A power tool includes a control for the motor of the power tool that senses an operating characteristic of the motor and controls the operation of the power tool based on the sensed characteristic. The sensed characteristic includes variations in reluctance of the motor. A controller may sense changes on load on the motor as a result of interaction between a working element such as a saw blade or drill bit and the work piece. The controlled operation may include variation in speed or torque or both, or may include stopping the motor. Emergency conditions may be sensed by changes in reluctance.

Provided is a technique for detecting at least wear of a tool. A machine tool includes a spindle that causes the tool to rotate, a housing that contains the spindle, a plurality of strain sensors provided on the housing, and a detector that detects wear or chipping of the tool, based on a waveform of a cutting force measured from an output signal from each of the plurality of strain sensors. The detector measures a waveform of a first cutting force, measures a waveform of a second cutting force, after measuring the waveform of the first cutting force, makes a comparison between the waveform of the first cutting force and the waveform of the second cutting force, and detects wear of the tool based on a result of the comparison.

The invention relates to a method for monitoring a machining tool that is used for machining primarily metal materials, comprising a cutting tool, wherein the cutting force, feed force, and passive force can be adjusted during machining, and comprising sensors to measure forces. In order that machining can be stopped 2 to 60 seconds, preferably 2 to 10 seconds, prior to failure of the cutting body, the invention proposes that the sensors continuously sense at least one of said forces during machining and machining is stopped if a sudden reduction in the sensed force occurs.

A device for measuring and monitoring tools of a machine tool, wherein the machine tool comprises a spindle shaft for the tool, the shaft being arranged in a spindle housing, wherein a work piece with good electric conductivity can be machined using the tool, wherein the spindle shaft is electrically insulated from the spindle housing, includes a measuring and monitoring system. The measuring and monitoring system measures at least one electric measurement, which depends on the contacting state between the tool and the work piece. A rotary transmitter contacts the rotating spindle shaft to measure the measurement detectable between the tool and the work piece, wherein the rotary transmitter is connected with the spindle housing in an electrically insulated manner.

A main spindle load monitoring device indicates a main spindle load in a machine tool that includes a tool with a plurality of edges on a main spindle and performs a process of a workpiece while the tool rotates with the main spindle. The main spindle load monitoring device includes a main spindle load detecting unit configured to detect a load on the main spindle, a main spindle load conversion unit, and a display control unit. The main spindle load conversion unit is configured to convert a time course of the main spindle load detected by the main spindle load detecting unit into a change of the main spindle load with respect to a main spindle rotation angle. The display control unit is configured to indicate a value of the main spindle load converted by the main spindle load conversion unit on a display screen in a polar coordinates system.

A food slicer for slicing food items includes a slicer body, a slicer knife mounted for rotation relative to the slicer body, the slicer knife having a peripheral cutting edge, and an associated knife drive motor. A food product carriage is mounted to the slicer body for reciprocating movement back and forth past a cutting zone of the slicer knife. A knife edge evaluation system includes at least one imaging device positioned and configured for imaging the peripheral cutting edge.

A lathe includes a spindle, an opposite spindle, a tool post, a controller, and a contact-type breakage detector. The controller determines whether the cut-off tool is broken according to a control parameter for controlling at least one of the spindle and the opposite spindle at a first detection timing immediately after the cut-off tool cuts off the bar material while the opposite spindle holds the bar material held by the spindle. The controller determines whether the cut-off tool is broken according to a detection result by the contact-type breakage detector at a second detection timing different from the first detection timing.

A fault prediction system based on sensor data on a numerical control machine tool and a method therefor. The fault prediction system includes a plurality of sensors for collecting numerical control machine tool operation state data serving as multi-channel data, wherein an output end of a sensor is connected to an input end of a multi-channel sensor interface circuit, and an output end of the multi-channel sensor interface circuit is connected to a controller. The plurality of sensors can be multi-path temperature sensors, multi-path vibration sensors or multi-path noise sensors. The defects in the prior art of there being no model for researching a cross correlation of multi-channel data, collected by a plurality of sensors, of an operation state of a numerical control machine tool, and a device fault subspace of the multi-channel data being unable to be obtained are effectively prevented.

A sensorless method for cutting tool health monitoring which continuously evaluates the health of a cutting tool and requires no sensors to be added to the machine tool. During a machine tool cutting operation, time series data for one or more machine tool parameter such as spindle torque or servo motor velocity is collected and converted to the frequency domain. The magnitude of the data at the spindle frequency is divided by the magnitude of a reference data set for the same parameter at the spindle frequency, where the ratio is designated as a tool breakage indicator. The tool breakage indicator is monitored over time to identify any increase in value, and its value is also compared to predefined thresholds. Various criteria may be defined which trigger the replacement of the cutting tool based on the value and/or the rate of change of the value of the tool breakage indicator.

A tool abnormality detection system includes a detector configured to detect a sound wave generated in processing a workpiece with a tool and output a detection signal based on the sound wave, and a controller configured to generate, based on the detection signal, determination signals indicating intensities in respective frequency bands: a fundamental frequency band of a wear-indicative sound wave; and a higher frequency band that is higher than the fundamental frequency band, and determine whether the tool is worn by comparing each of the determination signals to its respective wear threshold which is set for the respective frequency bands.