Grinding Wheel Profile Research Articles

The second envelope method of point-vector and its application on worm wheel grinding modified gear

A conventional worm wheel profile is obtained by establishing the meshing equation of the wheel and gear and determining the contact trace, which is difficult to use in calculating the non-standard profile gear. The second envelope method of point-vector (PV) is then proposed, which is actually a digital calculation method. The grinding wheel profile is formed by generating motion of the gear surface. The generating motion is divided into the first and second envelope motion. Using a PV approximation method, a gear profile is dispersed into a series of PVs to establish the PV envelope principle and the envelope approximation algorithm, determine the envelope point with the minimal orientation-distance to the wheel in the PV group, and obtain the wheel profile by fitting all the envelope points. In this paper, a detailed description of the wheel profile forward and gear profile backward calculation processes is provided using the second envelope method of PV. Experimental verification of the calculation results demonstrates that this method can be employed to calculate and machine any gear profile and achieve high accuracy.

Pulsed Laser Profiling of Grinding Wheels at Normal and Quasi-Tangential Incidence

A new methodology for normal and quasi-tangential pulsed laser profiling of grinding wheels is proposed, with laser path planning calculated according to a pre-specified angle of incidence and radial laser progression or predicted single-pass incision depth. Though tangential laser profiling has previously been investigated, few works have addressed the issue of negligible laser absorption under these conditions other than to apply a focal offset that effectively reduces the angle of incidence below 90∘. In the present work, the angle of incidence is specified explicitly, with normal and quasi-tangential profiling experiments performed on rotating bronze-bonded diamond and porous aluminum oxide grinding wheels with a 1064 nm nanosecond pulsed fiber laser source with 20 W average power. Triangular incisions are cut into each sample, following which analyses are performed with an optical profiler operating in confocal mode and x-ray computed tomography to determine the material removal rate and profile accuracy under all tested conditions. The angle of laser incidence is found to be of particular relevance to profiling operations, with more than one order of magnitude difference in material removal rates observed between 70∘ and 80∘ incidence, with improved profile accuracy in the latter case. Specifically, material removal rates of 0.12−0.14 mm 3/s, 0.075−0.1 mm 3/s and 0.002 mm 3/s are achieved at normal, 70∘ and 80∘ laser incidence, respectively, for bronze-bonded diamond, and 0.1 mm 3/s is achieved at 70∘ incidence for porous aluminum oxide. For both materials, profile accuracy of 50−70 μm is achieved under optimum conditions. The presented results highlight the necessity for precise specification and control of the angle of incidence during laser profiling operations. They furthermore confirm that laser profiling of grinding wheels is a viable alternative to electrical discharge machining for bronze-bonded diamond grinding wheels and a potential complementary process to hard-on-hard abrasion for ceramics.

Finishing production of spiroid worm shaft by varied centre distance and by appling grinding wheel banking angle correction

The objectives of this publication are to present a production technology which is a finishing production of conical worm using changing of centre distance between the worm and the grinding wheel and banking angle correction at the same time. We will determine the necessary optimum grinding wheel profiles for the manufacturing in light of the production tolerances. We will determine the function connections between the main production parameters.

Online, efficient and precision laser profiling of bronze-bonded diamond grinding wheels based on a single-layer deep-cutting intermittent feeding method

In this study, an online, efficient and precision laser profiling approach that is based on a single-layer deep-cutting intermittent feeding method is described. The effects of the laser cutting depth and the track-overlap ratio of the laser cutting on the efficiency, precision and quality of laser profiling were investigated. Experiments on the online profiling of bronze-bonded diamond grinding wheels were performed using a pulsed fiber laser. The results demonstrate that an increase in the laser cutting depth caused an increase in the material removal efficiency during the laser profiling process. However, the maximum laser profiling efficiency was only achieved when the laser cutting depth was equivalent to the initial surface contour error of the grinding wheel. In addition, the selection of relatively high track-overlap ratios of laser cutting for the profiling of grinding wheels was beneficial with respect to the increase in the precision of laser profiling, whereas the efficiency and quality of the laser profiling were not affected by the change in the track-overlap ratio. After optimized process parameters were employed for online laser profiling, the circular run-out error and the parallelism error of the grinding wheel surface decreased from 83.1μm and 324.6μm to 11.3μm and 3.5μm, respectively. The surface contour precision of the grinding wheel significantly improved. The highest surface contour precision for grinding wheels of the same type that can be theoretically achieved after laser profiling is completely dependent on the peak power density of the laser. The higher the laser peak power density is, the higher the surface contour precision of the grinding wheel after profiling.

Measuring Method of Distribution of Abrasive Grain Cutting Edge by Means of AE Sensors

In grinding process, the grinding wheel profiles are copied to workpiece surface. Therefore, the finished workpiece surface can be estimated by the grinding wheel surfaces. In this paper, new measuring method of the distribution of cutting edge in grinding wheel surface by two AE sensors is proposed. From experimental results, it is confirmed that the distribution of cutting edges in wheel surface can be measured easily by the proposed method compared to another measuring method.

Measuring Method of Distribution of Abrasive Grain Cutting Edge by Means of AE Sensors

In grinding process, the grinding wheel profiles are copied to workpiece surface. Therefore, the finished workpiece surface can be estimated by the grinding wheel surfaces. In this paper, new measuring method of the distribution of cutting edge in grinding wheel surface by two AE sensors is proposed. From experimental results, it is confirmed that the distribution of cutting edges in wheel surface can be measured easily by the proposed method compared to another measuring method.

Closed-Loop Feedback Flank Errors Correction of Topographic Modification of Helical Gears Based on Form Grinding

To increase quality, reduce heavy-duty gear noise, and avoid edge contact in manufacturing helical gears, a closed-loop feedback correction method in topographic modification tooth flank is proposed based on the gear form grinding. Equations of grinding wheel profile and grinding wheel additional radial motion are derived according to tooth segmented profile modification and longitudinal modification. Combined with gear form grinding kinematics principles, the equations of motion for each axis of five-axis computer numerical control forming grinding machine are established. Such topographical modification is achieved in gear form grinding with on-machine measurement. Based on a sensitivity analysis of polynomial coefficients of axis motion and the topographic flank errors by on-machine measuring, the corrections are determined through an optimization process that targets minimization of the tooth flank errors. A numerical example of gear grinding, including on-machine measurement and closed-loop feedback correction completing process, is presented. The validity of this flank correction method is demonstrated for tooth flank errors that are reduced. The approach is useful to precision manufacturing of spiral bevel and hypoid gears, too.

Computer Aided Design of Grinding Wheel for Drill Flute Production

Twist drill flute profile design is necessary in order to determine the required grinding wheel profile for a flute production. An accurate drill flute profile design is generated for two-flute conical twist drills using analytical equations to generate a drill flute profile design needed for the production of twist drills with straight lips. The required grinding wheel profile for a flute production was expressed in digitized form as well as in terms of two curve-fitted circular arcs. The drill flute profile geometry can never be precisely generated when required grinding wheel profile is represented by two circular arcs and the generated flute profile is just a very good approximation of the design flute profile. A CAD (computer aided design) software has been developed using MATLAB to determine the required grinding wheel profile for generating a given drill flute profile design.

脉冲激光切向整形径向修锐青铜金刚石砂轮

脉冲激光切向整形径向修锐青铜金刚石砂轮

Tool Profile Generation by Boolean Operations on Ball Nuts

Ballscrew drive mechanisms are widely used in the transmitting system of precision machine tools. The profile of the ball nut is a gothic curve combined by two equal radius arcs with offset centers. Most of gothic arc ball nuts are manufactured by form grinding, where the grinding wheel is shaped into the desired profile and the tool axis is tilted at the lead angle of the ball nut thread. In case of the internal ball nut grinding the high lead angle and long thread limits the manufacturing process. To avoid the collision between the internal surface of the workpiece and outer surface of the quill the optimal tilt angle is modified. The modified tilt angle affects to the profile of the formed grinding wheel. This paper presents a method for the generation of modified grinding wheel profile independently the tilt angle. The desired profile points are generated by solid boolean operations with programming of a parametric CAD system.

More efficient profiling and use of diamond grinding wheels

We consider the contact-erosion profiling of diamond wheels with metal binders, by means of a composite disk electrode. The productivity may be increased by increasing the height of the electrode profile, without loss of accuracy.

Determination of the grinding wheel profile and its setup for use in finishing cylindrical gears with an evolvent profile

The present work is a continuation of the first part of the article and is devoted to the geometric calculation of shape parameters of the working surfaces of disk-shaver teeth for use in finishing cylindrical gears with an evolvent profile. A method has been proposed for determining the shape of the working surfaces in disk-shaver teeth during the recessed shaving of cylindrical gears with technologically modified teeth. In this case, the machined gear tooth surfaces are discretely specified, and consequently familiar analytical methods of tool profiling are unacceptable.

Laser Prepared Cutting Tools

Abstract Laser pulses with a pulsewidth of a few picoseconds have recently received a lot of attention, solving the problem of manufacturing tools for new materials of superior mechanical properties. Processing thermally sensitive material, such as diamond and CBN structures, can be done without major material deterioration effects. The breakthrough of this new technology becomes possible, if the accuracy and life time requirements of those tools are met. The paper shows in three applications the potential of laser manufacturing of cutting tools. Manufacturing of cutting edges for CFRP cutting needs sharp and stable cutting edges, which are prepared in PCD tools by laser sources in the picosecond pulsewidth regime. Profiling of hybrid bond grinding wheels yields geometric flexibility, which is impossible by mechanical treatment so far. Touch dressing of grinding wheels substantially reduces cutting forces.

Relief Grinding of Pinion Cutters with Trapezoid Wheel

Relief grinding for involute helical pinion cutters with no profile error is realized by through grinding with a trapezoid-like grinding wheel. As a calculation example, an involute helical pinion cutter with semi-topping and protuberance cutting edges is used. First, a method for calculating the grinding wheel profile to finish the tooth flanks of the pinion cutter with the exact cutting edges is proposed. Next, the profile errors of cutting edges after regrinding are calculated and evaluated by means of the tooth profile of the work gear being shaped by the reground pinion cutter. As the results, it was found that the profile errors and the changes in shapes of the semi-topping and protuberance cutting edges after regrinding are very small. Finally, the usefulness of the proposed methods was confirmed through the grinding tests of the pinion cutter.

Calculation of Grinding Wheel Profile and 3D Simulation for Grinding Screw Rotor Flute

In order to describe the forming grinding principle of screw rotor, the mathematical model of screw rotor’s helical groove and forming grinding wheel are established by differential geometry theory and numerical analysis method. And the contact line equation is derived. To optimize the traditional method of calculating forming grinding wheel by known rotor end section profile, a numerical analysis method (Accumulated Chord Length Parameter Method) has been presented in detail. This method can improve the efficiency and reliability of the calculation of forming grinding wheel axial profile. Taking the asymmetry linear screw rotor (female) as an example, this paper calculates the grinding wheel axial profile and draws it using special designed software. The simulation examples are done by CAD (Computer Aided Design) based on the secondary development technology of UG. This study provides a precise 3D model which can be used in areas such as finite element analysis and virtual testing experiments.

Development of Calculating Grinding Wheel-Profile Software Applied to the Sharping Grinder Machine

The grinding wheel-profile is mostly formed by adjusting the angle of cylindrical profile model when regrinding gear hob with the large helix flute. Repeat trial cutting is needed with this method, which results in low efficiency. In order to improve the efficiency of processing, a mathematical model of grinding wheel profile was establish in according to forming principle of the rake face of gear hob and accurately calculate grinding wheel-profile. A automatic programming system of calculating grinding wheel-profile and automatically generate NC code is developed with the developing tool of VC++.

Research on Calculation and Smoothing of Grinding Wheel Profile for Machining Screw Rotor

Upon studying the form grinding principle of helical groove and the conjugate movement between the grinding wheel and screw rotor, the equation of their contact line is firstly derived. The problem of smoothing the profile of grinding wheel is then solved by using the point selection smoothing method which is concludes from the theory of complex curves and numerical analysis. Finally, with the help of computer, the simulation processing is done with the final result shows that this design method is reliable. It can not only reduce the time for design and the number of trial samples but also provides a 3D model which can be used in virtual test of screw rotor.

Modified-Roll Profile Correction for a Gear Shaping Cutter Made by the Lengthwise-Reciprocating Grinding Process

The tooth profile error of a gear shaping cutter made by the lengthwise-reciprocating grinding process (LRGP) is usually corrected by modifying the grinding wheel profile. However, such grinding wheel modification cannot eliminate the twisting profile error along the face of the shaping cutter. A kinematic modified roll motion for generating a shaping cutter is proposed to minimize such twisted profile errors even after cutter resharpening. The tooth profile errors of the work gears generated by the shaping cutter with various resharpening depths are represented as a novel topographic error map. Based on the error map and its sensitivity matrix, the roll ratio between the shaping cutter and the grinding wheel stroke is modified to reduce the twisted profile error as illustrated by the numerical examples. Combining this modified roll motion modification and the grinding wheel profile correction, the high accuracy resharpening depth of the LRGP helical shaping cutter is increased.

Dispersed grinding wheel profiles for accurate freeform surfaces

Dispersed grinding wheel profiles are proposed to replace its ideal ones for planning 3D tool paths in CNC grinding. Its advantage is to register irregular and discontinuous grinding wheel profiles and directly eliminate their form-truing error for the accurate freeform surfaces of a large-size workpiece. First, the actually form-trued grinding wheel profiles were dispersed to be a tool point cloud by rotating the measured 2D wheel-section profile points; then a discrete-form algorithm was constructed to plan 3D tool paths on the base of a mutual-tangency between tool point cloud and workpiece point cloud; finally, the effects of discrete-form variables such as wheel spacing angle, lattice grid size and searching interval were investigated on discrete-form accuracy and efficiency. It is shown that the discrete-form algorithm may improve the form accuracy of ground freeform surface by about 37% compared with a normal-form algorithm. In discrete-form algorithm, the discrete-form accuracy increases and the discrete-form efficiency greatly decreases with decreasing wheel spacing angle, lattice grid size or searching interval, but the discrete-form error may converge to the wheel-section profile error. It is confirmed that the lattice grid size in 0.5 mm and a large searching interval may be employed to enhance the discrete-form accuracy and efficiency simultaneously.

Automatic search for wheel position in flute grinding of cutting tools

The profile of helical flutes has a great influence on properties of cutting tools. This paper presents an automatic method of searching for a wheel position in flute grinding for a given shape of the helical flute and grinding wheel profile. The algorithm is based on the main loop and two subroutines. The first algorithm is dedicated to the simulation of the flute profile by splitting the grinding wheel into many thin disks. The second algorithm represents the numerical evaluation of the reached profile that results from previous grinding simulation. Finally, the experimental evaluation using particle swarm optimization is presented and obtained results discussed.