Rotary Dresser Research Articles

Rotary dressing and cylindrical grinding simulation for lead pattern prediction

A kinematic model of rotary dressing - cylindrical grinding for lead pattern prediction is presented. Analysis of dressing and grinding parameters, dressing forces, and wheel imbalance effects has been conducted, providing a comprehensive look at the interrelationships between them and the resulting lead pattern. For model validation, a series of experimental tests has been performed, where workpiece and simulation lead has been characterized according to MBN 31,007–7 standard. Results emphasize the significance of modelling and translate it into a useful tool for selecting optimal dressing and grinding parameters for achieving specific surface qualities where lead is minimised or eliminated.

On mechanics and monitoring of plunge-roll rotary dressing of grinding wheels

A study is made into the mechanics and monitoring of rotary plunge-roll dressing of grinding wheels using a roll with multi-layer diamonds contained in a hybrid, metal-ceramic bond. A fundamental relationship is obtained between grinding/dressing specific energy and the dressing aggressiveness number Aggrd, revealing a distinct size effect. Results also indicate (i) a nearly linear relationship between grinding and dressing specific energy, and (ii) direct proportionality between dressing specific energy and the acoustic emission (AE) signal. SEM observations indicate that smaller Aggrd produces a grit-dulling phenomenon different from grinding-induced dulling of the grits by attrition, which causes rapid workpiece-material adhesion.

Rotary dressing model for grinding wheel active surface prediction

A kinematic model of rotary dressing of corundum grinding wheels is presented. Based on wheel and dresser specifications and process kinematics, effects of rotary dressing parametres on wheel topography are predicted. For model validation, wheel surface is characterized by areal roughness parametres, obtaining a deviation less than 15%. Besides, influence of wheel topography on ground part surface quality is investigated. Results highlight the significance of modelling the dressing process and show the model translates into a useful tool for selection of most suitable dressing parametres for achieving specific surface qualities. Moreover, it eases the way to predicting dressing originated defects.

Resin Bonded Diamond grinding wheels conditioning using SiC rotary dresser

Superabrasive grinding of advanced materials parts with complex geometry is a critical issue for aerospace or energy industry. Likewise, conditioning of superabrasive is a key process in order to obtain the most effective grinding. While from industrial point of view the conditioning parameters and dressers are designed from the experience, from scientific point of view the last works are focused on achieving guidelines for optimising conditioning process. In this sense, the present work is focussed on the conditioning process of diamond resin bonded grinding wheels. To this end, SiC rotary dressers of different hardness and applying down-cut and up-cut are tested in order to achieve the best conditions. On the one hand, the wheel surface is deeply analyse. A software is developed in order to analyse the grain pull out, the new abrasive grains and the size evolution and grain concentration during conditioning. On the other hand, the wheel geometry is also measured due to the importance of geometry loss during the conditioning process on profile grinding wheels. The results shown that down-cut conditions are more aggressive obtaining a better wheel surface recovery and the wheel geometry of the incidence edge is lost, requiring a subsequent truing process to obtain the wheel profile. Finally, it is noteworthy that the methodology developed for the analysis of the diamond resin bonded grinding wheels is suitable for all types of grinding wheels even rotary dressers.

On The Influence of Rotary Dresser Geometry on Wear Evolution and Grinding Process.

Dressing is a critical issue for optimizing the grinding process. Dresser tool and dresser parameters must be designed according to the grinding wheel material, shape, or even the dimensional and geometrical tolerances of the workpiece and its surface roughness. Likewise, one of the problematic issues of dressers is the wear that they suffer. In order to tackle this issue, the present work characterized the wear of two rotary dressers by analysing the wear behaviour depending on the pit radius of the dressers while studying the influence of the wear on ground surfaces. This work showed that the rotary dresser with a higher pit radius presents wear that is approximately 28% higher than the dresser with a half pit radius.

Profiled rotary dresser with controlled size and distribution of abrasive grits: Performance assessment

This paper reports on a novel proprietary profiled rotary dresser which, in contrast with conventional tools, enables a controlled arrangement of geometrically defined abrasives over complex profiles. Output forces and abrasives’ wear were investigated during dressing and grinding tests. This showed a significant reduction in radial dressing forces (˜37%) and volumetric loss of material per grit (˜21%) when compared with conventional tools, together with low grinding forces and workpiece surface roughness variability for different wear conditions. The novel dresser proves the ability to obtain uniform wear rates along complex profiles, while allowing abrasive segment replacement to restore the dressing conditions.

On modelling the interaction between two rotating bodies with statistically distributed features: an application to dressing of grinding wheels.

The mechanisms of interaction between bodies with statistically arranged features present characteristics common to different abrasive processes, such as dressing of abrasive tools. In contrast with the current empirical approach used to estimate the results of operations based on attritive interactions, the method we present in this paper allows us to predict the output forces and the topography of a simulated grinding wheel for a set of specific operational parameters (speed ratio and radial feed-rate), providing a thorough understanding of the complex mechanisms regulating these processes. In modelling the dressing mechanisms, the abrasive characteristics of both bodies (grain size, geometry, inter-space and protrusion) are first simulated; thus, their interaction is simulated in terms of grain collisions. Exploiting a specifically designed contact/impact evaluation algorithm, the model simulates the collisional effects of the dresser abrasives on the grinding wheel topography (grain fracture/break-out). The method has been tested for the case of a diamond rotary dresser, predicting output forces within less than 10% error and obtaining experimentally validated grinding wheel topographies. The study provides a fundamental understanding of the dressing operation, enabling the improvement of its performance in an industrial scenario, while being of general interest in modelling collision-based processes involving statistically distributed elements.

On the performance of a novel dressing tool with controlled geometry and density of abrasive grits

This paper reports on an innovative rotary dresser, characterised by abrasive features with controlled geometries and spatial arrangements. The performance of the novel dresser has been evaluated against conventional dressers (random and handset grit distributions) in terms of output forces and wear of the abrasives supported by electron scanning microscopy and metrological investigations. The proposed dresser showed improved wear resistance and significant (50%) reduction of radial forces when compared with conventional tools. This novel approach opens the possibility to vary density of abrasives to obtain uniform wear rates for complex geometry tools while allowing easy restoration of their abrasive properties.

Kinematic analysis of dressing process using prismatic diamond rotary dresser

Kinematic analysis of dressing process using prismatic diamond rotary dresser

Computer-Aided Simulation of Dressing Using Diamond Rotary Dresser and Visualization of Dressing Process

The surface of a grinding wheel dressed by a diamond rotary dresser was generated by computer-aided simulation for the case of multipass dressing on the assumption that the grinding wheel is a homogeneous solid body and the dressing trajectories of the diamond grits are perfectly copied on the grinding wheel surface. The dressing process was visualized as a contour map of the dressed surface profile and the effects of the dressing strategy, i.e., down-cut dressing or up-cut dressing, on the grinding wheel removal process were investigated. It was found that the diamond grits remain the residual depth of cut on the surface of the grinding wheel, resulting in an actual depth of cut larger than that given by the rotary dresser.

Grinding Performance of Metal-Bonded CBN Wheels with Regular Pores

Metal-bonded cBN wheels with regular pores were fabricated using Cu-Sn-Ti alloy, cBN abrasive grains and alumina (Al2O3) bubble particles. Dressing experiments were carried out through rotary dressing method. Subsequently, grinding experiments were conducted on nickel-based superalloy GH4169. Comparative grinding performance was evaluated with vitrified cBN wheels in terms of grinding force and specific grinding energy. The results reveal that the pores in the working layer of the cBN wheels are exposed after rotary dressing. Compared to vitrified cBN wheels, grinding forces and specific grinding energy of the newly developed cBN wheels with regular pores are smaller.

Evaluation of diamond dressers and estimation of grinding performance by dressing force measurement

Equipment to measure the dressing force exerted by diamond dressers was developed and the performances of two types of diamond dresser, a single-point dresser and a multipoint rotary dresser, were examined focusing on the relationship between dressing force and grinding performance. It was found that both types of diamond dresser induce the same dressing force if their wear widths are equal and that a strong relationship exists between dressing force and grinding performance; a sharp-edged single-point diamond dresser can be used to control grinding performance with a low dressing force. The truing accuracy depends on the dresser type and a lower dressing force results in better truing accuracy.

Estimation of Grinding Wheel Performance by Dressing Force Measurement

Dressing force measuring equipment was developed and the performance of a single-point diamond dresser was examined focusing on the relationship between dressing force and grinding performance. It was found that a distinct relationship exists between dressing force and grinding performance, and that the sharp-edged single-point diamond dresser can control grinding performance with low dressing force. The single-point diamond dresser and multipoint diamond rotary dresser induce the same dressing force if their wear widths are equal.

Development of Solid-Type Diamond Rotary Dresser Utilizing CVD Diamond Disc - Application to Low-Speed Dresser -

A solid-type diamond rotary dresser consisting of a CVD diamond disc is developed and applied to the dressing of a vitrified CBN grinding quill for internal grinding. This dresser has a feature not found in the other discrete-type rotary dressers used thus far, in which it continuously contacts the grinding wheel and leaves a spiral on the grinding wheel surface. The solid-type diamond rotary dresser was mounted on a low-speed spindle supported by journal bearings, and its dressing performance was compared with those of two discrete-type rotary diamond dressers: a dressing roll on which surface single diamond grains are brazed and a dressing roll made of a metal-bonded diamond wheel. It is found that the solid-type diamond rotary dresser tends to bring about rough grinding conditions among the three dressers.

A Study on the Optimum Condition Selection of Rotary Dressing System of Ultra-Precision Centerless Grinding Machine for Ferrule

The optimum condition selection of rotary dressing operations using Hall and AE sensor is presented. The acquired current signals from a hall sensor were studied as one of the method to obtain the optimum condition of dressing and the correlations between dressing condition and AE signals were also evaluated with the root mean square (RMS). Dressing operation was performed to investigate the effects of depth of cut, rotating speed and coolant. In order to verify the optimum condition of dressing, AE and hall sensor signals were compared in RMS with the surface micrograph of grinding wheel. This verification experiment demonstrates the effective dressing condition selection for centerless grinding.

Grinding of Ceramic Coatings with Cast Iron Bond Diamond Wheels. A Comparative Study: ELID and Rotary Dresser

Ceramic coatings, including chemical vapour deposited silicon carbide (CVD-SiC), plasma spray deposited aluminium oxide (PSD-Al 2 O 3 ), plasma spray deposited chromium oxide (PSD-Cr 2 O 3 ), etc., have some special structural, physical, and mechanical properties. The precision and efficient machining of these ceramic coatings to the required quality has not yet been well established. In this paper, a comparative study was conducted to investigate the special aspects in the grinding of these ceramic coatings using the ELID method or the rotary dressing method. The stability of surface roughness, effects of material properties on the grinding results, and microscopic analysis of ground ceramic coatings by both methods were also analysed in detail.

Effects of Machine Rigidity on the Dressing Accuracy of CBN Grinding Wheels

The present paper aims to clarify the effect of machine rigidity on the dressing accuracy of CBN wheels. Because of super hardness of CBN, the rigidity required to machines in order to obtain enough dressing accuracy must also be much higher than the conventional one. The algorithm and program have been developed which can simulate both the wheel peripheral profile after dressing and the surface roughness of workpiece attainable by that wheel. The simulation for a variety of dynamic properties of machine could suggest a guide to design CBN grinding machine. A new type of rotary dresser which can dress CBN fine even for less rigid machines was developed.

成形研削加工に関する基礎的研究 (第4報)

Forming efficiency and grinding ability of metal-bonded, resinoid-bonded and vitrified-bonded diamond wheels for V-profile groove grinding of fine ceramics are experimentally investigated, analyzing initial profile of formed wheels, wheel wear, stock removal, grinding force, number of cutting edges on working wheel surface and so on. Main results obtained are as follows : (1) Initial profile of formed metal-bonded diamond wheel dressed by rotary dresser is better than that dressed by GC stick grindstone, while grinding force in the case of rotary dresser is larger than that of GC stick grindstone. (2) Geometrical error of the V-profile formed on metal-bonded diamond wheel is large and grinding force with this wheel is large, but the rate of change in V-profile is small. (3) V-profile is easily formed on resinoid-bonded and vitrified-bonded diamond wheel and grinding forces with those wheels are small, but the rates of cange in V-profile are large.

研削砥石のドレッシングに関する研究(第4報)

Crush dressing process and grinding performance of crush-dressed wheel are experimentally investigated, analyzing dressing force, grinding force, wheel wear, surface roughness and so on. SEM observations of cutting edges and measurements of characteristic values to quantify the condition of cutting edges on the wheel surface are performed. Main results obtained in this paper are as follows : (1) There exists three distinct states in crush dressing process ; transient state, steady state and crush-out state. (2) The higher the number of revolution of grinding wheel in crush-out dressing is, the larger grinding force and the less surface roughness and wheel wear rate become. (3) Higher infeed rate of crush roll results in sharper cutting edges and less cutting edge density, which leads to lower grinding force, larger surface roughness and higher wheel wear rate. (4) Softer wheel grade leads to lower grinding force and larger surface roughness. (5) Sharper cutting edges with lower cutting edge density are generated as compared with those in rotary dressing and conventional dressing.

研削砥石のドレッシングに関する研究(第3報)

Grinding performance of grinding wheel dressed with a diamond rotary dresser is experimentally investigated under various dressing conditions, analyzing size generation process, grinding force, surface finish, wheel wear and so on. Main results obtained in this paper are as follows: (1) Variation process of dressing force in rotary dressing is similar to that of grinding force in a plunge grinding cycle. (2) Wide variety of grinding performance can easily be obtained by changing dressing conditions such as infeed rate of dresser, speed ratio of dresser to wheel and relative dressing speed. (3) The integer revolution ratio of wheel to dresser should not be selected. (4) The grinding performance of wheel dressed with this technique can be kept constant longer than in any other methods, because of the remarkably less wear of rotary dresser.