Philip Allen, VP Sales and Marketing, Lowell Inc.05.20.20
Communicating clear design intent is an important indicator for success in medical device development. All too often, design intent is not communicated between medical device companies and contract manufacturers. The internal knowledge of how a device should work, and why, is key to starting production.
By investing time into developing a design intent strategy, companies can ensure this information isn’t left out of production conversations, and drive improved results that lead to better patient outcomes.
The Basics
A design intent strategy formalizes your approach to communicating how a product should work and why, and the methods used to communicate this information. Design intent is a blend of engineering and design knowledge, coupled with a clear approach to dimensioning drawings.
While the details should be specific to each company, there are three universal pillars important to a successful strategy:
Design intent discussions are best at the very beginning of a project, before any manufacturing work begins. Pre-production meetings (PPMs) are an ideal time for them to take place. During a PPM, key stakeholders from the manufacturer and customer discuss all aspects of manufacturing and inspecting a device.
From a design intent point of view, this meeting is a valuable opportunity to better understand the engineering and purpose of a product, and how it will be used in the operating room. The supplier can make recommendations on how to produce the device efficiently for manufacturing and inspection. Then, the customer’s engineering team can review the recommendations and discuss the design intent of the product and intended function. Within the same meeting, the customer can provide immediate feedback regarding a recommendation.
Providing or creating a physical sample to use during the meeting can also help to move discussions forward, especially for elements of a device that may be subjective or visual. This is especially true for features such as anodization, laser marking, and surface finish match.
Pillar 2: Define What’s Critical to Success with GD&T
Since the goal of design intent is to drive better product results and functionality, creating a drawing that clearly communicates device tolerances, dimensions, and conformance criteria is essential. Historically, there was a more-is-better approach to dimensioning a drawing. This led to drawings becoming cluttered with multiple datums and tolerance schemes. The lack of clarity created problems and delays throughout design, manufacturing, and inspection. It was difficult to determine which measurements actually affected function unless the customer specifically discussed the product’s design intent with the manufacturer.
Figure 1 was created as an example of potential issues raised by overly dimensioned drawings. As the number of measured points increases, so does the likelihood of introducing error and confusion. The design intent is lost.
GD&T is one way to simplify drawings and ensure design intent is clear to everyone involved in product development. It brings focus and clarity to designs, and conveys the design intent of the engineer. GD&T can transform Figure 1 into the much simpler drawing and 3D solid model in Figure 2.
Pillar 3: Clarify Design Intent with 3D Solid Models
When paired with GD&T, 3D solid models provide a clear understanding of the conformance criteria of the part. CAD/CAM software is used to design the mathematically nominal part and depict it in the 3D solid model. Perfect models always represent the mid geometry of the defined tolerance zone. The model contains nominal geometry of the mathematically perfect part. Querying digital elements provide the dimensions, relationships, and attributes necessary to manufacture and inspect the part. The model is only one component of the model based definition, used in parallel with the drawing graphic sheet and external documentation.
The 3D solid model becomes the baseline for the drawing in Figure 2. It starts by focusing on the information that relays the engineer’s design intent. In the drawing, only GD&T reference frames, datums, and engineering specifications are shown. Figure 2 clearly conveys how the gage ball should be toleranced, defined, measured, and analyzed. When executed correctly, GD&T results in a more robust drawing with more clearly defined information and less clutter than the traditional ± drawing. The 3D solid model used in tandem with 3D-model-based drawings eliminates many questions and ensures clarity at every step in the manufacturing process.
Clarity at this stage is critical for successful manufacturing because the models are used for computer-aided manufacturing and inspection, including machining programs and advanced CMM inspection protocols. Only one 3D solid model is used to generate design, manufacturing, and inspection data, ensuring harmonization between all disciplines. All this information is stored within the design history file for a clean record of all lifecycle activity, and can easily be shared with manufacturers.
Clear Design Intent Builds Relationships
There are many benefits for companies that adopt a design intent strategy supported by GD&T and 3D-model-based drawings. One of the greatest advantages is an engineer’s design intent survives changes in personnel, manufacturing, and inspection equipment.
It also builds relationships between device companies and manufacturers. When design intent is clear and understood, it can provide a path to a smooth product development process that meets time-to-market timelines. Simple, straightforward drawings that include conformance criteria are easier to interpret, manufacture, and inspect, which can reduce production delays.
Design intent should be a part of every project to ensure a clear understanding of what’s needed for a device’s success.
Philip Allen is vice president of sales and marketing for Lowell Inc., a Minneapolis, Minn.-based contract manufacturer of complex implants and instruments for the orthopedic and cardiovascular markets, focused on realizing its customers’ design intent.
By investing time into developing a design intent strategy, companies can ensure this information isn’t left out of production conversations, and drive improved results that lead to better patient outcomes.
The Basics
A design intent strategy formalizes your approach to communicating how a product should work and why, and the methods used to communicate this information. Design intent is a blend of engineering and design knowledge, coupled with a clear approach to dimensioning drawings.
While the details should be specific to each company, there are three universal pillars important to a successful strategy:
- Having the right discussions at the right time
- Ensuring drawings communicate only what is critical to the device’s function, measurement, and inspection, through geometric dimensioning and tolerancing (GD&T)
- Simplifying drawings by pairing GD&T with 3D solid models
Design intent discussions are best at the very beginning of a project, before any manufacturing work begins. Pre-production meetings (PPMs) are an ideal time for them to take place. During a PPM, key stakeholders from the manufacturer and customer discuss all aspects of manufacturing and inspecting a device.
From a design intent point of view, this meeting is a valuable opportunity to better understand the engineering and purpose of a product, and how it will be used in the operating room. The supplier can make recommendations on how to produce the device efficiently for manufacturing and inspection. Then, the customer’s engineering team can review the recommendations and discuss the design intent of the product and intended function. Within the same meeting, the customer can provide immediate feedback regarding a recommendation.
Providing or creating a physical sample to use during the meeting can also help to move discussions forward, especially for elements of a device that may be subjective or visual. This is especially true for features such as anodization, laser marking, and surface finish match.
Pillar 2: Define What’s Critical to Success with GD&T
Since the goal of design intent is to drive better product results and functionality, creating a drawing that clearly communicates device tolerances, dimensions, and conformance criteria is essential. Historically, there was a more-is-better approach to dimensioning a drawing. This led to drawings becoming cluttered with multiple datums and tolerance schemes. The lack of clarity created problems and delays throughout design, manufacturing, and inspection. It was difficult to determine which measurements actually affected function unless the customer specifically discussed the product’s design intent with the manufacturer.
Figure 1 was created as an example of potential issues raised by overly dimensioned drawings. As the number of measured points increases, so does the likelihood of introducing error and confusion. The design intent is lost.
GD&T is one way to simplify drawings and ensure design intent is clear to everyone involved in product development. It brings focus and clarity to designs, and conveys the design intent of the engineer. GD&T can transform Figure 1 into the much simpler drawing and 3D solid model in Figure 2.
Pillar 3: Clarify Design Intent with 3D Solid Models
When paired with GD&T, 3D solid models provide a clear understanding of the conformance criteria of the part. CAD/CAM software is used to design the mathematically nominal part and depict it in the 3D solid model. Perfect models always represent the mid geometry of the defined tolerance zone. The model contains nominal geometry of the mathematically perfect part. Querying digital elements provide the dimensions, relationships, and attributes necessary to manufacture and inspect the part. The model is only one component of the model based definition, used in parallel with the drawing graphic sheet and external documentation.
The 3D solid model becomes the baseline for the drawing in Figure 2. It starts by focusing on the information that relays the engineer’s design intent. In the drawing, only GD&T reference frames, datums, and engineering specifications are shown. Figure 2 clearly conveys how the gage ball should be toleranced, defined, measured, and analyzed. When executed correctly, GD&T results in a more robust drawing with more clearly defined information and less clutter than the traditional ± drawing. The 3D solid model used in tandem with 3D-model-based drawings eliminates many questions and ensures clarity at every step in the manufacturing process.
Clarity at this stage is critical for successful manufacturing because the models are used for computer-aided manufacturing and inspection, including machining programs and advanced CMM inspection protocols. Only one 3D solid model is used to generate design, manufacturing, and inspection data, ensuring harmonization between all disciplines. All this information is stored within the design history file for a clean record of all lifecycle activity, and can easily be shared with manufacturers.
Clear Design Intent Builds Relationships
There are many benefits for companies that adopt a design intent strategy supported by GD&T and 3D-model-based drawings. One of the greatest advantages is an engineer’s design intent survives changes in personnel, manufacturing, and inspection equipment.
It also builds relationships between device companies and manufacturers. When design intent is clear and understood, it can provide a path to a smooth product development process that meets time-to-market timelines. Simple, straightforward drawings that include conformance criteria are easier to interpret, manufacture, and inspect, which can reduce production delays.
Design intent should be a part of every project to ensure a clear understanding of what’s needed for a device’s success.
The commitment to communicating design intent is a true partnership between a medical device company and its contract manufacturer. Following are several considerations that may arise during pre-production meetings to help your contract manufacturing partner realize your design intent.
Only by partnering with a manufacturer that understands, invests in, and commits to clear communication of design intent can you experience its full benefits—designers and suppliers speaking in a common language that leads to better results. |
Philip Allen is vice president of sales and marketing for Lowell Inc., a Minneapolis, Minn.-based contract manufacturer of complex implants and instruments for the orthopedic and cardiovascular markets, focused on realizing its customers’ design intent.