Measurements of Lapping Plate Temperature

Journal of KONES. Powertrain and Transport

2015

Self Cite

Temperature on the chip-tool interface is important parameters in the analysis and control of turning process. Due to the high shear and friction, energies dissipated during a machining operation the temperature in the primary and secondary shear zones are usually very high; hence, affect the shear deformation and tool wear. In a single point cutting, heat is generated at three different zones i.e. primary shear zone, chip tool interface and the tool-workpiece interface. The primary shear zone temperature affects the mechanical properties of the work piece-chip material and temperatures at tool-chip and tool-work piece interfaces influence tool wear at tool face and flank respectively. Total tool wear rate and crater wear on the rake face are strongly influenced by the temperature at chip-tool interface. Therefore, it is desirable to determine the temperatures of the tool and chip interface to analyse or control the process. To measure the temperature at the tool-chip interface many experimental methods have been developed over the past century. Since at the interface there is a moving contact between the tool and chip in this work, authors propose infrared method for temperature measuring. To assure possibly high accurate of noncontact temperature measurement there is a need to keep in mind several factors, including determining appropriate value of emissivity. In this work, authors present results of experimental determining emissivity value of tool-chip interface. As initial value, emissivity of polished steel was taken.

Section: Methods Of Turning Temperature Measurementsmentioning

confidence: 99%

“…polished, oxidized or scaled) can influence emissivity more than the various materials themselves. The emissivity of a particular material can be determined during experiment by different methods [7,9,10,11].…”

Section: Determining the Emissivity Of Steelmentioning

confidence: 99%

Determining the Emissivity at the Tool-Chip Interface During S235jr Steel Turning

Journal of KONES. Powertrain and Transport

2015

Self Cite

“…4) or temperature control system or both [ Older machines, still operated, haven't such equipment, so there is a need to find other solution to the problem of uneven and excessive thermal plate expansion. As indicated in [11,12] some lapping parameters have influence on temperature rise of lapping plate.…”

Section: Workpiece Surface Formingmentioning

confidence: 97%

“…When the lapping plate has become convex (Fig. 3b), the conditioning rings should be placed slightly toward the center [2,9,10,11]. Fig.…”

Section: Workpiece Surface Formingmentioning

confidence: 99%

The Influence of Workpiece Hardness on Plate Temperature during One Side Lapping

Barylski

2013

SSP

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.

“…Wheel flatness is the key to the operation of free-abrasive machining as lapped parts take a mirror image of it. Hence, to reduce deviations of workpiece flatness, a constant temperature of the wheel should be provided [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Temperature of the Elements of the Lapping Machine Executory System on the Results of the Lapping Process

2015

SSP

Commonly used as a finishing operation, lapping has been applied for achieving ultra-high finishes and close tolerances between mating pieces. It can be carried out by applying loose abrasive grains between work and lap surfaces, and causing relative motion between them resulting in the finish of a multi-directional lay.The activity of grains (sliding and rolling) in the working gap causes not only the removal of the material but also a rise in the temperature of the lap plate. The authors of this work analyse the influence of the temperature of the elements of the lapping machine executory system on the results of the lapping process stimulated applying ABRALAP 380 lapping machine the executory system of which consisted of three working conditioning rings. The temperature of the elements of the executory system was measured employing Thermo Gear G100 infrared camera. The workpieces were ceramic (Al2O3) valve sealing parts. After grinding, they were being lapped during 15 and 20 minutes. Machining was started following 10, 140, and 270 minutes of the working time of the machine (tp). The abrasive mixture was boron carbide powder with grain number F400/17, mixed with kerosene and machine oil with grain concentration equal to m = 0.25. Two sets of lapping parameters were executed:lapping pressure p = 0.051 MPa, and lapping speed v = 27 m/min;lapping pressure p = 0.03 MPa, and lapping speed v = 38 m/min.The rate of material removal in g and mm and roughness parameters Raand Rkof the surface were analysed.The conducted studies showed that the temperature of the elements of the machine executory system affected only parameter Rawhich is higher for the surfaces that were processed starting from the 270thminute of the working time of the machine. Only a slight increase in the values of parameter Rawas observed. It can be caused by a change in conditions for the process of material removal due to different properties of grain carrier under a higher temperature. Its viscosity decreases with an increase in temperature, which implies direct interactions between the plate and workpiece surface. Normally those two surfaces interact indirectly via abrasive grains. The rest of the tested lapping results were independent of the temperature of the elements of the lapping machine executory system. The values obtained under different temperatures were almost the same.