WO2018058932A1 - 一种数控机床切削工步全过程中关键时刻的判断方法 - Google Patents

一种数控机床切削工步全过程中关键时刻的判断方法 Download PDF

Info

Publication number
WO2018058932A1
WO2018058932A1 PCT/CN2017/079735 CN2017079735W WO2018058932A1 WO 2018058932 A1 WO2018058932 A1 WO 2018058932A1 CN 2017079735 W CN2017079735 W CN 2017079735W WO 2018058932 A1 WO2018058932 A1 WO 2018058932A1
Authority
WO
WIPO (PCT)
Prior art keywords
cutting
time
state
cutting step
machine tool
Prior art date
Application number
PCT/CN2017/079735
Other languages
English (en)
French (fr)
Inventor
刘飞
庹军波
王超
杨大平
李聪波
Original Assignee
重庆大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 重庆大学 filed Critical 重庆大学
Priority to US16/336,121 priority Critical patent/US10719061B2/en
Publication of WO2018058932A1 publication Critical patent/WO2018058932A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/19—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/406—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by monitoring or safety
    • G05B19/4065—Monitoring tool breakage, life or condition
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/35—Nc in input of data, input till input file format
    • G05B2219/35349—Display part, programmed locus and tool path, traject, dynamic locus
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/37—Measurements
    • G05B2219/37533—Real time processing of data acquisition, monitoring

Definitions

  • the invention relates to the technical field of numerical control machine tools, in particular to a method for judging a critical moment in a whole process of a cutting step of a numerically controlled machine tool.
  • the whole process of the machine tool cutting step is composed of the start time of the work feed--empty cutter--cutting start time-cutting--cutting end time--empty cutter--the end of the work feed, wherein the cutting process refers to the machine tool
  • the tool contacts the workpiece and begins the process of material removal.
  • the online automatic judgment of the cutting process is the core of the machine's effective running time (cutting time), the effective utilization rate of the machine (cutting time/starting time) and other key operating parameters of the machine; secondly, the wear of the tool, the consumption of cutting energy, and the coolant Consumption and other cutting processes occur, so the judgment of the critical moments in the whole process of the cutting step also has important support for real-time acquisition of tool usage time, effective utilization of machine tool energy, and on-line monitoring of machine tool processing progress.
  • the cutting time obtained by the communication of the existing CNC machine tool is actually the working time of the machine tool, which is also called the working feed time.
  • the machine tool's infeed time includes the cutting time in addition to the cutting time.
  • the emptying time will increase.
  • the machine cutting time error generated by this method will also become more and more. The bigger.
  • the international research on the cutting process of the machine tool has been carried out.
  • the Chinese patent No. CN103838181A judges the working process of the machine tool according to the change characteristics of the current signal when the machine tool spindle is loaded, but the current change characteristic is not obvious due to part of the finishing process, and the current signal The uncontrollable random fluctuations make it difficult to judge the cutting start and end times of this type of machining;
  • US patent (US 20140212236 A1) judges the cutting process of CNC machine tools by installing multi-sensors on the tool and spindle, but in the machine tool spindle The cost of installing the sensor is high, and even affects the normal operation of the machine tool;
  • the Canadian patent (CA 2063887) realizes the tool path monitoring during the cutting process of the machine tool by using the multi-displacement monitoring device, but it cannot directly determine the exact moment when the tool contacts the workpiece.
  • the Chinese patent with the publication number CN 104808584A realizes the online monitoring of the utilization status of the machine tool by using the power variation characteristics of the machine tool and the human-computer interaction method.
  • the transparency of the cutting fluid and the safety gate of the machine tool will affect the accuracy of the artificial visual judgment and reduce the accuracy. Supervisor Accuracy.
  • the existing machine tool cutting process judgment technology mainly has problems such as high instrument cost and inconvenient installation, low precision of part of the finishing cutting process, and difficulty in judging the air knife.
  • the technical problem to be solved by the present invention is: how to provide an accurate judgment
  • the cutting state and the air-cutting state in the cutting step are beneficial to accurately judge the critical time of the CNC machine tool cutting step in the effective operation time of the machine tool and the effective utilization rate of the machine tool.
  • the present invention adopts the following technical solutions:
  • a method for judging a critical moment in a whole process of a cutting step of a numerically controlled machine tool characterized in that before the judgment, the input power range of the main shaft of the machine tool in the idle state is obtained as P Umin ⁇ P Umax and stored; Including the following steps:
  • the execution status of the CNC machining code of the machine tool is read in real time, and the execution start time t U1s of the cutting feed mode code is acquired and recorded, and it is determined that the machining feed start time t U1s in the cutting step is simultaneously It is also the starting time t U1s of the first air knife state in the cutting step;
  • the execution state of the numerical control machining code of the machine tool is read in real time, and the execution end time t U2e of the cutting feed mode code is acquired and recorded, that is, it is determined that the machining feed end time in the cutting step t U2e is also the end time t U2e of the second air knife state.
  • the cutting feed mode code in the step a) refers to the code executed for the cutting process, and is often represented by the numerical control worker feed code, and the previously executed numerical control code is often a fast feed code, and then executed.
  • the NC code is often a fast retraction code; therefore, the software often uses the feedrate and G code commands to perform fast feed, fast retraction, work feed recognition, and convert the fast feed code into the work feed code.
  • the time approximation is determined as the start time of execution of the cutting feed mode code, and the timing at which the work feed code is converted to the fast retraction code is approximately determined as the end time of execution of the cutting feed mode code.
  • Step b) and step c) use the variation characteristics of the spindle input power to determine the start and end timing of the cutting state. This is because during the cutting process of the machine tool, the energy consumed during material removal mainly comes from the spindle; in the idle knife state, Because the tool does not bear the load, the input power of the machine tool spindle is relatively small, and it is kept within a certain fluctuation range P Umin ⁇ P Umax .
  • the fluctuation is small and mainly caused by the unstable power supply voltage in the processing workshop; After the tool starts to contact the workpiece, the deformation or removal of the workpiece material will increase the spindle input power of the machine tool based on the state of the machine tool idler, and is usually greater than the maximum input power P Umax of the machine tool spindle in the idle tool state. Therefore, the input power of the machine tool spindle is compared with the spindle input power P Umin ⁇ P Umax in the idle tool state in real time, and the cutting start is judged when the input increases and exceeds the maximum input power P Umax of the idling state. time.
  • the input power of the machine tool spindle is reduced from a relatively large value in the cutting state to a relatively small value in the air knife state, and remains within P Umin ⁇ P Umax ;
  • the input power of the machine tool spindle is reduced below P Umax and maintained within P Umin ⁇ P Umax , it can be judged that the machine tool enters the air knife state from the cutting state, that is, the cutting end time.
  • the first air knife state, the cutting state, and the second air knife state in the cutting step can be accurately determined, and the start and end times of each state are recorded. In this way, the time taken by each state can be calculated, and the effective running time of the machine tool and the effective utilization rate of the machine tool can be accurately counted.
  • the average value of the duration of the first idler state is added to the machining start start time t U1s in the cutting step It is determined as the starting time t Cs of the cutting state in the cutting step; the average value of the duration of the second idle cutting state is subtracted from the machining end end time t U2e in the cutting step That is, it is determined as the end time t Ce of the cutting state.
  • the idle time of the machine tool is usually related to the operator's operating habits of the machine tool, but the difference is not large.
  • the above detection method is adopted, and the first air knife state duration T U1 in the machine tool history cutting step is adopted.
  • the second idle knife state duration T U2 is averaged, and the start time point and the end time point of the air knife and the cutting state in the above step are corrected, and the judgment accuracy of the whole process is improved.
  • the invention has the advantages of being able to accurately judge the cutting state and the idle cutting state in the cutting step, and is advantageous for accurately counting the effective running time of the machine tool and the effective utilization rate of the machine tool.
  • the present invention has the following advantages:
  • the judgment method of the critical moment in the whole process of the cutting step of the CNC machine tool is judged by the input power of the machine tool spindle.
  • the input power is obtained by the power parameter sensor or the power sensor, compared with the installation strain.
  • the method of film, acceleration sensor, etc. is simpler and more convenient to install, and the cost is lower.
  • the judgment method of the critical moment in the whole process of the cutting step of the CNC machine tool provided by this patent can accurately and accurately calculate the cutting time in the cutting step of the machine tool, which is convenient for the online acquisition of the effective utilization rate of the machine tool.
  • Figure 1 is a schematic diagram of the external turning process.
  • Figure 2 is a flow chart of the automatic determination of the cutting step.
  • Fig. 3 is a schematic structural view of a workpiece in the embodiment.
  • the path of a complete step is: machine reference point -> safety plane -> workpiece cutting -> safety plane -> machine reference point, where the safety plane refers to the machine tool to prevent rapid movement
  • the plane that the tool collides with the surface of the workpiece to establish in the space close to the surface of the workpiece, and between the plane and the surface of the workpiece, the speed of the tool is the cutting feed rate.
  • the process of the tool approaching the surface of the workpiece from the safety plane at the feed rate (or back to the safety plane from the workpiece surface after cutting) is called the air knife.
  • a complete cutting step consists of two empty passes: the first idle pass is the process of cutting the tool away from the safety plane at the feed rate and approaching the surface of the workpiece before cutting; the second idle pass is after the cutting is completed.
  • the two idle cutters in the outer turning process are the pass processes near the ends of the workpiece.
  • the time of taking a complete emptying process is the emptying time. In actual engineering, the emptying time often depends on the worker's operational habits and the machine's own processing space, and the processing type such as finishing, semi-finishing, rough The choice of processing is not very relevant.
  • the key judgment of the whole process of the CNC machine cutting process includes the following steps:
  • the acquisition of the start time of the work feed is obtained by reading the NC machining code executed by the CNC machine in real time and analyzing the change characteristics.
  • the NC machining code is changed from the fast moving mode code to the cutting feed mode code, It is recorded as the cutter step feed start time t U1s (that is, the first air knife start time).
  • the cutter step feed start time t U1s that is, the first air knife start time.
  • the machine input power P i is obtained in real time, and compared with the input power P Umin ⁇ P Umax of the spindle in the idle tool state of the machine tool.
  • the cutter's step-feeding end time is realized by analyzing and monitoring the CNC machining code executed by the CNC machine in real time: when the CNC machining code currently executed by the CNC machine tool changes from the work feed code to the fast retraction code, the moment is Recorded as the cutter's step feed end time. For example, if the current execution code of the machine FANUC numerical control system changes from the industrial feed code "G01Z_F_" to the fast retraction "G00X 0 Y 0 Z 0 ", X 0 Y 0 Z 0 is the machine reference point.
  • the method of judging the key moments in the whole process of the cutting process of CNC machine tools is as follows: Firstly, the NC machining code executed by the CNC system of the machine tool is obtained by numerical control communication technology, and the cutting machine of the CNC machine tool is judged according to the transformation characteristics. The feed start time and the end time; then, on the basis of this, the start time and the end time of the cutting step are judged by the real-time input power of the machine tool and its change characteristics, and the flow of the whole judgment process is shown in the solid line part of FIG. 2 .
  • the judgment of such cutting steps according to the characteristics of power variation is often not accurate and prone to misjudgment. Therefore, for the cutting step in which the power change is not obvious during the process of the feed, the judgment of the start and end of the cutting is the historical average of the length of the idle cutter and the time of the feed. The process of the judgment process is shown in the dotted line in Fig. 2. Specifically
  • the first air knife state duration T U1 and the second air knife state duration T U2 in all the historical cutting steps of the machine tool are obtained, and the average of the duration of the first air knife state is calculated respectively. value And the average of the duration of the second idler state
  • the average value of the duration of the first idler state is added to the machining start start time t U1s in the cutting step. Judging as the starting time t Cs of the cutting state in the cutting step, that is,
  • the average value of the duration of the second idler state is subtracted from the machining feed end time t U2e in the cutting step It is judged as the end time t Ce of the cutting state, that is,
  • T U1 t U1e -t U1s
  • t U1e -------- is the end time of the first empty knife state of history processing
  • t U2e -------- is the starting time for the second empty knives state of history processing
  • the first air travel of such a cutting step needs to be calculated by means of on-site investigation. Specifically, the human-machine interaction is entered according to the machine operator's habits, or The empty tooling time of this type of machine is subject to long-term manual judgment and statistics, and then manually entered.
  • the following is a description of the process of machining a part with a CNC lathe.
  • the schematic diagram of the workpiece is shown in 3, and the machining process is rough outer circle->fine car outer circle->rough car slot.
  • the sensor used is the HC33-C3 fuel gauge, and the CNC machining code is read from the CNC system in real time at 0.25s intervals.
  • the numerical control machine is offline and the input power of the spindle is in the range of 260W to 275W.
  • the moment when the CNC machining code currently executed by the CNC machine tool changes from "G00 X8.3" to "G1 Z1" is the starting time of the external feed of the outer roughing.
  • the time at which the NC machining code changes is 15:37:29.000 (in this example, the time is expressed as "hour:minute:second.millisecond"), that is, the start time of the work feed is 15:37:29.000; and at 15 : 37:40.000 hours change from "G01 X13 W-1.2" to "G00 X200;", that is, the end time of the external feed is 15:37:40.000.
  • the spindle input power is 269W
  • the machine spindle input power is changed from 269W to 489W at 15:37:29.500, which is much larger than 269, that is, the cutting start time of the rough outer circle of the CNC lathe is 15: 37:29.500, after which the machine is in the cutting state.
  • the maximum fluctuation range is 13W, until 15:37:39.000, the power becomes 265W, that is, the cutting end time of the rough outer circle is 15:37:39.000.
  • the length of the first idler and the second idler of the roughing are 0.5s and 1s respectively.
  • the starting time of the finishing time of the finishing car is the time when the current execution code is changed from "G00 X7.935" to "G01 X8.05 Z-29.5F300", and the field measurement is 15:37:43.000, and at 15: At 37:52.000, the current CNC machining code is changed from "G01 X14 F300" to "G00 X200 Z1". Based on this, the start and end times of the finishing of the outer circle are 15:37:43.000 and 15:15 respectively. 37:52.000.
  • the starting time of the work feed (ie, the start time of the first empty pass) is 15:37:43.000, and the first empty run time of the rough outer circle is 0.5s into the formula.
  • the cutting start time of the outer circle of the finished car is 15:37:43.5000.
  • the time when the CNC machining code currently executed by the CNC machine tool changes from “G00 Z13.25” to “G1 X7.05 F100” is the starting time of the rough slot work, which is 15:37:56.000.
  • the current CNC machining code is changed from "G01 X8.5” to "G00 X10 Z1", that is, the end of the machining feed is 15:37:59.000.
  • the spindle power is 269W, and the input power is changed from 269W to 316W at 15:37:56.500, that is, the rough start cutting time is 15:37:56.500; after that, the machine is in the cutting state, the spindle power is in The 325W fluctuates within a range of about 12W from the center. Until 15:37:58.000, the power becomes 269W, that is, the cutting end time of the rough lathe of the CNC lathe is 15:37:58.000.
  • the paper uses the stopwatch record and the artificial judgment method to obtain the cutting time point for the accuracy comparison.
  • the cutting time points (“minutes: seconds. milliseconds") obtained by the two methods are shown in the following table.
  • the judgment accuracy of the cutting step of the patent is high: the error of the roughing cutting step is less than 0.5s, and the relative error of the finishing cutting step is larger, but it is also within 1s.

Landscapes

  • Engineering & Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Numerical Control (AREA)

Abstract

一种数控机床切削工步全过程（工进给开始时刻--空走刀--切削开始时刻--切削--切削结束时刻--空走刀--工进给结束时刻）中4个关键时刻的判断方法。该方法包括：根据数控加工代码的实时执行状态进行工进给开始时刻和结束时刻的判断；通过实时比较机床主轴的输入功率与空走刀功率进行切削开始时刻和结束时刻的判断；对于工进给过程中功率变化不明显的特殊切削工步，切削开始、结束时刻的判断则是结合空走刀时长的历史统计平均值和工进给时刻点来实现的。基于4个时刻点的判断，可实现切削工步中切削时长和两种空走刀时长的获取，从而有效地解决了数控机床切削时间和机床有效利用率难以准确获取的难题。

Description

一种数控机床切削工步全过程中关键时刻的判断方法 技术领域
本发明涉及数控机床技术领域，特别涉及一种数控机床切削工步全过程中关键时刻的判断方法。
背景技术
机床切削工步全过程由工进给开始时刻--空走刀--切削开始时刻—切削--切削结束时刻--空走刀--工进给结束时刻构成，其中，切削过程是指机床刀具与工件接触并开始进行材料去除的过程。切削过程的在线自动判断是机床有效运行时间(切削时间)、机床有效利用率(切削时间/开机时间)等机床关键运行参数获取的核心；其次，刀具的磨损、切削能量的消耗、冷却液的消耗等均发生切削过程中，因此切削工步全过程中关键时刻的判断对于刀具使用时间实时获取、机床能量有效利用率和机床加工进度在线监测等也具有重要支持作用。
目前，现有数控机床通讯获取的切削时间实际上是机床的工进刀时间，也叫工进给时间。然而，机床工进刀时间除包含切削时间外，还包括空走刀时间，随着机床服役时间的增长，空走刀时间将越来越多，该方法产生的机床切削时间误差也将越来越大。
国际上对机床切削过程做了一定研究：公布号为CN103838181A的中国专利根据机床主轴负载时电流信号的变化特征对机床工作过程进行判断，但由于部分精加工过程电流变化特征不明显，并且电流信号无法控制的随机波动较大，使得该类加工的切削开始和结束时刻难以判断；美国专利(US 20140212236 A1)通过在刀具和主轴处安装多元传感器进行了数控机床切削过程的判断，但在机床主轴处安装传感器成本高，甚至会影响机床正常工作；加拿大专利(CA 2063887)通过采用多位移监测设备实现了机床切削过程中的刀具路径监测，但其无法直接判断出刀具与工件接触的准确时刻点；公布号为CN 104808584A的中国专利利用机床功率变化特征和人机交互方法实现了机床设备利用状态的在线监测，但切削液以及机床安全门的透明情况均会影响人工视觉判断的准确性，降低了监测精度。
综上所述，现有机床切削过程判断技术主要存在仪器成本高且安装不方便、部分精加工切削过程判断精度较低、空走刀难以判断等问题。
发明内容
针对上述现有技术的不足，本发明所要解决的技术问题是：如何提供一种能够准确判 断切削工步中的切削状态和空走刀状态，有利于准确统计机床有效运行时间和机床有效利用率的数控机床切削工步全过程中关键时刻的判断方法。
为了解决上述技术问题，本发明采用了如下的技术方案：
一种数控机床切削工步全过程中关键时刻的判断方法，其特征在于，在判断前，先获取机床在空走刀状态下主轴的输入功率范围为PUmin～PUmax并储存；判断时，包括如下步骤：
a)对工件进行加工时，实时读取机床的数控加工代码的执行状态，获取并记录切削进给模式代码的执行开始时刻tU1s，判断为切削工步中工进给开始时刻tU1s，同时也是切削工步中第一次空走刀状态的开始时刻tU1s；
b)切削工步中第一次空走刀开始后，获取机床主轴的实时输入功率Pi；当输入功率Pi增大并超过空走刀状态下主轴的最大输入功率PUmax时，记录该增大时的时刻，判断为切削工步中切削状态的开始时刻tCs，同时也是第一次空走刀状态的结束时刻；
c)切削工步中切削状态开始后，当输入功率Pi减小至PUmax以下并保持在空走刀状态下主轴的输入功率范围PUmin～PUmax内时，记录该减小时的时刻，判断为切削工步中切削状态的结束时刻tCe，同时也是第二次空走刀状态的开始时刻；
d)切削工步中切削状态结束后，实时读取机床的数控加工代码的执行状态，获取并记录切削进给模式代码的执行结束时刻tU2e，即判断为切削工步中工进给结束时刻tU2e，同时也是第二次空走刀状态的结束时刻tU2e。
上述方法中，步骤a)中切削进给模式代码是指用于切削加工所执行的代码，常表现为数控工进给代码，其之前执行的数控代码常为快速进刀代码，其后执行的数控代码常为快速退刀代码；因此，软件中常利用进给速度和G代码命令进行快速进刀、快速退刀、工进给的识别，并将快速进刀代码转变为工进给代码时的时刻近似判断为切削进给模式代码执行的开始时刻，以及将工进给代码转变为快速退刀代码的时刻近似判断为切削进给模式代码执行的结束时刻。
步骤b)和步骤c)采用主轴输入功率的变化特征进行切削状态开始与结束时刻的判断，这是因为在机床切削过程中，材料去除时消耗的能量主要来自于主轴；空走刀状态时，刀具因不承受负载，故机床主轴的输入功率相对较小，且保持在一定的波动范围PUmin～PUmax 内，该波动较小且主要是加工车间供电电压不稳造成的；切削状态时，在刀具开始接触工件后，工件材料变形或去除将使得机床的主轴输入功率会在机床空走刀的状态时的基础上增加，且通常大于空走刀状态下的机床主轴的最大输入功率PUmax；由此，实时对机床主轴的输入功率与空走刀状态下的主轴输入功率PUmin～PUmax进行比较，当输入增大并超过空走刀状态最大输入功率PUmax时则判断为切削开始时刻。同理，当刀具离开工件时，机床主轴的输入功率由切削状态下的相对较大值减小变成空走刀状态时的相对较小值，并保持在PUmin～PUmax内；由此，当机床主轴的输入功率减小至PUmax以下并维持在PUmin～PUmax内时可判断机床由切削状态进入空走刀状态，即切削结束时刻。基于上述过程，可以准确判断出切削工步中的第一次空走刀状态、切削状态以及第二次空走刀状态，并记录各状态时的起始和结束时刻。这样，可以计算出每中状态所占用的时间，准确统计出机床有效运行时间和机床有效利用率。
实际工程，有些切削工步因切削量很小，工件材料去除消耗的能量很小，使得切削过程中机床主轴的主轴功率变化不明显，作为进一步优化，针对此类切削工步，即在切削进给模式代码执行过程tU1s～tU2e中，机床主轴的实时输入功率Pi始终保持在空走刀状态下主轴的输入功率范围PUmin～PUmax内时，还包括如下步骤：
读取所有取第一次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000001
和第二次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000002
将切削工步中工进给开始时刻tU1s加上上述第一次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000003
判断为切削工步中切削状态的开始时刻tCs；将切削工步中工进给结束时刻tU2e减去上述第二次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000004
即判断为切削状态的结束时刻tCe。
实际工程中，机床的空走刀时间通常与操作者对机床的操作习惯相关但差距不大，采用上述检测方法，通过将机床历史切削工步中的第一次空走刀状态持续时间TU1和第二次空走刀状态持续时间TU2进行平均，对上述工步中的空走刀及切削状态的起始时刻点和结束时刻点进行修正，提高了全过程的判断精度。
综上所述，本发明具有能够准确判断切削工步中的切削状态和空走刀状态，有利于准确统计机床有效运行时间和机床有效利用率等优点。
相比于现有技术，本发明具有如下优点：
1、本专利提供的数控机床切削工步全过程中关键时刻的判断方法能够准确判断出数控机床切削工步全过程中刀具与工件的接触或者分离时刻。
2、本专利提供的数控机床切削工步全过程中关键时刻的判断方法采用机床主轴的输入功率进行判断，通常该输入功率是通过电量参数传感器或功率传感器进行获取的，相比于采用安装应变片，加速度传感器等方法，其安装更简单方便，成本更低。
3、本专利提供的数控机床切削工步全过程中关键时刻的判断方法能够实时准确统计出机床切削工步中的切削时间，便于后续进行机床有效利用率的在线获取。
附图说明
图1为外圆车削过程示意图。
图2为切削工步自动判断流程图。
图3为实施例中工件的结构示意图。
图1中：1-车刀、2-工件、11-快速进刀路径、12-第一次空走刀路径、13-切削路径、14-第二次空走刀路径、15-快速退刀路径。
具体实施方式
下面结合附图对本发明作进一步的详细说明。
具体实施时：机床加工时，一个完整工步的走刀路线为：机床参考点->安全平面->工件切削->安全平面->机床参考点，其中安全平面是指机床为防止快速移动的刀具与工件表面发生碰撞而在接近工件表面的空间里建立的平面，且在该平面与工件表面之间，刀具的速度为切削进给速度。在这个走刀过程中，刀具以进给速度从安全平面接近工件表面(或切削完后从工件表面返回安全平面)的过程称为空走刀。通常，一个完整的切削工步包括两次空走刀：第一次空走刀为切削前刀具以进给速度离开安全平面并接近工件表面的过程；第二次空走刀为切削完成后，刀具以进给速度离开工件表面并接近安全平面的过程，或者刀具以进给速度离开工件表面走向机床坐标原点的过程。例如，如图1所示，外圆车削过程中的两个空走刀为工件两端面附近的走刀过程。走完整个空走刀过程的时间即为空走刀时间，实际工程中，空走刀时间往往取决于工人的操作性习惯和机床自身加工空间，与加工类型如精加工、半精加工、粗加工的选择关联不大。
由此，数控机床切削工步全过程关键判断包含以下步骤：
a)离线获取机床在空走刀状态下主轴的输入功率PUmin～PUmax并储存。
b)切削工步工进给开始时刻的判断
工进开始时有一个显著特点，刀具的走刀速度发生明显变化，执行的代码明显不同。工进给开始时刻的获取正是通过实时读取数控机床执行的数控加工代码，并分析这一变化特征获得的，当数控加工代码由快速移动模式代码变为切削进给模式的代码时，则记为切削工步工进给开始时刻tU1s(也就是第一个空走刀开始时刻)。例如，当FANUC系统当前执行由快速移动代码“G00X_Y_Z_”变为工进给代码“G01Z_F_”时，即为切削工步工进开始时，式中“X_Y_Z_”为机床坐标，”F_”为机床进给速率。
c)切削工步切削开始时刻和结束时刻的判断
空走刀开始后，实时比较机床空走刀状态下主轴的输入功率PUmin～PUmax和实时输入功率Pi的关系，当
Pi＞PUmax
时，则记录此时刻为切削开始时刻。
切削状态下，实时获取机床输入功率Pi，并与机床空走刀状态下主轴的输入功率PUmin～PUmax进行比较，当
Pi≤PUmax
且维持PUmin≤Pi≤PUmax时，则记录此减小时的时刻为切削工步切削结束时刻。
d)切削工步工进给结束时刻的判断
切削工步工进给结束时刻是通过分析和监测数控机床实时执行的数控加工代码来实现的：当数控机床当前执行的数控加工代码由工进给代码变为快速退刀代码时，该时刻则记为切削工步工进给结束时刻。如机床FANUC数控系统当前执行代码由工进给代码“G01Z_F_”变为快速退刀“G00X0Y0Z0”的时刻，式中X0Y0Z0为机床参考点。
综上所述，数控机床切削工步全过程中关键时刻的判断方法为:首先，通过数控通信技术获取机床数控系统实时执行的数控加工代码，并根据其变换特征判断出数控机床切削工步工进给开始时刻和结束时刻；然后在此基础上，通过机床实时输入功率及其变化特征判断切削工步开始时刻和结束时刻，整个判断过程的流程见图2中实线部分。
但由于部分精加工因切削余量较小，功率需求小，根据功率变化特征进行此类切削工步的判断往往准确度不高，容易出现误判。因此，对于工进给过程中功率变化不明显的切削工步，其切削开始、结束时刻的判断则是结合空走刀时长的历史统计平均值和工进给时 刻点来实现的，其判断过程的流程见图2中的虚线部分。具体为
首先，获取该机床所有历史切削工步中的第一次空走刀状态持续时间TU1和第二次空走刀状态持续时间TU2，分别计算获取第一次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000005
和第二次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000006
然后，将切削工步中工进给开始时刻tU1s加上第一次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000007
判断为切削工步中切削状态的开始时刻tCs，即
Figure PCTCN2017079735-appb-000008
将切削工步中工进给结束时刻tU2e减去第二次空走刀状态持续时间的平均值
Figure PCTCN2017079735-appb-000009
判断为切削状态的结束时刻tCe，即
Figure PCTCN2017079735-appb-000010
而关于历史空走刀状态持续时间，其获取分两种情况。
如果机床之前进行过功率变化明显的加工，空走刀时长TU1计算为
TU1＝tU1e-tU1s
TU2＝tU2e-tU2s
式中，tU1e--------为历史加工第一次空走刀状态的开始时刻；
tU1e--------为历史加工第一次空走刀状态的结束时刻；
tU2e--------为历史加工第二次空走刀状态的开始时刻；
tU2e--------为历史加工第二次空走到状态的结束时刻；
如果数控机床之前未进行过加工，则此类切削工步第一个空走刀行程需借助现场调研方式计算获取，具体为：根据该机床操作者的习惯进行估算后人机交互录入，或者对该类型机床的空走刀时间进行长期人工判断和统计，然后手动录入。
下面结合某数控车床加工某零件的过程为例进行说明，该工件的示意图见3，其加工过程为粗车外圆－>精车外圆－>粗车槽。所采用的传感器为HC33-C3电量测量仪，数控加工代码则是采用软件以0.25s为间隔实时从数控系统中读取获得的。判断前，离线测得该数控机床在空走刀状态下，主轴的输入功率为波动范围260W～275W。
一、粗车外圆过程
1、工进给开始时刻和结束时刻获取
数控机床当前执行的数控加工代码由“G00 X8.3”变为“G1 Z1”的时刻即为外圆粗车时工进给的开始时刻。测得数控加工代码发生该变化的时刻为15:37:29.000(本例中时间表示为“时：分：秒.毫秒”)，即工进给开始时刻为15:37:29.000；并在15:37:40.000时由“G01 X13 W-1.2”变为“G00 X200；”，即外圆粗车时工进给结束时刻为15:37:40.000。
2、切削开始时刻和结束时刻的获取
进入空走刀后，测得主轴输入功率为269W，并在15:37:29.500时机床主轴输入功率由269W变为489W，远大于269,即数控车床粗车外圆的切削开始时刻为15:37:29.500，之后机床处于切削状态。现场测量该状态下主轴功率一直在489W左右的波动，最大波动范围为13W，直到15:37:39.000时，功率变为了265W，即粗车外圆的切削结束时刻为15:37:39.000。
综上，此次粗加工第一次空走刀时长和第二次空走刀时长分别为0.5s和1s。
二、精车外圆时过程
1、工进给开始时刻和结束时刻获取
精车外圆时工进给开始时刻为当前执行代码由“G00 X7.935”变为“G01 X8.05 Z-29.5F300‘’的时刻，现场测量为15:37:43.000，而在15:37:52.000时，当前执行数控加工代码由“G01 X14 F300”变为了“G00 X200 Z1”。基于此，精车外圆时工进给开始时刻和结束时刻分别为15:37:43.000和15:37:52.000。
2、切削开始时刻和结束时刻的获取
将工进给开始时刻(即第一个空走刀开始时刻)15:37:43.000，和粗车外圆时的第一次空走刀时长0.5s带入公式
Figure PCTCN2017079735-appb-000011
中，得出精车外圆的切削开始时刻为15:37:43.5000。
同理，将工进给结束时刻(第二个空走刀结束时刻)15:37:52.000，和粗车外圆时的第二次空走刀时长1.0s带入公式
TU2＝tU2e-tU2s
中，得出精车外圆的切削结束时刻为15:37:51.000。
三、粗车槽过程
1、工进给开始时刻和结束时刻判断
数控机床当前执行的数控加工代码由“G00 Z13.25”变为“G1 X7.05 F100”的时刻即为粗车槽工进开始时刻，为15:37:56.000。而在15:37:59.000时，当前执行数控加工代码由“G01 X8.5”变为了“G00 X10 Z1”，即工进给结束时刻为15:37:59.000。
2、切削开始时刻和结束时刻判断
工进开始后，主轴功率为269W，并在15:37:56.500时输入功率由269W突变为316W，即粗车槽切削开始时刻为15:37:56.500；之后机床处于切削状态，主轴功率在以325W为中心12W左右范围内波动，直到15:37:58.000时，功率变为了269W，即数控车床粗车槽时的切削结束时刻为15:37:58.000。
四、判断结果分析
在采用上述方法的进行切削工步关键时刻获取的同时，本文为了进行精度比较，采用了秒表记录，人为判断的方式进行了切削时刻点获取。为了便于结果对比，并将秒表测试结果转换成上述方法的时间模式，两种方法获取的切削时刻点(“分：秒.毫秒”)见下表。
Figure PCTCN2017079735-appb-000012
对比实验结果可知，本专利的切削工步关键时刻的判断精度较高：粗加工切削工步判断的误差不到0.5s，精加工切削工步相对误差大一些，但也在1s以内。
以上所述仅为本发明的较佳实施例而已，并不以本发明为限制，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。

Claims (2)

  1. 一种数控机床切削工步全过程中关键时刻的判断方法，其特征在于，在判断前，先获取机床在空走刀状态下主轴的输入功率范围为PUmin～PUmax并储存；判断时，包括如下步骤：
    对工件进行加工时，实时读取机床的数控加工代码的执行状态，获取并记录切削进给模式代码的执行开始时刻tU1s，判断为切削工步中工进给开始时刻tU1s，同时也是切削工步中第一次空走刀状态的开始时刻tU1s；
    切削工步中第一次空走刀开始后，获取机床主轴的实时输入功率Pi；当输入功率Pi增大并超过空走刀状态下主轴的最大输入功率PUmax时，记录该增大时的时刻，判断为切削工步中切削状态的开始时刻tCs，同时也是第一次空走刀状态的结束时刻；
    切削工步中切削状态开始后，当输入功率Pi减小至PUmax以下并保持在空走刀状态下主轴的输入功率范围PUmin～PUmax内时，记录该减小时的时刻，判断为切削工步中切削状态的结束时刻tCe，同时也是第二次空走刀状态的开始时刻；
    切削工步中切削状态结束后，实时读取机床的数控加工代码的执行状态，获取并记录切削进给模式代码的执行结束时刻，即判断为切削工步中工进给结束时刻tU2e，同时也是第二次空走刀状态的结束时刻。
  2. 如权利要求1所述的数控机床切削工步全过程中关键时刻的判断方法，其特征在于，在切削进给模式代码执行过程tU1s～tU2e中，当机床主轴的实时输入功率Pi始终保持在空走刀状态下主轴的输入功率范围PUmin～PUmax内时，还包括如下步骤：
    读取所有该机床历史切削工步中的第一次空走刀状态持续时间TU1和第二次空走刀状态持续时间TU2，分别取第一次空走刀状态持续时间的平均值
    Figure PCTCN2017079735-appb-100001
    和第二次空走刀状态持续时间的平均值
    Figure PCTCN2017079735-appb-100002
    将切削工步中工进给开始时刻tU1s加上上述第一次空走刀状态持续时间的平均值
    Figure PCTCN2017079735-appb-100003
    判断为切削工步中切削状态的开始时刻tCs；将切削工步中工进给结束时刻tU2e减去上述第二次空走刀状态持续时间的平均值
    Figure PCTCN2017079735-appb-100004
    即判断为切削状态的结束时刻tCe。
PCT/CN2017/079735 2016-09-27 2017-04-07 一种数控机床切削工步全过程中关键时刻的判断方法 WO2018058932A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US16/336,121 US10719061B2 (en) 2016-09-27 2017-04-07 Method for judging key moments in whole process of machining step for computer numerical control machine tools

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201610854249.8 2016-09-27
CN201610854249.8A CN106154977B (zh) 2016-09-27 2016-09-27 一种数控机床切削工步全过程中关键时刻的判断方法

Publications (1)

Publication Number Publication Date
WO2018058932A1 true WO2018058932A1 (zh) 2018-04-05

Family

ID=57340965

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2017/079735 WO2018058932A1 (zh) 2016-09-27 2017-04-07 一种数控机床切削工步全过程中关键时刻的判断方法

Country Status (3)

Country Link
US (1) US10719061B2 (zh)
CN (1) CN106154977B (zh)
WO (1) WO2018058932A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111209519A (zh) * 2020-01-17 2020-05-29 嘉兴云切供应链管理有限公司 钢板切割设备稼动率采集计算方法

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106154977B (zh) 2016-09-27 2018-03-27 重庆大学 一种数控机床切削工步全过程中关键时刻的判断方法
JP6693409B2 (ja) * 2016-12-26 2020-05-13 ブラザー工業株式会社 数値制御装置と制御方法
CN107703886B (zh) * 2017-10-31 2020-04-21 上海航天精密机械研究所 数控机床铣削过程中关键时长的实时统计方法
CN110434361A (zh) * 2019-07-17 2019-11-12 中山市六六六智能装备有限公司 一种加工车床的控制方法及车床系统
CN112835326B (zh) * 2020-12-30 2022-06-17 天津重型装备工程研究有限公司 一种大型铸锻件加工智能化方法及系统
CN112859741A (zh) * 2020-12-31 2021-05-28 上海交通大学 一种机床顺序动作单元运行可靠性评价方法及系统
CN113050542B (zh) * 2021-03-24 2023-01-03 武汉科技大学 一种数控机床加工状态判别方法
CN113835396B (zh) * 2021-11-26 2022-03-04 四川省机械研究设计院(集团)有限公司 Cnc刀具监测方法和系统及调度管理方法和系统
CN117742242B (zh) * 2023-12-26 2024-05-17 巨野县职业中等专业学校 一种数控机床动态调控方法和系统

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2063887A1 (en) * 1991-04-01 1992-10-02 Karl Thomas Bagdal Roll roundness measuring and machining apparatus and method
JP2013188831A (ja) * 2012-03-14 2013-09-26 Mitsubishi Electric Corp 工作機械の制御装置およびそれを備えた工作機械
CN103838181A (zh) * 2012-11-22 2014-06-04 财团法人资讯工业策进会 机床状态判断方法以及系统
CN103901813A (zh) * 2014-03-04 2014-07-02 浙江大学 变切削速率过程材料切削功率及能耗的获取和节能控制方法
CN103941644A (zh) * 2014-04-04 2014-07-23 武汉科技大学 一种基于时间参数的数控铣床能耗预测方法
CN104808584A (zh) * 2015-02-17 2015-07-29 重庆大学 机床多源能耗系统多信息在线检测系统
CN106154977A (zh) * 2016-09-27 2016-11-23 重庆大学 一种数控机床切削工步全过程中关键时刻的判断方法

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5727912A (en) * 1992-12-28 1998-03-17 Omat Ltd. Controller for CNC-operated machine tools
US6874980B1 (en) * 2002-10-25 2005-04-05 Controller for the electric motor of a high-speed spindle attachment used with computer-controlled milling machines
JP2007203346A (ja) * 2006-02-02 2007-08-16 Fanuc Ltd レーザ制御方法及びレーザ制御装置
DE102009054829A1 (de) * 2009-12-17 2011-06-22 Siemens Aktiengesellschaft, 80333 Verfahren und Einrichtung zum Betrieb einer Maschine aus der Automatisierungstechnik
CN102354155B (zh) * 2011-07-22 2013-05-01 江俊逢 开放式数控系统的实时内核及刀路曲线的实时控制方法
TWI472399B (zh) * 2012-02-10 2015-02-11 中原大學 Online cutting tool real-time monitoring method
US10055512B2 (en) * 2012-07-16 2018-08-21 Omc2 Llc System and method for CNC machines and software
JP5513571B2 (ja) * 2012-09-06 2014-06-04 ファナック株式会社 放電開始を判定する機能を有するガスレーザ発振器
EP3213161B1 (en) * 2014-10-31 2022-12-07 Big Data in Manufacturing GmbH Method for optimizing the productivity of a machining process of a cnc machine
EP3213160B1 (en) * 2014-10-31 2024-05-22 Big Data in Manufacturing GmbH A computer-implemented method for part analytics of a workpiece machined by at least one cnc machine
TWI571820B (zh) * 2014-11-06 2017-02-21 財團法人資訊工業策進會 工具機耗電量預測系統與方法
TWI650625B (zh) * 2017-11-16 2019-02-11 財團法人工業技術研究院 刀具磨耗檢測裝置、其檢測方法及刀具磨耗補償方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2063887A1 (en) * 1991-04-01 1992-10-02 Karl Thomas Bagdal Roll roundness measuring and machining apparatus and method
JP2013188831A (ja) * 2012-03-14 2013-09-26 Mitsubishi Electric Corp 工作機械の制御装置およびそれを備えた工作機械
CN103838181A (zh) * 2012-11-22 2014-06-04 财团法人资讯工业策进会 机床状态判断方法以及系统
CN103901813A (zh) * 2014-03-04 2014-07-02 浙江大学 变切削速率过程材料切削功率及能耗的获取和节能控制方法
CN103941644A (zh) * 2014-04-04 2014-07-23 武汉科技大学 一种基于时间参数的数控铣床能耗预测方法
CN104808584A (zh) * 2015-02-17 2015-07-29 重庆大学 机床多源能耗系统多信息在线检测系统
CN106154977A (zh) * 2016-09-27 2016-11-23 重庆大学 一种数控机床切削工步全过程中关键时刻的判断方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WANG, QIULIAN ET AL.: "On-line Monitoring and Analysis System for Energy Efficiency of CNC Machine Tools", MODERN MANUFACTURING ENGINEERING *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111209519A (zh) * 2020-01-17 2020-05-29 嘉兴云切供应链管理有限公司 钢板切割设备稼动率采集计算方法
CN111209519B (zh) * 2020-01-17 2023-04-14 嘉兴云切在线科技有限公司 钢板切割设备稼动率采集计算方法

Also Published As

Publication number Publication date
US10719061B2 (en) 2020-07-21
CN106154977A (zh) 2016-11-23
CN106154977B (zh) 2018-03-27
US20190278253A1 (en) 2019-09-12

Similar Documents

Publication Publication Date Title
WO2018058932A1 (zh) 一种数控机床切削工步全过程中关键时刻的判断方法
CN109909804B (zh) 基于主轴驱动电流和工步的刀具磨损破损在线监测方法
CN103676782B (zh) 数控铣床加工过程中能量效率在线检测方法
CN101477351B (zh) 具有三级加工自优化功能的智能数控方法
CN105500113B (zh) 基于非接触位移传感器的机床主轴夹屑报警装置及方法
CN112372379B (zh) 航空发动机用复杂曲面型叶尖的磨削加工方法
TWI616272B (zh) 加工參數調整系統及加工參數調整方法
CN108803495A (zh) 一种执行车削加工程序时数控车床能耗预测方法
CN116352607B (zh) 基于数控分析的无心磨床补偿控制系统及方法
CN105866524B (zh) 数控铣床加工过程中净去除材料比能在线检测方法
CN114273976A (zh) 一种数控加工中心在线监测智能调控管理云系统
CN106407622A (zh) 一种大螺距螺纹车削刀具设计方法
CN103273376A (zh) 基于数控滚齿机床的自动二次对刀方法
CN113199304B (zh) 一种基于扩展卡尔曼滤波与切削力模型的换刀监测方法
Wang et al. Identification of instantaneous cutting force coefficients using surface error
US11226613B2 (en) Anomaly detection device, anomaly detection server and anomaly detection method
CN105033719A (zh) 一种基于动态可靠度确定换刀时间的方法
CN113031521A (zh) 数控机床的刀具监控系统和方法
CN217096927U (zh) 一种数控机床刀补检测系统
CN206848793U (zh) 超大薄壁零件五轴数控加工系统
CN112835326B (zh) 一种大型铸锻件加工智能化方法及系统
CN115716218A (zh) 一种数控刀具状态在线监控系统
CN110842644B (zh) 一种基于数控负载信息的机床运动部件接触刚度退化率监测方法
CN111716249A (zh) 一种加工路径智能调整测量结构及测量方法
Shi et al. Current study and innovative ideas of online monitoring technology of tool wear

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17854391

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17854391

Country of ref document: EP

Kind code of ref document: A1