Antistatic clothing

Abstract

An electrostatic discharge protection tool for reducing electrostatic charge present on a workpiece within a workpiece processing module has a moveable head and forms an at least partially conductive path between a tip of the tool and a body of the tool for grounding a charged workpiece in contact with the tip.

Description

TECHNICAL FIELD

[0001] The present invention relates to an electrostatic discharge protection tool, a tooling block, a printing machine and a method of protecting a workpiece from electrostatic discharge. BACKGROUND

[0002] Industrial screen printing machines typically apply a conductive printing medium (such as solder paste, silver paste or conductive ink) to a planar workpiece (such as a circuit board) through a pattern of holes in a thin planar layer or mask, such as a stencil (which is a solid material, such as stainless steel, with a pattern) or a screen (which is a mesh material coated with emulsion). The present invention is equally applicable to screen printing and stencil printing, and for the sake of convenience, the term "stencil" will be used to refer to any such patterned mask in the remainder of this document. The printing medium is applied using an angled blade or squeegee while the workpiece is clamped in a fixed printing position. The same machines can also be used to print certain non-conductive media (such as glue or other adhesives) onto the workpiece. After printing is complete, the squeegee is lifted off the stencil top surface, the stencil is separated from the printed workpiece, and the printed workpiece is then released.

[0003] After such a printing operation within the printing machine, the printed workpiece can be transferred to other processing modules within the production line. In particular, the printed workpiece can be transferred to an assembly machine which can mount electrical or electronic components onto the workpiece.

[0004] To ensure high quality printing, the workpiece must be supported so that the surface to be printed is parallel to the printing screen, which is usually horizontal, the workpiece support is able to withstand the pressure exerted on it during the printing operation, in particular the downward pressure exerted by the squeegee, while maintaining the correct alignment of the workpiece.

[0005] It is also necessary to provide suitable support for the workpiece during the mounting operation, although the downward pressure exerted on the workpiece during the mounting operation is usually much lower than the downward pressure exerted during the printing operation.

[0006] The simplest type of support is to use a flat or platen onto which the workpiece can be mounted. However, in many cases, this arrangement is not possible, in particular when the underside of the workpiece has already been printed and equipped with components (for example, in a previous mounting operation) and it is necessary to support this underside during a printing or mounting operation applied to the top of the workpiece. The presence of components on the underside of the workpiece means that the workpiece will not be flat, and the components are also vulnerable to damage if they are "squashed" during the printing or mounting operation. For this reason, a specialist support solution known as "tooling" is used.

[0007] There are currently two common tooling options available to provide support for printed circuit boards (PCBs) during printing and mounting operations:

[0008] 1) Specialized tooling blocks - these are large blocks of material with a top surface that has a three-dimensional profile, e.g., by machining, intended to accommodate a particular PCB that is to be mounted on it. The tooling blocks can conveniently be located on a flat lower support plate or "tooling table."

[0009] 2) Tooling pins - these are thin posts that are positioned to contact the circuit board in use, avoiding contact with any components on the bottom side (or other delicate or critical areas). The pins are typically magnetic, i.e., they include a permanent magnet or electropermanent magnet inside to non-permanently attach the pin to the tooling table, which can conveniently be made of a magnetically permeable material such as steel. For example, ASM currently uses simple, low-cost molded plastic tooling pins with a neodymium permanent magnet at the bottom of each pin. In the print shop, the tooling pins are typically placed on the tooling table manually (although automated mounting systems are starting to be introduced), while the mounters (such as those produced by ASM) can offer both manual and automated mounting options. With a manual system, it is both time-consuming and labor-intensive for an operator to consistently mount the pins with the required precision. An automated mounting system can save time and reduce defects by accurately mounting the pins. The automated mounting system typically uses a "pin picker" device that is operable to engage with the pins from above, the pins being located on the tooling table or in a storage magazine. The pin picker can then pick up the pins, move them laterally to the desired position, and then lower them onto the tooling table.

[0010] An example of such an automated mounting system is schematically shown in Figure 1 . This automated mounting system uses a "pin picker" 102, which is a device that is operable to engage with one or more tooling pins 101A, 101B from above at a time, the individual tooling pins 101A, 101B being located on a support surface 123 of a tooling table or in a storage magazine 110. The pin picker 102 can be moved in a vertical or "Z" direction to engage with and subsequently lift the tooling pins 101A, 101B, and can be moved in orthogonal "X" and "Y" directions to move the tooling pins laterally to the desired position. The pin picker 102 can then lower the tooling pins onto the support surface 123 of the tooling table, which the tooling pins are magnetically attracted to. As shown, the pin picker 102 is movable in the Z direction relative to a support gantry 120 that it is suspended from, and is movable in the X direction along the gantry 120. Movement in the Y direction is provided by moving the gantry 120 in the Y direction. Although not shown in Figure 1The gantry 120 can be supported within a processing module such as a printer or a placement machine, but it can also be supported in a separate location. The placement positions of the tooling pins 101A, 101B on the support surface 123 are selected manually or automatically depending on the workpiece 130 to be supported subsequently. The workpiece 130 shown comprises a substrate 131, for example a board or a semiconductor wafer, which in this example has a number of features on the underside which obstruct the support of the workpiece 130. These features can include components 132, vias 133 and the like, as will be appreciated by the skilled person. The positions and types of tooling pins 101A, 101B to be placed on the support surface 123 will depend on the positions of these features. In the example shown, relatively wide tooling pins 101A are used where there is space between the features, while relatively thin tooling pins 101B are used where there is little space between the features.

[0011] Typically, once the workpiece has been transported into the printer or placement machine, the tooling is brought into supporting contact with the workpiece above it by raising the tooling, for example by lifting the tooling table.

[0012] Electronic components present on a workpiece during a printing or placement operation are vulnerable to damage from electrostatic discharge ("ESD"), which can occur if the workpiece becomes electrically charged. There are many opportunities for a workpiece to become electrically charged, for example it has been found that the risk of becoming electrically charged is particularly high during printing due to contact and separation between the following parts:

[0013] - the squeegee and the stencil,

[0014] - the stencil and the workpiece, and

[0015] - the workpiece and the clamps which hold it in the printing position.

[0016] While the tooling can provide ESD protection (for example, the tooling pins are typically made of a dissipative material to dissipate the build-up of electrostatic charge), this is not always reliable. For example, there can be imperfect contact between the pins and the workpiece at any stage where the squeegee is not exerting a downward force on the stencil above it.

[0017] The present invention seeks to overcome this problem and to provide reliable ESD protection during a processing operation such as printing or placement.

[0018] According to the present invention, this is achieved by providing a variable height ESD protection element associated with the tooling, which can be ensured to be in contact with the workpiece over a range of distances. Furthermore, the optimal position of the ESD protection element can be determined by analysing Gerber data associated with the workpiece, and the element can be placed at the determined position. SUMMARY

[0019] According to a first aspect of the present application there is provided an electrostatic discharge protection tool for reducing electrostatic charge present on a workpiece within a workpiece processing module, comprising:

[0020] a body,

[0021] a head,

[0022] a tip distal of the head, the tip being at least partially electrically conductive,

[0023] the head being movable relative to the body between an extended position in which the tip is at a maximum distance from the body and a retracted position in which the tip is at a minimum distance from the body,

[0024] biasing means for biasing the head to the extended position, and

[0025] an at least partially electrically conductive path formed between the tip and the body for earthing a charged workpiece in contact with the tip.

[0026] According to a second aspect of the present application there is provided a tooling block for supporting a workpiece during a processing operation, comprising the electrostatic discharge protection tool of the first aspect.

[0027] According to a third aspect of the present application there is provided a printing press comprising the electrostatic discharge protection tool of the first aspect.

[0028] According to a fourth aspect of the present application there is provided a method of protecting a workpiece from electrostatic discharge, comprising the steps of:

[0029] i) positioning a tooling on a tooling table of a workpiece processing module to support a workpiece during a processing operation, the tooling comprising the electrostatic discharge protection tool of the first aspect,

[0030] ii) transporting the workpiece to a processing position located above the tooling, and

[0031] iii) moving the workpiece and the tooling table relatively to bring the tooling into supporting contact with the workpiece and the tip of the electrostatic discharge protection tool into contact with the workpiece, thereby earthing the workpiece via the at least partially electrically conductive path. BRIEF DESCRIPTION OF DRAWINGS

[0032] The present application will now be described with reference to the accompanying drawings (not to scale) in which:

[0033] Figure 1 a known automated pick and place system is shown schematically in cross-section;

[0034] Figure 2 an embodiment of the present application is shown schematically in cross-section, comprising an electrostatic discharge protection tool fitted within a tooling block;

[0035] Figure 3Aand Figure 3B An electrostatic discharge protection tool is shown schematically in cross-section in an extended position and a retracted position respectively;

[0036] Figure 4 An electrostatic discharge protection tool incorporating a digital potentiometer is shown schematically;

[0037] Figure 5 An alternative embodiment of an electrostatic discharge protection tool is shown schematically in cross-section;

[0038] Figure 6 A further alternative embodiment of an electrostatic discharge protection tool is shown schematically in cross-section;

[0039] Figure 7 and Figure 8 An alternative embodiment is shown schematically in cross-section in an extended position and a retracted position respectively; and

[0040] Figure 9 An electrostatic discharge protection tool formed as a free standing column is shown schematically in cross-section.

[0041] BRIEF DESCRIPTION OF DRAWINGS:

[0042] 1, 11, 31, 41, 51, 61, 81 - electrostatic discharge protection tool

[0043] 2, 12, 42, 62, 82 - head

[0044] 3, 13, 43, 63, 83 - tip

[0045] 4, 14, 44, 64, 84 - body

[0046] 5, 48 - insulating collar

[0047] 6, 21, 59 - ground connection

[0048] 7, 67 - tool block

[0049] 8 - resistor

[0050] 9 - opening

[0051] 15, 45, 65 - compression spring

[0052] 16 - resistor network

[0053] 17 - resistor

[0054] 18 - first resistor

[0055] 19 - second resistor

[0056] 20, 46, 56, 66 - Electrical contacts

[0057] 32 - Digital Potentiometer

[0058] 33 - Controller

[0059] 47, 57, 68 - Dissipative materials

[0060] 58, 70 - Conductive contacts

[0061] 69 - poles

[0062] 71-hole

[0063] 85 - Tooling Table

[0064] 86 – Connecting Device

[0065] 87 - Top of the main body

[0066] 88-pin pickup

[0067] 89 - Latch

[0068] 101A, 101B - Tooling Pins

[0069] 102 - Pin Pickup

[0070] 110 - Repository

[0071] 120 - Stand

[0072] 130 - Workpiece

[0073] 131 – Substrate

[0074] 132 - Components

[0075] 133 – Via

[0076] W - Workpiece. Detailed Implementation

[0077] One embodiment of the present invention is as follows: Figure 2 As shown in the diagram, the electrostatic discharge protection tool 1 is schematically illustrated in cross-section within the tooling block 7. The tooling block 7 is located on a tooling table (not shown) and is used for vertical movement into and out of engagement with the workpiece W above it.

[0078] In more detail, the electrostatic discharge protection tool 1 comprises a head 2 having a tip 3 at a distal end (i.e. top) of the head 2. The head 2 is connected to a body 4 so as to be moveable relative to the body 4. As shown, the head 2 is moveable relative to the body 4 along a vertical axis or Z-axis, the body 4 being held stationary relative to a tool block 7 in use. The head 2 is moveable relative to the body 4 between an extended position (as shown in Figure 2 Fig. 1) at which the tip 3 is at a maximum distance from the body 4, and a retracted position (not shown) at which the tip 3 is at a minimum distance from the body 4. By way of example only, such an arrangement can be achieved by providing a cylindrical vertically extending channel (not shown) in the body 4 and locating the head 2 within the channel for sliding vertical movement therein, the sides of the channel limiting lateral movement of the head 2. By closing at least partially the distal end of the channel, for example the lower end of the channel can be closed completely, vertical movement of the head 2 beyond the retracted position or the extended position can be prevented. However, the upper end of the channel must remain partially open so that a portion of the head 2 including the tip 3 can pass through. Advantageously, the head 2 can comprise a collar or shoulder portion at its lower end which is greater than the lateral extent of the upper portion of the head 2, the collar preventing the head 2 from exiting through the opening at the upper end of the channel. Located within the electrostatic discharge protection tool 1 is a biasing means (not shown) for biasing the head 2 to the extended position. The biasing means can comprise, for example, a compression spring or a compressible foam material.

[0079] The tip 3 is at least partially electrically conductive and can be formed, for example, from a metallic material. Thus, the tip 3 forms part of an at least partially electrically conductive path formed between the tip 3 and the body 4 for earthing a live workpiece W when it comes into contact with the tip 3. As shown in Figure 2 Fig. 1, the body 4 is earthed at an earth connection 6 at the lowermost end of the electrostatic discharge protection tool 1 via a resistor 8, which is selected to safely allow a rapid discharge if a live workpiece comes into contact with the tip 3. A resistance of around 1 MΩ has been found to be suitable for many workpieces, although this will depend on the particular application. The electrostatic discharge protection tool 1 is located within an opening 9 formed in the tool block 7 and is electrically isolated therefrom by an insulating collar 5 or sleeve formed from an insulating material. Typically, the tool block 7 can comprise a bulk material in which the opening 9 is formed. From Figure 2 It can be seen that, in the extended position, the tip 3 protrudes beyond the upper surface of the tool block 7 so that, in use, a workpiece W will contact the tip 3 before the tool block 7.

[0080] In use:

[0081] - the tool block 7 is located on a tooling table (not shown) of a workpiece machining module to support a workpiece W during a machining operation, the tool block comprising the electrostatic discharge protection tool 1;

[0082] - the workpiece W, possibly with a high electrostatic charge, is conveyed to a processing position above the tool block 7, into Figure 2 the position shown;

[0083] - the workpiece W and the tool table are moved, in this case by lifting the tool table. The tip 3 of the electrostatic discharge protection tool thereby comes into contact with the workpiece W to ground the workpiece W via the at least partially electrically conductive path. Subsequently, by further lifting of the tool table, the head is pushed down against the biasing means in the retracted position, while remaining in contact with the underside of the workpiece W, until the tool block 7 forms a supporting contact with the workpiece W. When the workpiece is fully supported on the tool block 7, the processing operation can be performed.

[0084] It is beneficial for the tip 3 of the electrostatic discharge protection tool 1 to contact a conductive area on the underside of the workpiece W, for example a conductive pad or a conductive track that is pre-printed onto the workpiece W. The method outlined above therefore preferably comprises an initial step of determining the position of the electrostatic discharge protection tool 1 in the horizontal plane so that it is located below the conductive area of the workpiece W. A preferred way of doing this is to analyse Gerber data associated with the workpiece W, which accurately provides position information of the conductive area of the workpiece W.

[0085] The above-described embodiment provides a robust method for protecting a workpiece W from electrostatic discharge. In an alternative embodiment, a more complex electrostatic discharge protection tool can be provided, in which the electrical resistance of the at least partially electrically conductive path varies as a function of the distance between the tip and the main body, to optimise the discharge through the tool.

[0086] Figure 3A and Figure 3B schematically shows a cross-sectional view of an electrostatic discharge protection tool 11 in an extended position and Figure 3A and a retracted position, respectively. The electrostatic discharge protection tool 11 likewise comprises a head 12 with a tip 13 that is relatively movable between Figure 3B the extended position shown and the retracted position shown, with respect to a main body 14. The head 12 is biased to the extended position by a biasing means in the form of a compression spring 15. The main body 14 comprises a resistor network 16 having a plurality of resistors 17 each of a different resistance value. These resistors are arranged so that when the distance between the tip 13 and the main body 14 is a first distance, the at least partially electrically conductive path comprises a first resistor of the plurality of resistors, and when the distance between the tip 13 and the main body 14 is a second distance, the at least partially electrically conductive path comprises a second resistor of the plurality of resistors, as will be described below. The head 12 comprises an electrical contact 20 at its lowest extent, which is configured to electrically contact a single resistor 17 of the plurality of resistors at any point along its range of travel between the extended position and the retracted position. In Figure 3AAt the extended position shown, the electrical contact 20 is in electrical contact with the first resistor 18, while... Figure 3B At the retracted position shown, electrical contact 20 is in electrical contact with the second resistor 19, and the first resistor 18 and the second resistor 19 have different resistances. At the midpoint of the travel along the distance between the extended and retracted positions, electrical contact 20 is in electrical contact with the other resistors in the plurality of resistors. The resistor network 16 is grounded at ground connection 21. In this way, the discharge of electrostatic charge on the workpiece in contact with tip 13 can be controlled, thereby providing a slower discharge for the charged workpiece.

[0087] Figure 4 An alternative embodiment of an electrostatic discharge (ESD) protection tool 31 is schematically illustrated. In this embodiment, a variable resistor (in this case, a digital potentiometer 32 connected to the lower end of the ESD protection tool body) is used to change the resistance of at least a partially conductive path. The digital potentiometer 32 is controlled by a controller 33 (e.g., a processor, etc., operated or controlled by suitable software or hardware). When the workpiece is clamped, such a system can be used to provide a 1 MΩ to 0 Ω transition to provide relatively slow discharge and negligible impedance, such as 0 Ω, while when the workpiece is not clamped, it provides a direct grounding path to transfer any static electricity generated during the printing process.

[0088] Figure 5 An alternative embodiment of the electrostatic discharge protection tool 41 at the extended position is schematically shown in cross-section. In this embodiment, ESD protection is provided by using a dissipative material in at least a partially conductive path, and... Figure 3A and Figure 3BSimilar to the embodiment shown in the middle, the resistance of the at least partially electrically conductive path varies as a function of the distance between the tip and the body to optimize the discharge of static electricity by the tool. The static electricity discharge protection tool 41 likewise comprises a head 42 with a tip 43 that is relatively movable with respect to a body 44 between an extended position and a retracted position (not shown) as shown. The head 42 is biased to the extended position by a biasing means in the form of a compression spring 45. The body is held in an opening of a tool block (not shown) via an insulating collar 48. The body 44 comprises a plurality of dissipative materials 47, for example each having a different resistance, more for example in the form of a collar or ring formed around the travel path of the head 42. These dissipative materials are arranged such that when the distance between the tip 43 and the body 44 is a first distance, the at least partially electrically conductive path comprises a first dissipative material of the plurality of dissipative materials, and when the distance between the tip 43 and the body 44 is a second distance, the at least partially electrically conductive path comprises a second dissipative material of the plurality of dissipative materials, which will be described below. The head 42 comprises an electrical contact 46 located at its lowest extent, the electrical contact 46 being configured to electrically contact a single dissipative material 47 of the plurality of dissipative materials at any point along its travel extent between the extended position and the retracted position. In the extended position as shown for example, the electrical contact 46 is in contact with the uppermost dissipative material 47. Along its travel between the extended position and the retracted position, the electrical contact 46 is in electrical contact with other dissipative materials of the plurality of dissipative materials. In this way, the discharge of static electrical charge on a workpiece in contact with the tip 43 can be controlled.

[0089] Figures 3 to Figure 5 The embodiment shown provides different resistances throughout the travel extent. In some advantageous embodiments of the invention, the idea can be extended such that the ESD protection mechanism can shift between a conductive path and a dissipative path as a function of the travel extent of the head between the extended position and the retracted position.

[0090] Figure 6 Such an embodiment is shown schematically in cross-section. The static electricity discharge protection tool 51 is very similar to the static electricity discharge protection tool 41 of Figure 5 comprises a plurality of dissipative materials 57 each having a different resistance, the electrical contact 56 sequentially contacting the plurality of dissipative materials 57 throughout its travel extent. In addition, a low resistance electrically conductive contact 58 is provided near the lowest extent of the travel extent, arranged to contact the electrical contact 56 when in the retracted position. The electrically conductive contact 58 is electrically connected to a ground connection 59, which is grounded.

[0091] Figure 7 and Figure 8 An alternative embodiment is shown schematically in which the ESD protection mechanism can shift between a conductive path and a dissipative path as a function of the travel extent of the head between the extended position and the retracted position. Figure 7The electrostatic discharge protection tool 61 is shown in the extended position. The head 62 with the tip 63 is movably mounted in the body 64 and biased into the extended position by a biasing means in the form of a compression spring 65. The head 62 comprises an electrical contact 66 configured to contact one of a plurality of dissipative materials 68 located in the body when the head 62 is moved from the extended position to the retracted position, as shown in Figure 8 The electrostatic discharge protection tool 61 is shown in the retracted position. The electrostatic discharge protection tool 61 is again located within the opening of the tool block 67. The head 62 with the tip 63 is movably mounted in the body 64 and biased into the extended position by a biasing means in the form of a compression spring 65. The head 62 comprises an electrical contact 66 configured to contact one of a plurality of dissipative materials 68 located in the body when the head 62 is moved from the extended position to the retracted position, as shown in Figure 8 The arrangement of the dissipative material 68 and the electrical contact 66 can be similar to the arrangements described above, for example with reference to Figure 5 and Figure 6 The head 62 comprises a stem 69 depending downwardly from the electrical contact 66 and, like the tip 63, is electrically conductive, thereby forming an electrically conductive path between the tip 63 and the lowermost part of the stem 69. The stem 69 is slidably arranged within a bore 71 formed in the bottom of the body 64. An electrically conductive contact 70 in the form of a leaf spring is provided at the bottom of the opening in the tool block 67 and is arranged upwardly inclined to contact the stem 69 when the head 62 approaches and enters the retracted position, as shown in Figure 8 The electrically conductive contact 70 is grounded, thereby effectively grounding an electrically charged workpiece (not shown) that can come into contact with the tip 63.

[0092] The above-described embodiments all employ an electrostatic discharge protection tool embedded in a tool block, which can be used in the manner described with reference to the first embodiment, i.e.

[0093] - the tool block is located on a tool table (not shown) of a workpiece machining module to support the workpiece W during a machining operation, the tool block comprising an electrostatic discharge protection tool;

[0094] - the workpiece W, which can be electrically charged with static electricity, is transferred to a machining position located above the tool block, and

[0095] - the workpiece W and the tool table are moved together, for example by lifting the tool table. The tip of the electrostatic discharge protection tool thereby comes into contact with the workpiece W to ground the workpiece W via the at least partially electrically conductive path. Subsequently, by further lifting the tool table, the head is pushed down against the biasing means into the retracted position while maintaining contact with the underside of the workpiece W until the tool block forms a supporting contact with the workpiece W. When the workpiece is fully supported on the tool block, the machining operation can be performed.

[0096] Furthermore, for all these embodiments, it is beneficial that the tip of the electrostatic discharge protection tool contacts a conductive area on the underside of the workpiece W, such as a conductive pad or a conductive track previously printed onto the workpiece W. The method outlined above therefore preferably comprises an initial step of determining the position of the electrostatic discharge protection tool within the horizontal plane such that it is located below a conductive area of the workpiece W. A preferred way of doing this is to analyze Gerber data associated with the workpiece W, which accurately provides information on the location of the conductive areas of the workpiece W.

[0097] As previously mentioned, it is common to use other types of tooling, in particular tooling pins. The present invention is equally applicable to such systems, and the electrostatic discharge protection tool can comprise a free-standing column, optionally adapted to provide support for the workpiece during a machining operation, similar to a standard tooling pin. Here, the term "free-standing column" is used to denote an article in the form of an elongate, having a main axis along its length, which can be affixed to a flat horizontal surface such that the main axis extends vertically, without the article being supported by anything other than that flat horizontal surface. Such an electrostatic discharge protection tool can also be affixed by a smart pin affixing system.

[0098] Figure 9 An electrostatic discharge protection tool 81 is shown schematically, formed as a free-standing column, and can be used as a tooling pin. The electrostatic discharge protection tool 81 comprises a head 82 having a tip 83 at its upper end, the head 82 being relatively movable with respect to a body 84. A biasing device (not shown), such as a compression spring, biases the tip 83 away from the body 84 into the extended position shown. The top of the body is designated 87. Formed between the tip 83 and the lowermost end of the body 84 is an at least partially conductive path, which can ground a charged workpiece (not shown) in contact with the tip 83, with grounding being achieved through a tooling table 85 to which the electrostatic discharge protection tool 81 is affixed. Internally, the electrostatic discharge protection tool 81 can therefore be similar to the electrostatic discharge protection tool 1 shown in Figure 2 The electrostatic discharge protection tool 81 comprises an engagement device 86 in the body 84, here in the form of a pawl. The engagement device 86 is provided to allow engagement with a latch 89 of a pin pick-up 88 of a pin affixing mechanism.

[0099] In use, the head 82 will be pushed towards its retracted position, at which the tip 83 will be at or slightly above the top of the body 87. The top of the body 87 can therefore provide support for the workpiece, similar to a standard tooling pin.

[0100] In an alternative embodiment (not shown), the resistance of the at least partially conductive path can vary as a function of the distance between the tip and the body, similar to the previously described electrostatic discharge protection tools 11, 31, 41, 51, 61.

[0101] An advantage of this jig pin arrangement is that the placement of the electrostatic discharge protection tool 81 has greater flexibility. Advantageously, the position of the electrostatic discharge protection tool 81 is determined in the horizontal plane so that it is located under a conductive region of the workpiece when in use. A preferred way of doing this is to analyse Gerber data associated with the workpiece which accurately provides position information of the conductive regions of the workpiece. The electrostatic discharge protection tool 81 can then be advantageously positioned on the jig table 85 at the determined position using the pin picker 88 of the pin placement mechanism (although manual placement by an operator is also possible). Once any other required jig pins have also been placed, the workpiece can then be transported to a machining position located above the placed jig pins and electrostatic discharge protection tool 81. This is achieved by moving the workpiece and jig table 85 closer together, for example by raising the jig table 85. This brings the tip of the electrostatic discharge protection tool 81 into contact with the workpiece to ground the workpiece via the at least partially conductive path. Subsequently, by further raising the jig table 85, the head 82 is pushed down to the retracted position against the biasing means whilst remaining in contact with the underside of the workpiece until the jig pins make supporting contact with the workpiece. In this position, the electrostatic discharge protection tool 81 can also provide support for the workpiece. When the workpiece is fully supported on the jig pins, the machining operation can be performed. After machining, the jig pins and electrostatic discharge protection tool 81 can remain in place, be repositioned as required, or returned to a store (not shown) for future use.

[0102] The above embodiments are merely exemplary, and other possibilities and alternatives within the scope of the present application will be apparent to those skilled in the art.

Claims

1. An electrostatic discharge protection tool for reducing electrostatic charge on a workpiece within a workpiece processing module, comprising: main body, head, The tip located at the distal end of the head is at least partially conductive. The head is movable relative to the body between an extended position at the maximum distance between the tip and the body and a retracted position at the minimum distance between the tip and the body. A biasing device for biasing the head to the extended position, and A path that is at least partially conductive is formed between the tip and the body for grounding a charged workpiece in contact with the tip; The resistance of the at least partially conductive path varies depending on the distance between the tip and the body; The at least partially conductive path includes a resistor network having a plurality of resistors each having a different resistance value, the resistor network being arranged such that when the distance between the tip and the body is a first distance, the at least partially conductive path includes a first resistor of the plurality of resistors, and when the distance between the tip and the body is a second distance, the at least partially conductive path includes a second resistor of the plurality of resistors.

2. An electrostatic discharge protection tool for reducing electrostatic charge on a workpiece within a workpiece processing module, comprising: main body, head, The tip located at the distal end of the head is at least partially conductive. The head is movable relative to the body between an extended position at the maximum distance between the tip and the body and a retracted position at the minimum distance between the tip and the body. A biasing device for biasing the head to the extended position, and A path that is at least partially conductive is formed between the tip and the body for grounding a charged workpiece in contact with the tip; The resistance of the at least partially conductive path varies depending on the distance between the tip and the body; The at least partially conductive path includes a variable resistor; the variable resistor includes an electrically controlled potentiometer.

3. An electrostatic discharge protection tool for reducing electrostatic charge on a workpiece within a workpiece processing module, comprising: main body, head, The tip located at the distal end of the head is at least partially conductive. The head is movable relative to the body between an extended position at the maximum distance between the tip and the body and a retracted position at the minimum distance between the tip and the body. A biasing device for biasing the head to the extended position, and A path that is at least partially conductive is formed between the tip and the body for grounding a charged workpiece in contact with the tip; The resistance of the at least partially conductive path varies depending on the distance between the tip and the body; The at least partially conductive path includes a plurality of dissipative materials with different resistances, the plurality of dissipative materials being arranged such that when the distance between the tip and the body is a first distance, the at least partially conductive path includes a first dissipative material of the plurality of dissipative materials, and when the distance between the tip and the body is a second distance, the at least partially conductive path includes a second dissipative material of the plurality of dissipative materials.

4. The electrostatic discharge protection tool according to any one of claims 1 to 3, further comprising conductive contacts arranged to form part of the at least partially conductive path when the head is in the retracted position, but not to form part of the at least partially conductive path when the head is in the extended position.

5. The electrostatic discharge protection tool according to any one of claims 1 to 3 further includes a freestanding column adapted to provide support for the workpiece during machining operations.

6. The electrostatic discharge protection tool according to claim 5 further includes a bonding device for bonding with the pin mounting mechanism of the workpiece processing module.

7. A tooling block for supporting a workpiece during machining operations, comprising an electrostatic discharge protection tool according to any one of claims 1 to 4.

8. The tooling block according to claim 7 further includes a bulk material, wherein the electrostatic discharge protection tool is located within an opening formed in the bulk material.

9. The tooling block of claim 8, further comprising a dissipative material disposed between the tip and the tooling block, such that the at least partially conductive path is arranged to be grounded via the bulk material.

10. A printing press comprising an electrostatic discharge protection device according to any one of claims 1 to 6.

11. The printing press of claim 10, further comprising a tooling table for supporting the tooling thereon, the electrostatic discharge protection tool being located on the tooling table.

12. A method for protecting a workpiece from electrostatic discharge, comprising the following steps: i) Positioning the fixture on the tooling table of the workpiece processing module to support the workpiece during processing operations, the fixture comprising an electrostatic discharge protection tool according to any one of claims 1 to 6. ii) Transporting the workpiece to the machining position located above the tooling, and iii) Move the workpiece and the tooling table together relative to each other so that the tooling makes supporting contact with the workpiece and the tip of the electrostatic discharge protection tool contacts the workpiece, thereby grounding the workpiece via the at least partially conductive path.

13. The method of claim 12, further comprising an initial step of determining the position of the electrostatic discharge protection tool so that it is located below a conductive region of the workpiece.

14. The method according to claim 13, wherein, The initial steps for determining the location of the electrostatic discharge protection tool include analyzing Gerber data associated with the workpiece.

15. The method according to claim 12, wherein, The tooling includes tooling blocks.

16. The method according to claim 12, wherein, The tooling includes multiple tooling pins.

17. The method according to claim 16, wherein, Step i) includes using the pin mounting mechanism of the processing module to move the tooling pins and the electrostatic discharge protection tool.

18. The method according to claim 12, wherein, The processing module includes a printing machine.

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