Study on the Shape Error in the Cylindrical Traverse Grinding of a Workpiece with High Aspect Ratio

Onishi, Takashi; Kodani, Takuya; Ohashi, Kazuhito; Sakakura, Moriaki; Tsukamoto, Shinya

doi:10.4028/www.scientific.net/amr.1017.78

Cited by 3 publications

(8 citation statements)

References 4 publications

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“…Using this model, the elastic deformation of the workpiece during grinding was calculated. The calculated elastic deformation agreed well with the measured form error after the grinding process (Onishi et al, 2014a). The Young's modulus E of the solid cylindrical workpiece is 206 GPa.…”

Section: Simulation Of Elastic Deformation Of Workpiece Using Beam Model 31 Beam Model Without Steady Restsupporting

confidence: 77%

“…As mentioned before, the elastic deformation of the workpiece during the grinding process was simulated using the beam model without a steady rest in our previous study (Onishi et al, 2014a). In this study, a new beam model that considers the effect of steady rest is proposed.…”

Section: Beam Model With Steady Rest 321 Case Of Steady Rest Placed At Grinding Partmentioning

confidence: 99%

“…Before the grinding wheel passed the contact point (Zg < 150 mm), the elastic deformation of the workpiece was estimated using Equations (3). After the grinding wheel passed the point (Zg > 150 mm), the elastic deformation of the workpiece was estimated based on a previous study (Onishi et al, 2014a) as shown in Fig. 6, because the workpiece was no longer supported by the steady rest.…”

Section: Beam Model With Steady Rest 321 Case Of Steady Rest Placed At Grinding Partmentioning

confidence: 99%

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Improvement of form accuracy in cylindrical traverse grinding with steady rest by controlling traverse speed

Fujii

Onishi

Lin

et al. 2021

JAMDSM

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In cylindrical traverse grinding, a slender workpiece is bent by the normal grinding force due to its low stiffness. Consequently, a form error is generated by the elastic deformation of the workpiece during the grinding process. To prevent such deformation of the workpiece, a steady rest is generally used. However, when the contact point between the workpiece and the steady rest is ground, the pushing force of the steady rest is lost, and the elastic deformation of the workpiece is increased immediately. As a result, a step shape error is generated at the contact point. To improve the use of the steady rest, the elastic deformation of the workpiece during the grinding process is simulated using the beam model considering the steady rest in this study. From the analysis results, it was determined that placing the steady rest outside the grinding part can reduce the elastic deformation of the workpiece. In addition, the traverse speed was controlled to maintain a constant elastic deformation. Through grinding experiments, it was confirmed that the form accuracy of the slender workpiece was improved by setting the steady rest outside the grinding part and adjusting the traverse speed.

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Section: Simulation Of Elastic Deformation Of Workpiece Using Beam Model 31 Beam Model Without Steady Restsupporting

confidence: 77%

Section: Beam Model With Steady Rest 321 Case Of Steady Rest Placed At Grinding Partmentioning

confidence: 99%

Section: Beam Model With Steady Rest 321 Case Of Steady Rest Placed At Grinding Partmentioning

confidence: 99%

See 1 more Smart Citation

Improvement of form accuracy in cylindrical traverse grinding with steady rest by controlling traverse speed

Fujii

Onishi

Lin

et al. 2021

JAMDSM

Self Cite

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show abstract

“…Although, for slender parts, the part itself is the least rigid element of the system, system stiffness and headstock-center eccentricity must be considered to determine the shape error in slender parts [5]. Several studies have demonstrated that the main cause of workpiece deformation during the traverse grinding cycle is the normal force [6,7]. The grinding wheel pushes the workpiece, and the part is not ground to the required diameter because of its elastic deformation, so the material removal rate decreases at the point where the flexibility is the highest [8].…”

Section: Introductionmentioning

confidence: 99%

“…High-frequency oscillations are induced in the radial depth of the wheel in the workpiece. Modifying wheel transversal speed along the workpiece is another technique [6] that has been proposed for turning operations [12]. Due to a decrease in the zone of the workpiece, where the stiffness is most critical, the normal forces decrease, thus decreasing the shape error.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Shape Error for Slender Parts in Cylindrical Traverse Grinding by Part-Deformation Modelling and Compensation

Mendez¹,

Alvarez²,

Barrenetxea³

et al. 2021

Metals

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Achieving geometrical accuracy in cylindrical traverse grinding for high-aspect slender parts is still a challenge due to the flexibility of the workpiece and, therefore, the resulting shape error. This causes a bottleneck in production due to the number of spark-out strokes that must be programmed to achieve the expected dimensional and geometrical tolerances. This study presents an experimental validation of a shape-error prediction model in which a distributed load, corresponding to the grinding wheel width, is included, and allows inclusion of the effect of steady rests. Headstock and tailstock stiffness must be considered and a procedure to obtain their values is presented. Validation of the model was performed both theoretically (by comparing with FEM results) and experimentally (by comparing with the deformation profile of the real workpiece shape), obtaining differences below 5%. Having determined the shape error by monitoring the normal grinding force, a solution was presented to correct it, based on a cross-motion of the grinding wheel during traverse strokes, thus decreasing non-productive spark-out strokes. Due to its simplicity (based on the shape-error prediction model and normal grinding force monitoring), this was easily automatable. The corrective compensation cycle gave promising results with a decrease of 77% in the shape error of the ground part, and improvement in geometrically measured parameters, such as cylindricity and straightness.

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A Method of Increasing the Accuracy of Low-Stiffness Shafts: Single-Pass Traverse Grinding Without Steady Rests

Sułkowicz

Babiarz

Burek

et al. 2022

Acta Mechanica Et Automatica

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The article presents a method of increasing the shape and dimensional accuracy of low-stiffness shafts manufactured in a single pass of a grinding wheel in traverse grinding. One-pass manufacturing is one of the ways for reducing machining time and increasing efficiency, thus lowering production costs. However, maintaining the necessary accuracy proves to be a challenge because the whole machining allowance has to be removed at once, leaving no room for errors that could be fixed in additional passes of the tool. It is especially true in finishing operations, such as traverse grinding. In addition, grinding the workpiece in a single pass of a grinding wheel leads to high forces, which cause elastic deformation of the part. The lower the stiffness of the part, the more difficult it is to achieve the required accuracy. As a result, there are many methods of improving the accuracy of grinding such parts, but they tend to be either expensive or reduce the machining efficiency. Thus, it is important to seek new methods that would allow improving the accuracy of the machining without reducing its efficiency. The proposed method does not require using steady rests and is based on the measurement of the normal grinding force component. Knowing the value of the grinding force when grinding with a set grinding depth, the elastic deformation of the machine tool–tool–workpiece system is calculated in each position of the grinding wheel. Based on the calculated deformation, the additional infeed of the grinding wheel is implemented in order to stabilise real grinding depth and to increase the accuracy of the produced part. The experimental tests were conducted to prove the effectiveness of the proposed method.

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Study on the Shape Error in the Cylindrical Traverse Grinding of a Workpiece with High Aspect Ratio

Cited by 3 publications

References 4 publications

Improvement of form accuracy in cylindrical traverse grinding with steady rest by controlling traverse speed

Improvement of form accuracy in cylindrical traverse grinding with steady rest by controlling traverse speed

Improvement of Shape Error for Slender Parts in Cylindrical Traverse Grinding by Part-Deformation Modelling and Compensation

A Method of Increasing the Accuracy of Low-Stiffness Shafts: Single-Pass Traverse Grinding Without Steady Rests

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