Spring Contacts Research Articles

Divided-Time Data-Transmission System Uses a Microchip Storage Ball

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22368, “Study and Implementation of a Large Amount of Data From a Divided-Time Transmission System Using Microchip-Storage-Ball Release While Drilling,” by Sanguo Li, State Key Laboratory of Shale Oil and Gas Enrichment Mechanism and Effective Development and SINOPEC, and Ruixiang Gao and Jibo Li, SINOPEC, et al. The paper has not been peer reviewed. Copyright 2022 International Petroleum Technology Conference. Reproduced by permission. _ A key question posed in the field is how to transmit logging-while-drilling (LWD) data losslessly back to the surface effectively. Conventional LWD tools face challenges in transmitting all data to the surface efficiently. The complete paper proposes a method that uses the concept of a flash drive downloading and exchanging data among computers. Methodology Two conventional methods exist for data exchange between computers, one of which is network data transmission. The speed of network data transmission determines the efficiency of data exchange between computers. The other method is to use a flash disk to copy and transfer data between computers. Similarly, the downhole LWD tool and the surface data computer can be regarded as two computers. When the bandwidth of the real-time network between surface and underground is limited, the principle of a flash drive dumping and exchanging data between the computers can be used. First, LWD data are dumped into a microchip storage ball (MSB). The circuit sends a release command to the power device to release the MSB from the drill collar. The MSB is carried up to the ground by the drilling fluid and will be recovered on the ground. The data in the MSB then will be uploaded to a computer. The releasable time-divisional data-transmission system mainly consists of MSBs for storing LWD data, sealed chambers for storing the MSBs, a power device for releasing the MSBs, and a circuit for detecting the release signal and controlling the release operation. Large-Capacity MSBs An MSB essentially is a flash drive for storing LWD data. Because of the space constraints of downhole release tools and the limitations posed by the downhole drilling environment, an MSB must have characteristics such as large capacity, small size, high pressure resistance, high temperature resistance, low power consumption, high performance, and high-speed data-dumping capability. In the presented method, the control and power management module controls the data read/write (R/W) command and the power supply to the MSB so that it can read data from the LWD tools and save it using the RS485 communication mode. The network topology of the RS485 mode can send data to multiple MSBs simultaneously. The MSB uses an MSP430 chip to manage reading, writing, and erasing of data. The capacity of the memory chip determines the data capacity of the MSB. Currently, the data capacity of one MSB is 1 Mbit. The diameter of the MSB circuit board is 11 mm. The power supply cable and RS485 cable are connected to the circuit board. This type of wired power supply and data transmission eliminates the need for a battery and a wireless data-exchange module. The MSBs are installed in the sealed chambers of a downhole release tool. Four contacts are designed on an MSB to supply power and to connect the data-circuit system. The four contacts on the MSB are connected to the corresponding four spring contacts in the sealed chambers.

Characterization of Harmonic Generation by Spring Contacts in Mobile Devices

Spring contacts are used in mobile communication devices to connect metal planes near the antennas. Inappropriate design of the spring contacts will cause harmonic generation at the contact which can deteriorate receiver sensitivity at the harmonic frequency. In this article, the passive radio frequency (RF) harmonic generation phenomenon on spring contacts is studied. A spring contact harmonic generation measurement system is developed. The measurement system comprises of spring contact test vehicle, force sensor, xyz-stage with step motors, and RF path. The factors that may have an impact on the spring contact harmonic generation, such as contact material, contact force, and contact resistance are investigated. It is found that the overall harmonics generated at the spring contact decreased as the contact force increased. The gold-to-gold contact is found to be superior to the stainless-steel contacts. Indications are found that the nonlinearity at the stainless-steel spring contact is the combination of metal-insulator-metal junctions and p-n junctions formed by the surface oxide layer on the stainless steel. Recommendations to reduce the harmonic generation are discussed.

Displacement Correlations in Disordered Athermal Networks

We derive exact results for correlations in the displacement fields \(\{ \delta \mathbf {r} \} \equiv \{ \delta r_{\mu = x,y} \}\) in near-crystalline athermal systems in two dimensions. We analyze the displacement correlations produced by different types of microscopic disorder, and show that disorder at the microscopic scale gives rise to long-range correlations with a dependence on the system size L given by \(\langle \delta r_{\mu } \delta r_{\nu } \rangle \sim c_{\mu \nu }(r/L,\theta )\). In addition, we show that polydispersity in the constituent particle sizes and random bond disorder give rise to a logarithmic system size scaling, with \(c_{\mu \nu }(\rho ,\theta ) \sim \text {const}_{\mu \nu } - \text {a}_{\mu \nu }(\theta )\log \rho + \text {b}_{\mu \nu }(\theta ) \rho ^{2} \) for \(\rho ~(=r/L) \rightarrow 0\). This scaling is different for the case of displacement correlations produced by random external forces at each vertex of the network, given by \(c^{f}_{\mu \nu }(\rho ,\theta ) \sim \text {const}^{f}_{\mu \nu } -( \text {a}^{f}_{\mu \nu }(\theta ) + \text {b}^{f}_{\mu \nu }(\theta ) \log \rho ) \rho ^2 \). Additionally, we find that correlations produced by polydispersity and the correlations produced by disorder in bond stiffness differ in their symmetry properties. Finally, we also predict the displacement correlations for a model of polydispersed soft disks subject to external pinning forces, that involve two different types of microscopic disorder. We verify our theoretical predictions using numerical simulations of polydispersed soft disks with random spring contacts in two dimensions.

Stoneley waves with spring contact and evaluation of the quality of imperfect bonds

In this paper, the propagation of Stoneley waves along the interface between two orthotropic elastic half-spaces is investigated. The half-spaces are compressible or incompressible and they are in spring contact with each other. The main aim of the paper is to derive secular equations and formulas for the ratios of displacement components at the interface and to show that Stoneley waves are a good tool for evaluating the quality of imperfect bonds modeled as spring contacts. First, the secular equation and the formulas for the displacement-component ratios for the compressible case (two half-spaces are compressible) are derived. Then, those for the incompressible cases (one or both half-spaces are incompressible) are obtained by using the incompressible limit method. The obtained secular equations reveal that, while Stoneley waves are non-dispersive for the welded contact and the sliding contact, they are dispersive for the spring contact. Employing the obtained secular equations and formulas for the displacement-component ratios, two particular examples are carried out for determining the spring constants from the measured values of the displacement-component ratios and the wave velocity. It is shown that the ratios of displacement components at two sides of the interface are the best choice for evaluating the quality of imperfect bonds.

Understanding of the Static Contact Behaviors of Rod and Spring for Microelectromechanical Relay

The structure configuration of rod and spring contacts is widely used in the microelectromechanical relay. Low and stable electrical contact resistance is a fundamental requirement for reliability and electrical life of relays. In this paper, a theoretical model of rod and spring is presented to calculate the constriction resistance and compared with the classical Holm's models. Furthermore, the relationship between electrical contact resistance and contact force of rod and spring is investigated explicitly with our designed test rig. A power law for contact resistance versus contact force R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> = KF <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-m</sup> is established. A schematic model of contact pair with a rough surface is introduced to explain the variation of contact resistance during the loading process. In particular, the transition phenomena from the initial single contact asperity to the whole rectangular contact area are analyzed. Finally, the effects of surface roughness of the Au coating and operating cycles on the static contact behavior are also discussed.

Nonlinear load-deflection and stiffness characteristics of coned springs in four primary configurations

Even though coned disk springs have been used as preload or isolation elements in mechanical design for over a century, prior research has used several simplifying assumptions in determining their static load-deflection relationships and their stiffness properties have been largely ignored. Accordingly, the entire displacement range is considered in this article, from fully unloaded height to flat height under quasi-static loading conditions. Friction is accounted for at the face-to-face disk spring contacts and at the disk spring edge-to-surface contacts, but is ignored in edge-to-edge contacts. New experimental results for a single coned disk element, the primary parallel stack configuration, and two primary series stack configurations are presented. Measured load-deflection characteristics are analyzed in the context of newly defined nine distinct regimes that are motivated by the physics. Hysteresis curves are also examined and compared with a refined load-deflection relation with interfacial and edge friction coefficients. Finally, a continuously nonlinear stiffness expression is analytically derived, which matches well with measurements but only over a limited range of displacements.

Study on the Fast Tool Servo (FTS) with the Stiffness Adjustable

This paper introduced a kind of fast tool servo (FTS) that its stiffness is adjustable. Based on in the frame rack, flexible hinge, piezoelectric ceramic driver, tool base, diamond tools and so on, a spring assembly appendixes on. The spring assembly is consisting of spring rack, the sleeve, spring, and lock circle etc. Spring rack is fixed in front of the frame rack; there is a screw hole in the middle of the spring rack; there is also a screw outer side of the sleeve that mounted through the screw hole. The spring is installed inside sleeve; one end of the spring contacts with the bottom of the sleeve, and the other end contacts with the flexible hinge on frame rack. It can adjust the force of the spring that presses to the flexible hinge by rotating the sleeve. Through replaced the spring, it can makes stiffness of the FTS changed. It is verified that the device has the stiffness adjustable function through calculation and simulation.

Introduction of new industry standards for cardiac implantable electronic devices: balancing benefits and unexpected risks

The DF-4 connector is a novel industry standard for the connection of a defibrillator lead to the generator. It aims at reducing the bulk created by two or three pins at the proximal end of the defibrillator lead and its corresponding ports at the header of the device. Having only one connection port between the lead and the device reduces the material in the pocket, the risk of lead-to-port mismatch, may lower the risk of lead abrasion, and probably makes the implantation procedure a little easier since only one set screw is required. However, all these conceived benefits are related to convenience rather than to a medical need.After the recent experiences with the possible negative clinical impact of ‘minor’ changes like simply downsizing a defibrillator lead, a word of caution is warranted. The lead is the weakest part of the defibrillator system, complex in design and undergoing constant stress through movement. It is very hard to predict which issues may evolve over time with the changes in lead design. Does the perceived benefit really outweigh an unpredictable risk in a sensitive medical product like a defibrillator? This article tries to address the possible issues of the new spring contacts instead of set screws, the proximity of the low- and high-voltage connections as well as the inability of adding a pace/sense or an additional shock lead without a special adaptor, and advocates a measured speed in the introduction of this technology.

Investigation of a connector electrical failure

AbstractA PC product built by Celestica experienced a high rate of functional failure. Failure was associated with the CPU and CPU connector (known as a zero insertion force, ZIF type) since mechanically flexing the CPU stack induced failure. This problem became particularly serious when the customer adopted an uncontrolled (manual) “press” test, resulting in a large amount of rejected product which may have been functional under normal operating conditions.A failure analysis method involving static loading the CPU and epoxy potting the connector stack was developed to mechanically “trap” the fail condition. Sectioning and electrical probing was used to determine which of the 240 active connector pins have high resistance.Analysis of suspect connector pins and contact surfaces pointed to several possible causes of failure. SEM‐EDX revealed localized damage to the Au plating with exposed Ni and NiO. XPS and TOF‐SIMS with depth profiling confirmed the presence of a ∼100 nm layer of a fluorocarbon on the Au surface. Although it was not possible to clearly locate the individual electrical contact spots (1–10 µm diameter) to identify localized contamination, the presence of a probable insulating coating was sufficient evidence to follow‐up with the connector supplier. The connector spring contacts were found to be coated with an “anti‐flux” agent to prevent wicking of liquid solder onto contact surfaces during the wave solder assembly process. The corrective action was to change the ZIF connector to a type without anti‐flux coating and the failure rate was significantly reduced. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Wafer-Level Packaging With Soldered Stress-Engineered Micro-Springs

Micro-springs for integrated circuit test and packaging are demonstrated as soldered flip chip interconnects in a direct die to printed circuit board package. The spring interconnects are fabricated with thin film metallization as the last step in a wafer-scale process. The z-compliance of the interconnects can be used to test and/or burn-in parts in wafer form. After the parts are diced from the wafer, the springs then become the first-level (and often the last-level) interconnect between the chip and the board. The xy-compliance of the interconnect enables considerably large die to be soldered to an organic printed circuit board without underfill using a surface mount compatible process. To demonstrate this concept, daisy chain test vehicles were fabricated on die measuring 11.5 mm times 6.5 mm with 48 spring contacts on a 0.8 mm times 0.65 mm grid array, each spring measuring 400 mum times 100 mum. The parts were placed onto organic boards with screen printed solder paste using a pick and place machine. The parts were reflowed to complete the solder connection to each spring using eutectic and lead-free solder. Assembled parts have undergone >20 000 hot plate thermal cycles and >1000 oven thermal cycles without failure.

Thermal limitation of the mean power rating of coaxial transmission lines for ICRH

A limitation of the mean power rating of a coaxial transmission line arises from the coupling elements, which connect adjacent sections of the inner conductor by means of contact springs that are subjected to thermal degradation. This paper is focused on the design applied in a commercially available transmission-line coupling element. The main scope is to demonstrate the possibility to extend the working range of its spring contacts up to 200 °C. Presently this component is extensively used in several transmission lines of fusion experiments working with short pulses and operating with a maximum temperature of 150 °C at the inner conductor. Test components are successively exposed to a well controlled temperature of 200 °C over certain time periods and are characterized afterwards with regard to the resilient forces of the contact lamellae with an accurate experimental setup. The weakening of the spring force in dependence of the cumulative annealing time is studied and the remaining spring force is compared to the minimum required force to ensure proper electrical contact, which is also determined experimentally within this work.

Reliability of spring pressure contacts under environmental stress

Spring contacts are an excellent solution for connecting a power module with a printed circuit board (PCB). They can be applied in a wide current range from sensor currents of a few milliamps to load currents of several amps. They offer many advantages like easy assembly without soldering and also easy disassembly for maintenance purposes. The reliability of spring contacts under environmental stress by mechanical wear, rapid temperature change and corrosive atmosphere is significant for the application. The experimental results presented in this paper certify that spring contacts are reliable even under harsh environmental conditions.

P-67: Chip on Glass Bonding Using StressedMetal™ Technology

COG) interconnections require finer pitch to han- dle denser displays with more integrated driver chips, particularly for mobile devices. We report recent developments utilizing tiny micro-machined springs to replace ACF (anisotropic conductive film). Liquid, ultraviolet light-cured adhesives permit the attach- ment of chips to the glass without heating. We fabricated and tested daisy chain test vehicles with 800 spring contacts on 20 µm pitch.

Reliability of low current electrical spring contacts in power modules

Reliability of low current electrical spring contacts in power modules

Quantitative Examination of Reverse-Biased Semiconductor Devices using Off- Axis Electron Holography

The characterisation of device properties relies on quantitative determination of dopant distribution within the device structure. With the size of device features approaching the nanometre scale, the microelectronics industry requires characterisation techniques to image dopants with a spatial resolution of better than 10 nm. Electron holography satisfies this need, generating two-dimensional maps of electrostatic potential with sub 10 nm resolution using a field emission gun transmission electron microscope (FEGTEM) [1]. The technique uses an electrostatic biprism (typically a quartz wire coated with gold) to overlap an electron wave that has passed through an electron-transparent sample with a wave that has passed through vacuum. The interference pattern (or hologram) that forms in the overlap region contains information about the phase change of the electron wave caused by the sample. The electrostatic potential in the sample can be determined through examination of the reconstructed holographic phase image [2]. A systematic series of experiments have been conducted using a Philips CM300 FEGTEM, illustrating the application of electron holography to a Si p-n junction. The electrostatic potential distribution was examined as a function of applied reverse bias and membrane thickness. A single-tilt biasing holder (Fig. 1a) was used to examine cleaved wedge specimens, which have spring contacts made to their front and back faces. A membrane of uniform thickness was micro-machined in the cleaved samples using focused ion beam (FIB) milling (Fig. 1b).

Flexible, automatic test system for characterizing superconducting junctions and devices

A system has been designed for the characterizing of both low and high Tc junctions and devices. Fully automated measurements of resistance versus temperature, current versus voltage, and critical current versus applied field can be carried out on up to eight devices in one cooldown cycle. The system has been proven to reduce the repetitive nature and time involved in characterizing many junctions and devices, and greatly speeds up the analysis of changes in their parameters. Connections are made to the sample using spring contacts which eliminate the need for soldering to contact pads. One or two substrates with ten connections per substrate can be placed in the probe at the one time. A microcomputer with an IEEE488 interface, four standard instruments (two constant current sources, one digital multimeter, and one voltmeter), and a specially designed probe and software has been incorporated to provide a system which is very flexible and yet very simple to operate.

High density pin board matrix switches for automated MDF systems

High-density, low-cost pin board matrix switches for automated main distributing frame (MDF) systems are described. The MDF system has two basic functions, cross connection and route setting for line test functions. These two functions can be performed automatically using a robot hand to insert a connecting pin into a crosspoint hole on the matrix board. Each crosspoint hole has four isolated cylindrical contacts that are connected to X/sub A/, Y/sub A/, X/sub B/, and Y/sub B/ conductive patterns, which represent the A and B wires of a telephone set circuit. Corresponding to the four contacts of a crosspoint hole, a connecting pin has two spring contacts, one spring contact to connect X/sub A/ and Y/sub A/ conductive patterns, and the other for connecting X/sub B/ and Y/sub B/ conductive patterns. In addition, arrangements have been made to perform the route setting for line testing. A matrix board with crosspoint holes on a 1.5-mm grid has been attained using the low-contact-force design and minimum insulation spacing between the neighboring conductive patterns. The design also considers requirements for the robot hand interface. These pin board matrix switches allow the MDF system to be automated. >

Electrical performance of high density probe array for testing Josephson circuit chips

An assembly has been constructed and successfully evaluated for contacting 228-pad Josephson test chips. Miniature spring contacts mate with the 228, 100 μm diameter pads arranged on 200 μm centers in a double row about the edge of a 6.35 mm chip. Measurements have been made at 4.2K of contact reliability, resistance, self and mutual inductances, and current capacity. Experimental values of electrical characteristics compare well with computer simulations. This probe array is being incorporated into a non-magnetic cryoinsert for Josephson chip testing. The design uses materials such as pyrex, molybdenum, silicon, machineable ceramic, and aluminum to be consistent with a microgauss ambient magnetic field.

Initial Performance of the NAL 200-MeV Linear Accelerator

The first three months of operation of the NAL linac after first achieving a 200-MeV beam have been encouraging. The design performance has been achieved at beam intensities of about 20 mA both in the transverse emittance and the momentum spread. Attempts have not been made to go to intensities of 100 mA or greater as yet, and it will be interesting to see how the beam quality is affected by intensity. It is expected that when the linac rf phase and amplitude controls are properly working, the beam quality will be less than the design values. In particular, the momentum spread at the present operating currents is sufficiently small so that a debunching cavity currently is not envisioned. The beam measurements made so far confirm the theoretical results obtained with the PARMILA dynamics program. The particle distributions used in the program are those measured at the entrance to the linac. The large number of components in the systems have lead to concern over the reliability of the linac. The performance over the last three months has dispelled some of this concern. As running periods have increased the failure rate has decreased. Only two major problems stand out at this time. The first is the failure of the spring contacts on the filament leads to the power amplifier tubes. Installation care and the elimination of two of the contact rings which were not water-cooled seem to be providing at least a temporary solution.

Electrical contacts on organic single crystals

A technique is described for providing an organic crystal with evaporated metal electrodes, which may include a guard ring. The technique can be used even when the crystal is quite small or volatile. The crystal is then mounted, together with spring contacts, on to a standard B7G valve base to form a robust unit. Subsequent electrical measurements on the crystal are greatly facilitated by this method of mounting.