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What Is CMM Machine: Components, Uses, and Benefit

The most important thing in manufacturing is measuring the parts and components precisely. A knowledgeable manufacturer knows that accurate measurements matter so that a device can function properly.

But sometimes, due to carelessness or shortcomings in fabrication, the dimensions of the manufactured part come out wrong. It leads to improper operation of the products and causes losses in the business.

Even though the traditional methods included the use of handheld machines like calipers and gauges, the process was slow, and human errors were quite common. So, that is where the Coordinate Measuring Machine came to be a solution for such a problem. Let’s get to know more about it in detail.

Understanding CMM

Broadly, it is a metrology instrument that measures in 3 dimensions (X, Y, and Z axis). This device inspects the advanced and complex geometry of any object and provides measurements, ensuring the manufactured parts meet the design requirements. By using technologies such as laser scanning, it ensures precision, accuracy, and productivity on a higher level.

What are its Main Components?

CMM is made of some complex modules that aid in its movement, stability, and overall efficiency.

What are its Main Components

It includes a simple element like a fixture or even a software part. To make it easier to understand, all the components can be divided into 4 parts.

So, let’s take a look at each one of the components in this device.

Structure

Getting an accurate reading for a part in case the CMM is shaky or thermally unstable is difficult.

That’s why the machine’s structure provides stability to the entire measurement device, especially when a part is on the observation belt or a fixture.

A structure consists of various other modules, such as bridges, columns, gantry, guideways, and bases.

Base

It is a precisely leveled unit that provides stability to the machine, protecting it from external forces that may affect the reading. It is made of structural alloys such as cast iron for better strength.

Columns

Columns are erected on the base under the bridges with a motive to provide vertical support. They are designed to support heavy loads when a component is on the machine.

Bridges

To provide a probe with the flexibility to move across 3 dimensions, bridges are placed between columns. In a gantry-type CMM, a horizontal arm is used instead of bridges.   

Guideways

These are the surfaces on which a bridge moves. A coating of anti-friction material is used to provide smooth movement. The most common types of guideways in the industry are V-shaped and dovetail profiles.

Probes

Probes collect the data from an object placed on the fixture. These are attached to the machine structure. Generally, there are a variety of probes for different purposes. Some of the most commonly used probes are touch-trigger and non-contact.

The touch trigger works by assessing the data from the touch points. A measurement is triggered whenever the stylus hits the point, and then it notes it as valuable data.

In the case of delicate materials, non-touch probes are used as they make use of lasers without physically touching the surface. They also provide accurate readings.

As per varying requirements, some CMMs use a couple of other sensors, such as white light and infrared sensors.

The white light sensors are capable of analyzing varying patterns of light on the object, while the infrared ones rely on infrared light. Thus, these are commonly used in cases of delicate workpieces.

Control system

The probes move around a specific path to get the coordinates, and the control system ensures path planning and smooth motion for measurements. Basically, it triggers the measurements for the object. Along with this, it communicates with metrology software, sensors, and CNC to provide feedback. Plus, it also provides emergency signals in case of malfunctions or failures and shuts the machine if required.

Software

The software has multiple functions, from generating reports to ensuring coordination among different parts of the machine. Mainly, it imports CAD models for the workpiece and communicates with a control system to fetch data from data points. It performs complex calculations to generate reports and even create visual representations for a better understanding.

How does it work?

Instead of complicating it with technical jargon, let’s understand it with the help of an example. Consider a space company that wants to measure an engine.

how CMM Machine work

Given the size and structure of an engine, the complexity of measuring a workpiece like this can greatly vary from a small part of the rocket. Therefore, it starts with CAD programming in which the users define the probing paths and specific things to be measured. Think of it like an instruction copy for the machine.

Once the engine is placed over the fixture, the machine comes to a home position (like a frame of reference). Then, probes move along the touchpoints. Depending on the pre-setup, either the lasers or probes will be used to mark the X, Y, and Z coordinates based on the mentioned areas.

The data is then compiled and sent to the software for further analysis. The machine compares this data with pre-specified tolerances and generates the overall report for the workpiece. To double-check, it also comes with a calibration feature.

Uses of CMM machines in different industries

It can be used in various industries where accurate 3D measurements are important, ranging from aerospace to pharmaceuticals to healthcare. Let’s take a look at how we can use them to perform different tasks.

Aerospace industry

CMM Machine industries

Every minute detail matters in aerospace. With the help of top-notch control systems and software, CMMs can check the dimensions of any object with complex geometry, like chassis, turbine blades, and fuselage parts. This is how aeronautical engineers make sure the components meet the design standards.

Energy sector

To ensure the safety and dependability of energy equipment, CMM machines cross-check the equipment needed to achieve conversion efficiency. Having such a reliable tool helps energy companies adhere to compliance regulations.

Medical industry

Its applications are not just limited to complex objects but simple products with tight tolerances. For instance, it is used to measure the design accuracy of prosthetic limbs, implants, and precision instruments.

Automobile industry

Much like every other industry, the automobile industry also needs high precision in designs. CMMs are employed to inspect the components, such as axles and other structural elements. Moreover, it is also used for mold measuring to ensure consistency in the components. The micro CMMs can even measure the tiny components of vehicles. The best part is that its precision levels are satisfactory; all you need is the right probe.

Advantages

From a business perspective, there are a lot of advantages to incorporating a high-precision machine in the manufacturing process. Let’s take a look at some of them:

Faster product life-cycle

The CMM machines do complex computations and give results in less time than a hand inspection method, making the process faster. Plus, it needs very little time to set up and even fewer operator commands for tasks like batch inspections. Because of this, the businesses can manage both time and quality constraints, leading to a better presence in the market.

Higher quality products

Not only do the CMMs measure the basic parameters such as length or surface area, but they can also take cylindricity and angularity into consideration, ensuring better quality. Especially when a CNC creates a prototype, the CMM thoroughly checks its dimensions to ensure it meets design requirements. It even maintains a light or sometimes no contact at all, keeping the higher quality and integrity of a product.

Flexibility

These machines are flexible in more than just one aspect. It can handle multiple sensors that allow it to measure different products of varying sizes and shapes. It is compatible with different types of probes as per the user’s specifications.

Enhanced productivity

Thanks to its automation capabilities, it can assist manufacturers in high-volume production and repeating measurement tasks repeatedly. This helps in reducing the workload on labor, leading to improved productivity.

Challenges and considerations

Undoubtedly, a CMM machine can boost the operational efficiency and quality of any product, but it comes with a couple of challenges.

High capital investment

Like every other complex machine, CMM requires high capital investment. The development of high-quality components, such as sensors, scanners, probes, and software, comes at very high costs. Apart from this, licensing and training costs contribute to the overall price.

Extensive training

CMM Machine industries-Extensive training

To operate and troubleshoot CMM, there’s a requirement for trained personnel, which means the companies have to incur additional costs in training.

High maintenance

The large systems need extra space and temperature-controlled rooms to maintain optimal performance. Plus, in some cases, a regular software update requires modification in existing programs.

Compliance

Each industry has its own specific regulations and quality standards in dimension analysis. Hence, deciding on the best CMM machine requires research.

The Importance of CMM in Injection Molding and Mold Making

Manufacturing parts that have complex geometry requires more precision, and for that reason, many companies rely on mold-making and injection molding. Here is how CMMs add value to this process:

Decision making

CMMs provide important insights into the injection molding process, such as surface roughness and defect analysis (such as voids or warpages). Also, it provides data about areas of improvement. These inputs help manufacturing companies make the right decision and develop a perfect end product.

Accurate measurements

Given the compatibility of CMMs with different sensors and probes, they can accurately measure a mold within a tight space of as little as a nanometre. This also adds up to the quality of the product,  

Quality control

Even a minor error in a mold’s measurements can lead to rework and a waste of time. CMM’s probes measure the complex parts accurately to check whether the mold meets the specified design or not. Because of this, it helps in performing quality checks.

Production efficiency

The CMMs are used in different stages of injection molding, from FAI (First-Article Inspection) to post-inspection. It measures the parts and reports any discrepancies in time, allowing teams to make iterative improvements.

Minimizing waste

Due to enhanced accuracy in measurements of molds, the number of rejected parts decreases significantly.

Documentation and compliance

CMM’s well-documented reports allow manufacturers to track the injection molding process over time. Not only does this help them make informed decisions about products, but it also helps protect them legally.

Documentation and compliance-CMM Machine

Market players like Hitop use reliable machinery such as CNC and mirror spark machines in mold-making and even gain a competitive edge in injection molding. Such infrastructure helps them achieve a higher level of accuracy even in a margin of 0.002 mm.

Parting comments

CMMs can be a great investment if you are looking to take your manufacturing business to the next level in terms of productivity and efficiency. Even if it requires high investment initially, it could be a promising asset for boosting ROI over the years. While choosing the CMM that best suits your business needs, make sure to balance your budget with your long-term goals.

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Hi, I am Sparrow Xiang, COO of the HiTop company, me and my team would be happy to meet you and learn all about your business, requirements and expectations.