Experimental Study On Abrasive Recycling Of Abrasive Suspension Water-jet Cutting System

As the only cold high-energy beam machining technology,abrasive waterjet cutting has a lot of unique advantages,such as wide Machinable materials,no heat affected zone,high machining accuracy and so on.At present,the global market for waterjet cutting machines has been billion dollars,and it will continue to grow in the next few years.High cost is one of the main disadvantages in the industrial application of water jet,especially the cost of abrasives,which is over 50% of the total cost.Abrasive recycling is an effective way for reducing the cost.In addition,it is also beneficial to environmental protection by reduce the mining of abrasive mineral resources,which meets the requirements of the current era.Abrasive suspension water jet(ASJ)has the inherent advantage for abrasive recycling than traditional abrasive water jet(AWJ)because ASJ does not need to use dry abrasives,its abrasive recovery has a broad prospect.Unfortunately,very few companies can make profits from the recycling of abrasives because the recovery process for AWJ generally includes abrasive washing,drying,chip separating and sieving,and these steps require a large amount of money cost a lot.The feasible recycling scheme in industrial applications requires the recycling process to be simple and cost-effective,ensures the full utilization of the abrasive,and maintains the cutting performance in every reuse cycle basically at the same level.In this thesis,based on the simple and effective recycling process,abrasive recycling for ASJ was experimented.Cutting depth and surface roughness are the most significant characteristics in cutting,which are regarded as the standard of cutting quality in this study.First of all,an abrasive recovery scheme is proposed to meet the above requirements,and then the feasibility of this scheme is verified by experiments.Meanwhile the cutting quality prediction model of ASJ multi cycle cutting is established.And then the thesis conducts the recharge experiment,determines the effect of the recharge operation on the repeated continuous recovery of abrasive,and designs an automatic abrasive recycled ASJ cutting system according to the above recovery scheme.In the end of this thesis,the disintegration principle of abrasive particles in ASJ cutting process is analyzed in detail,and the relationship of abrasive disintegration with the physical parameters of abrasives and targets is given.The conclusions drawn from this study are as follows:(1)It is found that the recycled abrasives with only big particle impurity being sieved out still have strong cutting ability.An simplified abrasive recovery scheme of ASJ cutting system has been proved to be feasible.With 30% of recharge in each cycle,the abrasive can be fully utilized and its cutting performance can remain basically the same in every cycle of continuously recycling process.The abrasives between 90-180 ?m are optimal abrasives for the cutting surface roughness,compared with the larger size abrasives,the smaller size abrasives have more negative influence on the surface roughness,which should be concerned in the recycling process.(2)This thesis have designed a kit of automatic abrasive recycling system,which can automatically realize all the steps of cutting,abrasive collection,removing large particle impurities,recharging with specific proportion,abrasive canning and secondary cutting.The whole process does not need to shutdown the cutting system and easy to operate.And it can greatly reduce the volume of the abrasive tank,which can convenient improve the working pressure,to achieve better cutting ability.If this system can be used in actual production,it should be able to achieve good results.The follow-up research can be extended to other kinds of abrasives.Try to build the database of influences on cutting quality for ASJ processing parameters,target material physical parameters and the recharge percentage.(3)The whole process of abrasive recovery in ASJ cutting system was analyzed.The abrasive disintegration is divided into two parts and three stages creatively.The reason of abrasive disintegration is discussed based on the theory of abrasive crushing size effect.The relationship between the disintegration coefficient B and the decrease of average particle size is given.After the analysis of relationship between the physical parameters of abrasives and the disintegration of abrasives in ASJ cutting,it is found that strength,ball milling toughness and hardness are the most important factors affecting the disintegration of abrasives,White corundum with its balanced performance,no obvious short board characteristics,whether in the conditions off cutting with or without target materials shows excellent performance,on the technical level,has the highest recycling value.The relationship between the physical parameters of the target and the abrasive disintegration in the ASJ cutting process is analyzed qualitatively.The results show that the hardness of the target materials has the greatest influence on the abrasive disintegration,followed by the density,and the young's modulus has relatively small influence.There are 45 figures,15 tables and 82 references in this dissertation.