Papers by Author: Adam Barylski

Abstract: In this paper new kinematics systems were studied for a single lapping process. In order to ensure the constant profile wear of the tool a standard kinematic system can be changed. Lapping is carried out by applying loose abrasive grains between two surfaces and causes a relative motion between them. The result is a finish of multi-directional lay. During process, the mechanism of surface formation are decisively affected by a pressure force, a process time and a motion type of grains. It has been proven, that providing the additional movements of the conditioning ring affects the profile wear of the lapping plate. First of all, the kinematics equations of the lapping process have been developed and the process has been simulated. A type of the abrasive particle trajectories in standard single-disk lapping depends on rotational speed ratio of a tool and a conditioning ring. In addition, two new kinematic systems were presented: with radial and secant movement of the conditioning ring. Finally, comparison and analysis of abrasive trajectories were carried out.

Abstract: New tools for flat grinding are the subject of the paper. Electroplated diamond tools with different grains - D64 and D107 - were used in a modified single-disc lapping machine configuration. The results from flat grinding, such as the material removal rate (MMR), surface roughness and plane-parallelism are presented in the paper. Apart from ceramic samples, the additional experiments were carried out on cemented carbide workpieces (H10S) with the use of a diamond electroplated tool (D64). SEM microscopic images of unworn and worn active tool surface are presented with abrasive grains worn by attrition and cavities in the nickel bond after the grains pull out.

Abstract: Previous studies on one-sided lapping allow to state that not only parameters of lapping elements (i.e. properties of workpiece, abrasive grains and lapping plate) impact on a lapping efficiency. Influential are also kinematics and dynamics of the process. It is crucial to control an average velocity of lapping (v), a distribution of tangential acceleration (at), a nominal pressure (p), a lapping time (t) and disposal of workpiece in separator.Based on kinematics equations and the tribological models, the dimensionless distribution of the material removal volume and the trajectories of abrasive grains cutting on the lap were numerically simulated. Obtained information about excessive wear on lapping plate was the starting point to work out non-standard, single-plate lapping systems.In this paper ideas of unconventional lapping systems were presented. After numerous simulations and careful analysis it was observed, that the most desirable system is radial lapping system. It was point out that other systems are not very different from the standard kinematic system. Generated trajectories of an abrasive grain were almost identical. What is more, effects of kinematical parameters on the trajectories, velocities and accelerations observed in radial lapping system are shown.

Abstract: Performance and security are software (SW) application attributes situated on the opposite corners of system design. In the most drastic example the most secure component is the one totally isolated from the outside world, with communication performance reduced to zero level (e.g. disconnected physically from the network, placed inside a Faraday cage to eliminate possible wireless accessibility). On the other hand the most performance-optimized system is the one with all security rules taken off. Obviously such extreme implementations cannot be accepted, thus a reasonable trade-off between security and performance is desired, starting from the appropriate design, resulting in the adequate implementation, confirmed by security and performance testing in production environment. Unit testing (UT) is a well-know method of examining the smallest portion of SW application source code – units: methods, classes, interfaces in order to verify whether they behave as designed. Ideally, each UT test case is separated from others, taking advantage of stubs and mocks to provide full isolation from external test factors. This paper is an extension to research about joint security testing and performance testing for improving quality of distributed applications working in public-private network environments,addressing SW quality assessment at different, unit test level.

Abstract: This paper will present the results of research on single-disc lapping of flat surfaces of small ceramic elements. Machining with the use of different tools such as metallic, two-metallic and abrasive-metallic will be analyzed. The basics and techniques of reinforcement of laps will be discussed. The results of the influence of parameters on the surface quality of ceramic conponents (sealing0 for three treatments on lapping machines will be presented on the paper.

Abstract: New tools for flat grinding of ceramics (Al₂O₃) are presented in the paper. Electroplated CBN tools (B64 and B107) were used in a modified single-disc lapping machine configuration. The results from experiments, such as the material removal rate and surface roughness parameters are presented and analyzed. Numerical simulations, based on the model for the shape error and tool wear estimation in machining with flat lapping kinematics, are also presented. The tool life of electroplated tools can be extended by choosing appropriate parameter K related to the process kinematics.

Abstract: Lapping leads to a surface with low roughness and high precision. Because of required parts accuracy tool flatness is the key to the successful machining. To avoid its excessive thermal expansion, plate temperature research was taken. The goal was to determine the correlation between the basic lapping conditions and wheel temperature. In work [1] authors developed model to estimate the maximum and average temperature rise of the work surface in lapping. According those models temperature rise depends also on workpiece and plate hardness. Because the second is constant during process, this part of research refer only to the influence of workpieces hardness. They were conducted during lapping the samples made of steel 45. To vary the hardness, samples were divide into three groups each with different Knoop hardness value: 175, 471 and 687. The different hardness values were a result of different heat treatment methods used. Every group after grinding were lapped with the same lapping conditions. In the next step the statistical analysis was conducted. It was verified if the plate temperature is influenced by the workpieces hardness. A hypotheses testing method was use. Results were calculated for temperature rise values measured after 300 minutes of machine working. According to them the influence of workpiece hardness on plate temperature is statistically insignificant.

Abstract: Commonly used as a finishing operation, lapping has been used for achieving ultra-high finishes and close tolerances between mating pieces. Its carried out by applying loose abrasive grains between work and lap surfaces, and causing a relative motion between them resulting in a finish of multi-directional lay. The grains activity (sliding and rolling) in the working gap causes not only the material removal but also the temperature rise of lap plate. This work presents the results of lapping plate temperature rise research. The investigation has been conducted to check the influence of grains size on. It was made during flat lapping with use of ABRALAP 380 lapping machine and infrared camera Thermo Gear G100. The lapping machine executory system consisted of three working conditioning rings. Plate temperature was measured during ceramic (Al2O3) elements lapping. The elements were valve sealing parts. After grinding they were processing with three abrasive grains sizes: F400/17, F800/6.5 and F1200/3. The abrasive mixture was boron carbide powder mixed with kerosene and machine oil with grain concentration 0.25. Other lapping parameters remained constant during process. The wheel speed was 60 rev/min and lapping pressure 0.04 MPa. In the next step the statistical analysis was conducted. It was analysed if the plate temperature is influenced by the grains size. A hypotheses testing method was use. Results were calculated for temperature rise values measured after 300 minutes of machine working. According to them the influence of abrasive grains size on plate temperature rise is statistically insignificant, what is not consisted with the model.

Abstract: Lapping of plane surfaces is the technology which allows achieving high surface quality. Kinematics of lapping has the main effect on the flatness of active plane of the lapping tools as well as on the quality and flatness of the machined surface. Lapping machines can be used for grinding without the chuck-related problems as encountered in conventional surface grinding. The configuration of a conventional single-disk lapping machine was modified and the rotational velocity of a workpiece holder can be precisely controlled by a stepper motor. Two types of tools were used for experiments on a modified machine. The first tool was equipped with grinding inserts made of resin and synthetic diamond micrograins (grit size 3/2 m). In the second stage of experiments the single-layer electroplated diamond tool (D107 – grit size 106/90 m) was applied. Ceramic workpieces (Al2O3) were machined on the modified single-disc lapping machine with the use of both tools and with additional loose abrasive. Experimental results of removal rates, technological parameters and kinematical analysis are the subject of the presented paper.