Patent Publication Number: US-2023150080-A1

Title: Method for estimating tool life in a cutting machine

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates to one or more cutting tools installed in a cutting machine, and in particular to a method of individualized estimation of tool life in the cutting machine. 
     BACKGROUND OF THE DISCLOSURE 
     Generally, an operator would use his/her experience to operate various cutting tools installed in the cutting machine in order to cut one or more workpieces. However, the tools used in the cutting machines will eventually be worn out after a period of time. Therefore, any evaluation on the life of the cutting tool installed on the cutting machine is mostly conducted based on the experience of a skilled operator by judging, e.g., the type and usage of the cutting tool, and/or material of the workpiece to be cut. 
     Currently, there are proposals to install multiple sensors on the cutting machine to collect data on the cutting process in order to construct a simulation model in order to derive the optimal result of cutting. However, there is no effective or specific technology to evaluate tool life. In addition, it has been proposed to install multiple sensors on each system of the cutting machine to warn against improper operation and to avoid machining under adverse production conditions. Still, the aforementioned proposals do not have a specific and valid assessment capability for the tool life, and lack any tool life assessment technique with any reference value. In addition, the aforementioned proposals require the installation of a large number of sensors, so the overall cost, including the cost of sensors, installation costs and computer systems, is high and not conducive to the industrial use. 
     Indeed, there is no known technology related to evaluating the tool life, much less any technology for effective evaluation of the tool life in the cutting machine as provided by the present disclosure. 
     SUMMARY OF THE DISCLOSURE 
     It is therefore an object of the present disclosure to disclose an individualized tool life estimation method for cutting machines, which can specifically and effectively provide the evaluation results for the remaining life of the cutting tool. 
     In order to achieve the above object, the present disclosure provides a method for estimating the tool life of an individualized cutting machine, comprising the steps as discussed below. Setting up in step A by installing at least one force sensor on the cutting machine, which senses the cutting thrust of the tool of the cutting machine when a workpiece is cut. Establishing basic data in step B by setting several different cutting rate settings for the cutting machine, operating the cutting machine to cut the workpiece with the tool according to each of the cutting rate settings, and recording after each cut the type of the tool, the material of the workpiece, and the length of the workpiece being cut. Numerical processing in step C by factorizing and counting down characteristic signal corresponding to each cut in step to obtain the complex value, which is defined as the complex remaining life index of the tool on the workpiece. Graphical processing in step D by using the cutting rate as the horizontal axis, with the higher value of the cutting rate going to the right, and using the remaining life index as the vertical axis, with the greater value going up. The remaining life indicators and their corresponding cutting rates in step C are drawn and connected via a line graph according to the values of the vertical axis and the horizontal axis. 
     From the above steps, the present disclosure provides a specific and effective method to evaluate the remaining life of the cutting tool for the user&#39;s reference, thereby solving the problem in the conventional technology, which cannot evaluate tool life. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional features and advantage of the present disclosure will be made apparent from the following detailed description of one or more exemplary embodiments with reference to the accompanying figures, which are given for illustrative purpose only, and thus are not limitative of the present disclosure, wherein: 
         FIG.  1    is a flowchart according to an exemplary embodiment of the present disclosure; 
         FIG.  2    is a schematic illustration showing the structure of the exemplary of the present disclosure; 
         FIG.  3    is a chart showing the life estimation line of the exemplary embodiment of the present disclosure. 
         FIG.  4    is a chart showing another life estimation line of the exemplary embodiment of the present disclosure; and 
         FIG.  5    is a chart showing a further life estimation line diagram of the exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT 
     An exemplary embodiment according to the present disclosure will be described below with references to the accompanying figures. It should be understood that the figures are not depicted to scale. 
     Referring to  FIGS.  1  to  3   , one of the exemplary embodiments of the present disclosure provides a method for estimating tool life of an individualized cutting machine, having steps as discussed below. 
     Step A involves sensor installation on a cutting machine  11 . Specifically, a force sensor  12  is installed on the cutting machine  11 . The cutting machine  11  has a feed seat  14  and a cutting tool  16 . A band saw is used as the cutting tool  16  in the exemplary embodiment. The force sensor  12  is mounted on the feed seat  14 , and a workpiece  91  is placed on the feed seat  14 . The cutting force of the cutting tool  16  acting on the workpiece  91  can be measured when the workpiece  91  is fed to the tool  16  by the feed seat  14  and cut accordingly. By mounting the force sensor  12  on the feed seat  14  and placing the workpiece  91  on the feed seat  14 , the cutting thrust of the cutting tool  16  on the workpiece  91  can be measured when the workpiece  91  is cut by feeding the workpiece  91  to the cutting tool  16  through the feed seat  14 . In the exemplary embodiment, the force sensor  12  is mounted on the feed seat  14  only as an example since the force sensor  12  may also be mounted on, for instance, a cutting tool holder mounted in the cutting machine  11  for holding the cutting tool  16 . In addition, the material of the workpiece  91  depends on the user preferences or needs. For instance, carbon steel S45C, tool steel SKD61, and stainless steel SUS304 are common metal workpiece materials in the industry. 
     Step B involves establishing basic data. Different cutting rate settings are provided to operate the cutting machine  11  that uses the tool  16  to cut the workpiece  91  according to each cutting rate setting. The force sensor  12  measures the cutting thrust of the cutting tool  16  during each aforementioned cut, and defines the maximum cutting thrust of the cutting tool  16  measured a characteristic signal during the cut. In addition, the type of the cutting tool  16 , the material of the workpiece  91 , and the length of the workpiece  91  are recorded during the cut. In the exemplary embodiment, the cutting rate is used as the setting reference, but such cutting rate can be replaced by the feeding rate. If the cutting rate is used as the setting reference, then the unit is used is the area/time, whereas if the feeding rate is used as the setting reference, then the unit is used is the length/time. 
     Step C involves numerical processing. The characteristic signal corresponding to each cut in the aforementioned step B is factorized (dimensionless processing) and counted down (reciprocal processing) to obtain a complex value, which is defined as the complex remaining life index RLI of the cutting tool  16  on the workpiece  91 . The aforementioned dimensionless processing is performed using following equation (1): The characteristic signal/length of cut of the workpiece. For the reciprocal processing, the following equation (2) is used: 1/(the characteristic signal/the length of the workpiece being cut). 
     Step D involves graphical processing. As shown in  FIG.  3   , the cutting rate is reflected on the horizontal axis, with the faster cutting rate going rightward, and conversely, with the slower cutting rate going leftward. The remaining life and cutting thrust are reflected on the vertical axis, with the longer value of the remaining life and larger value of the cutting value going upward, and conversely, with the shorter value of the remaining life and larger value of the cutting thrust going downward. The aforementioned step C of the plural remaining life indicator RLI and its corresponding cutting rate according to the values of the vertical axis and the horizontal axis are plotted and connected to form a line graph in  FIG.  3   . As marked in the complex remaining life indicator as shown in  FIG.  3   , points corresponding to the values of RLI and their corresponding cutting rates are referenced as RLI, with line A in the line graph as the line formed by the remaining life index RLI of the tool  16  against the workpiece  91 . Thus, the remaining life of the cutting tool  16  is estimated by the line graph in  FIG.  3   . 
     As shown in  FIG.  4   , the lines are presented for the same workpiece  91  and the same cutting tool  16  after the life estimation by the aforementioned method of the present disclosure under different wear and tear of the cutting tool  16 , where lines A to D represent the lines connected by different remaining life indicators RLI from no wear and tear to severe wear and tear of the tool  16 . In  FIG.  4   , the interpretation of line A is that even if the cutting rate is adjusted to the fastest, the remaining life index is still nearly half of the value, while the interpretation of lines B to D is that the bottom ends of lines B to D represent the shortest remaining life index at its corresponding cutting rate. 
     As shown in  FIG.  5   , if the cutting tool  16  is evaluated out to be the state of the line D, then if the cutting rate is adjusted to be faster than the cutting rate represented by the bottom end of the line D when the cutting tool  16  is used, then this cutting tool  16  may be damaged and cannot be used, so the user can set the cutting rate when the tool  16  is used with reference to the position of the bottom end of the line D so that it is not faster than the cutting rate represented by the bottom end of the line D. In this way, the user can ensure that the cutting tool  16  will not be damaged during use. It can be seen that the lines A to D can be used to understand the life evaluation basis of the cutting tool  16  in the current state, and the upper cutting rate of the cutting tool  16  can be known to the user, and then the cutting tool  16  can be used safely without causing damage to the cutting tool  16 . 
     In the actual implementation of the above steps B to D, a computer (not shown) can be used to perform the relevant processing operations and to draw the line diagram, which is displayed on a display (not shown) connected to the computer. The computer and the display screen are known technologies and are not the technical focus of this case, so they will not be described. 
     To summarize, the present disclosure first establishes the basic data of the cutting tool  16  cutting on the workpiece  91 , and then numerically processes and draws a chart for the user&#39;s reference to evaluate the remaining life of the cutting tool  16  cutting on the workpiece  91 . Particularly, the individualized nature of the disclosure, i.e., in evaluating the tool life on the cutting machine, the evaluated value is only applicable to a particular tool on that cutting machine, but not applicable to any other tool of the same material on a different cutting machine. In other words, even if the cutting tools on different cutting machines are of the same material, they still need to be evaluated separately, i.e. the tools on different cutting machines need to be evaluated independently by the above-mentioned method of the present disclosure in order to evaluate the remaining life of the tool. As such, the individualized character of the present disclosure for the estimation of the tool on the cutting machine is realized. 
     Therefore, the present disclosure is a specific and effective method for evaluating the remaining life of a tool for a user&#39;s reference, solving the problem that the conventional technology cannot handle in evaluating tool life. 
     Although the present disclosure has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. It should be understood that the scope of the present disclosure is not limited to the above-mentioned embodiment, but is limited by the accompanying claims. It is, therefore, contemplated that thee appended claims will cover all modifications that fall within the true scope of the present disclosure. Without departing from the object and spirit of the present disclosure, various modifications to the embodiment are possible, but they remain within the scope of the present disclosure, will be apparent to persons skilled in the art.