Load-energy efficiency evaluation and monitoring method for achieving energy conservation and emission reduction of numerical control machine tool

Abstract

A load-energy efficiency evaluation and monitoring method includes an actual part processing number and a theoretical part processing number of the numerical control machine tool within an evaluation period are obtained to calculate a loading performance of the numerical control machine tool. A waste time value and a standby power value of the numerical control machine tool are obtained to calculate a waste energy value of the numerical control machine tool. A single-part actual processing energy consumption is obtained and used, together with a single-part ideal processing energy consumption, to calculate the load-energy efficiency of the numerical control machine tool. A relationship model between the load-energy efficiency and the loading performance of the numerical control machine tool is built based on the obtained model of the load-energy efficiency of the numerical control machine tool and the obtained model of the loading performance of the numerical control machine tool.

Claims

1. A load-energy efficiency evaluation and monitoring method for achieving energy conservation and emission reduction of a numerical control machine tool, comprising the following steps: at step 1, processing parts by a numerical control machine tool within a given time period, wherein each part is provided with a radio frequency identification (RFID) tag, and after processing a part, automatically perceiving, by an RFID reader, the processed part and automatically increasing a tally of the quantity of processed parts by 1 each time a part is processed to obtain an actual part processing number, denoted as O.sub.actual, of the numerical control machine tool within a given time period; at step 2, calculating a theoretical part processing number of the numerical control machine tool based on an available time of the numerical control machine tool within the given time period and a single-part ideal part processing time, wherein the calculation of the theoretical part processing number uses a theoretical part processing model as follows: $O_{\mathrm{theory}}=\frac{T_{\mathrm{available}}}{T_{\mathrm{ideal}-CT}};$ wherein, O.sub.theory refers to the theoretical part processing number of the numerical control machine tool within the given time period, T.sub.available refers to the available time of the numerical control machine tool within the given time period, and T.sub.ideal-CT refers to the single-part ideal processing time; at step 3, calculating a loading performance of the numerical control machine tool based on the obtained actual part processing number of the numerical control machine tool within the given time period and the obtained theoretical part processing number of the numerical control machine tool within the given time period, wherein the calculation of the load performing of the numerical control machine tool uses a load performance model thereof as follows: ${\eta }_{\mathrm{performanc}e}=\frac{O_{actual}}{O_{\mathrm{theory}}};$ wherein, η.sub.performance refers to the loading performance of the numerical control machine tool, O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, and O.sub.theory refers to the theoretical part processing number of the numerical control machine tool within the given time period; at step 4, measuring a single-part processing energy consumption value of the numerical control machine tool under given ideal processing parameters several times by using an energy consumption measuring device mounted at an air switch of the numerical control machine tool and performing averaging for the obtained energy consumption values, so as to obtain a single-part ideal processing energy consumption value denoted as E.sub.ideal; at step 5, calculating a waste energy value of the numerical control machine tool within the given time period based on a waste time of the numerical control machine tool within the given time period and a standby power value of the numerical control machine tool, wherein the waste energy value of the numerical control machine tool within the given time period uses a waste energy value model as follows:
E.sub.waste=T.sub.waste×P.sub.standby; wherein, E.sub.waste refers to the waste energy value of the numerical control machine tool within the given time period, T.sub.waste refers to the waste time of the numerical control machine tool within the given time period, and P.sub.standby refers to the standby power value of the numerical control machine tool; at step 6, obtaining a single-part actual processing energy consumption value according to the obtained waste energy value of the numerical control machine tool within the given time period in combination with the actual part processing number of the numerical control machine tool within the given time period, wherein the single-part processing energy consumption value is obtained using a model as follows: $E_{actual}=\frac{O_{actual}\times E_{\mathrm{ideal}}+E_{waste}}{O_{actual}};$ wherein, E.sub.actual refers to the single-part actual processing energy consumption value, O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, E.sub.ideal refers to the single-part ideal processing energy consumption value, and E.sub.waste refers to the waste energy value of the numerical control machine tool within the given time period; at step 7, calculating a load-energy efficiency of the numerical control machine tool based on the obtained single-part ideal processing energy consumption value and the single-part actual processing energy consumption value, wherein the load-energy efficiency of the numerical control machine tool uses a load-energy efficiency model as follows: ${\eta }_{\mathrm{performance\_e}}=\frac{E_{\mathrm{ideal}}}{E_{actual}};$ wherein, η.sub.performance_e refers to the load-energy efficiency of the numerical control machine tool, E.sub.ideal refers to the single-part ideal processing energy consumption value, and E.sub.actual refers to the single-part actual processing energy consumption value; at step 8, obtaining a relationship model between the load-energy efficiency of the numerical control machine tool and the loading performance of the numerical control machine tool through derivation operation based on the obtained calculation model of the loading performance of the numerical control machine tool and the obtained calculation model of the load-energy efficiency of the numerical control machine tool, wherein the relationship model is expressed as follows: ${\eta }_{\mathrm{performance\_e}}=\frac{O_{actual}\times E_{\mathrm{ideal}}\times T_{\mathrm{available}}^{-1}}{\begin{array}{c}{O}_{\mathrm{actual}}\times E_{\mathrm{ideal}}\times T_{\mathrm{available}}^{-1}+\\ \left(1-{\eta }_{\mathrm{performanc}e}\right)\times P_{standby}\end{array}};$ in the above formula, η.sub.performance_e refers to the load-energy efficiency of the numerical control machine tool, O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, E.sub.ideal refers to the single-part ideal processing energy consumption value, T.sub.available refers to the available time of the numerical control machine tool within the given time period, η.sub.performance refers to the loading performance of the numerical control machine tool, and P.sub.standby refers to the standby power value of the numerical control machine tool; at step 9, comparing the obtained load-energy efficiency η.sub.performance_e of the numerical control machine tool within the given time period with a preset alarming lower limit value η.sub.performance_e.sup.L of the load-energy efficiency of the numerical control machine tool; if the expression η.sub.performance_e>η.sub.performance_e.sup.L is satisfied, the load-energy efficiency of the numerical control machine tool being normal; if the expression η.sub.performance_e≤η.sub.performance_e.sup.L is satisfied, prompting by alarming that the load-energy efficiency of the numerical control machine tool is abnormal, and displaying the load-energy efficiency of the numerical control machine tool, the corresponding loading performance of the numerical control machine tool and the waste energy value of the numerical control machine tool within the given time period on a display screen at the same time; at step 10, according to the alarming prompt at step 9, making, by production personnel, specific adjustment to a part processing procedure of the numerical control machine tool to reduce the waste energy value of the numerical control machine tool so as to increase the load-energy efficiency of the numerical control machine tool to a normal range.

2. The load-energy efficiency evaluation and monitoring method according to claim 1, wherein at step 2, the available time T.sub.available of the numerical control machine tool within the given time period is obtained by subtracting a downtime of the numerical control machine tool within the given time period from a planned processing time within the given time period based on the calculation model as follows:
T.sub.available=T.sub.planed−T.sub.downtime; in the above model, T.sub.available refers to the available time of the numerical control machine tool within the given time period, T.sub.planed refers to the planned processing time of the numerical control machine tool within the given time period, and T.sub.downtime refers to the downtime of the numerical control machine tool within the given time period.

3. The load-energy efficiency evaluation and monitoring method according to claim 1, wherein at step 5, the waste time T.sub.waste of the numerical control machine tool within the given time period is obtained by subtracting an overall ideal part processing time from the available time of the numerical control machine tool within the given time period based on the calculation model as follows:
T.sub.waste=T.sub.available−O.sub.actual×T.sub.ideal-CT; in the above model, T.sub.waste refers to the waste time of the numerical control machine tool within the given time period, T.sub.available refers to the available time of the numerical control machine tool within the given time period, O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, and T.sub.ideal-CT refers to the single-part ideal processing time.

4. The load-energy efficiency evaluation and monitoring method according to claim 1, wherein at step 5, the standby power value P.sub.standby of the numerical control machine tool is obtained by measuring the power value of the numerical control machine tool in a standby state several times using a power measuring device mounted at the air switch of the numerical control machine tool and performing averaging for the obtained power values.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

(1) FIG. 1 is a flowchart of a method according to an example of the present disclosure.

(2) FIG. 2 is a schematic diagram of a device configuration of a method according to an example of the present disclosure.

DETAILED DESCRIPTIONS OF EMBODIMENTS

(3) The present disclosure is described in detail now in combination with examples and accompanying drawings.

(4) The present disclosure provides a load-energy efficiency evaluation and monitoring method for achieving energy conservation and emission reduction of a numerical control machine tool. A flowchart of the method according to the present disclosure is as shown in FIG. 1. Firstly, an actual part processing number of the numerical control machine tool within a given time period is obtained through perception by means of an RFID tag and an RFID reader attached to parts. Next, a theoretical part processing number of the numerical control machine tool is calculated according to an available time of the numerical control machine tool within the given time period and a single-part ideal processing time. A loading performance of the numerical control machine tool is calculated based on the obtained actual part processing number of the numerical control machine tool and the obtained theoretical part processing number of the numerical control machine tool. A single-part ideal processing energy consumption value is obtained by measuring a single-part processing energy consumption value of the numerical control machine tool under ideal processing parameters several times and performing averaging for the obtained energy consumption values. An waste energy value of the numerical control machine tool within the given time period is calculated based on a waste time of the numerical control machine tool within the given time period and a standby power value of the numerical control machine tool. Further, the single-part actual processing energy consumption value is obtained according to the obtained waste energy value of the numerical control machine tool within the given time period in combination with the actual part processing number of the numerical control machine tool within the given time period. The load-energy efficiency of the numerical control machine tool is calculated according to the obtained single-part ideal processing energy consumption value and the obtained single-part actual processing energy consumption value. A relationship model between the load-energy efficiency of the numerical control machine tool and the loading performance of the numerical control machine tool is built based on the built model of the loading performance of the numerical control machine tool and the built model of the load-energy efficiency of the numerical control machine tool. The load-energy efficiency of the numerical control machine tool is monitored based on the above relationship model to realize an over-limit alarming function, so as to control the load-energy efficiency of the numerical control machine tool within a required range.

(5) As shown in FIG. 2, a device configuration involved in the present disclosure mainly includes: a power analyzer, an RFID tag, an RFID reader, a computer installed with Sql database and a display screen. The power analyzer is used to measure the standby power of the numerical control machine tool and the part-processing energy consumption of the numerical control machine tool; the RFID tag is attached to the part for part identification; the RFID reader obtains a part processing number by perceiving the RFID tag; the computer installed with the Sql database is configured to store the collected part processing number of the numerical control machine tool, and the collected power, energy consumption and energy efficiency of the numerical control machine tool; the display screen is connected with the computer to display the load-energy efficiency, the loading performance and the waste energy of the numerical control machine tool.

(6) In an example of the present disclosure, a numerical control machine tool CK6153i is taken as an example with the processed parts being cylindrical parts for wholesales and retails. The method of the present disclosure is adopted to evaluate and monitor the load-energy efficiency of the numerical control machine tool and perform over-limit alarming for the load-energy efficiency of the numerical control machine tool.

(7) 1. The actual part processing number of the numerical control machine tool is obtained.

(8) The load-energy efficiency of the numerical control machine tool is evaluated every other one hour, and thus the given time period is one hour. An initial value of the actual part processing number of the numerical control machine tool is set to 0 (O.sub.actual=0). The RFID tag is attached to each part. After being processed on the numerical control machine tool, the part will pass through the RFID reader, and the RFID reader can automatically perceive the passing RFID tag and automatically accumulate 1 to the actual part processing number of the numerical control machine tool (O.sub.actual=O.sub.actual+1). July 28th 9:00 to 10:00 AM is taken as an example. The numerical control machine tool CK6153i totally processes 24 parts, and the RFID perceives 24 RFID tags and obtains the actual part processing number of the numerical control machine tool, that is, O.sub.actual=24 pieces.

(9) 2. The theoretical part processing number of the numerical control machine tool is obtained.

(10) Since the load-energy efficiency of the numerical control machine tool is evaluated every other one hour, it is required to obtain the theoretical part processing number of the numerical control machine tool within one hour.

(11) July 28th 9:00 to 10:00 AM is still taken as an example. The planned processing time of the numerical control machine tool within the time period is 60 minutes (T.sub.planed=3600 seconds), and the downtime of the numerical control machine tool caused by adjustment is 5 minutes (T.sub.downtime=300 seconds). In this case, the available time of the numerical control machine tool is calculated in the model T.sub.available=T.sub.planed−T.sub.downtime. In the model, T.sub.available refers to the available time of the numerical control machine tool, in the unit of second (s); T.sub.planed refers to the planned processing time of the numerical control machine tool, in the unit of second (s); T.sub.downtime refers to the downtime of the numerical control machine tool, in the unit of second (s). Data of T.sub.planed=3600 and T.sub.downtime=300 for July 28th 9:00 to 10:00 AM is substituted into the formula to obtain the available time of the numerical control machine tool within the evaluation period, that is, T.sub.available=T.sub.planed−T.sub.downtime=3600−300=3300 seconds. The single-part ideal processing time of this part is obtained according to historical information, that is, T.sub.ideal-CT=120 seconds/piece. The theoretical part processing number of the numerical control machine tool is calculated in the model

(12) $O_{\mathrm{theory}}=\frac{T_{\mathrm{availab}le}}{T_{\mathrm{ideal}-\mathrm{CT}}}.$
In the model, O.sub.theory refers to the theoretical part processing number of the numerical control machine tool within the given time period, in the unit of piece; T.sub.available refers to the available time of the numerical control machine tool within the given time period, in the unit of second (s); T.sub.ideal-CT refers to the single-part ideal processing time, in the unit of second (s). The obtained available time of the numerical control machine tool within the evaluation period, T.sub.available=3300 seconds, and the obtained single-part ideal processing time, T.sub.idea-CT=120 seconds/piece, are substituted into the formula

(13) $O_{\mathrm{theory}}=\frac{T_{\mathrm{available}}}{T_{\mathrm{ideal}-CT}}$
to calculate the theoretical part processing number of the numerical control machine tool, O.sub.theory=27 pieces.

(14) 3. The loading performance of the numerical control machine tool is obtained.

(15) The loading performance of the numerical control machine tool is calculated according to the obtained actual part processing number and the obtained theoretical part processing number of the numerical control machine tool within the evaluation period based on the calculation model

(16) ${\eta }_{\mathrm{performanc}e}=\frac{O_{actual}}{O_{\mathrm{theory}}}.$
In the model, η.sub.performance refers to the loading performance of the numerical control machine tool, O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, in the unit of piece; O.sub.theory refers to the theoretical part processing number of the numerical control machine tool within the given time period, in the unit of piece. By still taking July 28th 9:00 to 10:00 AM as an example, the actual part processing number of the numerical control machine tool within the evaluation period is obtained as O.sub.actual=24 pieces and the theoretical part processing number of the numerical control machine tool within the evaluation period is obtained as O.sub.theory=27 pieces. The above data is substituted into the formula

(17) ${\eta }_{\mathrm{performanc}e}=\frac{O_{actual}}{O_{\mathrm{theory}}}$
to calculate the loading performance of the numerical control machine tool, that is, ηn.sub.performance=88.9%.

(18) 4. The single-part ideal processing energy consumption is obtained.

(19) An energy consumption measuring device is mounted at an air switch of the numerical control machine tool CK6153i. The energy consumption measuring device used in this example is a power analyzer that can record the power and energy consumption during processing of the machine tool at the same time. The single-part processing energy consumption value of the numerical control machine tool under given ideal processing parameters is measured several times. 30 single-part processing energy consumption values under the given ideal processing parameters are obtained as shown in Table 1.

(20) TABLE-US-00001 TABLE 1 Measurement sequence number 1 2 3 4 . . . 29 30 Energy consumption 152.6 153.1 149.7 153.9 . . . 148.3 150.2 value (kJ)

(21) The single-part ideal processing energy consumption value E.sub.ideal=151.7 may be obtained by performing averaging for the 30 energy consumption values in Table 1.

(22) 5. The waste energy value of the numerical control machine tool is obtained.

(23) The waste energy value of the numerical control machine tool within the given time period is jointly determined by the waste time and the standby power value of the numerical control machine tool. Therefore, it is required to firstly obtain the waste time and the standby power value of the numerical control machine tool.

(24) 5.1 The waste time of the numerical control machine tool is obtained.

(25) By still taking July 28th 9:00 to 10:00 AM as an example, the available time of the numerical control machine tool within the evaluation period is obtained as T.sub.available=3300 seconds, the single-part ideal processing time is obtained as T.sub.ideal-CT=120 seconds/piece and the actual part processing number of the numerical control machine tool within the evaluation period is obtained as O.sub.actual=24 pieces. The waste time T.sub.waste of the numerical control machine tool within the given time period is calculated in the model T.sub.waste=T.sub.available−O.sub.actual×T.sub.ideal-CT. In the model, T.sub.waste refers to the waste time of the numerical control machine tool within the given time period, in the unit of second (s); T.sub.available refers to the available time of the numerical control machine tool within the given time period, in the unit of second (s); O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, in the unit of piece; T.sub.ideal-CT refers to the single-part ideal processing time, in the unit of second/piece. The obtained T.sub.available=3300 seconds, T.sub.ideal-CT=120 seconds/piece and O.sub.actual=24 pieces are substituted into the above formula to calculate the waste time of the numerical control machine tool within the given time period, that is, T.sub.waste=T.sub.available−O.sub.actual×T.sub.ideal-CT=3300−24×120=420 (s).

(26) 5.2 The standby power value of the numerical control machine tool is obtained.

(27) The power measuring device is mounted at the air switch of the numerical control machine tool CK6153i. The power measuring device used in this example is a power analyzer. The numerical control machine tool CK6153i is started and allowed to be in a standby state without any further operations, and 50 standby power values of the machine tool are measured as shown in Table 2.

(28) TABLE-US-00002 TABLE 2 Measurement sequence number 1 2 3 4 . . . 49 50 Standby power value (kW) 0.31 0.32 0.31 0.32 . . . 0.30 0.33

(29) The standby power value P.sub.standby=0.32 (kW) of the numerical control machine tool, that is, is obtained by performing averaging for the 50 standby power values of the machine tool in Table 2.

(30) The waste energy value of the numerical control machine tool within the given time period is calculated in the model E.sub.waste=T.sub.waste×P.sub.standby. In the model, E.sub.waste refers to the waste energy value of the numerical control machine tool within the given time period, in the unit of kilojoule (kJ); T.sub.waste refers to the waste time of the numerical control machine tool within the given time period, in the unit of second (s); P.sub.standby refers to the standby power value of the numerical control machine tool, in the unit of kilowatt (kW). The obtained T.sub.waste=420 seconds and P.sub.standby=0.32 kW are substituted into the above formula to calculate the waste energy value of the numerical control machine tool, that is, E.sub.waste=420×0.32=134.4 (kJ).

(31) 6. The single-part actual processing energy consumption is obtained.

(32) By still taking July 28th 9:00 to 10:00 AM as an example, the waste energy value of the numerical control machine tool is obtained as E.sub.waste=134.4 kJ, the actual part processing number of the numerical control machine tool within the given time period is obtained as O.sub.actual=24 pieces, and the single-part ideal processing energy consumption value is obtained as E.sub.ideal=151.7 kJ. Thus, the single-part actual processing energy consumption value is calculated in the formula

(33) 0$E_{actual}=\frac{O_{actual}\times E_{\mathrm{ideal}}+E_{waste}}{O_{actual}}.$
In the formula, E.sub.actual refers to the single-part actual processing energy consumption value, in the unit of kilojoule (KJ); O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, in the unit of piece; E.sub.ideal refers to the single-part ideal processing energy consumption value, in the unit of kilojoule (KJ); E.sub.waste refers to the waste energy value of the numerical control machine tool within the given time period, in the unit of kilojoule (KJ). The obtained E.sub.waste=134.4 kJ, O.sub.actual=24 pieces and E.sub.ideal=151.7 kJ are substituted into the above formula to calculate the single-part actual processing energy consumption value within the given time period, that is,

(34) $E_{actual}=\frac{\begin{array}{c}{O}_{actual}\times \\ E_{\mathrm{ideal}}+E_{waste}\end{array}}{O_{actual}}=\frac{24\times 151.7+134.4}{24}=157.3\left(\mathrm{kJ}\right).$

(35) 7. The load-energy efficiency of the numerical control machine tool is obtained.

(36) The load-energy efficiency of the numerical control machine tool is calculated according to the obtained single-part ideal processing energy consumption and the obtained single-part actual processing energy consumption of the numerical control machine tool based on the calculation formula

(37) ${\eta }_{\mathrm{performance\_e}}=\frac{E_{\mathrm{ideal}}}{E_{actual}}.$
In the formula, η.sub.performance_e refers to the load-energy efficiency of the numerical control machine tool; E.sub.ideal refers to the single-part ideal processing energy consumption value, in the unit of kilojoule (KJ); E.sub.actual refers to the single-part actual processing energy consumption value, in the unit of kilojoule (KJ). By still taking July 28th 9:00 to 10:00 AM as an example, the single-part ideal processing energy consumption value within the period is obtained as E.sub.ideal=151.7 kJ, and the single-part actual processing energy consumption value within the period is obtained as E.sub.actual=157.3 kJ. The above data is substituted into the formula

(38) ${\eta }_{\mathrm{performance\_e}}=\frac{E_{\mathrm{ideal}}}{E_{actual}}$
to calculate the load-energy efficiency of the numerical control machine tool within the period, that is,

(39) ${\eta }_{\mathrm{performance\_e}}=\frac{1517}{157.3}=96.4\%.$

(40) 8. The relationship model between the load-energy efficiency and the loading performance of the numerical control machine tool is obtained.

(41) The relationship model between the load-energy efficiency of the numerical control machine tool and the loading performance of the numerical control machine tool is obtained through derivation operation according to the built calculation model of the loading performance of the numerical control machine tool and the built calculation model of the load-energy efficiency of the numerical control machine tool, and the relationship model is expressed as

(42) ${\eta }_{\mathrm{performance\_e}}=\frac{O_{actual}\times E_{\mathrm{ideal}}\times T_{\mathrm{available}}^{-1}}{\begin{array}{c}{O}_{\mathrm{actual}}\times E_{\mathrm{ideal}}\times T_{\mathrm{available}}^{-1}+\\ \left(1-{\eta }_{\mathrm{performanc}e}\right)\times P_{standby}\end{array}}.$
In the formula, η.sub.performance_e refers to the load-energy efficiency of the numerical control machine tool; O.sub.actual refers to the actual part processing number of the numerical control machine tool within the given time period, in the unit of piece; E.sub.ideal refers to the single-part ideal processing energy consumption value, in the unit of kilojoule (KJ); T.sub.available refers to the available time of the numerical control machine tool within the given time period, in the unit of second (s); η.sub.performance refers to the loading performance of the numerical control machine tool; P.sub.standby refers to the standby power value of the numerical control machine tool, in the unit of kilowatt (kW). By still taking July 28th 9:00 to 10:00 AM as an example, the actual part processing number of the numerical control machine tool within the period is obtained as O.sub.actual=24 pieces, the single-part ideal processing energy consumption value is obtained as E.sub.ideal=151.7 kJ, the available time of the numerical control machine tool is obtained as T.sub.available=3300 s, and the standby power value of the numerical control machine tool is obtained as P.sub.standby=0.32 kW. The above data is substituted into the relationship model between the load-energy efficiency of the numerical control machine tool and the loading performance of the numerical control machine tool to further express as follows:

(43) ${\eta }_{\mathrm{performance\_e}}=\frac{1.1}{142-0.32\times {\eta }_{\mathrm{performanc}e}}.$

(44) 9. Monitoring and over-limit alarming are performed for the load-energy efficiency of the numerical control machine tool.

(45) The obtained load-energy efficiency η.sub.performance_e of the numerical control machine tool within the evaluation period is compared with a preset alarming lower limit value η.sub.performance_e.sup.L of the load-energy efficiency of the numerical control machine tool. In the present disclosure, the alarming lower limit value η.sub.performance_e.sup.L of the load-energy efficiency of the numerical control machine tool is determined according to statistical analysis of historical data of the load-energy efficiency of the numerical control machine tool in combination with experiences of managers. By still taking July 28th 9:00 to 10:00 AM as an example, if the alarming lower limit value of the load-energy efficiency of the numerical control machine tool in this example is η.sub.performance_e.sup.L=95% and the load-energy efficiency of the numerical control machine tool within the evaluation period is obtained as η.sub.performance_e.sup.L=96.4%, the expression 96.4%=η.sub.performance_e>η.sub.performance_e.sup.L=95% is satisfied, which indicates that the load-energy efficiency of the numerical control machine tool is normal. Based on the above example, if the alarming lower limit value of the load-energy efficiency of the numerical control machine tool is η.sub.performance_e.sup.L=97%, the expression 96.4%=η.sub.performance_e≤η.sub.performance_e.sup.L=97% is satisfied; at this time, it is prompted by alarming that the load-energy efficiency of the numerical control machine tool is abnormal and lower than the lower limit of the load-energy efficiency of the numerical control machine tool, and the load-energy efficiency (η.sub.performance_e=96.4%) of the numerical control machine tool within the evaluation period, the corresponding loading performance (η.sub.performance=88.9%) of the numerical control machine tool within the evaluation period and the waste energy value (E.sub.waste=134.4 kJ) of the numerical control machine tool within the evaluation period are all displayed on the display screen at the same time.

(46) 10. Parameters of the numerical control machine tool are adjusted according to the alarming prompt to increase the load-energy efficiency to the normal range.

(47) Machine tool operator makes specific adjustment to the processing parameters of the numerical control machine tool according to the alarming prompt at step 9, so as to increase the load-energy efficiency of the numerical control machine tool to the normal range.

(48) The method of the present disclosure may be used in scientific evaluation and monitoring of the load-energy efficiency of the numerical control machine tool in the manufacturing industry to control the load-energy efficiency of the numerical control machine tool within the required range and realize high-efficiency and energy-saving operations of the numerical control machine tool. The method of the present disclosure provides an effective method and a technical support for realizing energy conservation and emission reduction in the manufacturing industry.

(49) It is finally to be noted that the above examples are only intended to describe the technical solutions of the present disclosure rather than limit the technical solutions of the present disclosure. Modifications or equivalent substitutions made to the technical solutions of present disclosure without departing from the spirit and scope of the present disclosure shall all be encompassed in the scope of claims of the present disclosure.