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Moldmaking processes in the past have often relied on CMM machines to get the precise dimensions of the mold correct. Coordinate Measuring Machines use a probe for data collection. This probe typically moves through various axes and each point of contact is recorded. The probe will establish a certain amount of contact points with the object, build a sufficient dimensional database, and develop a profile of the surface. When making molds, the ability to define 3D shapes becomes essential. This is why automated measuring is most suited for this role.

Scanning Capabilities

For a CMM to define a complex shape in 3D, it is critical for it to be able to take in large amounts of data at one go. This is to enable it to build an accurate picture of the object that is being scanned. This also means that the moldmaker collects the data he or she needs quickly and accurately. This data can then be used in design programs such as CAD or can be stored for future reference.

Continuous Scanning

Traditional CMMs use a process that is known as stitch scanning to collect the data that it needs to define the surface. In this case, the probe makes contact with a part of the surface and then is lifted to reinitiate the contact at another point on the same surface. This process works effectively for surfaces that are fairly even and don’t need multiple data contact points for the CMM to define the surface. When it comes to moldmaking, large amounts of data are needed so continuous analog scanning works better here. The probe is always in contact with the surface and the data stream remains uninterrupted.

New Technology

New technology is redefining how CMMs scan and collect data. Areas of improvement lie primarily in three areas namely the CMM controllers, data sensors, and software.

Controller Technology

Under this category, new technology is making it possible for controllers to control the probe more autonomously and react to unexpected features on the surface. Modern controllers are able to change the direction of the probe and reformulate their calculations to incorporate new features that are encountered along the way. Controllers are also moving in the direction of greater autonomy. This means that machine operators can start the scanning process, and the controller will execute the scan without requiring any further input from the machine operator.

Sensor Technology

CMMs are shifting away from contact sensors to non-contact sensors. This is driving significant improvement in scanning speed, as well as allowing the device to be used on materials that may otherwise be damaged by a contact probe. Other improvements in sensor technology include the rise of CMMs with multi-sensor capabilities. This creates room for more flexibility as the CMM can perform both tactile scanning and precision single-point scanning.

Software Improvements

This focuses on how information collected by the new CMM machines is processed. Advances in software have seen user-friendly interfaces with commands in English rather than complex programming languages. This makes it possible for operators with no knowledge of coding to analyze data quickly and easily. Modern CMM software also allows for greater precision. A good example is a point-smoothing function that enables the machine to distinguish between surface features and other aberrations such as dirt and scratches. Machine operators can also define the limits of the search and mark features that do not require scanning (such as holes) so the machine avoids scanning them.

Digital height gages are devices that are used to measure the height of objects. As part of the process of measuring heights, most digital height gages are capable of marking the object itself in order to record the reading. Outside precision tooling, similar tools are used in hospitals to measure the height of patients. Height gauges are used in a variety of processes and typically measure height along a single vertical axis. There are three main types of height gages namely vernier, dial, and digital height gages.

Vernier and Dial Height Gages

Vernier scales are finely tooled height gages that rely on a base and a vertical measuring scale. The vertical measuring scale is calibrated, and using an attached Vernier scale, readings can be made off the object being measured. Dial height gages, on the other hand, work in the same way as vernier height gages except for the fact that height readings are made on a dial display that’s attached to the machine.

Digital Height Gages

Digital height gages are the latest in the evolution of height gages and come with many new features that help improve ease of use and accuracy of readings. Here are some of the ways that digital height gages that can raise the standard of your work.

• Better accuracy

Digital height gages can significantly improve the accuracy of your measurements. This is because they come with greater stability and weight, making it hard for them to slide on the bench top. Digital height gages are now able to measure diameters and thicknesses of objects.

• Distance between centers

Digital height gages are now able to measure distances between two centers. They do this by having the ability to record the highest and lowest points between a sweep and thus can calculate the distance between these two points. These recordings are stored within the machine’s memory and can be retrieved with a simple push of a button.

• Diagonal measurements

These gages are capable of measuring diagonal measurements. You can do this by rotating the object 90 degrees and measuring it on the digital height gage.

• Other measurements

These gages are now capable of measuring horizontal flatness by simply pushing a single button and sliding the object (or the height gage) horizontally.

• Data output

These gages allow the user to do more with the data that is produced by the machine. With its various data ports, users can export data from the machine and into various spreadsheet programs, allowing them to analyze, as well as share the data easily through email. Users have the ability to put time stamps on the data as well, which enables better tracking and comparison of data sets over a period of time.

• Pre-measured points

These gages make it possible for an operator to take accurate measurements by making sure that no pre-measured points are overlooked. This is useful especially for a new operator who might overlook some points during measurement. Digital height gages are also able to compensate for the effects of temperature on various materials.

Orthopedic implants need to be highly accurate to ensure that they can fix medical problems. In addition, they need to be constructed with high-quality materials to ensure that they are long-lasting. To achieve this level of quality and accuracy, orthopedic device makers often use air gages in their manufacturing processes.

There are a variety of air gages used in the manufacturing process of orthopedic devices and their functionality differs depending on the desired outcomes. One type of air gage that is used is the fit-jam air gage that compares diametric differences between two points on the device and compares this with a pre-set master. This is useful in establishing if a part meets set parameters but does not give the actual readings of the diameter. To get actual diametric readings, machinists sometimes prefer to use another type of air gage known as the clearance style air gage. Below are some key reasons why air gages are used in these manufacturing processes:

Air Gages are Precise

Orthopedic devices often use tapers to align and keep the different parts of the device locked into each other. These tapers must be precisely tooled otherwise they will not function very well, or they will have a very short shelf life, forcing the patient to change medical products. Air gaging is particularly well suited for a process like this one because they have a very tight tolerance, which typically is less than ±0.001 in. Air gages are also able to measure surface roughness that is below 50 µin. Ra.

Air Gages are Flexible

Air gages have the additional advantage of being very easy to use. This means that technicians do not need to undergo extensive training to be able to operate these gages. In addition, air gages are durable as they are not affected by the usual wear and tear that comes with contact gages. These gages are also fairly fast, making them ideal for a fast-paced manufacturing process where accuracy is still critical. They are relatively small in size and this allows them to be carried around the workshop floor and be used at multiple locations on the assembly line.

Variety of Uses

Air gages can be used to measure a variety of parameters, making them an ideal tool in a wide range of manufacturing processes. Using an air gage, a technician can measure parameters such as diameter, radius, and many more. Air gages can also be used to determine certain surface features of a part.

Unconventional Forms

Orthopedic devices require precise tooling on all components of the device as a flaw on one part may affect the overall performance of the implant. That’s why tiny spaces, holes, and other unusual features must be measured in a precise manner. Air gages are ideal for this kind of measurements as they can measure all sorts of parameters on unusual shapes and forms. These would be very hard to measure with other types of gages.

Air gaging is one of the earliest forms of precision measurement and these systems have been employed on shop floors since the 1940s. In fact, it was the earliest form of submicron measurement and most of the air plug configurations developed during that era have not undergone major changes. If you are searching for an air gaging system, chances are products such as single master air gaging systems may have caught your attention. Before going into the specifics, here’s a quick recap on how air gaging works:

How Does Air Gaging Work?

When a jet of air is blown into an object, the pressure of that air will drop as the distance of the object increases. Air gaging systems are designed to maintain the consistency of that air pressure by precisely controlling various elements, such as machined characteristics, location, air jet, pressure, and more. This ensures that precise measurements can be reproduced in a manufacturing environment.

What are Single Master Air Gaging Systems and their Benefits?

Now that your memory of air gaging systems has been refreshed, let’s move on to their single master variants. These systems typically have the accuracy built into both the air gage display and air tooling. During the manufacturing process, these components are set to specific pneumatic characteristics. In other words, the displays will only work with pneumatically matched tooling. Due to how single master air gaging systems are built, one can set it to true pneumatic zero.

With that in mind, below is a quick look at the various benefits that single master air gaging systems can provide for their users:

• Users can verify the performance of the display units with certifiable restrictor kits and tools
• Recessed jets reduce clogging problems and other forms of damage
• Features greater jet clearance for longer tooling life
• Worn tooling body does not affect magnification
• Uses medium-to-high air pressure to clean parts (approximately 30 psi)
• Great response speed
• Doesn’t require additional masters for monitoring tooling performance
• Offers excellent stability; readings do not shift after being set
• Maintains linearity well over entire range
• Extremely easy to set up

How Has Air Gaging Evolved Over the Years?

The main elements that have changed over the years are the capabilities of air gaging systems and their readouts. Modern digital readouts offer significantly higher resolutions and more range. In addition, they have amplifiers that provide additional functions, such as switching between ID and OD display modes with a single switch; performing dynamic checks without needing to calculate results; and even displaying actual part sizes. These improvements have certainly made air gaging tasks much easier and faster to complete and most importantly, allow technicians to achieve better results at the end of the day.

Whatever the case may be; whether you purchase a single master or dual master air gaging system, the readout and tooling devices of the air gages must be manufactured to the highest standards. In addition, the air systems are atmospherically balanced and are not susceptible to minute pressure changes.

After layout work became a fundamental requirement, long-range height measurements are now common in a wide range of large manufacturing plants, small machine shops, and even among home hobbyists. With that in mind, a scribing height gage is a device used to determine the height of objects, allowing operators to mark items that need to be worked on (e.g. machined). The typical set-up of a height gage is comprised of a dial indicator, a scriber (often used in metalworking processes to mark lines on workpieces), a surface gage, and a surface plate. All in all, height gages are great for measuring and/or preparing an emergency replacement part, prototype piece, etc.

Sizes and Models

Scribing height gages are available in an array of sizes, ranging from 72 inches. They typically incorporate a motor or rapid hand crank to enable speed positioning. In addition, a scribing attachment makes positioning to 0.001 mm possible. There are various models of scribing height gages that incorporate quick-adjusting release features, allowing the scribing point to move directly to the desired reading. Some may also have a built-in, fine-adjustment mechanism that allows the user to “zero in” with ease.

You Can Replace the Gage’s Scriber Point

One of the best things about these height gages is that the scriber point can be replaced. This is a useful feature because the scribing point will become worn at some point; replacing the scriber is sometimes easier than sharpening it again. That’s not all. Modern systems allow operators to substitute the replaceable points with other adapters and tips, further expanding the capabilities of the height gage.

Handy Adapters

It is now common for scribing height gages to feature adapters. They can be fitted with test indicators and are highly recommended because they have a higher resolution than digital height gages. This is great if you need to turn your height gage into a high-resolution transfer stand.

With this set-up, you can inspect out-of-square deviations. You may need to use the reference pads that are built into the base and some additional fixturing. Next, you may need to turn the stand and the test indicator into a basic perpendicularity gage. Don’t forget to move up the part and zero in on its base.

Alternatively, you can set the test indicator to zero with the aid of a master or gage block before sliding it along the surface plate to the part. You can then proceed to compare the part to the reference standard.

Hassle-Free Procedure

Scribing height gages are easy to use; below are some basic steps you can follow:

• Place the workpiece on the surface plate
• Bring the scribing pointer to the reference surface
• Ensure that the pointer is flush to the surface plate (look out for angled or warped conditions)
• Once it’s confirmed that the contact is flush with the table, start zeroing the height gage
• Now you can start scribing your workpiece!

With today’s digital height gages, you may even skip these steps if it comes with a single-keystroke function. They make it easier to measure point-to-point dimensions and allow operators to read any changes in height at various locations.

Air gages offer exceptional flexibility and versatility when it comes to measuring dimensional and geometry characteristics, such as clearances/interferences; heights; thicknesses; feature locations; inside and outside diameters; parallelism; squareness; roundness and many more. Chances are you may have also use air gages to measure counterbores, blind holes, or very deep bores.

Now, can this relatively simple technology measure tiny small through holes? Thanks to their tremendous adaptability, the answer is yes!

Understanding Air Gaging Limitations

Traditional air gages that are designed to measure inside diameters are typically limited to a size of approximately 0.060 inches; below that, it becomes difficult to accommodate the precision jets/orifices and machine air passages in the plug tooling. Don’t worry. What you need is a simple change of approach. It is possible to tweak air gages to measure small through holes that are less than 0.040 inches in diameter.

Consider Using Back-Pressure Air Gaging

A majority of air gages measure back-pressure that builds up inside the system, especially when the tooling is positioned near the workpiece. Doing this often results in higher air pressure, which the gage comparator will convert into dimensional value. That’s why back-pressure air gaging has been used in an array of specialty applications, ranging from measuring hypodermic needles, fuel injection components, and more. To make things easier, one can consider using a special holder that allows parts to be attached quickly while maintaining good air seal. Once air flow and pressure are stabilized, you are ready for high-volume inspections.

With the availability of flow-type air gaging, one can even measure internal diameters that are as small as 12 micro inches, and as large as 0.050 inches. There many be some cases where the holes are too small that air flow becomes negligible. Don’t worry; operators can engineer bleeds into the system to boost the total flow to a measurable level. If you need to reduce the air flow through large bores, you can engineer restrictors into the system.

Are There Other Alternatives?

Yes, there are other methods that can be used to inspect small holes. These alternatives include:

• Go & No-Go gaging: Used with precision wires, this method is suitable for very low volume tasks.
• Optical comparators and microscopes: This method does not suit high-volume production applications but works decently for certain applications. In addition, the method only accepts a limited number of configurations.
• Two-station air gages: Fuel injection components often feature two holes that share a common air passage. In addition, they need to be measured twice; once independently, and once simultaneously. With that said, custom two-station air gages have been designed to accommodate this requirement. The first station will connect the air circuit to one of the holes while blocking the other. The second station then connects the air flow through all the holes.

Do you need to measure bores of various sizes? Are small holes making measurement tasks difficult for you? Don’t hesitate to reach out to Willrich Precision for assistance. Our team can help you find the best air gaging system for your application.

The best way to think about a coordinate system is to think of an elevation map with its referencing system that uses numbers and letters to help the map reader select a very precise point on the map. This coordinate system is the backbone of coordinate metrology that in turn is used in Coordinate Measuring Machines or CMMs that ensure that products coming off the manufacturing line meet very precise quality standards. The coordinate system is an invention of Rene Descartes, a French mathematician, and philosopher who created the system in the 16^th century. Here are some of the basic terms that you may hear in coordinate metrology and their meanings.

Coordinate Measuring Machines

Coordinate Measuring Machines or CMMs are precision measuring machines that use the coordinate system to measure the surfaces of a product. CMMs do this by running a probe (which could be mechanical, laser or optical) along a surface and the data collected is then relayed to a data reader. The probe can either be manually controlled by an operator or can be computer controlled. Typically, CMMs will be used alongside other measuring tools such as CT scanners.

Datum

Another common term that you are likely to hear is datum which refers to points on the coordinate system. To use the earlier example of a street map, the datum can be a hotel or a river that is featured on a map. In the world of coordinate metrology, the datum, in this case, might be a hole (on a product) or a protrusion. The CMMs precisely map these points and uses them to ensure that there is consistency from one part to another.

Translation

This refers to the process of determining the space between one feature on the product to another. To use the map analogy again, this is like moving from the river to the hotel and then on to a third point. In this movement, your starting point changes (from the river and then from the hotel). This shift of the starting point from one location to another is what is called translation. Going back to CMMs, the probe acts like your finger on the map and moves from one point to another on the surface of the product, essentially translating from point to point.

Rotation

Rotation is best understood by using the analogy of the map once more. When moving from one point to another, you will realize that not all points are located at right angles to where you are. What this means is that once you translate from the river to the hotel, you might realize that your third destination is not parallel to the hotel. If you were using a map, you would rotate the key to be parallel to your point of origin thus allowing you to measure the distance between your new point of origin and your next destination. CMM machines do this exact process when moving from point to point and measuring the distance from one datum to another.

These are just some of the terms that you may encounter when learning about coordinate metrology. All these terms refer to processes that make it possible for precision instruments like CMMs to measure product surfaces and ensure that parts conform to a very specific quality standard.

Although most people do not quite understand the role of quality control specialists in manufacturing processes, the reality is that they play a vital role in ensuring that we are all safe. For example, a vehicle part that is not manufactured to the correct standards could have serious repercussions for the driver of the vehicle if that part ever ended up in a car. Luckily, quality control specialists are able to ensure that for the most part, manufacturing processes adhere to the correct standards. To do these quality control checks, quality control specialists rely on a variety of tools and machines to do their job. Read on to learn about the various tools that are vital to this role.

Hand-held Tools

There are a variety of hand-held tools that quality controllers use in their work. These range from gages, slide-calipers, micrometers, and indicators. If you visit a typical manufacturing plant, you might notice quality control specialists randomly checking parts off the assembly line using these tools. Handheld tools offer great flexibility to these specialists, allowing them to walk around the manufacturing line and testing parts at different points of the manufacturing process. Another great benefit of these handheld tools is that they are easy to use and people quickly learn how to use them without a lengthy training process.

Fixed Coordinate Measuring Machine (CMM)

Coordinate measuring machines or CMM are machines that give a very precise measurement of surfaces by running a probe over the surface of the part. These probes can either be mechanical, laser or optical depending on the degree of precision that is required. These CMM machines are fixed thus are likely to be used at one point. This means that products being analyzed are likely to be brought to the unit unlike the hand held devises that the quality control specialist can walk around with. Fixed CMMs are very precise and can also be linked to data processing machines allowing quality control specialist to analyze quality control data across different periods and different production lines.

Portable CMMs

These machines go a step further and give quality control specialists the ability to move around with the CMM while at the same time enjoying the precision that comes with CMM. Portable CMM tools are however sensitive to environments where there are strong vibrations (such as manufacturing plants that use big machines) and thus cannot be used in all manufacturing environments.

3-D Scanners

3-D scanners offer greater precision and flexibility without any of the limitations that come with portable CMM machines. For example, 3-D scanners are not affected by vibrations or temperature variations and thus are likely to work in a wider range of manufacturing environments. 3-D scanners are also suited for complex manufacturing processes.

Quality control specialists rely on some or all of these machines to ensure that the manufacturing process continuously produces products that meet very precise specifications.

Air gaging is a common technique used in a wide range of manufacturing process. Technicians that work on the shop floor often utilize air gages due to the advantage that the product offers. Air gages are not only easy to use and fast, they can measure to very tight tolerances (down to a resolution of 5-50 millionths!) and even clean the part’s surface before measuring. When it comes to air gaging, most gage users automatically think of air plugs. There are, however, various styles of air forks and air rings. These tools provide similar benefits and a few additional ones too.

The Low-Down on Air Forks

In some cases, you can’t simply place a part in an air ring, e.g. on crankshafts. There are just too many journals and some of them have very tight tolerances. This means that there is no way to place an air ring over this area. This is when you will need an air fork.

You do not get air forks simply by slicing an air ring in half. There are some critical dimensions to consider. In addition, they come with precision-ground locating stops that are found at the back. These features allow the operator to create the reference based on the known part diameter and position the jets with precision.

Maximizing the Capabilities of Air Forks

You can get the air forks to really shine if it’s possible to customize the position of the air jets. For example, you can measure a diameter right up to a face by placing the jets near the end of the fork. Alternatively, you can also add multiple jets to measure up to three diameters simultaneously. You should be able to read the three diameters as one without a lot of computing power. Don’t forget to calculate shape and taper as well.

If you are measuring challenging outer diameters, it is a good idea to remove the mechanical snap or the bench stand and consider leveraging air.

The Low-Down on Air Rings

Air rings are the opposite of air plugs. They are typically utilized to measure outer diameters. These rings often have a basic design, e.g. a steel ring and a pair of jets attached to a particular location. Surprisingly, a lot of engineering is built into them.

If you need to calculate the size of the ring, ensure that you achieve a proper balance of clearance between the opening in the ring and the part. If there is too much clearance (it will measure a chord rather than the diameter), your readout will display a centralizing error. If you lack clearance, a geometry error can occur. In this case, you won’t be able to insert the part into the air tool.

You should check and ensure that the jets are positioned slightly lower than the body of the ring. It provides the air system with the correct differential characteristics to function properly. Additionally, it allows for ring wear.

Diameter Measurements with Air Rings

When it comes to measuring basic diameters, two-jet air rings will suffice. Gears and pullies, however, feature multiple ODs. In most cases, you will need to measure the diameter right up to the face where your rings are attached to. You will need to get a snout-type or shoulder-type air ring. They are basically blind hole rings that allow you to position the jets closely to the face and measure the outer diameter right to its end. Snout type rings can get around obstacles and clearances more efficiently. It is useful to note that air rings may be designed with between three and six jets.