US 12,240,072 B2
Detection apparatus and detection method for machine tool abnormality
Jaedoo Sim, Gimhae-Si (KR)
Assigned to DN SOLUTIONS CO., LTD., Changwon-si (KR)
Appl. No. 16/960,042
Filed by DN SOLUTIONS CO., LTD., Changwon-si (KR)
PCT Filed Jan. 2, 2019, PCT No. PCT/KR2019/000035
§ 371(c)(1), (2) Date Oct. 23, 2020,
PCT Pub. No. WO2019/135596, PCT Pub. Date Jul. 11, 2019.
Claims priority of application No. 10-2018-0000513 (KR), filed on Jan. 3, 2018.
Prior Publication US 2021/0053170 A1, Feb. 25, 2021
Int. Cl. B23Q 17/09 (2006.01); G01L 5/00 (2006.01); G05B 19/4065 (2006.01)
CPC B23Q 17/09 (2013.01) [G01L 5/0028 (2013.01); G05B 19/4065 (2013.01); G05B 2219/49001 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An apparatus for detecting an abnormality of a tool of a machine tool, the apparatus comprising:
a workpiece transferring member configured to transfer a workpiece;
a workpiece machining member configured to machine the workpiece by a tool, wherein the workpiece machining member comprises at least one of a boring machine, a drilling machine, a milling machine, a shaving machine, and a turret;
a controller, wherein the controller performs the following functions:
a data storage function configured to store information for detecting presence or absence of an abnormality of the tool;
a load measurement function configured to measure a load of the workpiece transferring member or the workpiece machining member;
a load calculation function configured to calculate a normal range of the measured load data; and
a data comparison function configured to detect the presence or absence of an abnormality of the tool by comparing the normal range of the load data calculated by the load calculation function and the data measured by the load measurement function;
wherein the controller repeatedly measures the load of the workpiece transferring member or the workpiece machining member and detects the presence or absence of an abnormality of the tool based on the normal range of the load data that are proportional to a standard deviation of the load data measured based on a mode value of the repeatedly measured load data and thereby improves reliability and accuracy of the machine tool, the normal range being calculated through the following Equation 1 and Equation 2:
Maximum normal range (a)=MODEMAX[Tx−Px]+σ[Tx−Px]*f(+)+a0,  [Equation 1]
wherein
MODEMAX [Tx−Px] is a maximum mode value,
σ[Tx−Px] is a standard deviation,
f(+) is a maximum application ratio, and
a0 is a maximum reference range;
Minimum normal range (b)=MODEMIN[Tx−Px]−σ[Tx−Px]*f(−)+b0,  [Equation 2]
wherein
MODEMIN[Tx−Px] is a minimum mode value,
σ[Tx−Px] is a standard deviation,
f(−) is a minimum application ratio,
and b0 is a minimum reference range;
wherein the controller further performs the following functions: a determination function configured to determine the result of determining the presence or absence of an abnormality by the data comparison function and whether workpiece machining is performed by the workpiece machining member; wherein the load calculation function comprises: a mode-value calculating function configured to calculate the maximum mode value and the minimum mode value among the load data measured by the load measurement function; a standard-deviation calculating function configured to calculate the standard deviation of the load data measured by the load measurement function; and a normal-range calculating function configured to calculate the maximum normal range and the minimum normal range based on the data stored by the data storage function and the values calculated by the mode-value calculating function and the standard-deviation calculating function; and
a display is configured to provide an alarm to notify an operator of the abnormality, thereby facilitating the maintenance of the machine tool.