Research On Sawing Performance Of Reciprocating Swing F Rame Saw Machine And Design Of Step Reinforced Pre-alloy Segment

Granite and other hard stone slabs are widely used in construction and decoration industry,and their demand has been increasing year by year.At present,the commonly used hard stone sawing equipment generally has problems such as low sawing efficiency,low resource utilization rate and serious environmental pollution.Diamond frame saw is currently widely used in sawing large-format slab of soft stone material such as marble due to its advantages of high processing efficiency,good slab quality and low processing cost.The phenomenon of sawblade instability and severe segment wear is prone to appear in the process of cutting granite and other hard stones with the horizontal frame saw,which seriously affect the slab quality and processing efficiency.In this paper,aiming at the problems existing in sawing large-format slab of hard stone,the mechanism of sawblade instability and segment wear in the process of cutting hard stone with the horizontal frame saw was investigated systematically,the sawing mode was innovatively designed,the reciprocating swing frame saw prototype was developed,the supporting tools and processes was optimized and the stable and low-wear sawing of large-format stone slab was realized in view of the problems existing in sawing large-format slab of hard stone.Based on the comprehensive analysis of the mechanism of sawblade instability and severe segment wear in sawing hard stone with the traditional frame saw,a kind of reciprocating swing sawing mode was proposed to break the continuous interaction between the segment and stone block,limit the duration of continuous action between the segment and stone block,effectively shorten the sawing arc length and reduce the number of segments participate in sawing simultaneously through the reciprocating swing of the sawblade.Firstly,on the basis of comprehensive analysis of the mechanism of sawblade instability and severe segment wear in sawing hard stone with traditional frame saw,the reciprocating swing sawing mode was proposed,the influence of swing mode of sawblade,swing Angle and stroke length on trajectory was analyzed,and the structural parameters were optimized.The maintained high number of segments involved in sawing simultaneously,the continuous contact between the segment and the block,and the plastic friction of diamond particles on hard stone surface are the main reasons for the sawblade instability and the severe segment wear in sawing hard stone with the traditional frame saw.The stone height difference and the vertical displacement difference of adjacent segment increased gradually with the increase of swing Angle.The increase of sawing stroke was helpful to increase the overlap area of motion trajectories in the middle of sawblade,thus helping to reduce the number of segments participate in sawing simultaneously,and avoiding the sawblade instability and relieving the segment wear.Secondly,the sawing characteristics of reciprocating swing frame saw were analyzed,and the model of chip thickness and the sawing stroke interval of single segment were established.The sawing force characteristics,the number of segments involved in sawing simultaneously,the stone sawn surface topography and the sawn slab flatness in the sawing process of the reciprocating swing frame saw were analyzed through experiments to verify the motion trajectory of the reciprocating swing frame saw and the feasibility of sawing hard stone.The results proved that the waveform characteristics of sawing force were consistent with the theoretical analysis of sawing trajectory of reciprocating swing frame saw.The sawing force of segments on sawblade surface changed periodically,and the sawing force of segment in the synchronous contact area is much higher than that in the sequential contact area.The application of reciprocating swing sawing mode effectively reduced the number of saws involved in sawing simultaneously and improved the flatness of the sawn slab to the qualified level.The processed surface of stone material mainly presents brittle fracture material removal mode,accompanied by scratches and local plastic flowThirdly,the distribution characteristics of chip thickness per diamond particle on sawblade surface under the new sawing mode were theoretically analyzed,the wear characteristics and wear mechanism of diamond particles and matrix bond were investigated,and the process parameters were optimized based on response surface method.The results revealed that a high proportion of macro-fractured and pull-out diamond particles appeared on segment surface in the synchronous contact area,the matrix bond was govern by typical abrasive wear,and the working surface of segment was inclined with a certain slope.Whereas,the number of diamond particles with cutting ability on segment surface increased obviously in the sequential contact area,the matrix bond of segment was mainly erosion wear,and the wear profile of the working surface of the segment was approximately flat.There is a good correspondence between the influence of process parameters on segment wear rate and the influence on the proportion of worn diamond particle.The increase of segment spacing resulted in the increase of diamond scratching length and the decrease of the number of segments involved in sawing simultaneously,which led to an increase of segment wear rate.Finally,the wear model of three-layer symmetrical segment was established,and the stepwise reinforcement design was carried out to optimize the size of the middle and side layers of the segment and the particle size and concentration of the diamond,and the component system and ingredient proportion of segment were determined.In addition,the sawing performance of homogeneous high cobalt segment and three-layer step reinforced pre-alloyed segment were compared by sawing hard stones.The results demonstrated that the lateral wear profile of the three-layer step reinforced pre-alloy segment is almost planar.Compared with homogeneous high cobalt segment,the wear resistance of the three-layer step reinforced pre-alloy segment was improved,but its sharpness was slightly insufficient.Although the thickness deviation of the sawn slab was slightly higher than that of homogeneous high cobalt segment,it met the standard of superior products.The completion of the project will expand and improve the large-format hard stone sawing new technology and process,enrich the research of stone sawing theory,sawing performance and wear characteristics of diamond tools and other aspects,and promote the development of stone industry along the direction of high efficiency,low energy consumption,low carbon and environmental protection.