Save Time & Money by Implementing GD&T in Your Medical Product Design

 In Engineering, Medical Product Design

No matter how precise the manufacturing process, there will inevitably be some degree of variation in the components that make up your medical product. All the parts that comprise the finished device will be minutely different from one another and from the spec. Even the most meticulous engineering drawings and detailed notes from the product design team can’t prevent these variations.

Medical devices feature complex curvilinear, ergonomic shapes that are more challenging to make than square parts. And yet the way engineers have traditionally made process drawings, defined dimensions and tolerances, and measured parts in manufacturing verification tests — called coordinate dimensioning — is better suited to simple shapes.

Building Tolerances into Medical Product Design

The engineering process allows for some variation, or tolerance, between manufactured parts. In coordinate dimensioning, defining those tolerances and measuring them in complex finished parts and products is difficult.

Medical device designers and engineers are beginning to borrow an advanced way of working from aerospace and other industries where, like the medical industry, safety is a top concern. Geometric dimensioning and tolerancing (GD&T) takes a 3D view of components rather than the traditional X-Y coordinate view. GD&T is a more accurate way of defining tolerances and allows more efficient manufacturing.

We won’t get too in the weeds here, but GD&T represents a completely different way of thinking and working for engineers. It focuses not on an imaginary axis of the part but its surfaces — because surfaces are what butt up against other parts. GD&T changes the perspective of how things go together. For a simple example, coordinate dimensioning & tolerancing typically locates centers of holes. But the center of a hole doesn’t touch or interfere with its mating part. It’s the surface of the hole that touches the mating part. GD&T doesn’t focus on where the hole center is; it’s concerned with the allowable range of the surface that makes up the hole.

With GD&T, engineers can dictate tighter tolerances between connected parts because the manufacturing process is more accurate. Parts are more likely to pass inspection and the finished product is of higher quality.

Why Medical Product Companies Should Implement GD&T

GD&T is relatively new in the medical product field, but it’s catching on. And there are good reasons why your organization should invest in the training needed to get your designers, engineers, and manufacturers up to speed on the methodology.

Cost Savings

At first glance, it may sound like tighter tolerances lead to higher manufacturing costs. But in fact, the opposite is true. Using GD&T more accurately translates the product design to the manufacturer because it’s focused on function rather than a plot of coordinates. It allows designers and engineers to to be very specific in what they demand of manufacturing, but at the same time allows freedom for the manufacturer to use their expertise to do things the best way.

The only higher cost is in training your design and engineering team; everything else is less expensive down the road.

Better Communication

Design engineers think that their schematics and accompanying notes make sense, but other people have difficulty deciphering their drawings. That leads to time-consuming back-and forth communication between manufacturing and design. If a part doesn’t pass manufacturing inspection for quality control, the project has to go back to design.

But the language of GD&T has specific meanings to everyone throughout the process. Design intent is baked into the tolerancing choices and the measuring methodology, so the designer’s instructions and expectations of how the finished part is supposed to look and perform are clear to the manufacturer. This is especially important if a designer leaves the project; there’s no second-guessing the drawings with GD&T.

Protection of IP

Your organization’s most valuable asset is its intellectual property. The accuracy of the GD&T methodology captures your innovation in a clear, concrete, and defensible way. It ensures that your foundational ideas are recorded precisely.

Improved Consistency

Whether you’re making one part or one medical device per second, GD&T provides complete, unambiguous, 3D definition of part geometry to maximize tolerance while still guaranteeing function. Designers and engineers can better define feature locations and profiles without tighter specifications.

Implementing GD&T in Your Company

Many manufacturers across industries already understand GD&T. And those that don’t are already fading away. Internationally, across cultural and language borders, GD&T eliminates the hand waving and sketching to clarify a component’s intent.

Implementing GD&T into your process will require training your design and engineering team. Depending on the size of your organization, that may require an up-front, one-time cost of $3,000 to $8,000. We recommend a combination of online and in-person training. You won’t need to invest in new tools or equipment — implementing GD&T is a matter of learning its concepts and vocabulary.

But there is a cost of not using GD&T. In the biotech industry, every part is critical. You need to ensure that what the designers and engineers create is actually manufacturable. GD&T is the highest quality standard for design drawings.

At MindFlow, our designers and engineers have become fluent in GD&T, and it’s now an essential part of our workflow. We find that it makes our work so much easier and more accurate. If you’re considering making the move, we’re happy to share what we’ve learned.


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