Models for Determining the Static Stiffness of Collet Sleeves

Soriano, Enrique R.; Rubio, Higinio; García-Prada, Juan Carlos

doi:10.1007/978-94-007-7485-8_46

Cited by 2 publications

(9 citation statements)

References 5 publications

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“…By using classical elasticity theories, the maximal deflection ε produced by the clamping force F s is estimated (see Equation (13)). The radial stiffness of the collet, k R , is given by Equation (14). Equation (15) gives the expression to compute the clamping force F s2 , which is used to deform the collet.…”

Section: Collet Initial Deflectionmentioning

confidence: 99%

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Automatic Expanding Mandrel with Air Sensing Device: Design and Analysis

et al. 2020

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In precision machining, expanding mandrels are used for jobs with close tolerances. An expanding mandrel consists of a tapered arbor or shaft, with a thin-slotted clamping sleeve or collet made of hardened steel. The internal tapered and external cylindrical surfaces are ground to a high degree of accuracy, and the mandrel expands to fit the internal bore of the workpiece. Expanding mandrels are, essentially, wedge mechanisms. This paper proposes an automatic expanding mandrel with a novel force transmission system for high stiffness within a novel air sensing system, which allows detection of the correct part position before starting machining. A computational model for determining the dynamic clamping force of the proposed mechanism is developed and implemented using MATLAB. This model considers the influence of the stiffness behaviors of the collet, force transmission structure and workpiece. Additionally, this paper presents the finite element method analyses which were conducted to check the proposed computational model. The amount of clamping force transmitted by a collet chuck holder depends strongly on: clearances, wedge angle, stiffness of the collet chuck holder and workpiece stiffness.

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Section: Collet Initial Deflectionmentioning

confidence: 99%

“…Because a collet chuck is basically a wedge mechanism, the static clamping force for a given acting force to the mechanism depends on the friction coefficients of the tapered and clamping surfaces, on clearance between the collet and the clamped part, and on collet stiffness [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Automatic Expanding Mandrel with Air Sensing Device: Design and Analysis

et al. 2020

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“…In the models proposed in the literature for jaw chucks [1,[4][5][6][7] and collet chucks [3,8] based on rigid solid mechanics, the loss in clamping force is equal to the total centrifugal force at each one of the contact elements. However, the elastic strains in the contact elements make it possible that not all centrifugal force will reduce the clamping force, and even that part of centrifugal force may deform the clamping system [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…When it is necessary to achieve a high clamping force with collet chuck holders, the operating nut will cause a misalignment that will negatively affect the concentricity and distribution of clamping forces (see Figure 1). This effect is solved by collect chuck holders actuated pneumatically or hydraulically, which can be actuated by pulling or pushing [8,22] as shown in Figure 2. The imbalance, due to the noncoincidence of the rotation axes of the workpiece and the collet contact elements with the main axis of inertia, strongly depends on the rotational speed and the eccentricity in the workpiece, which varies with the centering capacity of the collet chuck holder and with the displacement and inclination of the workpiece due to the action of the cutting force.…”

Section: Introductionmentioning

confidence: 99%

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Mathematical Analysis of the Process Forces Effect on Collet Chuck Holders

et al. 2021

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Chuck holders are widely used for jobs with high precision. A chuck holder consists of a nut with a tapered surface and a thin-slotted clamping sleeve typically made of hardened steel and named a collet. Chuck holders are, essentially, wedge mechanisms. In this paper, we investigated the reactions and strains due to the forces during the chip removal process in the contact elements or jaws of the collet by means of mathematical analysis. Deflections in the jaws of the collet arise with a high influence from the precision of the workpieces. The cutting or process forces cause an axial force, a radial force, a torsional moment, and a bending moment on the chuck collet, and, consequently, displacements and inclinations of the clamping system are caused. Therefore, the proposed analytical models are based on elasticity and contact theories. The mathematical model for determining the deflections of the clamping system force was developed and implemented using MATLAB. The results showed that the variation in the clamping force during rotation in a collet chuck holder mainly depends on the stiffness of the collet chuck holder and the stiffness of the workpiece. The results indicated that the collet should be vulcanized to minimize the deformations that affect the final product. The deflections of a collet chuck holder due to process forces depend strongly on the clearances, wedge angle, and stiffness of the collet.

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Models for Determining the Static Stiffness of Collet Sleeves

Cited by 2 publications

References 5 publications

Automatic Expanding Mandrel with Air Sensing Device: Design and Analysis

Automatic Expanding Mandrel with Air Sensing Device: Design and Analysis

Mathematical Analysis of the Process Forces Effect on Collet Chuck Holders

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