Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K13/00—Apparatus or processes specially adapted for manufacturing or adjusting assemblages of electric components
  • H05K13/0061—Tools for holding the circuit boards during processing; handling transport of printed circuit boards
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K13/00—Apparatus or processes specially adapted for manufacturing or adjusting assemblages of electric components
  • H05K13/04—Mounting of components, e.g. of leadless components
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/0008—Apparatus or processes for manufacturing printed circuits for aligning or positioning of tools relative to the circuit board
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/0011—Working of insulating substrates or insulating layers
  • H05K3/0044—Mechanical working of the substrate, e.g. drilling or punching
  • H05K3/0047—Drilling of holes

Definitions

• the present invention refers to a machine tool for the processing of packs of printed circuits.
• the machine tools of the aforesaid type generally include a worktable, at least one operating head, with a tool-carrier spindle and means to obtain a relative shifting between the operating head and the table along three coordinated directions.
• the operating head is vertically movable on a support which, in turn, is movable on a crosspiece along one of the two horizontal coordinated directions.
• the movement along the other coordinated direction can be obtained by moving the table as regards the fixed crosspiece, or moving the crosspiece as regards the fixed table.
• a crosspiece is equipped with a series of operating heads able to perforate a set of printed circuit packs carried by the table.
• the crosspiece is fixed, while the table is movable in a direction perpendicular to the crosspiece.
• the heads are moved along the crosspiece independently of each other, by corresponding electric motors, each of which turns a nut screw engaged with a common screw.
• This known machine tool has the drawback of not allowing each head to move along the entire width of the usual work area of the table, so certain parts of the work area can be engaged by only one operating head. Therefore in the event of a breakdown of the only head able to act on one given part of the work area, this part of the table becomes unusable. Moreover, the machine does not allow the use of a second crosspiece, therefore its productivity is relatively limited.
• a machine tool design has been proposed with more than one crosspiece, in which the table is fixed, while the crosspieces are movable independently of each other as regards the table.
• Each crosspiece is fitted with various operating heads, each movable independently of each other.
• each operating head it is not possible .to arrange each operating head in a corresponding rest position, in order to enable each head of the crosspieces to move along the entire width of the work area of the table.
• this machine design proves to be difficult to realize and does not allow easy automatic tool change.
• each crosspiece carries a pair of operating heads, these also being movable independently of each other along a second direction.
• the two crosspieces are each driven by an electric motor, by means of a corresponding screw/nut screw pair.
• the two heads of each crosspiece are each moved by an electric motor by means of a corresponding screw/nut screw pair.
• One aim of the invention is to realize a machine tool for the processing of printed circuit packs, that allows high productivity and reliability with the least number of operating heads, and enables processing on the entire work area of the table, even if one head or one crosspiece remains inactive.
• Another aim of the invention is to carry out the shifting of the crosspieces and the heads by means of linear motors, integrated with the structure on which they are applied.
• the first of these aims is achieved by a machine tool for the processing of packs of printed circuit boards, including a rigid bed, carrying a worktable with a predetermined work area, a pair of crosspieces movable, as regards said table, along a first direction independently of each other, each of said crosspieces carrying at least one operating head movable along a second direction, characterized in that each of said crosspieces is able to be brought into a corresponding rest position disposed outside said work area, and is able to move along said first direction across the said entire work area, said rest positions being disposed on opposite sides as regards said work area.
• each crosspiece includes a pair of uprights able to slide on two parallel guides carried by said bed, each upright being movable along the first direction by a corresponding linear motor that can be operated under the control of a corresponding position indicator, each of said linear motors including a set of electrical windings carried by the corresponding upright, and a series of permanent magnets carried by said bed, each of said position indicators including a scale carried by said bed and a position transducer carried by said upright.
• Figure 1 is a perspective view of a machine tool for the processing of printed circuit packs according to the invention
• Figure 2 is a partial perspective view of a machine tool according to a variant of the invention
• Figure 3 is a perspective view of a detail of Figure 2, in enlarged scale
• Figure 4 is a center line cross-section of the machine of
• Figure 5 is a side view according to the line V-V of Figure 4;
• Figure 6 is a block diagram of the control unit of the machine .
• a machine tool for the processing of packs of printed circuit boards is generically denoted by 5, e.g. a perforating machine.
• a pack to be perforated is generically denoted by 6 and is illustrated with dotted lines.
• each pack of boards 6 is formed by some circuit boards packed between two support plates, connected to each other by two pins disposed along a center line of the pack 6. The positions of the holes to be made on the boards are arranged according to a matrix of rows and columns.
• the two pins of the pack 6 protrude from one of the two plates and are locked by a clamp fixture 8 including a pair of bars 9 separated by a slot 7, and movable as regards each other.
• the machine tool 5 essentially includes a rigid bed 10, carrying a worktable 11, on which the fixture 8 is fixed.
• the table 11 has a predetermined work area, which is entirely covered by the fixture 8..
• various fixtures 8 can be fixed on the table 11 of lesser dimensions, that cover the work area of the table and can hold as many packs 6 to be processed simultaneously.
• the machine tool 5 also includes a pair of crosspieces 12, which are movable as regards the table 11 parallel to themselves.
• the crosspieces 12 are movable independently of each other, along a first direction, or Y axis, perpendicular to the crosspieces 12 themselves. Therefore, the table 11 is normally fixed on the bed 10 and can be integrated, or en bloc, with the bed 10 itself.
• Each crosspiece 12 is fitted with a corresponding pair of operating heads 13, each carried by a corresponding carriage 14.
• the two carriages 14 are movable along a second direction, or X axis, parallel to the crosspieces 12, also independently of each other.
• the X and Y axes are parallel to the plane of the table 11, that is normally horizontal.
• the head 13 is able to slide on the corresponding carriage 14 along a third direction, or Z axis, perpendicular to the two X and Y axes.
• Each head 13 includes a rotating spindle 16, in which a tool, e.g. a drill bit 17 is fixed.
• each crosspiece 12 is able to be brought into a corresponding rest position 18, disposed outside the work area of the table 11, and is able to move along the Y axis across the entire work area of the table.
• the two work positions 18 are disposed on opposite sides as regards the work area of the table 11. In this way, when a crosspiece 12 is inactive for any reason, the other crosspiece 12 can carry out the processing in any point of the work area.
• the carriage 14 of each operating head 13 is able to bring the head 13 in a corresponding rest position 19 along the relative crosspiece 12.
• Such rest position is disposed also outside the work area of the table 11, while the carriage 14 is able to move the head 13 along the X axis across the entire work area itself.
• the two rest positions 19 of the two heads 13 of each crosspiece 12 are disposed on opposite sides as regards the work area of the table 11. In this way, when an operating head 13 is inactive for any reason, the other head 13 of the same crosspiece 12 can carry out the processing in any point of the work area.
• Each crosspiece 12 is fixed on a pair of uprights 21, which are able to slide on two parallel guides 22 carried on the bed 8.
• the guides 22 are of prismatic type and are common to the two crosspieces 12.
• each upright 21 is fitted with a pair of ball circulation sliding blocks 23, which engage the corresponding prismatic guide 22, as is more clearly shown for the alternative of Figure 2, where one of the crosspieces 12 has been removed for reasons of clarity.
• the two uprights 21 of a crosspiece 12 are moved along the Y axis by two corresponding linear motors, each generically denoted by 24.
• the two motors 24 are retroaction operated by a control unit 26 ( Figure 6) , under the control of a corresponding position indicator, generically denoted by 27 ( Figure 4) .
• the control unit 26 controls one of the two motors 24 as master and the other motor 24 as slave, in a way known in itself.
• Each linear motor 24 includes a stator formed by a series of permanent magnets 28 'carried by a structure 29. This is fixed on the bed 10, and is disposed on the outside as regards the corresponding prismatic guide 22.
• the structure 29 is C-shaped in the variant of Figure 1 and U-shaped in the variant of Figures 2-5, where it is housed in a lowered portion 31 of the bed 10.
• the structure 29 of the variant of Figures 2-5 includes a C-shaped profile 32, on whose wings are fixed two flat bars 33.
• the permanent magnets 28 are disposed on two rows fixed on the two bars 33 and facing each other. The magnets 28 in each row are equidistant from each other.
• Each linear motor 24 besides includes a set of three electrical windings 34 ( Figure 2) carried by a corresponding support 36.
• This element 36 is fixed on the corresponding upright 21 so as to slide between the two rows of permanent magnets 28.
• the structure 29 is common to the motors 24 of the two uprights 21 of the crosspieces 12 guided by the same prismatic guide 22.
• Each position indicator 27 includes a scale 37 formed by a thin strip with a series of signs, which are readable by a position transducer 38 ( Figure 4), e.g. of optical type, fixed on the corresponding upright 21.
• the scale 37 is fixed on the bed 8 inside the corresponding prismatic guide 22 and common to the position indicators 27 of the two uprights 22 of the crosspieces 12 guided by the same prismatic guide 22.
• the support 36 and the transducer 38 of each upright 21 are thus fixed on the two walls disposed on opposite sides as regards the relative pair of sliding blocks 23, so the two uprights 21 of each crosspiece 12 mirror each other, i.e. are symmetrical as regards a median plane of the machine 5, parallel to the Y axis .
• Each crosspiece 12 has a prismatic shape with a vertical wall
• each crosspiece 12 and the relative uprights 21 - are made of bent and welded sheet metal.
• each crosspiece 12 and the relative uprights are made of cast iron or suitable alloy.
• two prismatic guides 41, parallel to each other, are fixed on the wall 39. The two guides 41 are able to guide the two carriages 14 of the two operating heads 13 in the movements on the relative crosspiece 12 along the X axis.
• each carriage 14 On a vertical wall of each carriage 14, opposite the spindle 16 ( Figure 3), are fixed two pairs of ball circulation sliding . blocks 42, which engage the two prismatic guides 41, so that also these guides 41 are common to the two carriages 14 of the crosspiece 12.
• Each carriage 14 is moved along the crosspiece 12 by a corresponding linear motor 43, only one of which is visible in Figure 3.
• the linear motors 43 are retroaction operated by the control unit 26 ( Figure 6) under the control of a corresponding position indicator 44.
• Each linear motor 43 includes a stator formed by a series of permanent magnets 46 ( Figure 3) disposed on two rows and fixed on two flat bars 47 in a similar way to the magnets 28 of the linear motors 24.
• the two bars 47 are disposed in a groove 48 of the crosspiece 12, disposed between the two guides 41.
• Each linear motor 43 besides includes a set of three electrical windings 45 only one of which is visible in Figure 3.
• the windings 45 are carried by a corresponding support 49 fixed on the vertical wall of the corresponding carriage 14 between the two pairs of sliding blocks 42, so as to slide between the two rows of permanent magnets 46.
• the two bars 47 and the permanent magnets 46 are thus common to the two motors 43 of the two carriages 14 of each crosspiece 12.
• Each position indicator 44 includes a scale 51, similar to scale 37, which is fixed on the wall 39 of the crosspiece 12 and is read by a position transducer 52 fixed on an appendix
• the scale 51 is thus common to the position indicators 44 of the two carriages 14.
• the two crosspieces 12, together with the uprights 21 mirror each other, i.e. symmetrical as regards a median plane of the machine 5, parallel to the X axis, when they are in the respective rest positions 18.
• This arrangement and the form of the section of the crosspiece 12 has the advantage of reducing the minimum distance in which the two crosspieces 12 can work simultaneously, and hence .the distance of each rest position 18 from the work area of the table 11.
• each head 13 includes a support body 54 of the spindle 16, with a vertical wall, on which are fixed two pairs of ball circulation sliding blocks 56, engaged with the two prismatic guides 53.
• Figure 3 is visible only one sliding block 56 of one of the two pairs of sliding blocks on each of the two operating heads 13.
• Each operating head 13 is moved along the Z axis on the carriage 14 by a corresponding linear motor 57, retroaction operated by the control unit 26 (see also Figure) under the control of a corresponding position indicator 58.
• Each linear motor 57 includes a stator formed by a series of permanent magnets 59 carried by a structure 61, fixed on a lateral wall 62 of the carriage 14, facing the exterior of the machine 5.
• the structure 61 is formed by a C-shaped profile 63, on whose wings are fixed two flat bars 64.
• the permanent magnets 59 are disposed on two vertical rows and are fixed on the two bars 64 in the same way as the magnets 28 of the linear motors 24.
• Each linear motor 57 - also includes a set of three electrical windings similar to the windings 34 and not shown in the drawings, which are carried by a corresponding support 66 fixed on a lateral wall 67 of the body 54, so as to slide between the two rows of permanent magnets 59.
• Each position indicator 58 includes a scale 68, similar to the scale 37, which is fixed on the internal side of the body 54 and is read by a position transducer 69 fixed on the corresponding carriage 54.
• the two operating heads 13 and the relative carriages 14 of each crosspiece 12 thus mirror each other, i.e. symmetrical as regards a median plane of the machine 5, parallel to the Y axis, when they are in the respective rest positions 19.
• This arrangement has the advantage of reducing the minimum distance between the two carriages 14, in which the two heads 13 can work simultaneously, and hence the distance of each rest position 19 from the work area of the table 11.
• the bed 10 besides carries, at each rest position 18 ( Figure 1) of each crosspiece 12, a tool change device 71, joined to each operating head 13 of the crosspiece 12, and a corresponding pair of tool cribs 72 and 73, respectively for the new and used tools.
• Each tool crib 72, 73 can be of the tool rows and columns matrix type.
• Preferably each tool crib 72, 73 is able to contain a large number of tool sticks 17, known in themselves.
• the device 71 is able to change the tool 17 of a spindle 16 in a known way, when the crosspiece 12 and the relative head 13 are disposed in the corresponding rest positions 18 and 19.
• the tool cribs of the new utensils 72 are disposed towards the centre of the machine 5, as shown in Figure 1.
• the machine tool 5 operates in the following way.
• control- unit 26 arranges the two crosspieces 12 in the relative rest positions 18 along the Y axis, and the two pairs of operating heads 13 in the respective rest positions 19 along the X axis. Should it be necessary to replace the tool 17 of one or more spindles 16, the control unit 26 activates the corresponding change device (s) 71. Each device 71 then extracts the used tool 17 from the relative spindle 16 and puts it back in the relative tool crib 73. Then it selects the new tool 17 on the relative tool crib 72 and inserts it into the spindle 16.
• the control unit 26 When the crosspieces 12 and the operating heads 13 are in the relative rest positions 18, 19, the operator places the pack 6, of printed circuit boards to be processed, on the fixture 8, locking it between the two bars 9. Should the table 11 be fitted with several fixtures 8 to simultaneously process several packs 6, the operator places the corresponding packs 6, to be processed, on the fixtures 8.
• the control unit 26 now operates the motors 24 so as to carry the two crosspieces 12 in correspondence to the two rows of holes to be made on the pack or packs 6.
• the control unit 26 operates the motors 43 so as to carry the carriages 14 in correspondence to the two rows of holes to be made on each row.
• control unit 26 operates the motors 57 so as to move the respective operating heads 13 along the Z axis, carrying out the respective perforations.
• the movements of the crosspieces 12 along the Y axis, of the carriages 14 along the X axis and of the heads 13 along the Z axis are carried out independently of the two crosspieces 12, the carriages 14 and the heads 13, so the processing of the packs 7 of circuits can be optimized and programmed with high flexibility. Furthermore, should one operating head 13 require a tool 17 change, the control unit 26 carries such head 13 and the relative crosspiece 12 in the relative rest positions 19 and 18 to carry out such change of tool 17, while the heads 13 of the other crosspiece 12 continue the processing.
• one of the operating heads 13 In the event in which, for any reason, e.g. a breakdown or a maintenance operation, one of the operating heads 13 is unusable for perforation, it can be kept on the crosspiece 12 in the relative rest position 19, while the other head 13 can be moved on the crosspiece 12 along the X axis across the entire width of the work area of the table 11, so as to execute all the holes of each column. Similarly in the event in which, for any reason, one of the two crosspieces 12 is unusable, it is disposed in the corresponding rest position 18, while the other crosspiece 12 is moved along the Y axis across the entire length of the work area of the table 11, so as to enable the perforation of all the rows of holes of the pack(s) 6.
• the two crosspieces 12 and the two pairs of heads 13 allow the increase in productivity of the machine, in terms of holes per time unit.
• the independent movements of the crosspieces 12, of the carriages 14 and of the heads 13, enable optimization of the perforation programme.
• the use of the linear motors 24 and 43, integrated with the relative structures 10 and 12 enable the use of the same stator for the linear motors of two uprights 21 and, respectively of two carriages 14.
• the table 11, or the fixture 8 can be fitted with adjustment means of the position of the pack 6.
• one of the two heads 13 of a crosspiece 12 can be movable on the carriage 14 along the Y axis, in order to carry out the perforation on a row of the matrix different to those of the other head.
• one or more motors 24, 43 or 57 can be replaced by a hydraulic motor or a rotary motor joined to a screw/nut screw pair.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Details Of Cutting Devices (AREA)
• Machine Tool Units (AREA)

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Publications (1)

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ID=11458571

Family Applications (1)

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Cited By (7)

Citations (4)

• 2001
  • 2001-02-16 IT IT2001TO000141A patent/ITTO20010141A1/it unknown
• 2002
  • 2002-02-15 WO PCT/IT2002/000093 patent/WO2002067648A1/en not_active Application Discontinuation

Patent Citations (4)

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