Modeling micro-end-milling operations. Part III: influence of tool wear

There exists a wide variety of important applications for micro-and meso-scale mechanical systems in the commercial and defense sectors, which require high-strength materials and complex geometries that cannot be produced using current MEMS fabrication technologies. Micromilling has great potential to fill this void in MEMS technology by adding the capability of free form machining of complex 3D shapes from a wide variety and combination of traditional, well-understood engineering alloys, glasses and ceramics. Inefficiencies in micromilling result from the relationships between a cutting tool's breaking strength, the applied cutting force, and the metal removal rate. Because machining times in mesofeatures scale inversely to the part size, a feature 1/10 th as large will take 10 times as long to machine. Also, required chip sizes of 1 m or less are cut with tools having edge radius of 2-3 m, the cutting edge effectively has a highly negative rake angle, cutting forces are increased significantly causing chip loads to be further reduced and the machining takes even longer than predicted above. However, cutting forces do not increase with cutting speed, so faster spindles with reduced tool runout are the path to achieve efficient mesoscale milling.This research explored the development of new ultra-high speed micromilling spindles. A novel air-bearing spindle design is discussed that will run at very high speeds (450,000 rpm) and provide very minimal runout allowing the best use of micromilling cutters and reducing overall 3 machining time drastically. Two generations of this spindle design were completed; one with an air bearing supported tool shaft and one with a novel rolling element bearing supported tool shaft. Both designs utilized friction-drive systems that relied on diameter differences between the drive wheel (operating at speeds up to 90,000 rpm) and the tool shaft to achieve high rotational tool speeds. Runout, stiffness, and machining tests were conducted with the spindle designs and though they both showed promise for ultra-high speed machining, runout issues in the friction drive and in the stock tools kept the system from achieving sustained machining capability.4

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“…The helix angle plays an important role on tool life [6]. Bao and Tansel [7], [8] modified their analytical model [1] to represent tool wear.…”

Section: Cutting Edge Radiusmentioning

confidence: 99%

Next generation spindles for micromilling.

Pathak

Payne

Gill

et al. 2004

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“…An analytical force model for micro-end-milling including tool run-out and tool wear effects was investigated in a series of papers by Bao et al see [4][5][6]. In addition, Li et al [24] proposed a model of a three dimensional cutting force for micro-end-milling operation which includes a new nominal uncut chip thickness algorithm.…”

Section: Introductionmentioning

confidence: 99%

A statistical filtering method for denoising of micro-force measurements

Kazimierski

Piotrowska-Kurczewski

Böhmermann

et al. 2016

Int J Adv Manuf Technol

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Precise measurement of mechanical forces is crucial to efficient micro-manufacturing. The quality of such measurements depends heavily on the properties of the noise inevitably accompanying every measurement process. In the micro-range, the signal-to-noise ratio tends to be very low, and the noise dynamic varies for different frequencies. In result, common denoising methods that assume white noise perform poorly in this setting. In this paper, a novel, easily implementable denoising method based on a local statistic of the measured data's spectrum is proposed. By testing it on a representative dataset, it is shown that the proposed method is robust and stable. Particularly, it allows for an efficient retrieval of the force signal encountered in micro-milling processes.

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“…Cutting force model of micro-milling (part materials are NAK-55 steel, graphite, and aluminum alloy) was built by Bao and Tansel [10,11], which considered the effects of feed rate per tooth, tool radius, tool run-out, and tool wear. A series of slot milling experiments on single ferrite base, pearlite base, multiphase ferrite, and pearlitic ductile iron were carried out by utilizing carbide end milling cutter with two flutes, whose diameter is 0.5 mm, by Vogler et al [12].…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional dynamic cutting forces prediction model during micro-milling nickel-based superalloy

Lü

Zhang

Wang

et al. 2015

Int J Adv Manuf Technol

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Nowadays, there are urgent demands of micro structure/parts which have high strength in hightemperature environment in the fields such as aerospace, energy, power, biomedical, etc. Nickel-based superalloy with high strength and high hardness under high temperature is the suitable material for manufacturing this kind of micro parts. Aimed at the problem of the complicated cutting force variation rule when micro-end milling nickel-based superalloy, the cutting forces model during micro-end milling of nickel-based superalloy processing is studied. Firstly, micro-end milling hole experiments are carried out to establish the radical run-out prediction model of cutting edge, which lays the foundation for establishing the cutting thickness calculation model during micro-end milling. Then, based on the minimum cutting thickness value, micro-end milling of nickel-based superalloy process is divided into two different cutting processes: shear-dominant regime cutting process and ploughing-dominant regime cutting process. Moreover, cutting forces prediction model during sheardominant regime cutting process is developed based on the cutting forces in proportion to cutting layer area, which takes the effect of ploughing into account. Meanwhile, cutting forces prediction model during ploughing-dominant regime cutting process is developed based on the cutting force in proportion to interference volume between the flank surface of cutting tool and the workpiece. The experiment results verify that the cutting forces prediction results and experiment results are well matched.

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Modeling micro-end-milling operations. Part III: influence of tool wear

Cited by 86 publications

References 11 publications

Next generation spindles for micromilling.

Next generation spindles for micromilling.

A statistical filtering method for denoising of micro-force measurements

Three-dimensional dynamic cutting forces prediction model during micro-milling nickel-based superalloy

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