Closed-loop CNC machine system and method

• US 20070067059A1
• Filed: 06/12/2006
• Published: 03/22/2007
• Est. Priority Date: 06/10/2005
• Status: Active Grant

• Current Assignee: Olati, LLC
• Original Assignee: Prototype Productions Incorporated (Prototype Productions)
• Inventors: Feldman, Ben, Binette, John, McLaughlin, Don, Travez, Italo, Travez, Joe, Travez, Jose
• Granted Patent: US 7,930,957 B2
• Time in Patent Office: Days
• US Class Current: 700/160
• CPC Class Codes: B23Q 15/12 Adaptive control, i.e. adjusting itself to have a performance which is optimum according to a preassigned criterion
• CPC Class Codes: B23Q 17/0971 by measuring mechanical vibrations of parts of the machine arrangements for measuring vibrations B23Q17/12
• CPC Class Codes: G05B 2219/33099 Computer numerical control [CNC]; Software control [SWC]
• CPC Class Codes: G05B 2219/37084 Display tool parameters
• CPC Class Codes: G05B 2219/37533 Real time processing of data acquisition, monitoring
• CPC Class Codes: G05B 2219/42038 Real time adaptive control
• CPC Class Codes: Y10T 82/10 Process of turning
• CPC Class Codes: Y10T 82/25 Lathe
• CPC Class Codes: Y10T 82/2502 with program control

Abstract

A closed-loop feedback system and method for performing a machining operation. A tool'"'"'s operational properties are measured in real-time. The operating parameters of the machining process are adjusted in real-time based on the measured properties.

Claims

1. A method for performing a machining operation on a workpiece, the method comprising:

providing a tool for physically removing material from the workpiece;

providing an algorithm setting the operating parameters for the machining operation;

measuring at least one physical property of the tool in real-time; and

adjusting the algorithm in real-time based on the at least one measured physical property.

2. The method of claim 1, wherein machining operation is a turning process.

3. The method of claim 1, wherein the operating parameters include at least one of the parameters selected from the group consisting of:

relative rate of rotation between the tool and workpiece and relative rate of translational movement between the tool and workpiece in the direction along the tool'"'"'s axis of rotation.

4. The method of claim 1, wherein the at least one measured physical property includes at least one of the properties selected from the group consisting of:

deflection of the tool, vibration of the tool, and force on the tool.

5. The method of claim 4, wherein the step of measuring comprises using at least one sensor selected from the group consisting of:

fiber optic sensors, magnetic sensors, and analog electronic strain gauges.

6. The method of claim 5, wherein the step of measuring comprises:

providing a light beam to a fiber optic sensor embedded in the tool;

receiving an optical signal from the embedded sensor;

converting the optical signal to digital parameters; and

analyzing the change of the digital parameters with respect to time to determine the change of the physical properties with respect to time.

7. The method of claim 1, wherein the step of adjusting comprises altering the code of a CNC program.

8. A closed-loop feed back CNC controlled inside turning process performed on a workpiece, the method comprising:

providing a boring bar;

providing an initial CNC code setting the spindle speed and feed rate for the process;

measuring in real-time during the inside turning process at least one of the elements selected from the group consisting of;

the force on the boring bar, the deflection of the boring bar, and the vibration of the boring bar; and

adjusting the CNC code in real-time to set a new spindle speed and feed rate based on the real-time measurement.

9. The method of claim 8, wherein the step of measuring comprises using at least one sensor selected from the group consisting of:

fiber optic sensors, magnetic sensors, and analog electronic strain gauges.

10. The method of claim 9, wherein the step of measuring comprises:

providing a light beam to a fiber optic sensor embedded in the tool;

receiving an optical signal from the embedded sensor;

converting the optical signal to digital parameters; and

analyzing the change of the digital parameters with respect to time to determine the change of the physical properties with respect to time.

11. The method of claim 8, further comprising the step of notifying a machine operator that the tool should be changed if the new spindle speed is less than a pre-determined spindle speed value or if the new feed rate is less than a pre-determined feed rate value.

12. The method of claim 8, further comprising the step of automatically stopping the turning process if the new spindle speed is less than a pre-determined spindle speed value or if the new feed rate is less than a pre-determined feed rate value.

14. The closed-loop feedback control machining system of claim 11, wherein the machine is a lathe.

15. The closed-loop feedback control machining system of claim 12, wherein the tool is a boring bar.

16. The closed-loop feedback control machining system of claim 11, wherein the at least one sensor is selected from the group consisting of:

fiber optic sensors, magnetic sensors, and analog electronic strain gauges.

17. The closed-loop feedback control machining system of claim 14, wherein the signal received from the tool is an optical signal.

18. The closed-loop feedback control machining system of claim 11, wherein the at least one controller is a CNC controller.

19. The closed-loop feedback control machining system of claim 11, further comprising a portable display device operatively associated with the at least one controller such that the portable display device can inform a user of the adjustments made by the controller.

20. The closed-loop feedback control machining system of claim 19, wherein the portable display device is selected from the group consisting of a cellular phone, a PDA, and a tablet PC.

13. A closed-loop feedback control machining system, the system comprising:

a machine comprising;

a workpiece holder;

a tool holder;

a spindle drive system for providing relative rotation between

a workpiece and a tool; and

a feed drive system for providing relative translational movement between a workpiece and a tool;

a tool;

at least one sensor operatively associated with the tool;

at least one signal converter operatively associated with the at least one sensor;

at least one signal analyzer operatively associated with the at least one signal converter; and

at least one controller operatively associated with the at least one signal analyzer and operatively associated with the spindle drive system and the feed drive system,

wherein the at least one sensor receives a signal from the tool and transmits the signal to the at least one signal converter, wherein the at least one signal converter converts the received signal to a set of digital parameters and transmits the digital parameters to the at least one signal analyzer, wherein the at least one signal analyzer determines in real-time at least one of the elements selected from the group consisting of;

the force on the tool, the deflection of the tool, and the vibration of the tool, and wherein the at least one controller adjusts the power exerted by at least one of the spindle drive system and the feed drive system in real-time based on the real-time determinations.