Various embodiments of the invention described herein relate to the field of pick and place machines, and more particularly to pick and place collets therefor.
SMT (surface mount technology) component placement systems, commonly called pick and place machines, are robotic machines used to place surface-mount devices (SMDs), integrated circuits and other electronic devices onto, for example, printed circuit boards (PCBs) or tapes for subsequent packaging and distribution to customers. Pick and place machines are used for high speed, high precision placing of a broad range of electronic components, such as capacitors, resistors, integrated circuits onto PCBs or tapes, or in reel pockets, and the like. Such machines typically use pneumatic collets, which are may be accurately manipulated in three dimensions.
When transferring electronic devices at high rates of speed from one location to another using a vacuum-operated collet, alignment errors can occur. For example, if electronic devices provided in tubes are to be transferred from the tubes to pockets on a reel, misalignments can occur as the devices are transferred by the collet from the tubes to the pockets, which can result in damage to the misaligned electronic device, or to other devices packaged on the same reel.
Among other things, what is needed is a pick and place machine having a reduced rate of electronic devices picked and placed thereby that are misaligned.
In one embodiment, there is provided a self-aligning pick and place collet having proximal and distal ends configured for use with a tape and reel machine comprising a vacuum aperture disposed between the proximal and distal ends of the collet and configured to pull a vacuum through a distal portion thereof, a suction area located at the distal end of the collet, the suction area being contiguous with and adjoining the distal portion of the vacuum aperture and defining a first outer periphery, the suction area being substantially perpendicular to an imaginary axis of the vacuum aperture, and a pick and place collet contact area located adjacent to and outwardly from the suction area, the pick and place collet contact area comprising tapered sidewalls that depend downwardly and outwardly away from the first outer periphery of the suction area, wherein the distal end of the collet and the suction area are configured to permit the suction area to be placed over a top surface of an electronic device, and the tapered sidewalls and the first outer periphery of the suction area are configured and dimensioned to cause the electronic device to substantially self-align and center itself with respect to the collet after the distal end of the collet has been placed over the electronic device and portions of the tapered sidewalls have engaged a second outer periphery of the top surface of the electronic device, the collet being configured to permit the electronic device to be picked up after the vacuum has been applied through the vacuum aperture thereto.
In another embodiment, there is provided a tape and reel machine for picking and placing electronic devices comprising a self-aligning pick and place collet having proximal and distal ends configured for use with the tape and reel machine, a vacuum aperture disposed between the proximal and distal ends of the collet and configured to pull a vacuum through a distal portion thereof, a suction area located at the distal end of the collet, the suction area being contiguous with and adjoining the distal portion of the vacuum aperture and defining a first outer periphery, the suction area being substantially perpendicular to an imaginary axis of the vacuum aperture, and a pick and place collet contact area located adjacent to and outwardly from the suction area, the pick and place collet contact area comprising tapered sidewalls that depend downwardly and outwardly away from the first outer periphery of the suction area, wherein the distal end of the collet and the suction area are configured to permit the suction area to be placed over a top surface of one of the electronic devices, and the tapered sidewalls and the first outer periphery of the suction area are configured and dimensioned to cause the electronic device to substantially self-align and center itself with respect to the collet after the distal end of the collet has been placed over the electronic device and portions of the tapered sidewalls have engaged a second outer periphery of the top surface of the electronic device, the collet being configured to permit the electronic device to be picked up after the vacuum has been applied through the vacuum aperture thereto.
In yet another embodiment, there is provided a method of picking and placing electronic devices with a tape and reel machine comprising placing a self-aligning pick and place collet having proximal and distal ends over a selected one of the electronic devices disposed on a reel, causing the collet to move downwardly and engage portions of the selected electronic device such that tapered sidewalls of a pick and place collet contact area located adjacent to and outwardly from a suction area disposed at a distal end of the collet, where the tapered sidewalls depend downwardly and outwardly away from a first outer periphery of the suction area, cause the selected electronic device to substantially self-align and center itself with respect to the collet, and picking the selected electronic device up with the collet after a vacuum has been applied through a vacuum aperture located in the collet.
Further embodiments are disclosed herein or will become apparent to those skilled in the art after having read and understood the specification and drawings hereof.
Different aspects of the various embodiments will become apparent from the following specification, drawings and claims in which:
The drawings are not necessarily to scale. Like numbers refer to like parts or steps throughout the drawings.
Experience has shown that during high speed automated pick and place operations the configuration and design of collet 20 shown in
Misalignment of device 42 with respect to pocket 16 can cause cascading problems, such as damage to device 42, damage to other devices 42 on reel 12, and damage to reel 12. Misalignment of device 42 with respect to pocket 16 can also cause distorted or bent leads on device 42, or pick and place machine stoppages.
Several factors have been discovered to contribute to device misalignments during pick and place operations, including, but not limited to, the vacuum being pulled through vacuum aperture 26 not being strong enough, suction force dropping to unacceptably low levels due to the accumulation or presence of dirt and debris in or around suction area 30 of collet 20 or other portions of distal end 24 of collet 20, and portions of distal end 24 of collet 20 having been subjected to excessive wear, tear, use, contamination, degradation, and/or abrasion.
Referring now to
Continuing to refer to
Referring now to
Tapered sidewalls 38, distal end 24 and suction area 30 may be configured, dimensioned, sized and shaped to permit electronic devices 42 of given dimensions and other physical characteristics such as friction or smoothness to be optimally picked up and self-aligned by collet 20. For example, sidewalls 38, distal end 24 and suction area 30 may be configured, dimensioned, sized and shaped to pick up Surface Mount Technology (SMT) parts, Surface Mount Device (SMD) parts, integrated circuits, and so on, depending on the particular requirements at hand.
According to various embodiments shown in
As further shown in
Set forth below in Table 1, and with further reference to
Corresponding to the teachings and disclosures made above are various methods of picking and placing electronic devices 42 with tape and reel machine 10. Such methods include steps comprising placing self-aligning pick and place collet 20 having proximal and distal ends 22 and 24 over a selected one of electronic devices 42 disposed on reel 12, causing collet 20 to move downwardly and engage portions of the selected electronic device 42 such that tapered sidewalls 38 of pick and place collet contact area 36 located adjacent to and outwardly from suction area 30 disposed at a distal end of collet 20, where tapered sidewalls 38 depend downwardly and outwardly away from first outer periphery 31 of suction area 30, cause selected electronic device 42 to substantially self-align and center itself with respect to collet 20. These steps are then followed by picking selected electronic device 42 up with collet 20 after a vacuum has been applied through vacuum aperture 26 located in collet 20, and may further include one or more of moving selected electronic device 42 over a tape 14 or reel 12, placing selected electronic device 42 in pocket 16, releasing the vacuum in collet 20 and moving collet 20 away from selected electronic device 42, and repeating the steps recited above with respect to another selected electronic device 42.
Referring now to
The steps described above and illustrated in
The above-described embodiments should be considered as examples of the present invention, rather than as limiting the scope of the invention. In addition to the foregoing embodiments of the invention, review of the detailed description and accompanying drawings will show that there are other embodiments of the present invention. Accordingly, many combinations, permutations, variations and modifications of the foregoing embodiments of the present invention not set forth explicitly herein will nevertheless fall within the scope of the present invention.