Control of workstations in assembly lines

• US 6,104,965 A
• Filed: 05/01/1997
• Issued: 08/15/2000
• Est. Priority Date: 05/01/1997
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lim, Hun Chiang, Lim, Ka Tiek
• Primary Examiner(s): Grant, William
• Assistant Examiner(s): Robinson, Victoria
• Application Number:
  US08/846,451
• Time in Patent Office: 1,202 Days
• Field of Search: 422/67, 306/414, 235/462, 82/125, 72/336, 198/419.3, 198/341, 700/3, 700/112, 700/115, 29/783
• US Class Current: 700/112
• CPC Class Codes: G05B 19/41865 characterised by job scheduling, process planning, material flow
• CPC Class Codes: G05B 2219/32019 Dynamic reconfiguration to maintain optimal design, fabrication, assembly
• CPC Class Codes: G05B 2219/32297 Adaptive scheduling, feedback of actual proces progress to adapt schedule
• CPC Class Codes: G05B 2219/32305 Fastest interrupt time, change jobs dynamically to fastest machine
• CPC Class Codes: G05B 2219/45035 Printed circuit boards, also holes to be drilled in a plate
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H05K 13/085 Production planning, e.g. of allocation of products to machines, of mounting sequences at machine or facility level
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A workstation (1) in an assembly line for placing components onto workpieces is associated with a conveyor (3) for conveying the workpieces into and out of workstation (1). A component placer (6) places components from a component feeder (5) onto the workpieces. Controller (4) controls conveyor (3) and component placer (6) and determines placement operations for a workpiece. Information may be provided by a preceding workstation to controller (4) to determine the operations. When an idle status signal from a subsequent workstation is received, controller (4) determines information on how much of the operations have been executed or unexecuted by workstation (1). This information, associated with the workpiece, is then provided to the subsequent workstation when the workpiece is conveyed to the subsequent workstation. Thereafter, workstation (1) provides an idle status signal to the preceding workstation to request for another workpiece.

Claims

1. A system for controlling multiple workstations in an assembly line, comprising:

a plurality of independent workstations coupled to each other by a conveyor, each workstation having an executing means for executing one or more operations on a workpiece and having a controller coupled to the executing means and the conveyors; and

wherein the controller of one of the plurality of workstations is adapted to control the executing means in that workstation to reduce said one or more operations in response to an idle status signal received from the controller of a subsequent workstation, and to communicate an idle status signal to the controller of a preceding workstation, and to control the conveyor to convey the workpiece to the subsequent workstation to complete a remainder of said reduced operations on the workpiece.

2. The system of claim 1, wherein said controller of one of the plurality of workstations is adapted to determine information indicative of unexecuted operations of said reduced operations and provide said information to at least one subsequent workstation.

3. The system of claim 1, wherein said controller of one of the plurality of workstations is adapted to determine information indicative of executed operations of said reduced operations and provide said information to at least one subsequent workstation.

4. The system of claim 1, wherein said controller of one of the plurality of workstations communicates an idle status signal to at least one preceding workstation when said workpiece is conveyed out of the workstation.

5. The system of claim 1, wherein when said workstation is inoperable, said controller is adapted to provide an idle status signal to at least one preceding workstation.

6. A method for controlling a workstation in an assembly line having a plurality of workstations in communication with each other, said method comprising the steps of:

receiving a workpiece from a preceding workstation;

determining one or more operations to be performed on said workpiece;

reducing the extent of said one or more operations in response to a signal received from a subsequent idle workstation; and

transferring said workpiece to said subsequent idle workstation in order to perform at least a portion of said reduced operations.

7. The method of claim 6, wherein said step of reducing further comprises the steps of:

determining information indicative of unexecuted operations of said one or more operations; and

providing said information to at least one subsequent workstation.

8. The method of claim 6, wherein said step of reducing further comprises the steps of:

determining information indicative of executed operations of said one or more operations; and

providing said information to at least one subsequent workstation.

9. The method of claim 6, further comprising the step of providing an idle status signal to at least one preceding workstation when said workpiece is transferred out of said workstation.

10. The method of claim 6, further comprising the step of receiving information from said preceding workstation to determine said one or more operations.

11. The method of claim 6, further comprising the step of providing, when said workstation is inoperable, an idle status signal to at least one preceding workstation.

12. A placement workstation comprising:

a component placer for executing one or more placement operations on a workpiece;

a conveyor for conveying said workpiece, said conveyor being associated with said component placer; and

a controller coupled to control said component placer and said conveyor, wherein said controller is adapted to control said component placer to reduce said one or more placement operations in response to an idle status signal communicated from a preceding workstation and, thereafter, to control said conveyor to convey said workpiece out of said placement workstation.

13. The placement workstation of claim 12, wherein said controller is adapted to determine information indicative of executed or unexecuted operations of said one or more placement operations and provide said information to at least one subsequent placement workstation.

14. The placement workstation of claim 12, wherein said controller is adapted to provide an idle status signal to at least one preceding placement workstation when said workpiece is conveyed out of said placement workstation.

15. The placement workstation of claim 14, wherein said controller is further adapted to receive information from said preceding placement workstation, said information being for said controller to determine said one or more placement operations.

16. The placement workstation of claim 12, wherein when said placement workstation is inoperable, said controller is adapted to provide an idle status signal to at least one preceding placement workstation.