Achieving precision in high density batch mode micro-electro-discharge machining

Richardson, Mark; Gianchandani, Yogesh B.

doi:10.1088/0960-1317/18/1/015002

Cited by 17 publications

(12 citation statements)

References 32 publications

(61 reference statements)

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“…The electrical contact springs are fabricated from 100µm thick stainless steel by micro-electro-discharge machining (µEDM) (Takahata and Gianchandani 2002;Richardson and Gianchandani 2008). The contact springs are 5.2 mm in diameter with four quadrants separated by 300µm wide slots (Fig.…”

Section: Fabrication and Assemblymentioning

confidence: 99%

Transdermal power transfer for recharging implanted drug delivery devices via the refill port

Evans

Chiravuri²,

Gianchandani

2009

Biomed Microdevices

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This paper describes a system for transferring power across a transdermal needle into a smart refill port for recharging implantable drug delivery systems. The device uses a modified 26 gauge (0.46 mm outer diameter) Huber needle with multiple conductive elements designed to couple with mechanical springs in the septum of the refill port of a drug delivery device to form an electrical connection that can sustain the current required to recharge a battery during a reservoir refill session. The needle is fabricated from stainless steel coated with Parylene, and the refill port septum is made from micromachined stainless steel contact springs and polydimethylsiloxane. The device properties were characterized with dry and wet ambient conditions. The needle and port pair had an average contact resistance of less than 2 Omega when mated in either environment. Electrical isolation between the system, the liquid in the needle lumen, and surrounding material has been demonstrated. The device was used to recharge a NiMH battery with currents up to 500 mA with less than 15 degrees C of resistive heating. The system was punctured 100 times to provide preliminary information with regard to device longevity, and exhibited about 1 Omega variation in contact resistance. The results suggest that this needle and refill port system can be used in an implant to enable battery recharging. This allows for smaller batteries to be used and ultimately increases the volume efficiency of an implantable drug delivery device.

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Section: Fabrication and Assemblymentioning

confidence: 99%

Transdermal power transfer for recharging implanted drug delivery devices via the refill port

Evans

Chiravuri²,

Gianchandani

2009

Biomed Microdevices

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“…Debris are created naturally during the discharge process, but problems occur when it is not flushed out of the discharge gap efficiently. The presence of debris can lead to spurious discharges, causing the discharge gap to increase, tool dimensions to decrease, and machining precision to be reduced [11], [12]. In batch-mode μEDM, this is very problematic because the path for debris to escape can be quite tortuous and becomes worse as feature density is scaled up [2].…”

Section: B Sensing Debris-dominated Machiningmentioning

confidence: 99%

“…Fig. 5(a) shows a 25-μm-thick stainless-steel antenna stent pattern machined with an ∼30-μm electroplated copper support layer on the backside of the workpiece and a passivated sidewall coating on the tool [11]. A close-up in Fig.…”

Section: Metal-metal Interface Sensingmentioning

confidence: 99%

Wireless Monitoring of Workpiece Material Transitions and Debris Accumulation in Micro-Electro-Discharge Machining

Richardson

Gianchandani

2010

J. Microelectromech. Syst.

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Wireless signals are inherently generated with each discharge in micro-electro-discharge machining (μEDM), allowing direct observation of discharge quality. While traditional methods of monitoring machining quality rely on electrical characteristics at the discharge supply terminals, the wireless method provides more accurate information because it is less affected by electrical parasitics in the supply loop and by spatial averaging. The depth location of a metal-metal interface can be distinguished in the wireless signal. This is useful for determining the stop depth in certain processes. For example, in machining through samples of stainless steel into an electroplated copper backing layer, the metal transition is identified by a 10-dBm change in wireless-signal strength for the 300-350-MHz band and a 5-dBm average change across the full 1-GHz bandwidth. As debris accumulate in the discharge gaps, shifts in the wireless spectra can also indicate spurious discharges that could damage the workpiece and tool. For example, when copper micromachining becomes debris dominated, the 800-850-MHz band drops 4 dBm in signal strength, with a 2.2-dBm average drop across the full 1-GHz bandwidth.[ 2009-0109]Index Terms-Batch-mode micromachining, process monitoring, spurious discharges, stainless-steel machining, wireless feedback control.

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“…Furthermore, its integration to microsystems is easier and simpler. That is why there have been research efforts to micro-machine steel using a batch mode micro-electro-discharge machining, where lithography and EDM are combined [14]. Similarly, in this work we use a novel fabrication method benefiting from the conventional lithography and electrochemical metal etching.…”

Section: Fabricationmentioning

confidence: 99%

Design and fabrication of two-axis micromachined steel scanners

Gökdel¹,

Sarioğlu²,

Mutlu³

et al. 2009

J. Micromech. Microeng.

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This paper presents the fabrication and the test results of two-axis micromachined micro-mirror steel scanners developed for display and imaging applications. The novel fabrication method uses the conventional lithography and electrochemical metal etching techniques. A single photomask is used to define the whole structure, resulting in a simple and inexpensive fabrication process. Two different devices are designed, fabricated and characterized to test the proposed methods. Both of them employ the magnetostatic actuation to generate excitation force/torque. First device (Type-A) is a gimballed cantilever one, and it is capable of an optical scanning angle of 11.7• and 23.2• in slow-and fast-scan directions, consuming a power of 42 mW and 30.6 mW, respectively. This structure has a quality factor of 287 in the slow-scan direction and a quality factor of 195 in the fast-scan one. The second device (Type-B) is a gimballed torsional one, and it has an optical scanning angle of 76• and 5.9• in slow-and fast-scan directions, consuming 37 mW and 39 mW, respectively. This structure has a quality factor of 132 in the slow-scan and 530 in the fast-scan directions, respectively. The maximum total optical scanning angles obtained for the slow-and fast-scan axes are 105• (gimballed torsional device, Type-B) and 42• (gimballed cantilever device, Type-A).

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Achieving precision in high density batch mode micro-electro-discharge machining

Cited by 17 publications

References 32 publications

Transdermal power transfer for recharging implanted drug delivery devices via the refill port

Transdermal power transfer for recharging implanted drug delivery devices via the refill port

Wireless Monitoring of Workpiece Material Transitions and Debris Accumulation in Micro-Electro-Discharge Machining

Design and fabrication of two-axis micromachined steel scanners

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