High-speed electrospindle running on air bearings: design and experimental verification

Belforte, Guido; Colombo, Federico; Raparelli, Terenziano; Trivella, Andrea; Viktorov, Vladimir

doi:10.1007/s11012-008-9135-5

Cited by 23 publications

(29 citation statements)

References 25 publications

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“…The bearing stiffness was improved respect to the prototype described in paper [9] because the diameter of the supply holes was changed. The electrospindle was tested also during machining using HSS and HSC tools of different diameter.…”

Section: Discussionmentioning

confidence: 95%

“…Each radial bearing is endowed with 16 calibrated holes of diameter 0.4 mm. This diameter was modified respect to the prototype described in paper [9] in order to obtain a higher stiffness on the bearings. On each disk of the thrust bearing are present 8 calibrated holes of 0.2 mm, equispaced on a circumference of diameter 65 mm.…”

Section: Prototype Descriptionmentioning

confidence: 99%

“…A numerical model [7,8] was used to calculate the pressure distribution in air bearings and obtain the stiffness and the load capacity of the spindle. In paper [9] the first tests without machining were shown. The spindle rotated in stable conditions but its dynamic runout was high, so a better grade of balancing was required.…”

Section: Introductionmentioning

confidence: 99%

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Experimental characterization of an electrospindle with gas bearings

Belforte

Colombo

Raparelli

et al. 2012

WIT Transactions on Engineering Sciences

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Fluid film bearings are a possible solution to be adopted in very high speed applications if the operating speeds overcome the maximum rotational speeds of rolling bearings. In particular, gas bearings offer important advantages thanks to the low viscosity of air and to the peculiarity of being non-contact systems. For these properties they are characterized by low friction, high accuracy and life almost unlimited.In machine tools, gas bearings are adopted in applications that usually are limited to electrospindles of small dimensions (like e.g. high speed grinding, milling, PCB drilling and coatings).For this reason in this paper the applicability of gas bearings for a larger electrospindle for machining process is investigated. The spindle, of 50 mm diameter, is accelerated by an asynchronous motor of nominal speed 75 krpm and power 2.5 kW.A test bench was designed and realized to perform static and dynamic characteristics of the spindle and to allow the measurement of the cutting loads during machining. The experimental characterization of the electrospindle is shown. In particular, the static stiffness of gas bearings and the air consumption were measured at different supply pressures. The dynamic tests consisted of measuring the rotor runout without external loads and also during the machining process. In this condition, the dynamic forces on the tool were detected using HSS and HSC cutters of diameters from 1 to 6 mm. Some preliminary results are reported.

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Section: Discussionmentioning

confidence: 95%

Section: Prototype Descriptionmentioning

confidence: 99%

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Experimental characterization of an electrospindle with gas bearings

Belforte

Colombo

Raparelli

et al. 2012

WIT Transactions on Engineering Sciences

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“…These disks are separated by a ring (10) whose thickness determines the size of the air gap. Supply air is delivered from an axial hole in the housing, is distributed through a circumferential slot, and then crosses a series of axial and radial channels machined in the disks to reach 0.25±0.01 mm diameter axial nozzles (14) and (15), which are also machined in inserts. Both the bushings and the disks were surface hardened and machined to produce a surface roughness of 0.2 and 0.4 μm, respectively at the air gaps.…”

Section: The Pneumatic Spindlementioning

confidence: 99%

High Speed Rotors on Gas Bearings: Design and Experimental Characterization

Belforte¹,

Colombo²,

Raparelli³

et al. 2013

Tribology in Engineering

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“…For this type of approach, both the dimensions and configuration of the air supply channels must first be analyzed under the microscope because of the significant influence that feeding system geometry has on the discharge coefficient. The results obtained with this method have been applied in numerical simulation programs for radial and axial bearings used in high-speed spindles: Belforte, et al, 2008. In Belforte et al, 2010, the effects of a groove on thrust bearing performance are investigated.…”

Section: Study Of Externally Pressurized Gas Bearingsmentioning

confidence: 99%