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surface profile

Why is surface profile used more now than it used to be in metrology?

Written by:

Emily Smith

The growing use of surface profile measurement has emerged as a defining characteristic in metrology. This blog explores the importance of surface shape and form in manufacturing and uncovers why surface profile is used now more than ever before.

  • Traditional Metrology Methods and their Limitations

Historically, traditional metrology methods relied on hand tools and first principles, making it challenging to measure free-form shapes and coming with a number of limitations. With the advent of 3D CAD systems in the 70s and 80s, engineers could design more complex shapes. 

However, a critical question emerged: How do we measure these shapes accurately?

The Rise of Surface Profile Measurement

The answer came in the form of surface profile measurement, introduced in 1966. This shift towards more advanced measurement techniques marked the beginning of a new era in metrology.

Now, surface profile measurement has become increasingly popular due to its compatibility with CAD/CAM and 3D scanning technologies. The benefits of these tools include easier inspectability of complex geometries and the ability to define shapes accurately in a 3D world.

Saving a lot of time, effort, money, and mistakes.

Importance of Surface Shape and Form in Manufacturing

The importance of surface shape and form resonates strongly, particularly in industries at the forefront of innovation, such as automotive and aerospace. 

The core of why this is important becomes evident when we require free-form shapes that directly impact performance, safety and reliability. 

For example, in the aerospace and automotive industry, aerodynamics play a huge role, some surfaces demand a non-traditional seamless and flowing shape to perform effectively. 

Let’s take a low pressure fan blade on an aero-engine for example…

The intricacies of the fan’s shape go far beyond aesthetics, its shape has a profound influence on the aeroplace efficiency, effectiveness, and importantly the safety of the passengers on board.

The shape makes air flow over the top faster than under the bottom. As a result, less air pressure is on top of the wing. This lower pressure makes the wing, and the airplane it’s attached to, move up.

In total, there are four main aerodynamic forces acting on an aircraft during flight. These are:

  • Lift: This force is generated by fluid flow across the wing, which counteracts gravity and is induced by airflow passing beneath the wing.
  • Drag: As fluid flows along the body of the craft, the fluid creates drag due to skin friction acting along the surface of the wing. There is also pressure drag that impedes the aircraft’s forward motion.
  • Thrust: Aircraft that are driven with a jet engine use thrust to generate the relative velocity required to create lift. Helicopters do not have a jet thruster, instead, the motion of the rotor blades creates the required lift.
  • Gravity: All aircraft experience gravity due to the weight of the aircraft. Gravity always points in the downward direction.

The Benefits of Measuring Surface Profile in GD&T

  • Defining and Verifying Non-Standard Geometric Shapes

Surface profile measurement plays a crucial role in enhancing Geometric Dimensioning and Tolerancing (GD&T). It allows engineers to be able to accurately define and verify non-standard geometric shapes, particularly verifying a datum coordinate frame. It’s the right shape in the right place!

  • Industry Applications when Surface Profile Measurement is Needed

Surface profile finds practical applications across various manufacturing sectors, especially when performance is directly related to shape. 

Understanding the nuances of free-form surface profiles and those within a coordinate reference frame is crucial for effective implementation.

Let’s take a look at some practical industry examples of when nonstandard shapes are needed ; 

  • Automotive – The front wing of a Red Bull Formula 1 racing car – this is a real example of where aerodynamics directly influences performance. 
  • Aerospace – The shape of a blade on an engine fan
  • Medical – The shape of a knee joint implant
  • Product design -The design of complex outer shapes for consumer appliances such as coffee makers, smartphones, and displays.

Addressing the Challenges of Surface Profile Measurement

While surface profile measurement offers numerous advantages, challenges exist. It’s essential to apply surface profile measurement where traditional methods fall short, and careful consideration must be given to achievable tolerances. 

Depending on the capabilities of the company in question, being aware that whatever tolerance you define will impact the method in which it is measured, can lead to the difference between possibly a 5-minute scan or let’s say a 6-hour CMM program.  

It is extremely important that tolerance chain analysis is conducted beforehand to find the numerical values that are put in the drawing

Awareness, up-to-date GD&T knowledge, and investments in 3D scanning technology are key to overcoming these challenges.

  • Defining Complex Geometries with 3D Technology

The challenge of defining complex geometries finds its solution in the rising popularity of 3D scanning technologies, such as RPS arms and the Sensofar S Wide.

As companies delve deeper into the capabilities of 3D technology, combining design intricacy and manufacturing feasibility becomes an achievable reality and an important part of the process.

Future Trends and Innovations 

The future of surface profile measurement in metrology holds exciting possibilities. As more manufacturers look to measure surface profile, technology within the industry has advanced to keep up. 

As CAD and 3D technology are becoming more affordable and tools such as the Sensofar S Wide are becoming more readily available, manufacturers can now tackle complex geometries and measure free form shapes easier than ever before.

Furthermore, we are seeing continual advancements within other areas such as  CT scanning, fringe projection technology, and triangulation laser tools which are driving the demand and evolution of measurement. This technology offers advanced ways to capture and analyse surface profiles to a high standard. 

Finally, the way CAD files are being used is also changing, we are discovering that they are now being viewed as more of a technical document, which transforms how engineers approach product design and quality control.

The Evolution of Metrology

In conclusion, the evolution of metrology has witnessed a significant shift towards surface profile measurement, transforming the way we perceive and assess intricate shapes and forms in manufacturing.

As industries demand greater precision and efficiency, the limitations of traditional methods have paved the way for advanced technologies like CAD/CAM, 3D scanning, to provide surface profile measurement.

The ability to accurately define and verify non-standard geometric shapes, crucial in fields such as aerospace, automotive, medical, and product design, underscores the importance of this transformative approach. 

For further information on the best solutions for measuring surface profile view our full product range and contact the team to arrange a free demo.

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