MBD (Model-Based Definition): Why It Matters
What is MBD (model-based definition)? And why is it important in today’s design, quality, and manufacturing disciplines?
MBD is the practice of having the ONE reference source: a 3D CAD model with semantic PMI (product and manufacturing information) or annotations be the definitive authority model.
From design to manufacturing and beyond, all product definition and its geometry is contained in one place– aka the “single source of truth.”
The 3D model with PMI would include all of the following data:
- GD&T (geometric dimensioning and tolerancing)
- Bill of materials (BOM)
- Surface finish
- Weld symbols
- Manufacturing or measurement process plan data
- Metadata & notes
- History of engineering change orders
- Legal/proprietary/export control notices
- And other definitive digital data
So why is MBD important especially when moving downstream from design to manufacturing?
Although we’re near reaching the first quarter of the 21st century, there is a disconnect between design and manufacturing processes. Designers develop in 3D CAD using tools like NX, CATIA, Creo, Solidworks, and others, however, their product and process information is then projected down into 2D drawings, which is not machine readable.
Thus it takes the manufacturing or quality control engineer to MANUALLY enter the GD&T and other vital details into their CMM (coordinate-measuring machine) or CAM (computer aided manufacturing) software.
This one bottleneck increases cost, time, and risk to the manufacturing process, especially as the complexity of the 3D model increases and number of disconnected documents pile up.
Benefits of MBD in Quality Control & Manufacturing
The biggest elephant in the room is the number of man hours wasted by design and manufacturing engineers.
Designers spend up to 33% of their time on creating and modifying 2D designs.
Programming a CMM can easily take up to 20 hours depending on the complexity of the part.
Manufacturing engineers usually sit side by side with the 2D drawing(s) on a second screen or even printed sheets of paper. They oscillate back and forth between the 2D drawing and CMM/CAM to read tolerance and surface finishes, and validate all information while manually entering in the requirements into their software.
The drawing-centric approach is an unnecessary complexity, introducing potential human reading and typing errors, wastes time on engineering documentation, increases hours for validation and manufacturing, and adds burden to the process.
Engineers freed from this manual task could focus on other important, value-add work.
An MBD workflow (or model-centric approach) using a 3D model with PMI is machine-readable and has all necessary manufacturing information embedded in the 3D model.
This leads to automation, resolves human error, provides cost-savings and speeds up the entire manufacturing process & iteration.
It’s simple math considering the benefits of MBD.
Multiply the hours saved per manufactured part X the number of parts produced X the number of plants = well you get the idea… it’s an the incredible number of cost-savings in time.
A recent study showed a time reduction up to 81% for CMM automation through MBD. Capvidia and its MBD partners generally have CMM automation at less than 3 hours.
MBD ensures the design intent and final product align throughout its product development cycle: one authority source, one single truth that everyone can depend on.
Need to Learn More About MBD Tools, Training, and Processes?
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Top 12 Reasons You Should Go MBD
- Man hours saved: up to 60% total process hours saved compared to drawing-centric approach.
- Frees up engineering time for improving design and products.
- Next generation of engineers see and design in 3D.
- Reduces human error through typing or interpretation
- Machine-readable 3D CAD & PMI for automation.
- Removes the “middle man” or engineering drawings.
- More feature-rich data for better instructions for the end user.
- More iteration and process breakthrough improvement.
- Higher quality inspections with measurement optimization algorithms
- Better products, better pricing, better margins.
- Shorter product development cycles, faster time to market.
- Staying competitive, first-mover advantage.
Why MBD Isn’t Being Adopted Faster?
One word: Repeatability.
Traditional practices, processes, and tools are about stability & repeatability. In the manufacturing world, it's crucial to maintain what works.
However, the complexity of today's dynamic business environment means change is inevitable and getting into MBD is about staying relevant in a world of change.
Change is hard and resistance to it is natural. The avoidance of risk, however, also coincides with the rewards of innovation. Innovation is RISK.
Tell that to once great market leaders who avoided risk rather than innovate:
- Kodak (Canon, Nikon)
- Blockbuster (Netflix)
- Nokia & Blackberry (Apple, Samsung)
- Yahoo (Google, Facebook)
- Xerox (Microsoft, Apple)
Top 9 Pitfalls of 2D Drawings
- Not machine-readable
- 3D visualization is mainstream, mobile, and affordable.
- Wasted effort to recreate 2D from 3D.
- Less information available — the product will exist in 3 dimensions, why reduce its definition to 2?
- More prone to interpretation and data inaccuracies.
- Aren’t adequate to convey design innovation.
- More back and forth and time wasted on clarifying designs.
- Not suitable for cross-department collaboration.
- Simple change in production definition requires changes to all 2D documentation.
The it’s-always-been-done-this-way mentality of using the 2D drawings with dimensions plus 3D models is a relic of last century practices when the only choice was flattening 3D models into 2D representations on paper.
However, engineers now design in 3D. They and all downstream users don’t need 2D drawings anymore since product data can be directly embedded in the 3D model.
Removing the 2D data from the workflow directly addresses quality assurance issues such as interpretation, duplication, ambiguity, and revision errors.
Other challenges to MBD include a lack of maturity of tools, data translation and validation issues, unknown risk with new technology, misconceptions of MBD, management buy-in, ROI justification, and retraining & rethinking of the business process.
How to Introduce MBD to Company Culture
All downstream organizations: quality, inspection, manufacturing, assembly, procurement, service, suppliers, and others benefit using MBD since it cuts through the complexity of today’s system to reduce time, cost, and risk.
But how does one start the process of MBD?
It can be overwhelming; however, starting with the engineers is a good starting point since the benefits are more immediate and obvious:
- Define the stakeholders: who uses 2D drawings and how are those drawings used within the company.
- Document current practices, data exchange, and technologies.
- Identify a pilot project to test MBD.
- Track progress during downstream handoff.
- Measure ROI with MBD.
- Continuously expand into other MBD projects in slow and sure manner while building up the education level of MBD users.
Other Important Things to Know About MBD
- MBD-ready File Formats: QIF (Quality Information Framework), STEP AP242
- ASME Y14.5 and ISO GPS (Geometrical Product Specifications): These standards govern the use of geometric dimensioning and tolerancing — GD&T. Having a solid understanding of the principles of GD&T will help to ensure that your MBD-based processes are well-defined, efficient, and stable.
- ASME Y14.41: This standard provides guidelines for how to go about creating your digital product definition in 3D.
- Machine Readable vs. Human Readable: Some formats (like 3D PDF) are meant to be used by human engineers to examine the 3D data. Other formats (like QIF and STEP AP242) are machine-readable formats, which can be opened and examined by human engineers, but also can be unambiguously imported by software tools. Make sure that you understand what your data will be used for before you start publishing MBD data.
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