Got GD&T? Exploring the Importance of Advanced Mechanical Inspection

Medical device manufacturers spend big dollars on research and development of new products. In many cases, the manufacturer relies on a series of vendors to produce the devices that are used in a variety of surgical procedures. One of the biggest challenges for a medical device maker, then, is to ensure that products are properly manufactured and meet very precise specifications. Thus, who does the medical device manufacturer trust to inspect the product before it is packaged, distributed and into the hands of a surgeon? In most cases, the manufacturer enlists a mechanical inspection team to complete a detailed and thorough evaluation of a product before a launch or as part of a continuous process of checks and balances.

Defining Advanced Mechanical Inspection

Mechanical inspection comprises tools, gauges and machines that enable professional inspectors to compare a product to an engineer’s print and verify that the product was manufactured to design dimensions and functional specifications. Mechanical inspection can be conducted by a cell operated within a medical device manufacturer, or by an outsourcing service provider. Advanced mechanical inspection involves highly skilled professionals and sophisticated equipment and tools.

The purpose of advanced mechanical inspection is to deliver objective evidence that a product meets the design and functionality standards required by the medical device manufacturer in order to best serve its customers. The inspection cell, whether internal or external, is the final check before a device is packaged and distributed. Moreover, the feedback that a mechanical inspection cell is in the position to provide can help the medical device manufacturer make important business decisions about suppliers and vendors. For example, if a medical device manufacturer receives objective data that indicates that one vendor’s ability to meet specifications is substandard, then the manufacturer can provide feedback to the vendor—or switch vendors.

There are several levels of inspection:

  • The first or entry level inspection is a review of incoming product that is handled by the receiving team. They are responsible for conducting inspection basics, such as evaluation of documentation, count verification of shipment, visual verification, gross shipping damage assessment, etching confirmation, etc.
  • The second or mid tier inspection is more complex, involving the use of hand tools such as calipers, gauges and basic comparators to complete simple measurements for fundamental dimensions.
  • The final or advanced inspection can involve complex inspection techniques and requires more sophisticated equipment and associated programming to perform a wide range of intricate measurements, such as diameter, pitch, positioning and internal dimensions. First article inspection, which necessitates a lengthy process to check every element of a design print as well as a highly detailed report, occurs at this level. The equipment used at this level includes coordinate measuring machines, optical comparators, vision systems and micro-hite measuring systems.

incoming inspection, the first step in the processAt left, incoming inspection, the first step in the process.

Experience, Experience, Experience

The best mechanical inspectors are usually the most experienced. Mechanical inspectors are expected to recognize over 100 combinations of symbols and understand the meaning of patterns created by the combinations in terms of dimensions and specifications. Geometric dimensioning and tolerancing (GD&T) skills are acquired over time, and usually cannot be learned quickly. A comprehensive training process is valuable, but experience is the most important characteristic of an expert in mechanical inspection. Another critical characteristic of a mechanical inspection expert is having an “eye for detail,” very loosely defined as the ability to identify and distinguish particular and sometimes minute features.

Top notch GD&T skills also help determine what tools are necessary for inspection. One example of advanced inspection in action involves a device that was inspected and approved by a vendor for a large medical device manufacturer. The outsourcing service provider, which served as a second check, inspected the product and determined that the vendor’s inspection was flawed because the device could not have been properly inspected using the tools that the vendor had employed in the first inspection. In this instance, the outsourcing service provider’s advanced mechanical inspection cell was able to evaluate the product and confirm with certainty that the device conformed to the manufacturer’s standards.

Some outsourcing service providers are using software to teach and test GD&T skills. One software program consists of 27 modules that instruct on a wide range of inspection capabilities, such as positioning, flatness, profile of surface, angularity, etc. This element of an overall training program can help test, enhance and build GD&T skills. In addition, the software program standardizes training so that inspectors use a similar approach and establish inspection consistency.

The best mechanical inspection cells are run by highly experienced inspectors with both GD&T and programming capabilities. Less experienced inspectors begin with basic projects that are checked by more knowledgeable inspectors. Gradually, inspectors move on to more complex projects as their level of competency increases. On the other hand, many mechanical inspection cells are organized differently and are staffed by inexperienced professionals, which can lead to lengthy turn times and increased risk to patients.

Companies that use internal or external mechanical inspection cells without the advantages of expert directors and programmers, skilled GD&T inspectors or state of the art equipment are in danger of missing critical pieces of information. In today’s world, many devices are similar. The difference between using rudimentary and sophisticated tools sometimes means misidentifying a product, overlooking a nonconformance issue or missing a larger functional problem. Using the best equipment and experienced inspectors confirms that products are properly manufactured, reduces cycle times and reduces risks associated with sending faulty devices out into the field.

Advantages of Outsourcing

Strategic outsourcing partners can offer a number of advantages over internal inspection cells. Internal inspection cells can sometimes be subject to an inherent conflict. If the goal is to produce an objective report on whether or not a device has been manufactured in accordance with the engineer’s specifications, validation by an external entity can help avoid such risk.

Outsourcing service providers are many times better positioned to manage small as well as large volumes of work. Outsourcing partners often have a deep bench of inspectors on hand who can handle the volume of inspection required by a product launch or a large medical device manufacturer. When a large project wraps up, the outsourcing companies are able to keep their inspectors active with projects for other customers. Internal inspection cells can suffer from too few inspectors when the volume is high and too many inspectors when the volume is low.

In fact, many internal inspection cells work against a perpetual backlog, which creates inefficiencies. At one large OEM, a work in process (WIP) within their internal inspection cell often resulted in a three month hold on inspection of a product. Sometimes the vendor would be paid even before the product was inspected, which could lead to a number of sticky issues. Meanwhile, at a top notch outsourced mechanical inspection cell, turn times can average two days as opposed to months. In addition to increased through-put and speed to market, this timing can allow a medical device manufacturer to more effectively manage vendor relationships.

Many outsourcing service providers often complete inspection as well or even better than the OEM. Outsourcing partners are motivated to continually invest in their inspection cells by purchasing state of the art equipment, hiring inspection experts and training their inspectors. The best outsourcing service providers serve as an extension of the medical device manufacturer. They use the device maker’s drawings and work closely with design engineers to ensure the accuracy of their prints and develop guide sheets that inspect a product’s critical features and the right tolerances needed for functionality.

Finally, outsourcing service providers employ best practices gained through industry knowledge and experience with a wide variety of products, projects and customers. By adopting the industry’s cutting-edge technology in terms of both equipment and programming capabilities, outsourcing service providers find faster ways to inspect product and can cut inspection time of a single product from hours to minutes. And, knowing what is happening in the industry with regard to inspection frequencies and critical feature determination can drastically decrease time and cost, as well.

What Success Looks Like

Ask an executive at a medical device maker what determines success, and he or she might say that full confidence in a product launch or distribution is the true measure of victory. At the same time, medical device makers cannot compromise speed or cost to achieve that high level of quality. Getting all three – quality, speed and cost-savings – might just be the hat trick of the medical device world.

There are two ways that an effective mechanical inspection cell can help medical device manufacturers reach that triumvirate. First, the ability to inspect anything is critical to streamlining inspection. A mechanical inspection cell that is adept at inspecting any product from the most basic to a new, complicated and intricate product helps speed along the inspection process without quality having to give way. The secret to being able to inspect everything is investment in equipment and in highly trained and experienced inspectors, and the opportunity to inspect a broad range of products. Second, providing timely feedback on a product and on vendors can enable manufacturers to effectively manage supply chains and, more importantly, avoid the risk that could accompany a design or manufacturing flaw.

While it might not seem terribly thrilling to the average person, an inspector’s day is full of challenge. The best mechanical inspection partners meet that challenge with experience in a broad range of products and inspection techniques, access to and the knowledge on use of sophisticated equipment, and the ability to turn product in days instead of months. It could be, exciting or not, that an advanced mechanical inspection partner is a medical device maker’s best friend.

Kelly Lucenti is President of Millstone Medical Outsourcing. Before becoming President, he was responsible for developing and directing Millstone’s quality systems as Vice President of Quality. Prior to joining Millstone, Lucenti was Director of Worldwide Operations for Flexcon Industries and served in a variety of capacities in the Orthopaedics and Codman divisions of Johnson & Johnson. He received a Bachelor of Science degree in Industrial Engineering and Operations Research from The University of Massachusetts at Amherst and a Doctorate of Law from Southern New England School of Law. Kelly Lucenti may be reached at This email address is being protected from spambots. You need JavaScript enabled to view it.. For more information about Millstone, please visit or call 508-679-8384.

Millstone Medical Outsourcing LLC

OMTEC 2011 Speaker

Continue learning from Mr. Lucenti during OMTEC 2011 by attending his lecture on Wednesday, June 15.

Lecture: Advance Mechanical Inspection: How to Make Inspection Better, Faster and More Cost-Effective

Session attendees will learn:

•The biggest inspection pitfalls and how to avoid them
•Innovative practices for enhancing mechanical inspection
•Requirements – from equipment to protocols to training – for Best in Class mechanical inspection

Session attendees will leave with:

•Checklist for evaluating existing mechanical inspection processes in-house or outsourced
•Ideas on how to reduce time required for mechanical inspection
•Information about qualifying an outsourcing partner
•Tips on gaining the most from an outsourcing relationship

A detailed abstract for this lecture is available online at