Clamp Design Research Articles

Optimization design and performance study of magnesium alloy vascular clamp

Purpose: This study investigates the effects of varying inner diameter of a vascular clamp made from an Mg–Nd–Zn–Zr alloy on its functional performance. The primary objectives are to optimize the clamp’s structure, assess its performance across different inner diameters, and ultimately determine the optimal configuration. Methods: We developed a V-shaped vascular clamp equipped with a locking mechanism and transverse teeth. The study involved comparing vascular clamps with various inner diameters (0.35 mm, 0.4 mm, 0.5 mm and 0.6 mm, denoted as R0.35, R0.4, R0.5 and R0.6, respectively), achieved by modifying the clamp design. Finite element analysis simulated the closure process of these clamps, both with and without blood vessels, to analyze stress and strain distribution. Subsequently, we manufactured a clamp with the optimized design and conducted performance evaluations, including a closing strength test and an in vitro immersion test. Results: Among the tested vascular clamps, the R0.5 clamp demonstrated the lowest strain (0.50798) and minimal stress on blood vessels (0.7629 MPa). Notably, the R0.5 clamp remained intact during clamping fracture experiments and demonstrated a maximum closing force of 334.98±15.4 mmHg. Regarding corrosion resistance, the clamped position showed a higher corrosion rate (0.179±0.00551 mg.cm-2.day-1) compared to the open clamp (0.161±0.00306 mg.cm-2.day-1). Conclusion: The R0.5 clamp demonstrated superior performance in finite element analysis, showing effective vascular closure, strong clamping force, and uniform corrosion behavior. Overall, these results highlight its potential as an effective tool for vascular closure.

Design and research of grounding current monitoring device for converter transformer core and clamp

The effective monitoring of the grounding current of the core and clamp of the converter transformer can prevent partial overheating, gassing of oil, and other abnormal conditions caused by the grounding fault of the core and clamp, ensuring the safety and stability of the power system. At present, the main detection and diagnosis method is to use the clamp current meter to detect the effective value of the grounding current. However, due to the larger capacity, higher voltage level, more complex structure and electromagnetic field distribution of the converter transformer, there is no clear standard and detection diagnosis method. Firstly, this paper analyzes the causes of grounding current and related calculations. And the design of the monitoring system for the grounding current of the converter transformer core and clamp design of the hardware system for the grounding current of the converter transformer is studied and the design process of the main circuit is given. Secondly, aiming at the problem of amplitude measurement deviation and non-integer frequency of harmonic generated by the grounding current of the core and clamp, a harmonic current detection and analysis scheme based on four Blackman-harris algorithms and the specific design process are proposed. Third, a diagnostic method based on probabilistic neural network is proposed, and a software platform is built to display and diagnose the grounding current state according to it. Finally, a prototype was manufactured and experimental study was carried out to verify the correctness of the proposed scheme.

A unique clamping mechanism for a cylindrical PEMFC for an enhanced performance

Polymer electrolyte membrane fuel cells with planar structures have been proven beneficial; however, cylindrical cells have higher gravimetric and volumetric power density with possible applications in aviation and portable power sources. In this study, a unique clamping mechanism for a cylindrically structured polymer electrolyte membrane fuel cell is developed to improve the performance of the cell through reduced contact resistance over the active area of the cell. The design is structurally modelled and simulated for the contact pressure distribution, followed by experimental validation of contact pressure distribution at the interface of the gas diffusion layer and current collector. The study results in a lower ohmic resistance due to the better electrical contact at the interface of gas diffusion layer and current collector using the new clamping system. The average contact pressure with the new system is observed to be 0.40 MPa, i.e. 33% higher than that of the strap clamping system. In addition, the contact resistance of the cell with new clamps is found to decrease by 18 %, thus resulting in 36 % better performance (55 mW/cm2 at 0.6 V) than that of the conventional clamping system (40 mW/cm2 at 0.6 V). Such enhancement is also attributed to more oxidant supply (12%) at the cathode current collectors due to better cell clamping design.

Virtual Planning and Patient-Specific Graft Design for Aortic Repairs.

Patients presenting with coarctation of the aorta (CoA) may also suffer from co-existing transverse arch hypoplasia (TAH). Depending on the risks associated with the surgery and the severity of TAH, clinicians may decide to repair only CoA, and monitor the TAH to see if it improves as the patient grows. While acutely successful, eventually hemodynamics may become suboptimal if TAH is left untreated. The objective of this work aims to develop a patient-specific surgical planning framework for predicting and assessing postoperative outcomes of simple CoA repair and comprehensive repair of CoA and TAH. The surgical planning framework consisted of virtual clamp placement, stenosis resection, and design and optimization of patient-specific aortic grafts that involved geometrical modeling of the graft and computational fluid dynamics (CFD) simulation for evaluating various surgical plans. Time-dependent CFD simulations were performed using Windkessel boundary conditions at the outlets that were obtained from patient-specific non-invasive pressure and flow data to predict hemodynamics before and after the virtual repairs. We applied the proposed framework to investigate optimal repairs for six patients (n = 6) diagnosed with both CoA and TAH. Design optimization was performed by creating a combination of a tubular graft and a waterslide patch to reconstruct the aortic arch. The surfaces of the designed graft were parameterized to optimize the shape. Peak systolic pressure drop (PSPD) and time-averaged wall shear stress (TAWSS) were used as performance metrics to evaluate surgical outcomes of various graft designs and implantation. The average PSPD improvements were 28% and 44% after the isolated CoA repair and comprehensive repair, respectively. Maximum values of TAWSS were decreased by 60% after CoA repair and further improved by 22% after the comprehensive repair. The oscillatory shear index was calculated and the values were confirmed to be in the normal range after the repairs. The results showed that the comprehensive repair outperforms the simple CoA repair and may be more advantageous in the long term in some patients. We demonstrated that the surgical planning and patient-specific flow simulations could potentially affect the selection and outcomes of aorta repairs.

SIMJig - Smart Independent Minimalist Jig

One of the most crucial parts of manufacturing is fixing the workpiece. Proper fixturing enables accurate machining, assembly, etching, etc. Most modern fixturing devices are static and difficult to adapt to varying workpieces. This letter introduces a new concept for a fixturing device–the SIMJig–that automatically adapts its structure to fix a given workpiece. Custom fitting the jig clamps to a workpiece can greatly improve the stability and accuracy of the manufacturing process. Reconfigurability is achieved by a unique clamp and gear design, as well as one of two optional external driving mechanisms. In total, the SIMJig only uses three actuators to control multiple clamps. The design of the SIMJig, as well as the two external drivers, are fully detailed. The method of operation is described, along with explanations of how the SIMJig is initialized. Two algorithms are presented that detail how the clamp configuration is derived from the workpiece model, and how the SIMJig derives the optimal reconfiguration scheme to achieve the clamp configuration. The SIMJig doubles as a turntable, which allows it to collaborate with robotic arms to vastly increase their workspace. This is illustrated for a notoriously difficult task of gasket insertion, using the SIMJig and two robotic arms.

Minimally invasive and robotic approaches to mitral valve surgery: Transthoracic aortic crossclamping is optimal

Minimally invasive and robotic approaches to mitral valve surgery: Transthoracic aortic crossclamping is optimal

Portable and Compact Tire-Clamping Mechanism for Medium Sized Tire

The purpose of this project is to improve the existing tire or wheel clamp design. The wheel clamp targets the comprehensive use in UTM to replace the heavy and inconvenient products. If this project is well received by its user, it may expand its use in many places in the future. This design is more lightweight and compact if compared to most existing product in market. The usage of three arms to lock the wheel or tire ensures its stability. CAD model of the design is developed using Solidworks software and the analysis is using Finite element analysis in Solidworks simulation. Stress, strain, displacement, and factor of safety analysis results from FEA analysis are studied and discussed with a focus on the critical location of the design. A full-size prototype cannot be done as during the execution of this project, Movement Control Order (MCO) by the government due to the spreading of the COVID-19 virus has taking place. A half scale model of the initial design is printed in 3D to check its functionality. Furtherimprovements of the design are showed through simulation and animation using Solidworks.

All-directional Electrostatic-discharge Protection Circuit with High Area-efficiency

This paper proposes a design for a wholechip all-directional electrostatic-discharge (ESD) protection circuit using a resistor-capacitor (RC) lateral insulated-gate bipolar transistor (LIGBT)-based 12 V power clamp and a silicon-controlled rectifier (SCR)-based 12 V input/output (I/O) clamp. The RC LIGBT-based power clamp detects pulses through an ESD detection circuit and applies a bias to the gate. Therefore, the proposed power clamp does not have snapback curve and has a low impedance during an ESD event. In addition, the structural characteristics of the proposed I/O clamp enable it to provide discharge paths for all four ESD discharge modes (PS, PD, NS, ND), and the clamp is more area efficient than conventional ESD protection circuits composed of gate-grounded n-type metal-oxide-silicon transistors or SCRs. Moreover, because floating regions are inserted in the I/O clamp and the clamp has a high holding voltage, the clamp design is resistant to latch-up, which is a critical drawback of snapback devices. Therefore, the proposed ESD protection circuit can effectively provide highly reliable protection to internal integrated circuits. The proposed circuit was fabricated using a 0.18 ㎛ bipolar-CMOS-DMOS process, and the electrical properties and ESD robustness of the circuit were verified through a transmission line pulse measurement method and human body model surge application tests.

Elimination of Non-stick on Leads Defect through Re-designed WCTP

This paper presents the reformation and fabrication resolved on the wire clamp and top plate (WCTP) design to eliminate the presence of lead finger bouncing resulting to high rejection of non-stick on leads (NSOL). Problem experienced was that the hollow or half-etched portion of the leadframe at the top and bottom units caused its bouncing effect. With the aim to improve localized massive NSOL defect, WCTP has been modified to provide positive bias to support its hollow part or the half-etched part of the leadframe at the top and bottom of the units. The re-designed WCTP was fabricated, extending its clamping with enhanced vacuum on top and bottom rows. The implementation of the improved WCTP design reduced the defect with 88 % improvement with the defect reduction during the lot runs.

Numerical investigation on the sensitivity of endplate design and gas diffusion material models in quantifying localized interface and bulk electrical resistance

A localized non-intuitive relationship between electrical interface contact resistance and bulk properties such as bulk electrical resistance and permeability in the fuel cell gas diffusion layer (GDL) is reported. A numerical method is adopted to investigate contact pressure and hence the interface contact resistance at the interfaces of bipolar plate (BPP)|GDL and GDL|Polymer electrolyte membrane (PEM). The results are observed to be sensitive to GDL material models as well as endplate designs. This means, endplates designed to improve the electrical contact resistance or contact pressure at the BPP|GDL interface may not necessarily assure an improvement in bulk properties, in fact, it is observed in this study that these properties are inversely related. Further, a differential deformation in GDL along with consolidation effect is predicted with compressible version of hyperelastic material model. More importantly, it is revealed that the selection of material models plays a significant role in the deformation behaviour of the GDLs irrespective of the clamping design adopted.

Use of modern research methods in the development of new clamp designs for restoring the operability of pressure fire hoses and assessment of their technical condition based on computer modeling

This article is devoted to the issues of restoring the performance of fi re pressure hoses in a fi re when punctures, cuts and fi stulas occur. Failure of fi re pressure hoses in a fi re occurs due to mechanical damage during the laying of main and working lines. In this case, an increase in the working pressure in the bag system leads to the loss of extinguishing agents and the appearance of fi stulas, longitudinal and transverse breaks. This article offers a technical solution aimed at developing a new clamp design to restore the performance of a fi re pressure hose with a diameter of 55 mm when it is damaged: a puncture or cut. For this purpose, a three-dimensional model of the clamp was developed and its strength analysis was performed using the Autodesk Inventor computer-aided design system. This device will allow you to restore the supply of fi re extinguishing agents in the shortest possible time if the pressure hoses are damaged in a fi re.

The use of optimization in new design of tribometer specimen clamping system

The article deals with the innovation of the clamping part of the tribometer, where the tested specimens are clamped. The new clamping system was designed in the CAD system CATIA V5. The advantages of the new clamping system are compared with the original clamping system of specimens on the tribometer type A30. The new clamping design is evaluated from technical, technological and marginally also from economical point of view. The new clamping design ensures easy handling and exchange of specimens. Easy handling is ensured by the conical collet, which is released by the fixation nut, and subsequently the specimen can be pulled out and replaced with a new one without disassembly the device. The content of the article is also the strength analysis of the conical clamping collet and subsequent optimization. In the strength analysis, the conical collet is pushed into the conical cavity of the tribometer rotor by an outer fixation nut. The result is a numerical simulation of the new designed clamping system which will consist of the rotor, the conical collet, fixation nut and the tested specimen. The von Misses stresses, deformations and reaction forces acting on the collet will be determined by the numerical analysis. Subsequent optimization consisting of defining the target function, boundary conditions and type of optimization will be found. The minimum necessary fixation force which will be obtained from the fixation nut to ensure the transmission of torque to the clamped specimen without slip.

Qualitative analysis of Amazon customer reviews of penile clamps for male urinary incontinence.

Penile clamps offer an alternative to manage male urinary incontinence in patients who are unfit for surgery. Patient experience with penile clamps is poorly understood. Our study elucidates patient opinions on commercially available penile clamps and the factors that associate with favorable and unfavorable opinions. We collected Amazon reviews of all penile clamps marketed for male urinary incontinence from November 2011 to January 2020 and qualitatively assessed the overall sentiment towards penile clamps, key praises and key complaints. Covariates such as designated Amazon star rating were further explored for association with coding patterns. Amazon reviews of penile clamps were found to be more positive (n = 425) in overall sentiment than negative (n = 294). The most frequent praise was effective incontinence control (n = 334) and the most frequent complaint was bad design or material (n = 166). The majority of reviews were for lower priced penile clamps, had higher Amazon star ratings, were written for Wiesner-produced clamps, and were written more recently (i.e., 2015-2020). Penile clamps with higher Amazon star ratings were more often coded positive and with a praise compared to lower rated penile clamps. Penile clamps are seen favorably by users as an effective treatment modality for male urinary incontinence. User reviews suggest opportunities for improvement in penile clamp design. The most frequently reviewed clamp seen positively is the Wiesner Incontinence Clamp Penile Clamp whereas the most frequently reviewed clamp seen negatively is the Pacey Cuff Male Incontinence Device.

Elimination of Smashed Ball Defect through Process and Design Improvement

This paper presents the modification and improvement done on the wire clamp and top plate (WCTP) design to eliminate the bouncing effect of the silicon die that leads to smashed ball reject during the formation of wire. The protrusion of the unit on the vacuum hole produced movement and slight vibration that affects the consistency of wirebonding. Through changing the standard vacuum hole to micro-holes provides underneath support to the unit and eliminates the overhanging or protrusion during the formation of wire. The implementation of the micro-hole design reduced the defect parts per million (dppm) occurrence to zero.

Low cost 3D printed clamps for external fixator for developing countries: a biomechanical study

BackgroundExternal fixation is a mainstream limb reconstruction technique, most often used after a traumatic injury. Due to the high rates of trauma in developing countries, external fixation devices are often utilized for immediate fracture stabilization and soft tissue repair. Proper external fixation treatment too often still fails to be adopted in these regions due to the high cost and trauma complexity. A novel, inexpensive, unilateral fixator was constructed using 3D printed clamps and other readily available supporting components. ASTM standard F1541 tests were used to assess the biomechanical properties of this novel external fixator.MethodsApplicable sections of ASTM standard F1541 were used to determine the biomechanical properties of the novel external fixator. 3D printed clamps modeled using SolidWorks and printed with chopped carbon fibers using a fuse deposition modeling (FDM) based 3D printer by Markforged (Boston, MA) were used. This study included 3 different testing configurations: axial compression, anterior-posterior (AP) bending, and medial-lateral (ML) bending. Using the novel unilateral fixator with 3D printed clamps previously sterilized by autoclave, an input load was applied at a rate of 20 N/s, starting at 0 N via a hydraulic MTS tester Model 359. Force and deformation data were collected at a sampling rate of 30 Hz. There was a load limit of 750 N, or until there was a maximum vertical deformation of 6 mm. Also, 4 key dimensions of the 3D printed clamps were measured pre and post autoclave: diameter, width, height and length.ResultsThe novel external fixator had axial compression, AP and ML bending rigidities of 246.12 N/mm (σ = 8.87 N/mm), 35.98 N/mm (σ = 2.11 N/mm) and 39.60 N/mm (σ =2.60 N/mm), respectively. The 3D printed clamps shrunk unproportionally due to the autoclaving process, with the diameter, width, height and length dimensions shrinking by 2.6%, 0.2%, 1.7% and 0.3%, respectively.ConclusionOverall, the biomechanical properties of the novel fixator with 3D printed clamps assessed in this study were comparable to external fixators that are currently being used in clinical settings. While the biomechanics were comparable, the low cost and readily available components of this design meets the need for low cost external fixators in developing countries that current clinical options could not satisfy. However, further verification and validation routines to determine efficacy and safety must be conducted before this novel fixator can be clinically deployed. Also, the material composition allowed for the clamps to maintain the appropriate shape with minimal dimensional shrinkage that can be accounted for in clamp design.

A standardized head-fixation system for performing large-scale, in vivo physiological recordings in mice

BackgroundThe Allen Institute recently built a set of high-throughput experimental pipelines to collect comprehensive in vivo surveys of physiological activity in the visual cortex of awake, head-fixed mice. Developing these large-scale, industrial-like pipelines posed many scientific, operational, and engineering challenges. New methodOur strategies for creating a cross-platform reference space to which all pipeline datasets were mapped required development of 1) a robust headframe, 2) a reproducible clamping system, and 3) data-collection systems that are built, and maintained, around precise alignment with a reference artifact. ResultsWhen paired with our pipeline clamping system, our headframe exceeded deflection and reproducibility requirements. By leveraging our headframe and clamping system we were able to create a cross-platform reference space to which multi-modal imaging datasets could be mapped. Comparison with existing methodsTogether, the Allen Brain Observatory headframe, surgical tooling, clamping system, and system registration strategy create a unique system for collecting large amounts of standardized in vivo datasets over long periods of time. Moreover, the integrated approach to cross-platform registration allows for multi-modal datasets to be collected within a shared reference space. ConclusionsHere we report the engineering strategies that we implemented when creating the Allen Brain Observatory physiology pipelines. All of the documentation related to headframe, surgical tooling, and clamp design has been made freely available and can be readily manufactured or procured. The engineering strategy, or components of the strategy, described in this report can be tailored and applied by external researchers to improve data standardization and stability.

Performance-Based Active Wafer Clamp Design for Wafer Heating Effects in EUV Lithography

To improve overlay and focus errors in lithographic applications, an active wafer clamp (AWC) concept is proposed. Using this concept, mechanical actuators deform the wafer to compensate thermally induced deformations. In [1] a localized feedforward (FF) control algorithm for the AWC concept was introduced. In this paper we aim to improve this algorithm and discuss practical implications for the design of an AWC concept, motivated by the optimal performance that can be achieved using the FF control scheme. This leads to a design, where the actuators are placed below the clamping electrode, and 3-degree-of-freedom (DOF) actuators can be reduced to 2-DOF actuators with negligible performance loss. Considering the fact that the AWC concept contains tens of thousands of actuators, this leads to a significant reduction. Finally, other methods are presented to further reduce the computational complexity to control the AWC.

Non-stick on Pad Defect Reduction through Clamp and Insert Design Augmentation

With new and continuous technology development and breakthroughs, few to several challenges in semiconductor assembly manufacturing are inevitable. One critical assembly process often affected with these technology trends and changes is the wirebond process. In due course, this paper focused on the elimination of non-stick on pad (NSOP) assembly defect at the wirebond process. Fishbone analysis and why-why analysis were done to comprehensively investigate the root-cause and eventually address the problem. High NSOP rejection rate was identified to be attributed to clamp and insert design, and was verified through series of analysis, design of experiment (DOE) and validation runs. Results revealed that by using the modified clamp and insert design with more holes would address NSOP rejection with around 90% defect reduction.

Research on three-stage amplified compliant mechanism-based piezo-driven microgripper

The microgripper based on the principle of lever amplification is easy to realize; however, the theoretical amplification factor is limited by the space size and the structure is not compact enough. The microgripper based on the triangular amplification principle has a compact structure and high amplification factor, but it is not conducive to miniaturization design. Considering compactness, parallel clamping, high magnification, and miniaturization design, a three-stage amplifier consisting of a semi-rhombic amplifier and lever amplifiers is designed. To begin with, the theoretical amplification ratio and the relationship between input variables and output variables are calculated by energy method. Furthermore, the finite element analysis software is used to optimize the structural parameters and analyze the performance of the model. Lastly, the experimental verification is carried out. At 150 V of driving voltage, the maximum output displacement was 530mm, and the actual magnification was 24 times. Microparts can be gripped in parallel and stably, which confirms the validity of the design.

Wirebond Process Improvement with Enhanced Stand-off Bias Wire Clamp and Top Plate

New design for a certain issue in semiconductor industry is another way to modify the standard configuration into specified limit or to make a possible solution of the problem. This paper presents a new modified design for wirebond top plate with a bias platform structure that will maintain a consistent second bond into a leadframe leads with half-etch configuration on quad-flat no-leads (QFN) packages especially in wirebond process. This paper used a side by side comparison to proof that the new design is better than the older design. With the new specialized wire clamp and top plate design, parts per million (PPM) level performances is improved by almost 90%.