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
  • H05K13/04—Mounting of components, e.g. of leadless components
  • H05K13/0404—Pick-and-place heads or apparatus, e.g. with jaws
• • 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
  • H05K13/02—Feeding of components
  • H05K13/021—Loading or unloading of containers

Definitions

• the invention concerns apparatus and methods for component placement during the manufacture of arrays of components.
• Arrays of components may be assembled for many purposes. Typically,
• a substrate such as a printed circuit board.
• integrated circuits may be of the dual in-line pin (DIP) form.
• DIP dual in-line pin
• Other components such as capacitors, resistors, sensor packages or piezoelectric sound transducers may have to be added to a printed circuit board to form a particular circuit.
• a variety of machines is available for assembling arrays of components. These machines tend to have certain common features. Amongst these is some form of feeder mechanism for bringing components to the machine, i.e. to the location where the component array is to be assembled. Some arrangement of picking and transporting device(s) will then take an individual component from the feeder mechanism and place it on the substrate on which the component array is being assembled.
• a known prior art component placement device includes actuators for moving a placing head in all three dimensions. This allows the head to be moved in each of the V, y and 'z' directions.
• the head itself has a motor or other rotating mechanism mounted on it which can rotate a component prior to placing it on the substrate. This motor or other rotating mechanism therefore puts the component which it holds into the correct orientation prior to placement on the substrate. This orientation is conventionally termed the 'theta' axis.
• Figure 1 shows a highly simplified view of a prior art component placement apparatus.
• the placing head 12 carries a motor 14.
• Motor 14 rotates a component into the correct orientation prior to placement on a printed circuit board.
• Motor 12 therefore sets the orientation angle 'theta' for the component.
• the placing head 12 may be slideably mounted on the cross-member 10.
• the cross-member 10 forms substantially a right angle with each of the guide rails 2 and 4.
• a component is first picked up from the component feeder mechanism by an engagement member which is part of the placing head 12.
• the engagement member may, for example, be constituted by a set of jaws or fingers mounted on the motor 14.
• the engagement member is not shown on figure 1, and would be obscured from sight by the motor 14 in the view of the apparatus shown in figure 1.
• the placing head 12 in figure 1 is moved to the point where it overlies the printed circuit board onto which the component is to be placed. This movement is facilitated by movement of the mounts 6 and 8 along their respective guide rails 2 and 4.
• the motor 14 rotates the component until its orientation is correct for placing on the printed circuit board.
• a component placement apparatus in accordance with the invention comprises: at least one component holder for placing a component on a substrate, the said component holder being mounted on a first linear support; second and third linear supports, the said first linear support being mounted on the said second and third linear supports by first and second moveable mounts respectively; the first and second moveable mounts being moveable along the second and third linear supports; and control means for setting a variety of orientations of the component holder relative to the substrate by varying the locations of the said first and second moveable mounts on the said second and third linear supports.
• the or each component holder of the component placement apparatus may further comprise an engagement member for engaging, holding and releasing components of various shapes and sizes.
• the second and third linear supports may have their axes lying substantially parallel.
• first and second moveable mounts may be movable along the second and third linear supports by means of actuators operated by the control means.
• the component holder(s) may be moveable along the first linear support by means of an actuator or actuators operated by the control means.
• the first linear support may be connected to the first and second moveable mounts by first and second joints respectively, the first and second joints permitting the angle between the first linear support and the respective one of the second and third linear supports to vary.
• One of the said first and second joints may hold the first linear support slideably and the other joint may then hold the first linear support without allowing sliding movement along the direction of the first linear support's axis.
• a rigid bar constitutes the said first linear support
• four component holders are mounted on this rigid bar
• a microprocessor constitutes the control means and there are two electrical actuators, each driving one of the moveable mounts independently of the other moveable mount under the control of the said microprocessor so as to set the orientation of the component holders relative to the substrate.
• the component placement apparatus may further comprise at least one actuator which translates the first linear support in the direction of its own axis.
• the component placement apparatus may further comprise a fourth linear support, the said fourth linear support bearing further component holders and being mounted on the said second and third linear supports by third and fourth moveable mounts respectively.
• the component placement apparatus may further comprise a further pair of linear supports serving as guide rails, onto which one or more further linear supports are mounted transversely on slideable mounts.
• the invention allows a greatly simplified mechanical and electro-mechanical construction in comparison with prior art arrangements such as that shown in figure 1.
• the lack of a motor or other active rotating mechanism on the placing head results in: (i) One motor fewer in the device;
• the bar on which the placing head is mounted and the guide rails which support the bar can be of a lighter construction.
• the reduction in the weight of the bar leads to less inertia in this element of the apparatus. This reduced inertia allows more rapid acceleration and deceleration, which therefore leads to a higher operating speed of the entire apparatus and greater substrate throughput.
• a further advantage of the arrangement of the invention lies in the precision with which the orientation of a component can be set. This depends on several parameters of the apparatus. Principally it depends on:
• Figure 1 shows a simplified view of a prior art component placement apparatus.
• Figure 2 shows a simplified view of a component placement apparatus in accordance with the present invention.
• Figure 3 shows the main elements of a component placement apparatus in accordance with the invention, including peripheral apparatus.
• Figure 4 shows an enhanced version of the embodiment of the invention shown in figure 3.
• Figure 5 shows a kinematic diagram which illustrates clearly the most basic principle of the invention.
• Figure 6 shows a detailed kinematic diagram illustrating the principle of one embodiment of the invention.
• Figure 7 shows the main elements of a component placement apparatus functioning in accordance with the principles illustrated in figure 6, including peripheral apparatus.
• Figure 8 shows an enhanced version of the embodiment of the invention shown in figure 7.
• Figure 2 shows simplified plan views 2A-2D of an embodiment of the present invention.
• figure 2A shows component holders 12,14,16 and 18 held by a bar 10.
• Bar 10 forms a first linear support.
• Each component holder includes an engagement member for grasping, holding and eventually releasing an individual component.
• Each engagement member may be suitable for use with a variety of shapes and sizes of component.
• the engagement member may be constituted by a set of jaws or fingers and it may use a Vacuum' suction arrangement.
• the engagement member may include a process related placement arrangement, such as a heater to enable bonding of the components after placement.
• guide rails 2 and 4 are also shown in figure 2B.
• Guide rails 2 and 4 form second and third linear supports.
• the guide rails are generally parallel.
• First and second moveable mounts 6 and 8 are shown, one on each of the guide rails 2 and 4. These movable mounts can slide along their respective guide rails. In the embodiment shown, each mount can be driven along its guide rail independently of the other mount. A variety of relative positions of the two mounts is thus possible.
• a control means which is not shown in figure 2, controls actuators to drive each mount to the desired position.
• the component holders may be designed to pick up a variety of components. These components arrive from a feeder mechanism which is not shown in figures 1 and 2. The components need to be placed on a substrate which can consist, for example, of a printed circuit board.
• the substrate can be considered to He in the plane containing the guide rails 2 and 4.
• the orientation of the substrate relative to the guide rails is constant whilst components are being placed onto the substrate.
• the scope of the invention includes an arrangement where the substrate itself is on a further mount which can change its orientation during the assembly of the components onto the substrate.
• the substrate is located in the region between the guide rails.
• a component holder e.g. component holder 14 moves to pick up a first component from the component feeder.
• This movement consists of a movement of the first and second mounts 6 and 8 along the guide rails 2 and 4 respectively.
• the actuators which move the first and second mounts 6 and 8 along their respective guide rails 2 and 4 can position the ends of bar 10 at any point along the length of the guide rails.
• the bar can be positioned such that it makes substantially a right angle with the guide rails.
• the actuators are also able to control the first and second mounts 6 and 8 independently.
• the mounts 6 and 8 can therefore be positioned such that the bar 10 is not perpendicular to the guide rails 2 and 4. Exactly this situation is illustrated in figures 2B and 2C.
• the bar 10 in each of figures 2B and 2C is not perpendicular to guide rails 2 and 4.
• the slight angle which the bar makes with respect to a perpendicular bisector of each guide rail is marked as theta in each of figures 2B and 2C.
• angle theta depends on the relative positions of mounts 6 and 8 on their respective guide rails 2 and 4. By incremental movement of one or both of mounts 6 and 8, the angle theta can be set with very fine resolution.
• the angle theta determines the exact orientation of the component.
• the invention therefore allows the setting of an exact orientation for a component to be inserted, by precise positioning of mounts 6 and 8.
• the control means which controls the position of mounts 6 and 8 therefore has control over the orientation of a component held by any or all of the component holders 12,14,16 and 18.
• the mounts 6 and 8 are designed such that bar 10 can take a variety of angles relative to the line of the guide rails 2 and 4. At least one of the mounts 6 and 8 allows the bar 10 to slide within it to facilitate this. This allows the bar to occupy orientations such as those in figures 2B and 2C, where the distance separating the mounts 6 and 8 is greater than in the position shown in figure 2A.
• the bar 10 it is also possible for the bar 10 to be arranged to slide along its axis, i.e. to slide in both of mounts 6 and 8. An actuator could then translate bar 10 along the bar's own axis. This motion would either add to or replace the movement of each individual head 12,14,16 or 18 relative to the bar by actuators.
• the invention shown in figures 2B and 2C does not require the component holders 12,14,16, or 18 to have an active component rotating mechanism, such as a motor, on them.
• the component holders can therefore be lighter.
• the bar 10, supports 6 and 8 and guide rails 2 and 4 can be of a fighter construction whilst providing the same rigidity. If the moving parts have lower mass then the moving system has lower inertia, allowing more rapid acceleration and deceleration. This in turn increases the throughput of the component placement apparatus and thus reduces the cost.
• An additional advantage of the arrangement of figure 2 is the accuracy with which theta can be set. If a motor were provided on a component holder such as 14, the motor would need to be of very high quality to provide a precise orientation for a component which it held.
• the precision with which theta can be set with the arrangement of figure 2 depends on the precision with which mounts 6 and 8 can be positioned on their respective guide rails 2 and 4. In general terms, the precision with which mounts 6 and 8 can be located is extremely high. 10
• the precision with which theta can be set also depends on the length of bar 10 and separation of guide rails 2 and 4. This follows from simple geometric considerations. To provide greater precision, the component placement apparatus can be designed with a longer bar 10 and more widely separated guide rails 2 and 4.
• Figure 2D reproduces the view shown in figure 2A
• Figure 2D also includes two superposed dotted representations of the same bar 10 offset at an angle relative to the perpendicular line joining the guide rails. These dotted representations in figure 2D correspond to those shown in figures 2B and 2C.
• control means of the invention directs the various movements necessary to pick up and to place each component on the substrate.
• this control means consists of a microprocessor.
• a suitably programmed industri ⁇ d Pentium processor or PowerPC is adequate for this purpose.
• Figure 3 shows a plan view of the main and peripheral elements of a component assembly machine in accordance with the invention.
• Figure 3 shows guide rails, mounts and two bars of the types already explained in connection with figure 2.
• FIG 3 the feeder mechanism which supplies components to the component assembly machine has been shown. See the upper part of figure 3.
• This feeder mechanism brings a number of components simultaneously to the location of the component assembly machine.
• the feeder mechanism may run slightly below the working surface of the component assembly machine. The feeder trays would therefore pass under the working level of the component assembly machine when the components have been removed from them.
• the component assembly machine includes a number of component extractors. Each component extractor serves to take a component out of the feeder mechanism and move it to a point and an orientation from which one of the component holders can collect it. These component extractors provide 1 1
• the orientation provided by the component extractor can be relatively coarse because the invention allows a further, more precise setting of the component's orientation by the procedure explained above in connection with figure 2.
• Figure 4 adds to the arrangement of figure 3 an additional pair of bars with multiple component holders.
• the provision of further bars and component holders further increases the rate at which components can be loaded onto substrates.
• Figure 5 is a kinematic diagram. This illustrates more clearly the most basic principle of the invention, without the detail of figures 2-4.
• figure 5 is not necessarily a scale representation of a real machine, it is clear that angle theta can take on a wide range of values.
• the upper limit of the value of theta is mainly constrained by the lengths of the guide rails and bar which are practicable.
• the precision to which theta can be set is partly determined by the separation between the guide rails and the length of the bar 10. The greater the separation between the guide rails and the greater the length of bar 10, the greater the precision with which theta can be set.
• FIG. 6 A detailed kinematic diagram is shown in figure 6. This diagram shows the right end of the bar mounted on a pivot. This pivot however prevents the bar from sliding along its length.
• the left end of the bar can also pivot relative to the guard rail which defines the X2 direction. It can however also slide through the mount which connects it to this guide rail. As the relative positions of the two mounts change, the angle theta changes. To accommodate these changes, the left end of the bar slides through its mount.
• the bar pivots relative to both mounts as theta changes.
• Figure 7 shows a similar arrangement to that shown in figure 3, but which functions as shown in principle in figure 6. Elements in figure 7 which correspond to those in figure 3 are not described again here.
• each of the four component holders on each bar can move along the bar.
• the component holders move to the component extractor located above the feeder mechanism concerned.
• each component holder can slide along the bar on which it is mounted in order to prepare for placing its component on the substrate.
• Figure 8 shows an arrangement of four bars.
• the arrangement of figure 8 corresponds largely to that of figure 4, but which functions as shown in principle in figure 6.
• the right ends of the bars are anchored to their mounts such that they can pivot but not slide through their mounts along their own axes.
• the left ends of the bars can both pivot on and slide through their mounts.
• the arrangement of figure 8 corresponds to the detailed kinematic diagram of figure 6.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Supply And Installment Of Electrical Components (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1998
  • 1998-02-12 GB GB9802959A patent/GB2321133B/en not_active Expired - Fee Related
  • 1998-07-10 IE IE980557A patent/IE980557A1/en not_active IP Right Cessation
  • 1998-07-13 JP JP2000531993A patent/JP2002503890A/ja active Pending
  • 1998-07-13 WO PCT/EP1998/004986 patent/WO1999041964A1/en not_active Ceased
  • 1998-07-13 EP EP98942678A patent/EP1053665A1/de not_active Ceased

Non-Patent Citations (1)

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