Failure Analysis of Medical Devices

2021 ◽  
pp. 736-753
Author(s):  
Matthew Bowers ◽  
Gabriel Ganot ◽  
Louis Malito ◽  
Babak Kondori ◽  
Anyanwu Ezechukwu ◽  
...  
Keyword(s):  
Medical Devices ◽  
Failure Modes ◽  
Patient Factors ◽  
Surgical Tools ◽  
Materials Engineering ◽  
Failure Investigation ◽  
Wear And Corrosion ◽  
Medical Device Failure ◽  
Cardiovascular Implants

Abstract Bearing in mind the three-legged stool approach of device design/manufacturing, patient factors, and surgical technique, this article aims to inform the failure analyst of the metallurgical and materials engineering aspects of a medical device failure investigation. It focuses on the device "failures" that include fracture, wear, and corrosion. The article first discusses failure modes of long-term orthopedic and cardiovascular implants. The article then focuses on short-term implants, typically bone screws and plates. Lastly, failure modes of surgical tools are discussed. The conclusion of this article presents several case studies illustrating the various failure modes discussed throughout.

scholarly journals Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 93 ◽  
Author(s):  
Riau ◽  
Aung ◽  
Setiawan ◽  
Yang ◽  
Yam ◽  
...  
Keyword(s):  
Medical Devices ◽  
Biofilm Formation ◽  
Culture Media ◽  
Silver Ions ◽  
Bacterial Biofilm ◽  
Surface Immobilization ◽  
Nano Silver ◽  
Gram Positive Bacteria ◽  
Tissue Microenvironment

: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates—high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.

scholarly journals Review of the Durability of Polymer Electrolyte Membrane Fuel Cell in Long-Term Operation: Main Influencing Parameters and Testing Protocols

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4048
Author(s):  
Huu Linh Nguyen ◽  
Jeasu Han ◽  
Xuan Linh Nguyen ◽  
Sangseok Yu ◽  
Young-Mo Goo ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Failure Modes ◽  
Polymer Electrolyte Membrane ◽  
Durability Test ◽  
Term Operation ◽  
Electrolyte Membrane ◽  
Transportation Applications ◽  
Testing Protocols

Durability is the most pressing issue preventing the efficient commercialization of polymer electrolyte membrane fuel cell (PEMFC) stationary and transportation applications. A big barrier to overcoming the durability limitations is gaining a better understanding of failure modes for user profiles. In addition, durability test protocols for determining the lifetime of PEMFCs are important factors in the development of the technology. These methods are designed to gather enough data about the cell/stack to understand its efficiency and durability without causing it to fail. They also provide some indication of the cell/stack’s age in terms of changes in performance over time. Based on a study of the literature, the fundamental factors influencing PEMFC long-term durability and the durability test protocols for both PEMFC stationary and transportation applications were discussed and outlined in depth in this review. This brief analysis should provide engineers and researchers with a fast overview as well as a useful toolbox for investigating PEMFC durability issues.

Safety Assessment of Long Term Serviced Pressure Vessels: A Case Study of Typical Refining and Chemical Plants in China

2021 ◽  
Author(s):  
Zhiyuan Han ◽  
Guoshan Xie ◽  
Haiyi Jiang ◽  
Xiaowei Li
Keyword(s):  
Pressure Vessel ◽  
Safety Assessment ◽  
Failure Modes ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Chemical Plants ◽  
Safety Specification ◽  
Detailed Assessment

Abstract The safety and risk of the long term serviced pressure vessels, especially which serviced more than 20 years, has become one of the most concerned issues in refining and chemical industry and government safety supervision in China. According to the Chinese pressure vessel safety specification TSG 21-2016 “Supervision Regulation on Safety Technology for Stationary Pressure Vessel”, if necessary, safety assessment should be performed for the pressure vessel which reaches the design service life or exceeds 20 years without a definite design life. However, the safety and risk conditions of most pressure vessels have little changes after long term serviced because their failure modes are time-independent. Thus the key problem is to identify the devices with the time-dependent failure modes and assess them based on the failure modes. This study provided a case study on 16 typical refining and chemical plants including 1870 pressure vessels serviced more than 20 years. The quantitative risk and damage mechanisms were calculated based on API 581, the time-dependent and time-independent failure modes were identified, and the typical pressure vessels were assessed based on API 579. Taking the high pressure hydrogenation plant as an example, this study gave the detailed assessment results and conclusions. The results and suggestions in this study are essential for the safety supervision and extending life of long term serviced pressure vessels in China.

Process Characterization and the Effect of Process Defects on Flip Chip Reliability

1999 ◽  
Author(s):  
Brian J. Lewis ◽  
Hilary Sasso
Keyword(s):  
Process Parameters ◽  
Flip Chip ◽  
Failure Modes ◽  
Shock Testing ◽  
Fine Pitch ◽  
Process Characterization ◽  
Solder Bumps ◽  
Optimum Height ◽  
High Yields

Abstract Processing fine pitch flip chip devices continues to pose problems for packaging and manufacturing engineers. Optimizing process parameters such that defects are limited and long-term reliability of the assembly is increased can be a very tedious task. Parameters that effect the robustness of the process include the flux type and placement parameters. Ultimately, these process parameters can effect the long-term reliability of the flip chip assembly by either inhibiting or inducing process defects. Therefore, care is taken to develop a process that is robust enough to supply high yields and long term reliability, but still remains compatible with a standard surface mount technology process. This is where process optimization becomes most critical and difficult. What is the optimum height of the flux thin film used for a dip process? What force is required to insure that the solder bumps make contact with the pads? What are the limiting boundaries in which high yields and high reliabilities are achieved, while maintaining a streamlined, proven process? The following study evaluates a set of process parameters and their impact on process defects and reliability. The study evaluates process parameters including, flux type, flux application parameters, placement force and placement accuracy to determine their impact. Solder voiding, inadequate solder wetting, and crack propagation and delamination in the underfill layer are defects examined in the study. Assemblies will be subjected to liquid-to-liquid thermal shock testing (−55° C to 125°C) to determine failure modes due to the aforementioned defects. The results will show how changes in process parameters effect yield and reliability.

Endotracheal and Enteric Tubes

Chest Imaging ◽  
2019 ◽  
pp. 35-39
Author(s):  
Tyler H. Ternes
Keyword(s):  
Mechanical Ventilation ◽  
Gas Exchange ◽  
Endotracheal Tube ◽  
Medical Devices ◽  
Esophageal Intubation ◽  
Ideal Position ◽  
Tracheostomy Tubes ◽  
Tube Malposition ◽  
The Ideal

The Endotracheal and Enteric Tubes chapter addresses these frequently used medical devices. An endotracheal tube (ETT) is a catheter placed into the airway for mechanical ventilation. It serves to protect the airway and provide adequate gas exchange. The ideal position of the endotracheal tube tip is approximately 5 cm above the carina. Complications of ETT placement include inadequate ventilation if placed too high or too low, esophageal intubation and tracheal injury. Tracheostomy tubes are used in patients who require long-term intubation. Enteric tubes are thin flexible hollow catheters that course into the stomach and beyond. They may be placed via nasal (nasogastic) or oral (orogastric) approach. When used for suctioning, the ideal position of the tube tip is within the stomach. When used for administration of drugs or nutrition, the tube tip is ideally advanced beyond the pylorus. Enteric tube malposition may be due to coiling within the esophagus or inadvertent malposition within the airway. Malpositioning could result in aspiration, lung injury, and pneumothorax.

Electromigration Performance of Flip-Chips with Lead-Free Solder Bumps between 30 μm and 60 μm Diameter

2012 ◽  
Vol 2012 (1) ◽  
pp. 000891-000905 ◽  
Author(s):  
Rainer Dohle ◽  
Stefan Härter ◽  
Andreas Wirth ◽  
Jörg Goßler ◽  
Marek Gorywoda ◽  
...  
Keyword(s):  
Flip Chip ◽  
Failure Modes ◽  
Solder Bump ◽  
Void Formation ◽  
Lead Free ◽  
Large Temperature ◽  
Flip Chips ◽  
Solder Bumps ◽  
Current Densities

As the solder bump sizes continuously decrease with scaling of the geometries, current densities within individual solder bumps will increase along with higher operation temperatures of the dies. Since electromigration of flip-chip interconnects is highly affected by these factors and therefore an increasing reliability concern, long-term characterization of new interconnect developments needs to be done regarding the electromigration performance using accelerated life tests. Furthermore, a large temperature gradient exists across the solder interconnects, leading to thermomigration. In this study, a comprehensive overlook of the long-term reliability and analysis of the achieved electromigration performance of flip-chip test specimen will be given, supplemented by an in-depth material science analysis. In addition, the challenges to a better understanding of electromigration and thermomigration in ultra fine-pitch flip-chip solder joints are discussed. For all experiments, specially designed flip-chips with a pitch of 100 μm and solder bump diameters of 30–60 μm have been used [1]. Solder spheres can be made of every lead-free alloy (in our case SAC305) and are placed on a UBM which has been realized for our test chips in an electroless nickel process [2]. For the electromigration tests within this study, multiple combinations of individual current densities and temperatures were adapted to the respective solder sphere diameters. Online measurements over a time period up to 10,000 hours with separate daisy chain connections of each test coupon provide exact lifetime data during the electromigration tests. As failure modes have been identified: UBM consumption at the chip side or depletion of the Nickel layer at the substrate side, interfacial void formation at the cathode contact interface, and - to a much lesser degree - Kirkendall-like void formation at the anode side. A comparison between calculated life time data using Weibull distribution and lognormal distribution will be given.

Metal injection moulding of surgical tools, biomaterials and medical devices: A review

2020 ◽  
Vol 364 ◽  
pp. 189-204 ◽  
Author(s):  
Ali Dehghan-Manshadi ◽  
Peng Yu ◽  
Matthew Dargusch ◽  
David StJohn ◽  
Ma Qian
Keyword(s):  
Medical Devices ◽  
Injection Moulding ◽  
Surgical Tools ◽  
Metal Injection Moulding

scholarly journals Failure Analysis of Biometals

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 662
Author(s):  
Reza Hashemi
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Failure Analysis ◽  
High Strength ◽  
Medical Implants ◽  
Load Bearing ◽  
Metallic Biomaterials ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance ◽  
Cardiovascular Implants

Metallic biomaterials (biometals) are widely used for the manufacture of medical implants, ranging from load-bearing orthopaedic prostheses to dental and cardiovascular implants, because of their favourable combination of properties including high strength, fracture toughness, biocompatibility, and wear and corrosion resistance [...]

Analytical Approach to Selecting and Designing a Miniature Downhole Refrigerator

1992 ◽  
Vol 114 (4) ◽  
pp. 339-344 ◽  
Author(s):  
G. A. Bennett
Keyword(s):  
High Temperature ◽  
Failure Modes ◽  
Thermal Protection ◽  
Selection Process ◽  
Systematic Analysis ◽  
Design Changes ◽  
Protection Technology ◽  
High Temperature Components ◽  
Final Selection

The design approach and results from a series of analyses used to select a miniature high-temperature multi-watt refrigerator for thermally protecting downhole instruments are described. Thirty-one systems from nine physical or chemical processes were investigated and compared against the design criteria and constraints. Preliminary thermodynamic analyses and the results of a search for high-temperature components and refrigerants eliminated all but three processes and seven systems. These seven systems were re-evaluated based on a set of proposed design changes that reflect natural evolution from a prototype to commercial system application. Final selection considered refrigerator interactions with the geothermal logging system to define failure modes, ensure compatibility, and allow adaptability to changing conditions. The selected refrigerator design permits reliable, long-term active cooling of downhole instruments in hot wells. The consistent design, systematic analysis and unbiased selection process represent a new body of research results that provide potential for substantial advances in downhole thermal protection technology.

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