Autonomous control method and process for an investment casting shell

• US 6,453,210 B1
• Filed: 07/23/1998
• Issued: 09/17/2002
• Est. Priority Date: 07/23/1998
• Status: Expired due to Fees

• Current Assignee: Amsouth Bank As Agent, Patriarch Partners Agency Services, LLC (LD Investment LLC), Vulcan Engineering Company
• Original Assignee: Vulcan Engineering Company
• Inventors: Ash, Darren, Hsu, Tao-Li, Belotserkovskiy, Aleksandr, Walton, Jack L.
• Primary Examiner(s): Picard, Leo
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US09/121,496
• Time in Patent Office: 1,517 Days
• Field of Search: 700/2, 700/7, 700/9, 700/17, 700/79, 700/86, 700/117, 700/96, 700/116, 700/118, 700/121, 700/146, 700/169, 700/201, 700/200, 700/83, 164/165, 164/166, 164/361
• US Class Current: 700/96
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling

Abstract

A predictive industrial control system for controlling individual cells of machines through multiple Programmable Logic Controllers in an investment casting processing and handling operation. An application server located in a remote, non-industrial environment executes an industrial control application (ICA) utilizing tagged reference names corresponding to individual machines and information input devices such as sensors on the production line. The ICA accesses local databases that hold casting shell part numbers and their associated recipe control words, and monitors the system for new shell part numbers as they appear on a load conveyor in the production line. Radio Frequency tags on the part signal the ICA to transfer the appropriate recipe control words and robot moves required to process the part in a primary processing cell'"'"'s PLC. The PLC then controls each machine in the primary processing cell in accordance with the downloaded commands from the ICA. The control program downloaded into the PLC at boot-up is written such that machines connected to the PLC may operate independently from the ICA during a selected number of dip cycles. Since processing instructions are downloaded in a predictive manner well ahead of any situation requiring new instructions, the processing of the ICA instructions on the remote server or communications on a slow industrial network does not limit the processing throughput of each cell; and therefore, the production line throughput. The system allows for alteration of the sequence of processing steps from automatic to manual modes as desired without seriously hampering the system throughput.

Claims

1. An industrial control system for controlling machines processing investment casting shells, comprising:

a. processing recipe means for describing a sequence of processing steps for a selected casting shell, each said recipe means including a series of dip cycles;

b. storage means for holding a plurality of said recipe means;

c. processing means for associating one of said recipe means with a casting shell loaded onto a loading conveyor, said processing means including means for identifying a single dip cycle within said associated recipe means;

d. programmable logic means for autonomous control over said machines after receipt of said single dip cycle; and

,

e. network means for passing said single dip cycle to said programmable logic means.

2. A control system as recited in claim 1, wherein said programmable logic means comprises:

a. a processor;

b. main processor memory;

c. an executable control program loaded into said main processor memory for processing by said processor;

d. means for local I/O communications with said machines on a production line;

e. a scanning memory for asynchronous communication with said machines over said local I/O means; and

,

f. network I/O means for bi-directional communications with said executable control program.

3. A control system as recited in claim 2, wherein said network I/O means comprises a network card installed in a computer workstation, a network card installed in said programmable logic means, and a communications cable connecting said cards, and wherein said network I/O means is capable of sustained communication rates of at least 10 mega-bits/second.

4. A control system as recited in claim 1, wherein said processing recipe means comprises electronically transmissible signals including representations of:

a. a series of processing cycles;

b. a single control word contained within each said cycle; and

,

c. a least one numbered robot subroutine specifying one or more robot moves in each said cycle.

5. A control system as recited in claim 4 wherein said control word comprises a 16 bit word for specifying processing parameters and for signaling said processing means to transfer a single dip cycle to said programmable logic means.

6. A control system as recited in claim 4, wherein said storage means comprises a bifurcated database for holding said recipe means in one half and production line status information to be held in said other half.

7. An industrial control system utilizing a computer workstation for controlling a series of machines on a production line, comprising:

a. means for holding a plurality of control parameters;

b. means for selecting a subset of said control parameters in response to signals received from said production line wherein said selecting means comprises an industrial control application program running on a computer workstation, said application program capable of tagging and communicating with various elements on said production line, and wherein said application program includes a customizable man machine interface for achieving said tagging;

c. programmable logic means for controlling said machines on said production line after receipt of said subset of control parameters, said logic means capable of autonomous control of said machines independent of activity by said selecting means after receipt of said subset; and

,

d. means for electronically connecting said selecting means to said programmable logic means for communicating said subset to said programmable logic means.

8. In combination with an investment casting shell production line including a computer workstation having means for network communication, at least one processing cell having a central robot and a plurality of processing machines, a plurality of conveyors for moving casting shells to and from said cell for processing, a sensor adjacent one of said conveyors signaling a loading of a new casting shell on one of said conveyors, and a pre-defined set of processing recipes means for describing a sequence of processing steps associated with a selected type of casting shell, an industrial control system comprising:

a. storage means for holding said set of processing recipes;

b. industrial control means running on said computer workstation for processing signals from said production line and in response supplying control parameters derived from a selected one of said recipes to said cell;

c. means for electronically transmitting said control parameters to said cell; and

,

d. logic means associated with said cell for distributing said control parameters to said processing machines, said logic means including processing means for detached autonomous distribution of said control parameters to said processing machines independent of actions by said industrial control means.

9. A control system as recited in claim 8, wherein said logic means comprises:

a. a processor;

b. main processor memory;

c. an executable control program loaded into said main processor memory for processing by said processor;

d. means for local I/O communications with said machines on said production line;

e. a scanning memory for asynchronous communication with said machines over said local I/O means; and

,

f. network I/O means for bi-directional communications with an industrial control program.

10. A control system as recited in claim 9 wherein said network I/O means comprises a network card installed in said computer workstation, a network card installed in said logic means, and a communications cable connecting said cards, and wherein said network means is capable of sustained communication rates of at least 10 mega-bits/second.

11. A control system as recited in claim 8, wherein said processing recipe means comprises:

a. a series of processing cycles;

b. a single control word contained within each said cycle; and

,

c. a least one numbered robot subroutine specifying one or more robot moves in each said cycle.

12. A control system as recited in claim 11 wherein said control word comprises a 16 bit word for specifying processing parameters and for signaling said industrial control means to transfer a single dip cycle to said programmable logic means.

13. A control system as recited in claim 8 wherein said storage means comprises a bifurcated database for holding said recipe means in one half and production line status information to be held in said other half.

14. A control system as recited in claim 8 wherein said processing means comprises an industrial control application program running on a computer workstation, said application program capable of tagging and communicating with various elements on said production line, and wherein said application program includes a customizable man machine interface for achieving said tagging.

15. In combination with an investment casting shell production line including a computer workstation running an industrial control program and having means for network communication, storage means accessible by said industrial control program, at least one processing cell having a central robot, a plurality of processing machines, and a programmable logic controller connected to said robot and said processing machines over a local network said logic controller having a processing memory and a scanning memory, a plurality of conveyors for moving casting shells to and from said cell for processing, a sensor adjacent one of said conveyors signaling a loading of a specified casting shell on one of said conveyors, and a pre-defined set of processing recipes stored in said storage means for describing a sequence of processing steps associated with a selected type of casting shell, a method for said logic controller to manage each machine in said processing cell through a discrete series of dip cycles, comprising the steps of:

a. downloading a single control parameter representing a dip cycle from said computer workstation to said logic controller;

b. setting up a logical device image corresponding to each processing machine specified in said control parameter and loading pre-defined machine settings into said logic image as specified in said control parameter;

c. transmitting said settings to each said machine over said local network;

d. processing a single dip cycle; and

,

e. moving said specified casting shell to a conveyor for drying.