Factors Affecting Plunge Grinding Force

Grinding force has a close relation to grinding inputs such as grinding wheel, work material, interference condition, grinding speed, grinding fluid and machine condition, and therefore varies widely with grinding inputs. On the other hand, grinding force affects significantly grinding outputs which are efficiency and quality evaluated with surface roughness, accuracy, surface integrity and so on. It is important to make clear the relations between grinding inputs and grinding force in order to control grinding outputs. In this paper, from the above point of view, the relations between grinding inputs and grinding force are experimentally investigated. It is pointed out that the normal grinding force, the tangential grinding force and its ratio are determined by the product of speed ratio of work speed to wheel speed and setting depth of cut as for interference conditions, and by the product of square of dressing feed and cutting depth of. dresser as for dressing conditions. Furthermore as for characteristics of work materials, the normal grinding force has a close relation to the yield stress, and the force ratio is related to the elongation of work material

Ranking of vitrified grinding wheel parameters by using analytical hierarchical process (AHP) for surface roughness of work piece in grinding operation

Objective of grinding process is to generate high quality surface finish on work piece. There are many parameters which influence on the work piece roughness. Work piece material and characteristics, grinding wheel specification, grinding conditions and dressing conditions influence on the surface quality of the work piece. Selection of grinding wheel is important aspect for producing good quality of surface finish on the work piece. The main components of grinding wheel are the abrasive grains, bond material and porosity. Selection of correct grinding wheel is necessary for generating better surface finish on the work piece. Analytical Hierarchical Process (AHP) is used for ranking of vitrified bond grinding wheel parameters on surface roughness on the work piece in sub sequent grinding operation. The grit, grade, (Hardness of wheel) structure and type of abrasive are critically assisted in terms of the surface finish produced on work piece in the subsequent grinding operation. Analytic Hierarchy Process (AHP) shows that the abrasive grit of grinding wheel has first rank and grade (hardness) of the wheel has Second rank for the producing surface finish on the work piece after grinding operation. Structure and type of abrasive of wheel have a third and fourth rank respectively. Thus, AHP gives qualitative way of controlling work piece surface roughness in sub-sequent grinding operation by selecting proper grinding wheel of vitrified bond which helps the user to select the correct grinding wheel

Evaluation of superalloy heavy-duty grinding based on multivariate tests

The quality and economy of grinding depend on proper selection of grinding conditions for the materials to be ground. In order to evaluate the effect of heavy-duty grinding, a new performance index, which includes specific material removal rate, size accuracy, and grinding forces, was proposed. Robust design of experiment, including orthogonal arrays, the signal-to-noise ratio (SNR) method, and analysis of variance (ANOVA) for multivariate data, was employed to estimate the effect of uniform experimental design and to optimize grinding parameters. Empirical models of grinding force were investigated for finite element analysis of new fixture design. These empirical models, based on robust design of experiments and multiple regression methodology, have been confirmed through further verification experiments. Correlation coefficients from 0.87 to 0.96 were achieved

The numerical evaluation of the grinding process and the basic mechanics of grinding wheel wear

During the production process development for the manufacture of an experimental supersonic aircraft , an unusual and difficult grinding problem was encountered. Arising from the experimental work carried out to solve this problem, a method of numerically evaluating the efficiency of grinding wheels and coolants, was developed. This evaluation is based on the fact that under constant and limited grit load conditions which can be set up in a surface grinding operation, the edge of the grinding wheel which makes initial contact with the workpiece breaks down and forms an approach angle as shown in Fig. 1. Once this angle is established, its dimensions remain almost constant, and with continued use of the wheel the angle recedes across the face of the wheel. It is the recognition of the variables which control the dimensions of this approach angle (alpha) together with the rate at which it recedes across the wheel face, and the amount of work done at each increment of recession, on which the numerical evaluation of the efficiency of the grinding wheel and the causes of the limitations are based. A description of the methods used for determining the characteristics of grinding wheels and coolants are included together with the calculations which are necessary when the data obtained from tests carried out on the surface grinding machine are to be interpreted and applied to the cylinder grinding internal grinding or form grinding processes

Grinding arrangement for ball nose milling cutters

A grinding arrangement for spiral fluted ball nose end mills and like tools includes a tool holder for positioning the tool relative to a grinding wheel. The tool is mounted in a spindle within the tool holder for rotation about its centerline and the tool holder is pivotably mounted for angular movement about an axis which intersects that centerline. A follower arm of a cam follower secured to the spindle cooperates with a specially shaped cam to provide rotation of the tool during the angular movement of the tool holder during the grinding cycle, by an amount determined by the cam profile. In this way the surface of the cutting edge in contact with the grinding wheel is maintained at the same height on the grinding wheel throughout the angular movement of the tool holder during the grinding cycle

A progress report on the evaluation of metal cutting coolants

An intensive investigation into the grinding process was carried out in The College of Aeronautics Machine Tools Laboratory during 1955-6. The outcome of this work was a method of evaluating the efficiency of grinding wheel specifications. Briefly, this consists of holding all other conditions constant and changing the grinding wheel specification from the grinding tests made then the rate of grinding wheel wear and the maximum metal removal rate is ascertained. This data may be used to compare one specification to another. The method has been used to select the best wheel specification for a wide range of materials, especially the more difficult machinable alloys examples being the stainless steel and the alloys intended for use at high temperatures. During the ten years since 1956 the method has been further developed by retaining the grinding wheel specification constant and varying the work piece material to determine the grinding machinability of alloys, and also a much more valuable criteria of the grinding process - the efficiency of coolants when used in the grinding process. This work on coolant evaluation has received detailed and extensive attention. The results of tests carried out on more than 300 coolant samples ranging from oil based and water soluble coolants with varying percentages of addative has revealed that the coolant can increase the life of the grinding wheel face by 10 times. All results found from the method of evaluation are expressed in terms of maximum metal removal rate and volume of metal which may be removed at maximum rate

The Analysis of the Cutting Forces and Surface Layer Stereometry in the Grinding Process of Abrasion-Resisting Materials

The article presents the investigation of the grinding process of flat samples made of materials that meet requirements of the lowest abrasibility, which belong to difficult to machine materials. Research enclosed measurement of cutting forces and surface layer stereometry during grinding without using cutting fluid. The tests were carried out with the aid of new generation grinding wheel, Quantum

Grinding Process Results with Oil Mist.

The paper presents a study of the process of grinding titanium grinding wheels with mikrokorundu, sanding at surfaces involving liquid - cooling lubricants using MQL, used machining fluid - propylene glycol and other liquids business dedicated to the administration with a minimum expenditure of the grinding zone. Were studied component of cutting forces - and tangent parameter

How to combine a hydrophobic matrix and a hydrophilic filler without adding a compatibilizer – Co-grinding enhances use properties of renewable PLA-starch composites

In order to avoid the use of compatibilizers or plasticizers, co-grinding was performed to produce PLA – starch composite materials. Fragmentation and agglomeration phenomena were analysed to propose a production mechanism. Co-grinding enhances dispersion of the filler in the matrix and interactions between the materials. Consequently while blending the two materials has a negative effect on mechanical properties, co-grinding permits to improve them if optimized operating conditions are applied. Water uptake and diffusion are also controlled by co-grinding conditions. This treatment allows the production of composite materials offering good use properties without any use of a compatibilizer or a plasticizer

Submicron metal powders produced by ball milling with grinding aids

In ball milling metal powders to submicron size, various salts are more effective as grinding aids than conventional surfactants. Absolute ethyl alcohol is used as the grinding liquid