US 5,559,713 A · Chip buildup detection and control method and apparatus

Abstract

A chip buildup detection and control apparatus having a flow transducer and flow monitor to measure and monitor coolant flow to a cutter of a machine tool for detecting excessive chip buildup on the cutter and removing the buildup on the cutter which decreases machining cycle time while increasing cutter life and machine tool production. Excessive chip buildup on the cutter is detected when coolant flow to the cutter drops below a minimum flow rate limit. Buildup is removed upon detection by initiating a "pecking" cycle where the cutter is retracted from its position of engagement with the workpiece being machined for a predetermined dwell period of time. The machining cycle is aborted if coolant flow does not rise above the minimum limit by the end of the dwell period. If coolant flow rises above the minimum flow limit, the cutter is advanced almost to its previous position of engagement with the workpiece and machining is resumed. Preferably, if coolant flow to the cutter rises above a maximum flow rate limit, the "pecking" cycle is initiated and, thereafter, the machining cycle is aborted if flow does not drop below the maximum limit during a predetermined dwell period. In a preferred embodiment, a "pecking" cycle is initiated if coolant flow to the cutter falls outside a normal flow rate window of between the minimum and maximum flow rate limits. Therefore, "pecking" cycles are only initiated when excessive chip buildup or cutter failure is detected.

Claims23

Dependent claims

An apparatus for detecting chip buildup on a cutter of a machine tool that is movable relative to a workpiece comprising:

a supply for providing coolant to the cutter;
a drive for relatively moving the cutter toward and away from the workpiece;
a transducer for sensing coolant flow to the cutter;
and
a monitor in communication with said transducer for monitoring said coolant flow to the cuter and causing the drive to move the cutter relatively away from the workpiece if said coolant flow is less than a minimum acceptable coolant flow rate limit indicating chip buildup on the cutter for enabling chip buildup to be removed from the cutter.

2 more elements

A method of detecting chip buildup on a cutter of a machine tool that is movable relative to a workpiece and having a coolant passage and orifice for enabling coolant to be provided to the cutter comprising:

(a) providing a drive for moving the cutter relative to the workpiece, a coolant supply for supplying coolant to the cutter, a transducer for sensing coolant flow to the cutter, and a monitor in communication with the drive and flow transducer for monitoring coolant flow and relatively moving the cutter away from the workpiece if coolant flow to the cutter is equal to or less than an acceptable minimum flow rate limit;
(b) supplying coolant to the coolant passage and orifice of the cutter;
(c) advancing the cutter toward the workpiece;
(d) feeding the cutter into the workpiece to machine the workpiece;
(e) monitoring coolant flow to the cutter while it is being fed into the workpiece during step (d) to determine if coolant flow to the cutter is equal to or less than the acceptable minimum flow limit;
(f) relatively moving the cutter away from its position of engagement with the workpiece if coolant flow to the cutter is equal to or less than the acceptable minimum flow limit;
(g) monitoring coolant flow after step (f) to determine if coolant flow is equal to or less than the acceptable minimum flow rate limit;
(h) repeating steps (d), (e), (f) and (g) if during step (g) coolant flow becomes greater than the acceptable minimum flow rate limit, otherwise removing and retracting the cutter completely free of the workpiece;
and
(i) retracting the cutter free of the workpiece if the cutter has finished machining the workpiece.

7 more elements

Dependencies are inferred from the claim text.

Chip buildup detection and control method and apparatus

Life of this patent

Chip buildup detection and control method and apparatus

Life of this patent

Abstract

Claims23