Research On Sawing Trajectories And Sawing Performance Of Eccentric Hinged Frame Saw Machine For Sawing Hard Stone

With the popularity of home decoration,the demand for hard stone such as granite is increasing.An investigation has been undertaken into the stone processing machines.Diamond circular saws and diamond wire saws present some technological limits,and the marble frame saw cannot process hard stone by now.In this paper,through innovative design of motion guiding mechanism,the eccentric hinged frame saw machine has been developed.The matching tools and techniques have been optimized to realize the sawing of large-scale hard stones.On the basis of systematically studying the motion characteristics of traditional hinged parallel rod guide mechanism,a new idea to realize the tailing of diamond grits was proposed.By changing the layout of guide mechanism to adjust and control the sawing path of saw machine,the similar one-way sawing method with small sawing depth in forward stroke and large sawing depth in backward stroke can be realized.Firstly,the influences of the placement mode,eccentricity direction,eccentricity and sawing stroke of the hinged guide mechanism on the trajectory of the saw blade were discussed.The kinematic characteristics of the horizontal reciprocating guide mechanism,the eccentric hinge guide mechanism symmetrically placed and the eccentric hinge guide mechanism placed on the same side were further analyzed.The results show that the displacements and velocities in the horizontal direction of the three guide mechanisms were equal,and the eccentric hinged guide mechanism ensured that the saw blade to be lifted to realize the state of sawing stone and breaking away from stone in the vertical direction.When the hinge mechanism was symmetrically placed,the saw blade sways in motion.While the hinge mechanism was placed on the same side,the sawing trajectories of the front and rear hinge mechanism were the same,and the swaying phenomenon would not occur.The research results provided strong guarantee for the design of sawing machine and the study of related experiments.Secondly,the experimental prototype of frame saw with eccentric hinge mechanism on the same side was developed.The influence of three different sawing trajectories on the wear characteristics of diamond segment in horizontal reciprocating sawing machine,the sawing machine with eccentric hinged guide mechanism placed symmetrically and the sawing machine with eccentric hinged guide mechanism placed on the same side was experimentally studied.According to the wear of diamond segment,the sawing machine was selected to realize the sawing of hard stone and uniform wear of segment.The results show that the eccentric hinged guide mechanism ensured the sharpness of segment in sawing process,realized the tailing of diamond grits,improved the holding force of matrix to diamond grits,and the proportion of diamond grits with sawing ability in eccentric hinged frame saw machine were higher than those in horizontal sawing machine;The eccentric hinged guide mechanism placed on the same side were more conducive to the uniformity of segment wear.Thirdly,according to the movement characteristics of the frame saw machine with eccentric hinged guide mechanism placed on the same side,the mathematical models of average chip thickness of single diamond grit in forward and backward stroke were established.The effects of sawing parameters on sawing forces for forward and backward stroke were experimentally analyzed.The regression mathematical model of sawing forces were also established.The results show that the average chip thickness of single diamond grit in backward stroke was larger than that of in forward stroke due to the effect of the sawing trajectory,which results in the sawing force in backward stroke was greater than that of in forward stroke,and the sawing force of the diamond segment increased with the increase of feed rate and stone length,and decreased with the increase of crank speed.The greatest influence on the sawing force was feed rate.Fourthly,the wear mechanisms of segment matrix and diamond grits were studied,the influence of feed rate and crank speed on the segment wear rate during sawing of different stones was discussed.The regularity of segment wear and the ideal matching process parameters were explored.The results show that the wear mechanism of segment matrix was mainly abrasive wear and erosion wear,and the wear mechanism of diamond grits was mainly cleavage fracture and friction wear.The more the diamond grits with sawing ability,the lower the wear rate of segment.Finally,typical granite varieties such as Wulianhong and Chengde Green were selected to study the effect of stone mineral composition,chemical composition and physical and mechanical properties on the sawing performance of the new type sawing machine,explored the influence on segment wear rate and production rate,established the performance prediction models.It provides guidance for production and processing of enterprises.The research of this subject will enrich and expand the research on the sawing force and wear characteristics of diamond tools by new sawing methods,perfect and develop the new technology on large-scale hard stone sawing process,solve the problems of low efficiency and high cost of hard stone sawing.It has important demonstration significance and popularization value for guiding production and promoting the industry to realize the low cost and high efficiency sawing of stone industry.