Everyone knows exact geometric and physical dimensions play a key role in manufacturing. Even tiny variations can cause products to fail, require expensive fixes, or put safety at risk. So how do you make sure your product fits the needed specs without relying on hand tools or visual comparators?
The answer lies in CMM manufacturing.
In this article, we’ll explain what is CMM in manufacturing and list common use cases in manufacturing and fabrication.
What Is CMM in Manufacturing?
CMM fill form is Coordinate Measuring Machine. These machines are used to measure the physical geometrical characteristics of an object. They can be controlled manually by an operator or programmed for automated measurement.
They use complex coordinate systems to capture an object's height, width, and depth on the X, Y, and Z axes. The machine then uses math formulas to look at the data points and figure out the object's features very
What Are the Types of CMM?
There are multiple types of CMM, each with its own set of advantages and disadvantages. Let’s take a deeper look into the most common types of CMM.
1. Bridge CMM
The Bridge CMM is one of the most widely used coordinate measuring machines. Its name comes from its bridge-like design, with a horizontal beam supported by vertical columns on either side, mounted on a stable granite table. This design allows for highly accurate measurements of small to medium-sized components.
The machine’s probe moves it along its X, Y, and Z axes to scan or touch specific points on the object. The probe then collects data points by either physically contacting the surface or scanning it. These data points are processed to create precise 3D models or to inspect the object against CAD designs or dimensional tolerances.
Bridge CMMs are used for inspecting machined components, molds, and dies - and even for reverse engineering. It’s relatively cost-effective compared to larger CMM. However, its accuracy is influenced by the machine's stability, the probe's precision, and environmental conditions. For this reason, it's best suited for parts within its size range and requires a controlled environment to maintain performance.
2. Gantry CMM
Gantry CMM is used to measure large and heavy parts. Its structure resembles a gantry crane, with a horizontal beam supported by vertical columns on either side. These elements allow it to span and measure wide, or even bulky components, with accuracy.
The machine moves along three axes (X, Y, and Z) that are at right angles to each other, guided by air bearings. These air bearings suspend the moving parts on a cushion of air. A vertical ram moves up and down relative to the machine’s head and is equipped with a probe. The probe collects cmm measurements by either scanning the surface continuously or touching discrete points on the part, capturing 3D data for analysis.
This CMM type is ideal for larger components and is able to provide exceptional precision. However, Gantry CMMs require a control space due to their sheer size. Other than that, it’s sensitive to external factors such as temperature fluctuations and vibrations.
3. Horizontal Arm CMM
Horizontal Arm CMMs are ideal for measuring large, flat, or asymmetrical components. Their structure includes a horizontally mounted arm that extends over the part being inspected. This makes it easier to measure components that other CMMs might struggle to handle effectively.
The machine operates along three axes (X, Y, and Z), which are positioned at right angles to each other. The horizontal arm moves and carries a probe at its tip, allowing it to collect data with higher accuracy. Depending on the application, the probe either scans the surface continuously or touches specific points. The 3D data collected by the probe is then analysed to verify whether the part meets the required specifications.
Because of their design, Horizontal Arm CMMs are ideal for large sheet metal parts, car bodies, and other oversized components. However, their size means they require larger floor space in the workshop and they are sensitive to environmental factors.
Why Is CMM Needed in Industry?
Coordinate Measuring Machines (CMMs) are needed in the industry due to their ability to provide precision. Traditional tools such as micrometers and calipers are unable to meet the strongest tolerances required in many industries.
CMMs can measure dimensions with micron-level accuracy, and have no problem inspecting complex, non-standard geometries. For example freeform surfaces and multi-axis features. Additionally, they have automation capabilities to reduce the risk of operator error, which makes them especially handy in high-volume production.
What Is CMM Limitations and Challenges?
As with everything, it does come with its limitations. A major limitation is their sensitivity to environmental conditions and costs. Below we’ve broken down the key challenges:
- External Conditions: Temperature changes can cause thermal expansion in both the machine and the part being measured, leading to micron-level inaccuracies. Meanwhile, vibrations can further compromise its precision.
- Costs: They’re expensive to not only purchase. But to maintain and operate.
- Constraints: Each CMM type has its own constraints. Bridge CMMs are ideal for small to medium parts, while larger systems like Gantry or Horizontal Arm CMMs require substantial floor space and infrastructure to handle bigger components.
What Is the Difference Between CNC and CMM?
CNC (Computer Numerical Control) and CMM (Coordinate Measuring Machine) serve different roles in manufacturing. But they complement each other well. CNC machines are used for production, shaping raw materials into finished parts. For example, through processes like milling, turning, or drilling. Essentially these machines follow programmed toolpaths to create components with high precision.
In contrast, CMMs are used for inspection purposes. They measure the dimensions, geometries, and tolerances of finished parts to verify they meet design specifications. While CNC machines focus on creating parts, CMMs validate their accuracy, working together to maintain quality and precision in the manufacturing process.
Frequently Asked Questions
What Are the Advantages of Using a CMM in Manufacturing?
The advantage of using CMM in manufacturing is their ability to measure the physical and geometrical characteristics of an object with micron-level accuracy.
What Is CMM in Manufacturing?
CMM full form is Coordinate Measuring Machine. These machines are used to measure the physical geometrical characteristics of an object. They can be controlled manually by an operator or programmed for automated measurement.
Can CMM Be Used for All Types of Materials?
The CMM machines can be used for common materials such as metals, plastics, composites and ceramics. However, they may face challenges in providing accurate measurements for highly reflective, transparent, soft, or elastic materials.
Conclusion: What Is CMM in Manufacturing?
In this article, we outlined what is CMM in manufacturing and its meaning in engineering. In recent years, CMMs have become the backbone of precision manufacturing.
Manufacturers use them to check if a product meets exact specifications, which helps to avoid expensive rework and product failures. Although CMMs need controlled settings and skilled workers, they have the ability to handle complex shapes and provide micron-level accuracy. This makes them essential in industries where perfection is a must.
If you're navigating the challenges of sourcing precision components, Haizol is here to help. We are a one stop sourcing solution that provide end-to-end OEM manufacturing services, and consulting and project management. Contact us at info@haizolglobal.com to get help today.