| With the acceleration of urbanization process,the demand of building decorative stone products and facing stone products is constantly increasing,the stone industry is in a rapid development stage.As known to us all,the stone processing industry is a energy-resource intensive industry,the stone products need to consume a large of energy and mineral resources.A large amount of energy consumption has not only become one of the main costs of stone processing industry,but also one of the main environment problems because of the carbon emissions converted from energy consumption in the stone industry aggregation areas.Therefore,the implementation of energy conservation and emissions reduction has important economic and environmental benefits in the stone processing industry.The modeling technique of cutting power and energy consumption is a key technology to predict the energy consumption in the stone processing process,and it is also an important scientific basis for stone processing industry to formulate specific energy saving and emission reduction strategies.The cutting power is dynamically vary in the process of variable rate(V-MRR).Therefore,compared with the process of constant-material(C-MRR),the power characteristics of V-MRR process are much more complex.In the field of stone process,there are a lot of V-MRR processes,such as raw stone sawing,plate edge chamfering,surface milling and grinding.This paper aims to establish an energy consumption modeling method considering the power characteristics of V-MRR process,which fully reflects the influence of dynamic changes of cutting parameters on the instantaneous power and energy in stone processing process.For the most critical process in stone machning process--the raw stone sawing process,the steps and processes of energy consumption modeling method are described in detail,and the energy consumption model of diamond disc sawing machine for raw stone sawing was built.In view of the diversity of stone categories and the matching problem of model universality,the evaluation system of stone sawability grading was studied.It is proposed that the same model can be used to analyze the power characteristics and predict the saw-cutting energy consumption for all types of stone within the same sawability grade.The established model was applied to a stone processing enterprise to optimize the saw-cutting parameters scheme in the Shandong province.An energy consumption modeling method considering the power characteristics of V-MRR stone machining process was proposed.Based on the idea of differential,the dynamic changes of cutting parameters were expressed in the stone machining process.The V-MRR process was divided into a lot of subintervals.The function relation between the instantaneous power and cutting parameters was studied in the each subinterval.Then,the relationship model was established of the dynamic cutting power and energy consumption relative to dynamic cutting parameters.Next,for the most critical process in stone machning process--the raw stone sawing process(using diamond disc machine),the construction process of energy consumption predicted model was studied and elaborated in detail.In the three different stages of raw stone sawing,the function relationship was constructed between saw-cutting parameters and time respectively.Based on the proposed energy consumption modeling idea,the numerical relationship structure was constructed between saw-cutting parameters and saw-cutting power in the each subinterval.The sawing experimental system and data acquisition system of diamond disc sawing machine were built.The saw-cutting parameters scheme was designed based on orthogonal experimental design method.The sawing experiment of Lotus red(G3768)granite was carried out,and the spindle power and idle power of sawing machine were collected in each subinterval,then the saw-cutting power was calculated.Based on the nonlinear least square method,the relationship function was numerically fitted between the saw-cutting power and the corresponding sawcutting parameters,and the conditional coefficient of the power and energy consumption model was determined.Thus,the energy consumption prediction model for the Lotus red(G3768)granite machining by diamond disk sawing machine was established.The energy consumption model was used to simulate the power curves of 4 saw-cutting parameters schemes and predict the energy consumption of each scheme.The validity of the modeling method and the accuracy of the established model were verified by comparing with the measured values.In view of the wide variety of stone categories and the limited universality of the established energy consumption model,the evaluation system of stone sawability grading was studied,which the aim of was that using the same energy consumption analyze the stone saw-cutting power characteristics and predict the machining energy consumption for all types of stone within the same grade.By carding,redundancy analysis and simplified aggregation of relevant sawability evaluation indexes,the sawability grading evaluation index system of stone was established,including uniaxial compressive strength(U),Schmiazek abrasivity factor(S),Mohs hardness(M)and Young's modulus(Y).In order to obtain the influence degree on the stone sawability of each index,the index weighting model was built based on Random Forest algorithm.The Random Forest weighting model of the index was established and the weight of the each index was determined.Based on matter element analysis,the stone sawability grading evaluation model was established.Combined with the weight of indexes,the sawability grade of any type of stone could be evaluated.The proposed energy consumption prediction model was applied to optimize and decide the sawcutting parameters scheme of White(G3765)granite in the production workshop of a stone machining enterprise.Based on the stone sawability analysis,it is found that the White(G3765)granite and Lotus red(G3768)granite belong to the same stone sawability grade,and the constructed saw-cutting energy consumption model of Lotus red(G3768)granite was used to predict the saw-cutting power and energy consumption of White(G3765)granite in the raw stone sawing process.The peak power and energy consumption in the sawing process corresponding to 4 alternative saw-cutting parameters schemes were predicted and analyzed in the workshop.According to the annual output of White(G3765)granite plate,the energy consumption difference of 4 schemes was analyzed.From the perspective of energy saving and emission reduction The most optimal saw-cutting parameters scheme was recommended to the enterprise,and the benefit value generated by saw-cutting parameters schemes optimization decision is evaluated from two aspects of environmental and economic benefit.The application case verified the value of the proposed energy consumption modeling method in the stone machining industry of implementing the strategy of energy conservation and cleaner production. |
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