 30 are applied to overlie the tabs 1 and to contact the substrates 4. The leg 1 b of the tabs extends beyond the applied masking material 8. Downstream of the robot 22 providing tab and mask application, there is provided a mask curing station in the form of a UV source 32 for curing the applied masking material 8 with UV radiation. In particular, as each substrate 4 passes on the primary conveyor 12, the UV source cures the units 30 of masking material 8 applied thereto.

Referring now to Figures 3A to 5B, in which like reference numerals are used for like parts, it will be apparent that the production line 2 produces masked substrates 4 having at least one tab 1 and at least one unit 30 of masking material 8 applied thereto. The masking material 8 overlies the tab 1 and masks the substrate 4 with the leg 1 b of the tab 1 exposed, i.e. at least a portion of the leg 1 b remaining uncovered by the masking material.

In the above-described production line 2, the tabs 1 are applied directly onto the surface of the substrates 4. The tabs 1 and/or masking material are, for example, positioned over an electrical contact or other region to be masked on the substrates 4. The substrates 4 may be any item to be masked, for example an electronic device or component, such as a PCB.

On curing, the masking material 8 adheres to the tab 1 and to the substrate 4, thereby providing desired masking of the substrates 4. Where an engagement formation, such as a hook 1 c is present in the tab 1 , the masking material 8 may be applied to abut or contact this formation to enhance adherence of the tab 1 to the masking material 8.

Referring now specifically to Figure 3A and 3B, in which the tab comprises a hook 1c, where desired a unit 30 of masking material 8 may be applied across the foot 1a of the tab 1 with the leg and hook 1c remaining substantially uncovered.

Alternatively, with reference to Figures 4A and 4B a unit of masking material 8 may be applied across the foot 1 a and the hook 1c, with only the leg 1 b remaining uncovered. Such application may further enhance adherence of the masking material 8 to the tab 1.

With reference to Figures 5A and 5B, a further alternative involves applying a unit of masking material 8 to cover the foot 1a, the hook 1c and a lower portion of the leg 1 b of the tab 1. This may further enhance tab adherence and cover an even wider area of substrate 4.

Referring now to Figure 6, in another embodiment of the invention, a production line 102 for masking substrates 4 comprises: a feed of substrates 4; a supply of tabs 1 ; a supply of masking material 8; and a masking mechanism 110. The production line 102 is substantially the same as that described with reference to Figure 2, save that the masking mechanism 102 is structured differently. Like reference numerals are used for like parts.

With reference to Figure 6, the masking mechanism 102 includes two robotic applicators 128 forming separate mask application stations and two separate UV sources 132 providing separate curing stations. In particular, the following are arranged sequentially along the direction of travel of substrates 4 on the primary conveyor 12:

- A first robotic applicator 128 to provide a first mask application station applying a first amount of masking material 8a onto the substrates 4;

- A first arrangement of UV lamps 132 providing a first curing station for curing the first amount of masking material 8a;

- A robot 122 providing an application station placing tabs 1 onto the first amount of masking material 8a;

- A second robotic applicator 128 to provide a second mask application station applying a second amount of masking material 8b onto the substrates 4;

- A second arrangement of UV lamps 132 providing a second curing station for curing the second amounts (and optionally also the first amounts) of masking material 8b.

In the production line 102 of Figure 6, the tabs 1 are applied onto a first amount of masking material 8a borne by the substrate 4, with a second amount of masking material 8b subsequently applied to overlie the tabs 1 and the first amount of masking material 8a. The first amount of masking 8a material may be at least partly cured before the tab 1 is applied.

It has been found that applying the first amount of masking material 8a to underlie the tabs 1 masking performance can be improved, compared to applying the tab directly to the substrate 4. At the same time, the benefits of the tab 1 can be retained by applying the second amount of masking material 8b to help adhere the tab to the masking material.

The first and second amounts of masking material 8a and 8b together form a unit 30 of masking material which can be removed with the tab. The relative size of the first and second amounts of masking material 8a and 8b may be varied as desired.

For example, referring now to Figures 7A and 7B, the first amount of masking material 8a may form a relatively small cushion for the tab, e.g. making up less than 30% of the unit of masking material 30 by weight. Alternatively, again by way of example only, referring now to Figure 8A and 8B, the first amount of masking material 8a may represent a larger blanket, e.g. making up more than 30% of the unit of masking material 30 by weight, or even more than 50% by weight.

Of course it will be appreciated that the second amount of masking material 8b may also be varied, for example to cover the foot 1 a of the tab only, to cover the foot 1a and a hook 1c, and/or to cover a lower portion of the leg 1 b of the tab.

Once masked, the masked substrates 4 produced by the production line described with reference to Figure 2 or Figure 6 may be subjected to a surface modification process (not shown in the Figures).

For example, in some embodiments the substrates may be exposed to a sub-atmospheric polymer deposition process, suitably plasma polymerisation, to form a coating on the substrates. The masking material prevents the coating from forming in masked regions.

The tab 1 facilitates the removal of masking material applied to the substrate 4, for example once a surface modification process is complete. In particular, the exposed leg 1 b of the tab can be readily gripped, whereby the tab 1 and masking material 8 can be pulled away from the substrate 4. Advantageously, the entirety of the applied masking material may be removed in this way, as units 30 of the cured masking material 8 hold together.

The tabs 1 and masking material may of course be removed manually. Alternatively, this can also be done in a production line.

With reference to Figure 9, in which like reference numerals are used for like parts, a production line for de-masking substrates 104 comprises a conveyor 12 carrying masked substrates 4 comprising masking material 8 and a tab 1 applied thereto, with the masking material 8 overlying the tab 1 and the tab protruding beyond the masking material 1 ; and a de-masking mechanism 200 for removing the masking material 8 from the substrates 4 by gripping the tabs 1 where they protrude from the masking material and removing the tabs 1 from the substrates 4 with the masking material 8 attached to the tabs 1.

The de-masking mechanism comprises a robot 222 having arms 224 configured to pick protruding tabs 1 from the conveyor and deposit tabs 1 with masking material 8 attached to tabs 1 in a receptacle 226. The tabs 1 may optionally be recycled by removing the attached masking material 8.

Claims

1. A method of masking a substrate, the method comprising: applying a masking material and a tab to the substrate with the masking material overlying a foot of the tab and a leg of the tab protruding beyond the masking material.

2. The method of claim 1 , comprising applying the tab with the foot locating the tab with respect to the substrate, optionally with the foot resting on or against the substrate or the masking material when applied.

3. The method of any preceding claim, comprising applying the masking material to underlie the tab between the substrate and the foot.

4. The method of any preceding claim, wherein the leg of the tab extends transversely from the foot, optionally at an angle in the range of from 30 to 150 degrees.

5. The method of any preceding claim, wherein the leg of the tab extends substantially orthogonally from the foot.

6. The method of any preceding claim, wherein the tab comprises an engagement formation to aid attachment of the masking material to the tab, the engagement formation optionally comprising a transversely extending element.

7. The method of claim 6, wherein the foot terminates in the engagement formation.

8. The method of claim 6 or claim 7, wherein the engagement formation comprises a hook for enhancing engagement of the foot with overlying masking material.

9. The method of any one of claims 6 to 8, wherein the leg projects from a first end of the foot and the engagement formation extends from an opposed, second end of the foot.

10. The method of any preceding claim, wherein the tab is unitary.

1 1. The method of any preceding claim, wherein the tab comprises a sheet or web of material.

12. The method of claim 1 1 , wherein the sheet or web comprises one or more bends defining a boundary between the foot and the leg, and optionally between the foot and the engagement formation if present.

13. The method of any preceding claim, wherein the tab comprises a flexible material.

14. The method of claim 13, wherein the flexible material permits flexing of the leg with respect to the foot.

15. The method of any preceding claim, wherein the tab has a thickness in the range of from about 0.05 to 1 mm.

16. The method of any preceding claim, wherein the tab has a width in the range of from 1 mm to 10 mm.

17. The method of any preceding claim, wherein the foot of the tab defines a footprint having an area in the range of from 1 to 25 mm².

18. The method of any preceding claim, wherein the tab has a projecting height, measured transversely from a foot to a projecting end of a leg of the tab, of in the range of from 1 to 10 mm.

19. The method of any preceding claim, wherein the centre of gravity of the tab lies within the footprint of the tab, such that the tab can be freestanding.

20. The method of any preceding claim, wherein the tab comprises a material with a Shore A hardness of at least 75 and/or a Shore D hardness of at least 50.

21. The method of any preceding claim wherein the tab comprises a metal or metal alloy.

22. The method of any preceding claim, wherein the tab comprises steel.

23. The method of claim 22, wherein the tab comprises a strip of steel having a thickness of at most 0.5 mm, bent to define the foot, the leg and optionally the engagement formation if present.

24. The method of any preceding claim, wherein the substrate comprises an electronic device or component.

25. The method of claim 24, wherein the substrate comprises a printed circuit board.

26. The method of any preceding claim, wherein the masking material is applied to mask an electrical contact on the substrate.

27. The method of any preceding claim, wherein the masking material comprises a curable resin.

28. The method of claim 27, wherein the resin is radiation curable, optionally UV curable.

29. The method of any preceding claim, wherein the masking material comprises a plurality of units of masking material.

30. The method of any preceding claim, comprising applying a plurality of discrete units of masking material.

31. The method of any preceding claim, comprising applying a first amount of masking material, applying the tab onto the first amount of masking material and applying a second amount of masking material to overlie the tab and the first amount of masking material.

32. The method of claim 31 , comprising at least partially curing the first amount of masking material before applying the tab.

33. The method of claim 31 or claim 32 comprising applying the second amount of masking material to contact the first amount of masking material and optionally fusing or adhering together the first and second amounts of masking material.

34. The method of any one of claims 31 to 33, wherein the first and second amounts of masking material together make up a unit of masking material, the first amount of masking material representing at least 30% by weight of the unit.

35. The method of any preceding claim comprising applying the masking material in an uncured state and curing the masking material.

36. The method of any preceding claim, comprising applying masking material to the substrate in uncured form and applying the tab by pushing the tab into the masking material.

37. The method of any preceding claim, comprising placing the tab on the substrate or placing the tab on masking material borne by the substrate.

38. The method of any preceding claim, comprising applying the tab to the substrate by a robotic gripping arm.

39. The method of any preceding claim, comprising applying the masking material to the substrate with a robotic apparatus, optionally a robotic dispensing arm.

40. The method of any preceding claim, comprising de-masking the substrate by

removing the applied masking material from the substrate by gripping the tab where it protrudes from the masking material and removing the tab from the substrate with the masking material attached to the tab.

41. The method of claim 40 comprising gripping and removing the tab with a robotic

apparatus, for example a robotic gripping arm.

42. The method of any preceding claim comprising masking the substrate during a

surface modification process, optionally plasma polymerisation.

43. The method of any preceding claim comprising applying a plurality of units of

masking material and a plurality of tabs to one or more substrates, with each unit of masking material overlying an associated one of the tabs and each tab protruding beyond its associated masking material.

44. The method of claim 43, wherein each of the units of masking material and tabs is, or is applied and optionally removed, as defined in any one of claims 1 to 43.

45. The method of claim 43 or claim 44, wherein the plurality of units and tabs is applied and optionally removed in a production line.

46. An apparatus or production line for masking substrates, the apparatus or production line comprising:

a feed of substrates;

a supply of tabs;

a supply of masking material; and

a masking mechanism for applying the masking material and tabs to the substrates in the feed, with the masking material overlying the tabs and the tabs protruding beyond the masking material.

47. The apparatus of claim 46 wherein the tabs comprise a foot and a leg and are

optionally as defined in any one of claims 4 to 23.

48. The apparatus of claim 46 or claim 47 wherein the feed of substrates comprises a conveyor bearing the substrates.

49. The apparatus of any one of claims 46 to 48 wherein the supply of tabs comprises a bowl feeder providing a feed of tabs.

50. The apparatus of any one of claims 46 to 49 wherein the supply of tabs comprises a conveyor bearing the tabs.

51. The apparatus of any one of claims 46 to 50 wherein the supply of masking material comprises a reservoir of curable resin, optionally UV curable resin.

52. The apparatus of any one of claims 46 to 50 wherein the masking mechanism

comprises a mask application station for applying the masking material to the substrates, the mask application station comprising a robotic applicator configured to obtain masking material from the supply of masking material and apply units of masking material to the substrates.

53. The apparatus of any one of claims 46 to 52 wherein the masking mechanism

comprises a curing station for curing units of masking material applied to the substrates.

54. The apparatus of any one of claims 46 to 53 wherein the masking mechanism

comprises a tab placement station for applying the tabs to the substrates in the feed, the tab placement station comprising a robot configured to pick tabs from the supply of tabs and apply them to the substrate.

55. The apparatus of any one of claims 46 to 54 wherein the masking mechanism

comprises sequential ones of said mask application, tab placement and curing stations such that: uncured masking material is applied to the substrates; the tabs are applied to the masking material; and the masking material is cured after the tabs are applied.

56. The apparatus of claim 55, wherein the masking mechanism comprises a preliminary curing station for at least partially curing the masking material before the tabs are applied.

57. The apparatus of claim 55 or claim 56 wherein the masking mechanism comprises a supplementary mask application station for applying further masking material to overlie the tabs after the tabs are applied.

58. An apparatus or production line for de-masking substrates, the apparatus or

production line comprising:

a feed of masked substrates comprising a masking material and a tab applied thereto, with the masking material overlying the tab and the tab protruding beyond the masking material; and

a de-masking mechanism for removing the masking material from the substrates by gripping the tabs where they protrude from the masking material and removing the tabs from the substrates with the masking material attached to the tabs.

59. The apparatus of claim 58, wherein the de-masking mechanism comprises a robotic arm configured to pick tabs from the supply and remove them together with the overlying masking material.

60. A production line comprising an apparatus or production line according to any one of claims 46 to 57 and an apparatus or production line according to claim 58 or 59.

61. A masked substrate comprising a masking material and a tab applied thereto, with the masking material overlying the tab and the tab protruding beyond the masking material.

62. The substrate of claim 61 obtainable by the method of any one of claims 1 to 45.

63. A tab for facilitating the removal of masking material applied to a substrate, the tab comprising: a foot upon which the tab can rest; and a leg extending transversely from the foot.

64. The tab of claim 63 wherein the tab is as defined in any one of claims 4 to 23.