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International Journal of Science and Research (IJSR)
ISSN: 2319-7064
Impact Factor 2023: 1.843
Volume 13 Issue 12, December 2024
Fully Refereed | Open Access | Double Blind Peer Reviewed Journal
www.ijsr.net
The Role of Process Capability, Gage R&R, and
TMV in Enhancing Medical Device Development
Bhavin Patel
Independent Author, Master of Science (Mechanical Engineering) | MBA (Supply Chain), Midvale, UT, USA
Email: bhavinspatel1350[at]gmail.com
Abstract: Process capability, a statistical measure of a process's inherent ability to produce output within specified limits, offers
substantial benefits throughout the product lifecycle. This paper explores the critical role of process capability analysis in enhancing
medical device product development while ensuring robust Test Method Validation (TMV) and Gage R&R. Rigorous inspection methods
are essential for assessing both internally manufactured and externally sourced components within the medical device development
process. During product development, understanding process capability enables proactive identification of potential manufacturing
challenges, facilitating Design for Manufacturability (DFM) and promoting robust process design. This paper delves into the
implementation of Test Method Validation (TMV) within this context, examining the types of studies conducted and the effective analysis
of their outcomes. Leveraging process capability analysis leads to improved product quality, reduced manufacturing timelines and costs,
strengthened regulatory compliance, and ultimately, enhanced patient safety.
Keywords: Process capability analysis; Test method validation (TMV); Gage R&R studies, Medical Device product development; Medical
device manufacturing
1. Introduction
Process capability studies are critical for evaluating the
effectiveness of manufacturing processes in meeting specified
requirements [1]. In the context of test method validation,
these studies assess the inherent variability of the
measurement system itself. This is crucial because an
inaccurate or imprecise measurement system can lead to
erroneous conclusions about product quality and performance.
Gage Repeatability and Reproducibility (R&R) studies are a
specific type of process capability analysis designed to
quantify the variability associated with measurement systems
[2]. These studies evaluate the extent to which variations in
measurements are due to the measurement system itself
(repeatability and reproducibility) versus true variations in the
product being measured. By understanding the contribution of
measurement system variability, manufacturers can
implement corrective actions to enhance the accuracy and
precision of measurement processes. This includes identifying
and addressing sources of variability such as operator
technique, equipment calibration, and environmental factors.
Ultimately, implementing process capability studies and
conducting gage R&R analyses ensures that measurement
systems are fit for their intended use, leading to more reliable
and accurate product data, improved process control, and
ultimately, enhanced patient safety and product quality [1].
Test Method Validation (TMV) is a critical process in
ensuring the reliability and accuracy of testing procedure. It
involves a systematic evaluation of a specific inspection
method to demonstrate that it consistently produces valid and
reliable results [3]. This validation process aims to confirm
that the chosen test method is suitable for its intended purpose
and can accurately measure the characteristics of interest.
Section 7.3 in ISO 13485:2016 lays out requirements of the
medical device design and development [4]. The
organizations shall provide all documents of below stages of
product development process during audit,
1) Design and Development Planning
2) Design and development inputs
3) Design and development outputs
4) Design and development review
5) Design and development verification
6) Design and development validation
7) Design and development transfer
8) Control of design and development changes
9) Design and development files
TMV and Gage R&R play integral roles at various stages of
product development. They can be used in Design and
Development verification and validation stages, where
manufacturing, mechanical, and quality engineers develop
new inspection methods for the new parts. Test method
validation and Gage R&R studies are also used to revalidate
the inspection methods during production when any
discrepancies are observed or there are any changes to the part
[5]. TMV is crucial part of Production Part Approval Process
(PPAP) as well.
General Steps in Test Method Validation
• A team of engineers (Mechanical, Manufacturing, Quality,
and Metrology) reviews the drawing and identifies the
critical dimensions that need to be inspected. Based on
critical dimensions, the team develops an inspection
method where they define criteria for which steps the
inspector will follow while inspecting parts, tolerances,
tools, CMM codes (if inspection will be on an automated
machine), etc.
• After the creation of the inspection method, the team
develops a test method validation protocol using company
procedures and templates to validate the inspection
method. It is very important to use criteria defined in
company procedures regarding sample size and test runs.
The TMV protocol shall provide information on how many
samples will be used, the steps the inspector will follow to
execute the protocol, the data collection sheet, and how
many inspectors will perform the inspection and in which
order.
• The sample size selection is one of the crucial areas to
focus in this process. Sample size should be able to give
Paper ID: SR241216075527
DOI: https://dx.doi.org/10.21275/SR241216075527
1051
International Journal of Science and Research (IJSR)
ISSN: 2319-7064
Impact Factor 2023: 1.843
Volume 13 Issue 12, December 2024
Fully Refereed | Open Access | Double Blind Peer Reviewed Journal
www.ijsr.net
great level of confidence to trust the process. A small
sample size might pass the test initially but could fail in
long run. A very large sample size could increase time in
the process. Thus, sample size matters a lot.
• Organization shall develop criteria for sample size
selection based on their medical device class and criticality
of the individual parts. If particular part is a critical
componence of the assembly, TMV shall be performed
with more samples to get at least 95% of confidence. Team
can consider severity and probability matrix from Failure
Mode and Effect Analysis (FMEA) and other risk
management files.
A risk-based approach for determining statistical sample size
in design verification testing connects Confidence and
Reliability requirements to the Severity of harm associated
with potential product failure [6]. For attribute tests (pass/fail)
results, below formula can be used to calculate sample size
based on confidence and reliability,
N = ln (1 – C) ÷ ln (R)
Where: N = sample size
C = Confidence (%)
R = Reliability (%)
Below Table 1 provides sample size information for attribute
tests based on the question, and Table 2 provide more
information regarding severity ranking based on patient,
business and quality system impact for the reference [6]. Table
2 can be used to identify severity level to find confidence and
reliability levels associated with them in order to calculate
sample size.
Table 1: Confidence and Reliability Levels based on
Severity
Severity of
Harm Confidence
Level ® Reliability
level ® Sample
Size (N)
Catastrophic 95% 99% 299
Critical 95% 97% 99
Serious 95% 95% 59
Minor 95% 90% 29
Negligible
95% 80% 14
Table 2: Severity Levels based on Patient, Business, and Quality System Impact
Severity
Ranking Patient/User Business Quality System
S5:
Catastrophic Results in death N/A
A serious and/or widespread failure in a
process or
system that could likely result in a significant
action by a notified body or regulatory authority
following an audit/inspection.
S4: Critical Results in permanent
impairment or life-
threatening injury
N/A A failure in a process or system that would be
potentially cited by a notified body, regulatory
authority, or customer as a significant non-
compliance.
S3: Serious Results in injury or
impairment requiring
professional medical
intervention
High impact to business; (results in scrap,
rework, or downtime or customer
dissatisfaction). Impact to customer as a
result of the nonconformity.
An issue potentially having a significant impact on
Quality System or compliance to standards or
regulations.
S2: Minor Results in temporary injury
or impairment not requiring
professional medical
intervention
Moderate impact to business (results in
scrap, rework, or downtime). May impact
customer as a result of potential delays.
An issue having little impact on Quality System or
compliance to standards or regulations, yet if not
addressed could become a problem.
S1: Negligible Inconvenience or
temporary discomfort No or little impact to business (results in
no scrap, rework, or downtime). No impact
to Customer.
No impact on the Quality System or compliance to
standards or regulations. Possible Opportunity for
Improvement.
Gage Repeatability and Reproducibility (R&R)
Gage R&R studies provide confidence in measurement
system performance, it is important to collect data from more
than one inspector in random samples [7]. Gage R&R studies
are used to assess the variability within a measurement
system. This helps determine if the measurement system itself
is accurate and precise enough for its intended use [8].
Organization shall develop their own criteria to accept gage
R&R results.
Key components of measurement error:
• Repeatability: Variation within an operator using the same
equipment.
• Reproducibility: Variation between different operators
using the same equipment.
• Part-to-part variation: Actual differences between the parts
being measured.
Below acceptance criteria are widely used in companies,
Total Gage R&R contribution in the % tolerance is:
• <= 10%; The measurement system performance is
Acceptable
• Between 10% to 30%; performance is Acceptable to
Marginal. Improvements can be made.
• >=30%; the measurement system performance is
Unacceptable
2. Summary
Process capability studies are crucial for evaluating
manufacturing processes, while Gage R&R studies assess
measurement system variability. Inaccurate measurement
systems can lead to erroneous conclusions about product
quality. Test Method Validation (TMV) ensures the reliability
and accuracy of testing procedures. Process capability, TMV,
and Gage R&R are indispensable tools in medical device
development. They ensure accuracy in measurements,
reliability in testing methods, and adherence to regulatory
standards. By integrating these processes effectively,
Paper ID: SR241216075527
DOI: https://dx.doi.org/10.21275/SR241216075527
1052
International Journal of Science and Research (IJSR)
ISSN: 2319-7064
Impact Factor 2023: 1.843
Volume 13 Issue 12, December 2024
Fully Refereed | Open Access | Double Blind Peer Reviewed Journal
www.ijsr.net
organizations can achieve higher product quality, reduced
costs, and improved patient safety.
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[2] Celano, G. (2022). A bootstrap method for the
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[3] Jewsbury, P. (2018). Diagnostic test score validation
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[4] ISO 13485:2016. (2016). Medical devices: Quality
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[6] Ramirez, T. (2022, August 18). Applying a risk-based
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based-approach-to-qms-processes/
[7] W, Y., Liu, W. Y., Chen, X., Han, F., Zhu, J. F., & Dai,
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[8] Gage Repeatability & Reproducibility (Gage R&R).
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Author Profile
Bhavin Patel received the M.S. degree in Mechanical
Engineering from California State University, Los
Angeles (Cal State LA) and MBA degree in Supply
Chain from Westcliff University in 2017 and 2022,
respectively. He has managed responsibilities of a
Quality Engineer in BYD Coach and Bus, Becton Dickinson (BD)
for more than 6 years. Bhavin has helped these organizations to
maintain robust quality systems and meet ISO and FDA guidelines.
He is with Edwards Lifesciences working on product development of
medical devices now.
Paper ID: SR241216075527
DOI: https://dx.doi.org/10.21275/SR241216075527
1053