Papers by Author: Zhen Jia Li

Abstract: Based on the experiments on milling the 3Cr-1Mo-1/4Vsteel which is the main part of the large chemical equipment hydrogenation reactor with several types of different grooves milling inserts, we have experiment study on the impact disrepair. Using the Orthogonal experimental design method, we have cutting experiments on machining the high-strength steel with several types of different grooves milling inserts, and find out the difference of the impact disrepair invalidation types among them. Based on the plentiful and systemic impact disrepair experiments, we build the impact disrepair life cumulating distribution function mathematic model by the mathematics statistic method. We have contrast analysis of the impact disrepair average lives among these types of milling inserts, and the different grooves milling inserts are optimized. All these studies provide the theoretic and experimental bases for solving the cutter disrepair which is the key problem in the actual production and groove optimization.

Abstract: This article takes the waved-edge milling insert (the rake face is curve plane) developed by Harbin University of Science and Technology as an example, as the goal of minimal impact disrepair, the optimization object function of the milling insert grooves is studied. Based on the force density function of the 3D complex groove milling insert, we have the finite element analysis on the stress fields of different cutting parameters, and have fuzzy synthetical judgement on the stress fields with fuzzy mathematic theory. We build the object function relation between the fuzzy synthetical judgement results and cutting parameters of the impact disrepair, so to have groove design optimization. All these studies provide the theoretic basis for the groove exploitation and the cutter disrepair which is the key problem in the automatization production and groove optimization.

Abstract: Based on the experiments on milling the carbon structural 45 steel with the flat rake milling insert and the waved-edge milling insert, the analysis and study on single physics field and coupling field are studied. On the basis of the milling force and milling temperature mathematical models, the force density function and heat density function of the waved-edge milling insert are built, the stress fields analysis and temperature fields analysis have been done. In order to discuss the distribution principle of equivalent stress and distortion under coupling condition, the coupling analysis on the stress field and temperature field is done. All these studies provide the theoretic and experimental basis for solving the cutter disrepair and groove optimization technology.

Abstract: Cut-in disrepair of milling inserts are closely related to dynamic equation of cut-in contact. According to the problem of serious cut-in disrepair, dynamic equation of cut-in contact for the waved-edge milling insert with 3D complex groove is studied. Rake face function of 3D complex groove waved-edge milling inserts is founded. Rake face equation of 3D complex groove inserts is founded. Rake face motion equation of 3D complex groove inserts is deduced. Appearance equation of workpiece machining region is deduced. Contact line (LM) equation is deduced, which is the contact line between rake face and workpiece cut-in side surface when rake face moving. Intersection line (C1D1) equation is deduced, which is the intersection line of cutting surface and side surface of workpiece. All the production above are the theory foundation for further researching the relationship between the cut-in style and cut-in disrepair, cut-in style optimization, 3D complex groove insert optimization.

Abstract: Based on the milling force testing experiments on machining the carbon structural 45 steel, the study on the distributing principle of force density function for complex three-dimension groove milling insert with the waved-edge milling insert (the curve rake plane) developed by Harbin University of Science and Technology is studied. On the basis of the milling force mathematical model, the force density function of the curve rake plane is built by the milling force experiments and tool-chip contact area experiments. Having quantitative calculation on the force density function and programming, the distributing model of force density function is shown with 3D figure, so to analyze its distributing principle. All these studies will provide a theoretic base for the stress field analysis and solving the cutter disrepair which is the key problem in the automatization production and groove optimization.

Abstract: The waved-edge milling insert is a kind of insert with 3D complex groove; its cut-in style and cut-in disrepair are different from the flat-groove insert. For researching the relationship between the cut-in style and the cut-in disrepair of the waved-edge milling insert, the cut-in simulation system of the waved-edge milling insert is developed, on the software of UG/Open API combined with VC++. By given different cut-in style parameters, the virtual cut-in process is founded and the proof is supplied for judging cut-in style and studying cut-in disrepair.

Abstract: Focusing on the machining complexity of large containers where difficult-to-cut materials are used a lot, a cutting process parameter optimization expert system for difficult-to-cut materials is constructed based on experts’ knowledge and computer soft wares (VC++ 6.0and SQL Server 2000). In this paper, we made construction analysis and module design for the expert system, then constructed the knowledge base according to certain constraint models, and realized the functions of every module of the expert system by using the forward inference. This expert system can play a scientific direction role in the process parameters selection for cutting large containers.

Abstract: This paper deals with chip breaking behaviour of 3-D complex groove inserts in machining carbon constructional steel-45 steel at high cutting speeds .Cutting experiments were performed at eleven different cutting speeds. Firstly, the results showed that by increasing cutting speeds, the changes of the critical feedrate and chip breaking scopes at high cutting speeds machining with 3-D complex groove inserts were nonlinear and not monotonous function relations. Then, mathematic models were built. Secondly, the results showed that the critical depth of cut was a constant value at various cutting speeds. And, the curves of the critical depth of cut were perpendicular lines. For this purpose, the critical depth of cut mathematic model has been built. The study above lays a theory and basis for future investigation of the mechanism of chip breaking with 3-D groove insert in high speed machining.

Abstract: For the cutting of the difficult-to-machine materials, such as stainless steel and dead-hard steel, is always puzzling and restricting manufacturing, it is necessary to deeply study and search after new machining methods in respect of both theory and practice. This paper chose waved-edge milling inserts and flat-groove milling inserts of different materials to make cutting force contrast experiments on stainless steel ZG0Cr13Ni5Mo, chose ultrafine-grain inserts, YT14 inserts (local product) and CY250 inserts(foreign product) to make cutting life contrast experiments on dead-hard steel ZG35CrMo, then researched in theory the disrepair appearance, the BSE image and the granularity. The research results show that the integrated cutting capability of ultrafine grain waved-edge milling insert is excellent for difficult-to-machine materials.

Abstract: The combination of metal cutting theory, computer technology and expert knowledge was used to study the use of knowledge-based engineering (KBE) for cutting large containers. This report includes information on the acquirement, expression, and inference and management of KBE. The structure of the KBE system was established by selecting the principles of processing parameters and optimizing the model of machining data and by using the method of expressing knowledge of combining producing type with frame type and by using the software SQL server 2000. The inferential mechanism of every functional module in the system was realized by applying the software, VC++ 6.0. The KBE technology will help technicians to share expert knowledge and experience, and to optimize cutting parameters to intellectualize cutting design and machining.