# Dimensional Measurement Blog

Optical illusion: parallel lines made from black and white pillows
There are many ways to inspect an object. You can use high-tech machinery, precision hand tools, and even the human eye. Every inspection method comes with strengths and weaknesses, and each application will work better with some methods than with others. Understanding these strengths and weaknesses can help you decide which types of inspections work and do not work for your specific application.

Visual inspection is perhaps the original method, and it is still often the first line of defense in inspection and verification processes. The eye is a powerful inspection tool mainly because it is connected to a human brain that possesses information and skills that machines do not. However, the eye can be tricked, so knowing its limitations is important.

## The Strengths of Visual Inspection

Almost all manufacturing applications should include visual inspection at some stage of the process for these primary reasons:
• Save money - If there is an obvious flaw that can be seen by the naked eye, there is no need to take the time and resources to continue the inspection process.

• The human element - Dimensional inspection evaluates just that: the dimensions. But what if the object produced is a mirror image of the intended result? This could be overlooked in an open setup or a non-model-based CMM inspection because the dimensions might exactly match the specifications. However, a visual inspection to compare the final product with the engineering drawings would quickly show the mistake.

• Evaluate workmanship - Certain types of dimensional inspection equipment measure the edges of an object but not the surfaces, or vice versa. Take the example of a cube. Your CMM might confirm that the surfaces of the cube are the correct dimensions, but it might not detect a large gash on one of the edges. Visually inspecting parts can help ensure that all of the specifications are met, not just the ones the equipment can see.

## The Weaknesses of Visual Inspection

Although the human eye is a sophisticated tool, it can also be easily tricked. Consider some of these weaknesses associated with visual inspection:
• Unreliability - Browse through these optical illusions to get a sense of just how unreliable the human eye can be. This does not mean that visual inspections are always unreliable, but that they shouldn't be your only method of inspection.

• Imprecision - The human eye is not capable of making precise measurements, especially on a very small scale. Even when comparing two similar objects, the eye might not notice that one is slightly smaller or larger than the other. This concept also applies to characteristics such as surface roughness, size, and any other factor that needs to be measured.

Clearly, visual inspection comes with advantages and disadvantages but the value of it should never be quickly counted out. The best approach to effective dimensional inspection is one that includes multiple methods. Q-PLUS Labs is here to help you decide which dimensional inspection approach is right for your application. Contact us today to schedule a consultation.

Dimensional inspection is used in a broad range of industries for a wide variety of applications. However, there are some common reasons why this type of measurement is used. Whether the objective is to compare a prototype to a drawing or to ensure that a finished product meets certain standards, the fundamentals of dimensional inspection remain the same. Highly accurate measurements are taken to determine how closely an object matches its originally intended dimensions.

In general, if dimensional measurement is required, the results must be both accurate and precise. Although multiple techniques and countless applications exist, there are four main categories of dimensional inspection.

Four Common Dimensional Inspection Applications

1. First article inspection. Implementing a manufacturing process requires extreme attention to detail, especially if the process is new or if the equipment has been specially designed. First article inspection is required to ensure that the equipment was properly installed and calibrated, and to verify the manufacturing process. Dimensional measurement is used to compare the first objects from the manufacturing line to 3-D CAD models or other specifications.
2. Quality control. When objects coming off a manufacturing line must meet certain quality standards, measurement equipment is used to confirm that the dimensions fall within the required tolerance levels. In some cases, when the tolerance levels are more rigorous, each object is measured automatically. In other cases, batches might be spot-checked for quality.
3. Regulatory compliance. In industries for which regulatory compliance is necessary, dimensional measurement ensures that the required specifications are met. Regulatory bodies such as the FDA or FAA often have requirements regarding the dimensions of certain components.
4. High-precision engineering. When creating a larger assembly from smaller parts, high precision is often required. If a minor flaw or inconsistency can impact an entire process, ensuring that such imperfections do not exist is critical.

Employing dimensional measurement in these scenarios offers many benefits, including reduced liability, improved quality, and lower costs.

If you need dimensional inspection services for your business, contact the professionals at Q-PLUS Labs. We provide outsourced measurement services for a range of industries including manufacturing, aerospace, medical, and more. Schedule a consultation today to learn more about how we can help you with your dimensional measurement needs.

How does your company use dimensional inspection?

Purchasing dimensional inspection equipment requires making a big decision, and in most cases a significant financial investment. It is important to be certain that the equipment you buy will serve its intended purpose and provide the results you need.

Because there are so many different types of equipment that can be used for a broad range of purposes, it helps to know what questions to ask before you buy.

## 11 Dimensional Inspection Equipment Questions You Need to Ask

1. What sensor type do you need?

Depending on the surface characteristics of the objects you intend to measure, you may need either a contact sensor or a non-contact sensor. Within each of these two categories are several other options and different sensor types. The more you know about the objects you will be measuring, the better able you will be to select the right types of dimensional inspection equipment.

2. What tolerance levels are required for your application?

There is a big difference between replicating an antique to sell in a gift shop and mass producing components that will be used in a medical device. In the former case, a certain amount of inaccuracy is tolerable, while in the latter case the requirements are more stringent. Make sure you know how precise you need to be, especially if you have to maintain regulatory compliance.

3. Does your equipment need to be portable?

Do you need a machine that will always sit at the end of a production line, or do you need a more portable unit that can take measurements in the field?

4. What size(s) are the objects you need to measure?

Some objects are small enough to be put into a machine, while others are simply too large or heavy. On the other hand, objects that are on the nano scale will require specialized equipment.

5. What shape(s) are the objects you need to measure?

Does your object have internal geometry that you need to measure? Bore holes, threads, and other complex geometry cannot always be measured by certain types of dimensional inspection equipment or without certain accessories.

6. How fast do you need results?

Measuring the occasional prototype is a different scenario than inspecting every component that comes off a production line. It is important to know how quickly you will need results so you can purchase a machine that is capable of meeting your needs.

7. Does your equipment need to be automated?

Some dimensional inspection equipment can be automated, but not all of it can be. If this is an important factor for your application, make sure it is a high priority in your purchasing decision.

8. Who will be using the equipment?

Ease of use should be considered if you are weighing multiple options. Will you need to hire new staff or train employees to use this new equipment? Does your budget support that?

9. What is required to maintain the equipment?

High-precision measurement equipment needs to be properly set up, regularly maintained, and periodically calibrated. Does your staff have the skills to do this, or can you outsource it?

10. How durable and reliable is the equipment?

Dimensional inspection equipment is an investment. It is important to compare multiple manufacturers and work with an expert who has experience will all of them.

Perhaps one of the most important factors is your budget, however, be sure to weigh all of the above before you make a decision.

If you would like to learn more about selecting the right dimensional inspection equipment for your application, download our free guide. You can also schedule a consultation with one of our dimensional inspection experts who can walk you through the entire process. Contact us today to schedule an assessment.

What type of dimensional inspection equipment are you looking for?

Dimensional inspection can be performed with a wide variety of methods and equipment, depending on the object being measured. When selecting equipment, remember the cardinal rule of dimensional inspection: The object being measured cannot be altered during the measurement process. This means that some objects cannot be touched because the resulting measurements will be inaccurate.

When touching an object with a probe will alter its dimensions, non-contact sensors must be used during the measurement process. Cases when this is appropriate include when the object is:
• Soft
• Elastic
• Very small
• Fragile

Examples include objects such as micro-gears, rubber gaskets, prosthetics made of soft plastic, or a fragile antique with a delicate surface.

## Non-Contact Sensors for Dimensional Inspection

Several types of non-contact sensors can be used for dimensional inspection, including:
• 3D scanners. There are two main types of 3D scanners: those that use structured light and those that use lasers. In both cases, light is projected onto the surface of an object and measurements are made based on the reaction of the light. With structured light, the distances are measured using the distortion of pixels, and with lasers, the reflection is used to triangulate distances. Clearly, the surface characteristics are a significant factor in determining whether 3D scanning should be used.
• Optical comparators. When light is projected onto an object, its resulting shadow or silhouette can be used to take measurements or compare the shape to the specifications. Fiber optic technology can also be used for edge detection.
• Vision systems. This type of equipment uses a similar concept to optical comparators in that light is projected onto a screen. However, vision systems also use cameras or zoom optics to relay an image to a display. Other accessories such as edge detection, touch probes, other types of sensors, and automation technology can also often be integrated into these systems.

If you're not sure what type of dimensional inspection equipment makes the most sense for your application, working with an expert is best to ensure accurate results. Q-PLUS Labs provides in-house or on-site dimensional measurement services for virtually any industry or application.

What types of objects do you need to measure? Do you think that using a non-contact sensor is the best approach?

3D scanning can be used for a broad range of applications. For example, you might want to create a replica of an artifact or inspect a sand casting to a 3D CAD model. However, not all dimensional measurement applications warrant the use of 3D scanning. In some cases, a different or simpler approach might be appropriate.

So how do you know when not to use 3D scanning? If any of these three applications are similar to yours, you might want to re-evaluate your approach:
1. You only need to measure one dimension - The whole point of using 3D scanners is to measure objects in three dimensions. If you only need to know the length or width of an object, a simpler (and less expensive) measurement system or gage may suffice.
2. You need an extraordinarily high level of precision - certain high-end 3D scanners have the ability to produce very precise results, but some applications call for an immensely high degree of accuracy and precision. If you are measuring the profile of a ground cam or a high-speed gear, a non-contact 3D scanner will not likely be a viable solution.
3. Your object has interior surfaces that cannot be seen - If you can't see a given surface, an optical 3D scanner can't see it either. In these cases, a contact probe can often reach the geometry of interest such as a bore hole or other interior surfaces. In other cases, however, sectioning or slicing of the object may be required. CT scanning is also a possible solution however this method has several limitations of its own.
Fortunately, 3D scanners are just one of many tools in the dimensional measurement toolbox. Other types of measuring devices you can use include:
• Direct computer control coordinate measuring machine (DCC-CMM)
• Optical video probes and comparators
• Contour and form testers
• Reverse Rapid Prototyping system (CGI)

This short list represents just a few of the options that might be useful for your dimensional measurement applications. The best way to determine what type of equipment best matches your needs is to work with a qualified dimensional measurement service provider that has the experience and expertise to help you decide.

Q-PLUS Labs provides 3D scanning and a range of other dimensional measurement and inspection services, so no matter what measurement problem you are trying to solve, we can help. Contact us today to schedule a consultation.

What projects are you considering for 3D scanning? Might another measurement method provide the results you need?

3D scanning can be used for a broad range of applications, some of which you might not expect. It can be employed in any situation where the size, shape, and surface characteristics of an object are important. Advances in the technology have further broadened the scope of its utility. It is possible to measure geometry with greater accuracy as well as to capture small details that were previously not possible to measure.

The purpose of 3D scanning is to capture surface geometry, but the reasons you might want to do this can vary significantly. Some of the most common applications include:
1. Reverse engineering and protoyping - There are many reasons that one might want to replicate an object through reverse engineering, and 3D scanning is one of the most effective ways to create an accurate representation of the original object. The level of accuracy required can also vary depending on the application, so it is important to understand the objectives for reverse engineering.
2. Manufacturing quality control - In many cases, parts coming off a manufacturing line must meet specifications within a certain tolerance range. 3D scanning can be used to accept or reject products for quality control, and to ensure that mass-produced parts are able to fit together properly and consistently.
3. Industrial metrology - A highly detailed 3D representation of a machine part can be used to evaluate wear patterns, confirm the final build, and analyze other complex surfaces. It can also be used to replace old parts that do not have an existing CAD model.
4. Medical applications - Teeth, bones, and even skin surfaces can be modeled using 3D scanner equipment. This information can be used to create prosthetics, orthotics, and other medical devices.
5. Movie production - The entertainment industry uses 3D scans for visual effects and other 3D graphics. This technology is also commonly used for video games and animation. View our 3D scanning gallery to see how 3D renderings of people and other objects can be generated.
6. Artifact documentation - Archaeologists and other scientists can use 3D imaging to create replicas of unique artifacts and other materials of interest without damaging them. The scans can also be used for modeling, documentation, and restoration.

The type of 3D scanning equipment you select depends on the application and a number of other factors. Choosing the right equipment early in the process can help you save money and produce the best possible results. Q-PLUS Labs is here to help you select the right equipment, or you can outsource some or all of your 3D scanning needs directly to us. Contact us today to learn more or to schedule a consultation.

3D scanners are increasingly used for dimensional inspection and reverse engineering. Much like other measurement tools, these devices do not offer a one-size-fits-all solution. In fact, selecting the right 3D scanner is a rigorous process that depends on a number of factors.

Understanding these five common misconceptions about 3D scanners is a good first step toward selecting the right one:
1. All 3D scanning equipment uses the same technology - While virtually all 3D scanners are designed to collect data about the shape of an object, the methods for data collection and measurement are not all the same. Some 3D scanners use contact probes, while others use non-contact measurement methods such as structured white light or lasers to measure surface characteristics.

2. All 3D scanners can be used on any object - A shiny or transparent object will require a different 3D scanning device than an opaque one with a matte surface. Similarly, elastic or delicate materials cannot be measured with contact devices because they may become altered or damaged during the measurement process. The characteristics of the object will help define which 3D scanning equipment should be used.

3. All 3D scanners provide the same level of accuracy - 3D scanners use multiple data points to model the dimensions of an object. The more data points, the more accurate the result can be. The accuracy of a 3D scanner depends on the type of technology used, the quality of the cameras, the level of calibration, and several other factors; not all 3D scanning equipment provides the same level of accuracy.

4. All 3D scanners cost the same - Because 3D scanners use different types of technology and provide various levels of precision, equipment costs can vary substantially. This is one of the reasons it's so important to select the right equipment for your specific needs.

5. 3D scanners can only be used in a very limited number of applications - Some of the better known uses of 3D scanners include reverse engineering, manufacturing quality control, and prototype development, but the potential applications are unlimited. For example, the entertainment industry frequently uses 3D scanning in the development of video games; archaeologists use it to replicate artifacts; marketers use it for promotional videos; and the medical industry uses it to create prosthetic limbs and other medical devices.

Q-PLUS Labs provides 3D scanning and other metrology services. We are also a reseller of a wide array of dimensional measurement devices and systems from top manufacturers, serving a broad range of applications. If you need 3D scanning solutions, we can help you select the best tools for your applications, or provide the scanning services for you. Contact us today to learn more about the products and services we offer.

What applications have you used 3D scanning tools for?

Dimensional measurement is useful for much more than just production line setup and quality control. Manufacturing businesses can also greatly benefit from dimensional measurement in both prototypes and research.

Dimensional inspection during the production process can help prevent costly errors such as:
• Flawed batches - A production line that creates duplicate products requires precision setup and alignment. Errors in the production line can lead to entire batches of flawed goods, which can be quite costly for business owners. Dimensional measurement is worth the investment to prevent these expensive mistakes.
• Defective parts - Using dimensional inspection as part of the quality control process for high-precision manufacturing ensures that each part meets the required specifications.
Quality control is essential for producing consistent products, but implementing dimensional measurement even earlier in the process can help you prevent costly manufacturing errors that can lead to the following problems:
• Friction - Using a part that is just a little too large can result in friction, which leads to a shorter equipment life and possibly even greater problems. Using dimensional inspection to create properly sized parts can help prevent this problem.
• Stiction - Surface characteristics and size of manufacturing components can be very important in preventing stiction problems that may cause motors to work harder and become less efficient. Ensuring that a component is properly sized and has the specified surface characteristics can reduce errors caused by stiction.
• Mechanical stress - Improper alignment can put unnecessary stress on ball bearings and moving parts, causing more wear and tear on the machinery and possibly leading to equipment failure. Laser alignment can help prevent this problem and lengthen equipment life.

The entire point of manufacturing is to create a process that is repeatable, scalable, and reliable. When successful, it results in lower manufacturing costs and lower pricing for the end user. However, precise, accurate measurements are required for any manufacturing line to be successful.

Q-PLUS Labs offers a broad range of dimensional measurement services to help you avoid these manufacturing errors and more. Starting with a capability study is an excellent way to save time and money and improve the efficiency of your manufacturing process. Contact us today to learn more or to discuss how we can work together.

Dimensional measurement has very different meanings for different industries, which is one of the reasons it can be so difficult to determine what type of equipment to purchase. Even if you know exactly what you need to measure, there are still a lot of steps in the process before you make a purchase.

Dimensional Measurement Criteria

Specifying the equipment is the first step in the process. You will need to ask and answer a series of questions, including the following:
• How precise do you need to be? This is perhaps the most important question you must answer. Precision is a limiting factor that must be addressed early in the purchasing process. If you buy equipment that is unable to meet your precision requirements, it will be useless for your project.
• Do you need to meet regulatory requirements? If you work in an industry that requires regulatory reporting or auditing, it is important to take the correct measurements at the correct level of precision.
• How long will you need to use the equipment? Testing a series of prototypes may require you to use the equipment for several months and then no longer have a need for it. On the other hand, testing equipment for a production line will be in operation more frequently and for a longer period of time. In this case, it's important to select equipment that is durable and reliable.
• Is your staff trained to use the equipment? When it comes to dimensional measurement, the testing procedure can be just as important the equipment itself. Make sure you have qualified staff or an adequate training budget before you make a purchase.
• What is your budget? Knowing how much money you have to spend on equipment, staff, training, and operation is a critical factor in purchasing dimensional measurement products. You may find that purchasing used equipment is more cost effective, or decide that you can only support one type of measurement in-house?
• What is the size range of the parts? Smaller parts need different equipment than larger parts.
• What are the parts made of? Measuring soft rubber requires different sensors than hard metal.
• How difficult is it to use, calibrate, and repair the equipment? While your staff may be trained to use the equipment, it's important to know what type of support you will receive from the manufacturer and the supplier.

Work with a Dimensional Measurement Expert

Because there are so many factors to consider when making such an important decision, it's important to work with a qualified specialist throughout the purchasing process. A good provider will work with you through every step of the process:
1. Specify - You should go through a rigorous process to determine exactly what type of equipment you need. This will include answering the above questions and many more to ensure that your new equipment can meet your needs and integrate successfully into the rest of your process.
2. Purchase - After deciding what type of equipment you need, you have to decide which manufacturer to go with, whether to rent or buy, and whether to buy new or used products.
3. Set Up - A good provider will continue to support you after you've made a purchase. Proper set up is critical for accurate results.
4. Integrate - If your new equipment is part of a larger process, integration with other systems is a necessary part of setting it up.
5. Validate - After setup and integration, your new equipment must be tested to ensure that it is working properly.

In addition to providing outsourced dimensional measurement services, Q-Plus Labs also resells new, pre-owned, and custom measurement and inspection equipment. We work with a broad range of manufacturers and only sell equipment that we have approved to work in our own lab, so you can be confident that it will work for you. Contact us today to learn more about the products and services we offer.