CNC machining is all about precision. It ensures that the machined parts are produced to the exact given measurements thanks to the use of specialized CNC measuring tools.
These instruments help you double-check if the dimensions of the measured object follow strict specifications, which affects the quality and functionality of your final product.
Measuring tools for CNC machines range from digital calipers and micrometers to more advanced coordinate measuring machines (CMMs). Each can read the dimensions and tolerances accurately, making it clear why everyone in the industry uses them – from a CNC machine shop to an industry giant.
If you want to improve each component’s quality and functionality, let’s dive in and see how CNC measurement tools can help you do it!
Types Of CNC Measuring Tools
As the name suggests, the role of measuring tools is to measure dimensions. They’re a big help to machinists and operators in better following the numbers on the technical drawings and design specifications. If you make the right choice of measuring equipment, you can expect even better results in improving the capability of a CNC machine.
Coordinate Measuring Machine (CMM)
A Coordinate Measuring Machine CMM is a sophisticated device that you can use to measure the geometry of physical objects. It does this by sensing discrete points on the surface of the object with a probe. You can control this machine manually or program it to work automatically.
There are several types of CMMs, including:
- Bridge. Widely used due to its ability to measure various sizes while providing excellent accuracy and speed.
- Gantry. Ideal for measuring large, flat objects like sheet metal, printed circuit boards, and automotive panels. It can also reach around obstacles and into tight spaces.
- Cantilever. Best suited for measuring medium-sized, complex parts with deep cavities or internal features.
Electric Micrometer
Electric micrometers are digital precision measuring tools that capture measurements with high accuracy. They do this by turning the linear movement of a spindle into an electronic signal, which is then displayed as a measurement on a digital screen. They can store and transfer data for quality control and record-keeping purposes.
Air Micrometer
As for air micrometers, they use a stream of air to measure dimensions and are particularly effective in situations where contact with the part could affect the workpiece’s measurement or surface finish. Because they’re non-contact, air micrometers are ideal for measuring delicate parts where even the slightest touch could result in damage or deformation.
Image Measuring Machine
Image Measuring Machines are another non-contact measurement solution. They use cameras and image processing software to capture the part’s dimensions and can also provide rapid and accurate measurements. You’ll find them particularly useful for parts with complex shapes.
Laser Scanning and Probing Systems
Laser scanning arms and probing systems are the most advanced measurement technology in CNC machining. These tools use laser beams to capture the shape and dimensions of a part with exceptional detail. Laser scanners quickly capture the surface of freeform shapes, while probes provide high-resolution data for features requiring precise measurements.
Profilometers
If you want to measure the surface roughness of a part, then you must use profilometers. They trace a stylus over the surface plate, recording the micro deviations in height, which are then analyzed to see what the surface texture is like. You can’t skip this measurement as it can significantly affect a part’s mechanical and physical properties, such as friction and wear.
Digital Gauges
Manual gauges haven’t been left behind. They were given a digital upgrade and are still widely used during the machining process. Some of the most used gauges are:
- Height Gauges. They measure the vertical distance between a reference point and the part’s surface, which is critical for maintaining tight tolerances.
- Feeler Gauges. These thin strips that incorporate internal sensors and displays are used to measure gap widths, ensuring parts fit together seamlessly.
- Ring Gauges. Used to verify cylindrical parts’ external and internal dimensions, ensuring they’re within the specified tolerance.
Applications of Metrology Tools for CNC Machining
You’ll need metrology tools in several stages of the manufacturing process, as they have multiple applications. You can literally use them for anything – from quality control to ensuring the industry standards are strictly followed.
Quality Control in Manufacturing
Quality control is a step of the manufacturing process you should never skip. Each CNC machining part must meet the required specifications and tolerances, and these tools play a vital role in maintaining product quality by accurately measuring dimensions and surfaces.
With devices such as calipers, micrometers, and coordinate measuring machines (CMMs), you can detect any deviations from the original design and make the necessary adjustments. It’s how you can ensure the functionality of the parts and prevent costly errors.
Inspection of Prototype Parts
In the prototyping phase, you can identify potential issues before going straight to mass production. During this phase, you must make sure that the initial samples of a CNC machining part are produced according to the design specifications.
The measurements from the metrology tools will help you confirm that the prototype’s dimensions, geometries, and tolerances align with the intended design.
Calibration of CNC Machines
Proper calibration ensures that CNC machines last longer and maintain the same precision each time they’re used. You can use calibration tools to measure the machines’ performance and ensure they operate within specified parameters. This includes checking alignments, spindle speeds, and tool positions.
When your machines are properly calibrated, not only will they last longer, but they will give more accurate measurements of the parts you’re machining. But, just like any other tool, using them regularly can lead to wear and tear, which will affect their precision.
Ensuring Conformance to Industry Standards
Standards like the ISO (International Organization for Standardization) and ASTM (American Society for Testing and Materials) are the benchmarks for quality and safety in manufacturing.
Metrology tools ensure that CNC machined parts comply with the criteria given in these standards. Through precise measurement and documentation, manufacturers such as JetCrafted can guarantee that their products meet the required standards, which helps them build trust with both their clients and regulatory bodies.
Advantages of Metrology Tools for CNC Machined Parts
CNC machining demands pinpoint precision. Errors, even tiny ones, can cause an unplanned production downtime and cost the manufacturer up to $260,000 a day!
Using CNC measuring equipment ensures the entire manufacturing process goes off without a hitch. It simplifies the quality control process and helps you scrutinize every detail, guaranteeing dimensional accuracy. But the perks go beyond just measurements.
| Category | Advantages | Examples |
| Precision and Quality | High accuracy and repeatability | CMMs, vision systems, surface roughness testers |
| Non-contact measurement | Optical and laser scanning techniques | |
| Comprehensive data collection | Detailed reports for analysis and quality control | |
| Efficiency and Productivity | Automated inspection | CMMs and vision systems with programmed routines |
| Real-time feedback | Integration with CNC machines for immediate adjustments | |
| Faster inspection | Simultaneous multi-feature inspection with vision systems | |
| Performance and Quality Optimization | Surface roughness analysis | Testers quantify texture and optimize machining processes |
| Roundness verification | Accurate measurements of cylindrical features for optimal fit and function | |
| Defect detection | High-resolution scans reveal microscopic flaws for better quality control | |
| Cost Savings and Better Reputation | Reduced scrap and rework | Early error detection minimizes waste and rework costs |
| Improved customer satisfaction | Consistent quality and accurate parts lead to happy customers and a stronger brand reputation | |
| Data-driven decision making | Analyze measurement data to identify and implement process improvements |
Limitations of Metrology Tools for CNC Machined Parts
While metrological equipment is a must for ensuring the precision and quality of CNC machined parts, it comes with its own set of limitations, such as the initial cost and investment required for high-precision tools. These instruments are complex and often carry a hefty price tag that might be a problem for smaller operations or start-ups.
Using these high-precision measuring instruments requires a certain level of training and expertise. You need people who are trained to use these specific CNC machine tools but also understand the data they produce.
As manufacturing demands rise and tolerances become stricter, businesses might find it financially challenging to upgrade their equipment continually in order to stay competitive.
Measuring Up: Final Thoughts
CNC measuring tools are integral in maintaining machining precision. They serve as the base to ensure every part meets every tolerance or industry standard. You need measuring tools like micrometers, calipers, and CMMs to give you measurements, without which you can’t continue the CNC machining process.
While they clearly are beneficial, you must also be able to recognize their limitations and the need for proper calibration and maintenance. As the industry evolves, it’s becoming more and more important to educate yourself in metrology, so make sure to stay informed about the latest advancements to use CNC measuring tools efficiently.
FAQs
1. Can measuring tools compensate for a poorly calibrated CNC machine?
No. Even the most accurate measuring tools cannot compensate for a poorly calibrated CNC machine. They can only measure the output. If you want to make parts that accurately fit the given dimensions, you need to calibrate your CNC machine properly.
2. What is the typical cost associated with high-precision measuring tools?
High-precision measuring tools can be costly, often ranging from a few hundred to several thousand dollars. The price depends on the tool’s accuracy, resolution, sophistication, and technology.