WO-2026094766-A1 - TOOL LIFE DETERMINATION APPARATUS AND TOOL LIFE DETERMINATION METHOD FOR MACHINE TOOL

WO2026094766A1WO 2026094766 A1WO2026094766 A1WO 2026094766A1WO-2026094766-A1

Abstract

A tool life determination apparatus (10) for a machine tool (MT) comprises: a tool wear measurement device (11) that acquires an image by capturing an image of a cutting edge part (50) of a tool (26) inside the machine tool (MT), and measures a tool wear amount indicating the amount of change in the diameter of the tool or the wear width of a flank or a rake face; a tool life index measurement unit (64) that measures, as a tool life index, at least one of the number of machined workpieces, machining distance, machining time, and machining workload which are acquired when workpieces have been machined on the basis of a machining program and machining conditions; a storage unit (66) that sequentially stores a set of the tool wear amount and the tool life index; and a calculation unit (70) that calculates a threshold for the tool life index by using the set of the tool wear amount and the tool life index and an inputted threshold for the tool wear amount.

Inventors

NEBUKA, Teppei
MATSUSHITA, Sakyo

Assignees

株式会社牧野フライス製作所

Dates

Publication Date: 20260507
Application Date: 20251023
Priority Date: 20241101

Claims (5)

In a tool life determination device for a machine tool that determines the lifespan of a tool used to process a workpiece, A tool wear measurement unit located inside the machine tool captures an image of the cutting edge of the tool, and measures the wear width of the flank face or rake face, or the change in tool diameter, based on the image. A tool life index measuring unit measures at least one of the following as a tool life index when the workpiece is processed based on the processing program and processing conditions input to the machine tool: the number of workpieces processed, processing distance, processing time, and processing work volume. For each of the aforementioned tools, a storage unit sequentially stores the measured tool wear amount and tool life index as a pair. A calculation unit that calculates a threshold value for the tool life index using the stored set of tool wear amount and tool life index, and the input threshold value for the tool wear amount, A tool life determination device for machine tools, characterized by being equipped with the following features.
The tool life determination device for a machine tool according to claim 1, further comprising a display unit that sequentially displays the threshold value of the tool life index calculated by the calculation unit and the current value of the tool life index measured by the tool life index measurement unit on the same screen.
The calculation unit determines that the tool is worn when the current value of the tool wear amount measured by the tool wear amount measuring unit exceeds the threshold value of the tool wear amount, or when the current value of the tool life index measured by the tool life index measuring unit exceeds the calculated threshold value of the tool life index, and transmits a spare tool replacement command to the machine tool to replace the worn tool with a spare tool of the same type, as described in claim 1.
A method for determining tool life using the tool life determination device for a machine tool described in claim 1, The steps include: importing the threshold value of the tool life index calculated by the calculation unit into another machine tool; The steps include sequentially measuring the tool life index of the other machine tool, The steps include displaying the tool life index measured sequentially and the threshold value of the acquired tool life index on the display unit of the other machine tool, A method for determining the tool life of a machine tool, characterized by including the following:
A method for determining tool life using the tool life determination device for a machine tool described in claim 1, The steps include: importing the threshold value of the tool life index calculated by the calculation unit into another machine tool; The steps include sequentially measuring the tool life index of the other machine tool, The steps include: determining that the tool is worn when the tool life index measured sequentially in the other machine tool exceeds a threshold for the acquired tool life index, and sending a spare tool replacement command to the other machine tool to replace the worn tool with a spare tool of the same type; A method for determining the tool life of a machine tool, characterized by including the following:

Description

Tool life determination device and tool life determination method for machine tools This invention relates to a tool life determination device and a tool life determination method for machine tools. In factories that mass-produce parts by machining them using machine tools, managing the lifespan of the tools used for machining is a crucial factor directly impacting production costs. Replacing tools before their lifespan is reached unnecessarily increases costs. Furthermore, continuing to use tools beyond their lifespan degrades the quality of the machined surface, increases cutting resistance, and can lead to tool breakage, potentially resulting in defective workpieces. Therefore, it is preferable to replace tools with new ones just before they reach the end of their lifespan. To replace a tool with a new one just before it reaches the end of its lifespan, it is necessary to accurately determine when a tool has reached the end of its lifespan at the machining site. Therefore, generally, the amount of wear on the tool's cutting edge is measured quantitatively and sequentially. When the wear exceeds a tool wear threshold set by the factory, a warning signal is issued to prompt tool replacement. If the tool is not replaced, an alarm signal is issued, forcibly stopping the machining process. Patent Document 1 discloses a tool management device that measures the flank wear width by imaging the cutting edge when the tool reaches a predetermined cutting distance (cumulative cutting feed distance), and determines the tool's lifespan by comparing this measurement value with a standard wear width. However, there are cases where the tool wear threshold is exceeded when the predetermined cutting distance is reached, which can lead to tool breakage or workpiece defects. On the other hand, looking at the machining site, data such as the number of workpieces cut, cutting distance, cutting time (cumulative cutting feed time), and cutting work (cumulative power consumption of the spindle motor while cutting feed is being performed), which are considered to have a strong correlation with tool life, can be easily and continuously acquired by the machine tool's control unit. Therefore, it is conceivable to use these as tool life evaluation indices (hereinafter referred to as tool life indices) to evaluate tool life. In other words, if the correlation between the amount of tool wear and the tool life index can be understood in the machining of a workpiece using a single tool, it is possible to understand that the tool life has been reached by the tool life index threshold without directly measuring the amount of tool wear, and to manage tool life by replacing the worn tool with a spare tool at the appropriate timing. However, tools come in many varieties, such as end mills, face milling cutters, drills, boring tools, turning tools, and cutting tools, and their materials also vary widely, such as high-speed steel, cemented carbide, ceramic, and whether or not they are coated. In addition to these, tools have many other parameters, such as the number of cutting edges, whether they are solid or insert type, length, and diameter. Furthermore, the workpieces subjected to machining using tools are diverse in material (cast iron, steel, aluminum, copper, titanium, etc.), shape (round, square, etc.), and depth of cut (with significant variation). In addition, machining conditions such as rotational speed, feed rate, depth of cut, and type and amount of cutting fluid can also be parameters. Therefore, it is practically impossible to pre-determine the correlation between tool wear and tool life indicators for each of these numerous parameters through machining tests. Figure 1 shows a block diagram of the tool life determination device according to this embodiment.Figure 2 shows a perspective view of the tool wear measuring device according to this embodiment.Figure 3(a) shows a side view of the tool, (b) shows a side view of the tool from (a) rotated 90 degrees, and (c) shows a bottom view of the tool from (a).(a) shows a side view of the first imaging unit that images the bottom of the tool, and (b) is a view taken along arrow A in (a), showing the bottom of the tool.(a) shows a side view of the second imaging unit that images the side of the tool, and (b) is a view taken along arrow B in (a), showing the bottom view of the tool.Figure 6 shows a transparent view of the inside of the first cleaning section.Figure 7 shows a transparent view of the inside of the first cleaning unit according to another embodiment.Figure 8 shows a transparent view of the inside of the second cleaning section.Figure 9 shows a plan view of the tool magazine.Figure 10 shows a plan view and a side view of the tool wear measuring device according to this embodiment.Figure 11 shows a plan view and a side view of a tool wear measuring device that cleans tools using a first cleaning unit.Figure 12 shows a plan view and a side view of a tool wear measuring device th