OPERATING HISTORY MANAGEMENT METHOD AND OPERATING HISTORY MANAGEMENT APPARATUS

• US 20120095724A1
• Filed: 09/26/2011
• Published: 04/19/2012
• Est. Priority Date: 10/13/2010
• Status: Active Grant

• Current Assignee: Okuma Corporation
• Original Assignee: Okuma Corporation
• Inventors: ANDO, Tomoharu, Ueno, Hiroshi
• Granted Patent: US 8,862,429 B2
• Time in Patent Office: Days
• US Class Current: 702/145
• CPC Class Codes: B23Q 17/007 for managing machine functions not concerning the tool
• CPC Class Codes: B23Q 17/12 for indicating or measuring vibration

Abstract

At least a rotation speed of a rotary shaft and a vibration acceleration in a frequency domain are stored as an operating history, and the operating history is stored not only when the rotation speed of the rotary shaft varies, but also when a maximum value of the vibration acceleration in the frequency domain exceeds a predetermined threshold. Therefore, variation in the rotation speed of the rotary shaft and the chatter vibration occurrence state can be stored in association with each other. Hence, an operator can learn the rotation speed of the rotary shaft and the chatter vibration occurrence state in association with each other. As a result, chatter vibration can be suppressed easily and effectively.

Claims

1. An operating history management method for managing an operating history of a machine tool that includes a rotary shaft for rotating a tool or a work piece, wherein

the method executes:

a first step of detecting a rotation speed of the rotary shaft and a vibration acceleration in a frequency domain occurring in the rotary shaft;

a second step of determining whether or not the detected rotation speed has varied from a previously detected rotation speed and determining whether or not a maximum value of the vibration acceleration in the frequency domain exceeds a predetermined threshold; and

a third step of storing at least the rotation speed of the rotary shaft and the vibration acceleration in the frequency domain as the operating history when the rotation speed has varied or the maximum value exceeds the predetermined threshold.

2. The operating history management method according to claim 1, wherein,

when the rotation speed has varied or the maximum value exceeds the predetermined threshold in the third step, a determination is made as to whether or not a rotation speed modification command has been input into the machine tool,

when the rotation speed modification command has been input, information relating to the rotation speed modification command is added and the operating history is stored in association with the added information relating to the rotation speed modification command, and

when the rotation speed modification command has not been input, the operating history is stored in association with most recently added information relating to a rotation speed modification command.

3. The operating history management method according to claim 1, wherein

machining point coordinates, an origin of a work piece, a type of the tool mounted on the rotary shaft, a type of a machining program currently underway in the machine tool, a sequence number or a code of the machining program, and either a time at which variation in the rotation speed has been detected or a time at which the maximum value has been determined to have exceeded the predetermined threshold are stored as the operating history in the third step.

4. The operating history management method according to claim 2, wherein

machining point coordinates, an origin of a work piece, a type of the tool mounted on the rotary shaft, a type of a machining program currently underway in the machine tool, a sequence number or a code of the machining program, and either a time at which variation in the rotation speed has been detected or a time at which the maximum value has been determined to have exceeded the predetermined threshold are stored as the operating history in the third step.

5. An operating history management apparatus that manages an operating history of a machine tool that includes a rotary shaft for rotating a tool or a work piece, comprising:

a rotation speed detection unit that detects a rotation speed of the rotary shaft;

a vibration detection unit that detects a vibration acceleration in a frequency domain occurring in the rotary shaft;

a rotation speed determination unit that determines whether or not the detected rotation speed has varied from a previously detected rotation speed;

a chatter vibration detection unit that determines whether or not a maximum value of the vibration acceleration in the frequency domain exceeds a predetermined threshold; and

a storage unit that stores at least the rotation speed of the rotary shaft and the vibration acceleration in the frequency domain as the operating history when the rotation speed has varied or the maximum value exceeds the predetermined threshold, wherein

the operating history management method according to claim 1 is executed to manage the operating history.