When it comes to manufacturing parts or prototypes, you have to pay attention to their geometric features and dimensions. That is because resulting errors can have a negative impact on the production process. For many years, manufacturers relied on traditional hand tools and optical comparators. Unfortunately, such tools need a lot of expertise and are prone to errors. As a result, a coordinate measuring machine (CMM) was created.
The CMM machine is a device that measures the dimensions and geometries of a machine by utilizing coordinate technology. This device uses the probing system to pinpoint discreet points on the surfaces of parts. The first CMM machine was created in the 1960s. The measurements taken are width, height, and depth in the X, Y, and Z axes.
With the CMM machine, you can test the part to find out whether it confirms the intended design. Taking into account how advanced your machine is, it can take measurements and record data.
CMM Machine Components
If you want to understand how the CMM machine works, you need to know its various components and their functions. These are the most important components:
Probe
This component is mainly used for measuring processes. It is commonly found in traditional CMM machines. Modern machines use lasers, digital cameras, and optical light. The probe has a tip made of stable material. Also, it needs to be temperature-resistant. In some cases, it has a needle-like or spherical shape.
Granite Table
This is a vital component of a coordinate measuring machine. This is because it ensures the CMM machine is stable. Since the material is resistant to temperature and has a lower rate of wear, it increases the lifespan of the machine. Moreover, its shape remains the same, ensuring accurate measurements.
Fixtures
These are tools used to provide support and stability during manufacturing operations. They ensure the parts being manufactured are positioned in the right place. This helps minimize measurement errors when dealing with moving parts. The common fixtures include magnets, fixture plates, and clamps.
Software
The software helps in analyzing probes and other components to ensure they are working properly.
CMM Applications
CMM machines have many applications in automobile manufacturing, machine tools, and electronics. These machines are widely used in testing and inspecting testing tools, gauges, and equipment. For instance, in space vehicles and aviation, most inspections are done by use of CMM machines. These are their main applications:
Measuring Volume
The measuring volume of the CMM machine is determined by the area where the probe can access. This can have either a rectangular or cubicle shape, and it determines the maximum height, length, and weight of the part being measured. These measurements are then used to determine the volume of the part.
Weight
The CMM machine can be used to measure the weight capacity of the part. Remember that if a part is subjected to part weight that exceeds CMM load capacity, it will result in deformation. The deformation can cause significant errors.
Speed
CMM machines can measure acceleration speed and measurement speed. This involves evaluating the CMM speed of parts needed to move the machine from one point to another.
Benefits of CMM Machines
The truth is that CMM machines play a critical part in manufacturing processes. This is because they have many advantages that outweigh their limitations. These are the various reasons manufacturers use CMM technology:
Time-Saving
The CMM machine is required in manufacturing because of its high accuracy and speed. In this era, manufacturing of complex parts is the norm, and CMM machines are best suited to measuring their dimensions and geometries. By using these machines, it is possible to reduce manufacturing time and cost.
Three-Dimensional Measurement
The CMM machines provide 3D measurement capabilities. This means they can carry out measurements in X, Y, and Z axes. As a result, they are more advanced as compared to hand tools such as vernier calipers and micrometers.
Excellent Accuracy
The good thing about the CMM machine is that it can measure that are challenging to measure and still provide a high degree of accuracy. Remember that it is impossible to measure virtual lines, points, and geometrical tolerances without using CMM technology.
Automated Inspection
CMM machines are widely used in automating inspection. You only need to create a program by feeding it with the dimensions of the part. After creating the program and establishing the origin point, it is easier to run an automated measurement process. Since the machine is operated through a program, it does not require a lot of human effort. This reduces errors during the inspection process.
Quality Assurance
When you compare the CMM machine to conventional measuring methods, the CMM machine provides exceptional reliability. This is because it digitally measures and analyzes the part whilst offering additional services that include tool certifications, CAD comparison, and dimensional analysis. All these are required for quality assurance.
Versatility
CMM machines are quite versatile and can be used with a range of tools and techniques. No matter how complex the product is, it can be measured by the CMM machine.
Limitations of CMM Machines
Although CMM machines play a vital role in production, they have their share of limitations. These are some of them:
– Contact with the part. To measure any given part, the probe of the CMM machine must come into contact with the surface. Although this is not a problem with durable parts, it can cause deterioration and defects in fragile parts.
– Not suitable for some materials. Using CMM machines on parts made of soft materials such as elastomers and rubber is not recommended. This is because it results in the product caving in. Such errors are evident with digital analysis.
– Choosing the right probe. There are various types of probes used by CMM machines. To select the ideal one, you need to consider factors such as design, probe ability, and the dimensions of the part.
Types of CMM Machines
The CMM machines are available in four types:
– Bridge
– Gantry
– Cantilever
– Horizontal Arm
Bridge
Bridge CMMs are widely used in manufacturing and inspection applications. They have a stable anchor for measuring tools and are ideal for measuring machined parts. This is because they have excellent accuracy and can achieve tight tolerances.
You should note that these machines are suitable for measuring small-sized parts that can fit onto the measuring table. Also, with these machines, you can encounter challenges accessing the parts you want to measure.
Gantry
Although they are similar to bridge coordinate measuring machines, they have unique differences when it comes to capability and design. For instance, this machine is mounted on a floor, allowing it to accommodate larger machined parts. It is also suitable for measuring parts with complex geometries.
Cantilever
This type of CMM machine has support at a single point, hence its name. As a result, it is less rigid as compared to bridge and gantry coordinate measuring machines. It is widely used in measuring low-weight parts. Since these machines are supported at a single point, they can move quickly and achieve high levels of accuracy as compared to other CMM machines. However, they are suitable for measuring small-sized machined parts.
Horizontal Arm
These machines have their probes mounted horizontally as opposed to vertically. The unique design makes it possible to measure large-sized parts. Although they are less accurate, they can measure parts with hard-to-reach features.
Ensuring Quality with CMM Machines
Some manufacturers consider CMM machines to be unnecessary costs. This is because these machines do not manufacture parts that can be sold for money. However, if these machines are used efficiently and correctly, they can result in the production of high-quality parts, hence higher profits.
With coordinate measuring machines, you can measure various components and parts. In addition, you can inspect their quality and maintain the required industry standards. When you manufacture quality parts, you gain a competitive edge and sell products that meet customer needs.
Sunrise Metal has equipped in-house with a precision Carl Zeiss CMM machine to check production parts, ensuring high-quality, lower-cost products through more exact measurements. Contact us today for your request.