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3 Surprising Facts about Dimensional Inspection

Posted by Mike Knicker on Nov 30, 2016 2:22:19 PM

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When you think about your daily life the topic of dimensional inspection will likely never come up. In fact, many people could go through their lives not understanding how dimensional inspection works, let alone how it fits into almost every aspect of their daily lives through the products they use. From the coffee cup that you may be holding right now as you read this article to the car you drive (hopefully not while you are reading this article), dimensional inspection was an integral part of the manufacturing process for all of the products you use in your daily life.

What Is Dimensional Inspection?

Simply put, dimensional inspection is the measurement of the distances between different features on a part. If you have a block that is supposed to be one inch long, then dimensional inspection will tell you exactly how long that block actually is. This is a simple case, but think about the intricate measurements required to make sure that each individual part of your car engine will fit together properly in order to move the pistons for you to be able to drive your car.

Even your simple water bottle needs to have very close dimensional measurements in order for the bottle top to screw onto the bottle and provide a tight seal for the water; if the dimensions are not correct then you may have trouble storing the bottle without spilling its contents, or even have an issue trying to fit the lid back onto it once you’ve removed it. This ability of the parts to connect correctly is designed into the dimensions of each part, but dimensional inspection of the individual parts to make sure they meet the design is what ensures the end product will work when it gets to you.

When it is not feasible to measure each dimension on each part, (for instance water bottles would become very expensive), dimensional inspection is used on the tools that make the parts such as injection molding dies that form a water bottle out of molten plastic. If the tool dies are ensured to have the right measurements, then the resulting bottles will be correct; a company can then check a sample product at intervals to make sure that the forming process is working properly as it progresses. So even then dimensional inspection is used on a sample basis.

Dimensional Inspection: 3 Surprising Facts

It should no longer surprise you that dimensional inspection is found throughout the manufacturing processes of almost every product that you use to ensure the safety and integrity of those products, but there are still some facts about dimensional inspection that you might find surprising.

  1. Tight tolerances: Dimensions are never measured to exactly what the design measurement should be (called the nominal dimension) so each design will have a tolerance on the dimension; basically, a stated amount that the dimension can be different from the nominal dimension. So, if you have a measurement that needs to be at one inch, but can be different from this measurement by one-sixteenth of an inch, your tolerance would be +/- (plus or minus) one sixteenth of an inch. In some industries, such as the space industry that builds satellites or parts for the space station these tolerances can be very tight, such as one ten thousandth of an inch (0.0001”) in order for the parts to work reliably in the space environment. This is for the safety of the astronauts or for the reliability of the satellite since you cannot fix a problem once in orbit.

  2. Tighter measurements: A general rule of dimensional inspection is that the dimensional measuring equipment should be ten times better than the tolerance being measured. That means if you are measuring something to the nearest inch your measuring equipment needs to be able to measure to one tenth of an inch. For the above example, if you are measuring to one ten thousandth of an inch (0.0001”) your measuring equipment needs to be accurate to one hundred thousandth of an inch (0.00001”). So, dimensional measurement equipment can be extremely accurate.

  3. Calibration: Equipment for dimensional inspection needs to be checked on a regular basis to make sure that it is still measuring as accurately as it is designed to measure. This verification is done against a very accurate standard part or specimen that has been designed and verified to a certain dimensions and tolerances. By ensuring that the dimensional equipment measures the standard correctly you can be confident that the equipment is functioning properly. Most of these standards are traceable back to the National Institute of Standards and Technology (NIST), which is part of the United States Department of Commerce, but is a non-regulatory agency. NIST is the foremost measurement standards laboratory and is used as the standard for calibrations in most industries.

Dimensional Measurements: In-House or Outsourced

While many companies keep all of the equipment they need to perform all of their dimensional inspections sometimes the equipment is so expensive, and the measurements taken so infrequently, that it makes more sense to have an expert laboratory do the measurements for you. In either case the experts at Q-PLUS are the place to turn for either help on the right equipment to purchase, or the accurate tools to measure your most intricate dimensions and the skilled operators to run that equipment.

Q-PLUS Labs has been a leading dimensional measurement laboratory since 1987; providing one place for precision measurement solutions. As a lab registered to ISO 9001 and accredited to ISO 17025, you can be certain that you will get the right dimensional measurements and calibrations every time.

Nano Measurement Ebook

 

 
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Topics: dimensional measurement, dimensional inspection, dimensional inspection equipment, dimensional measurement services, nano, measurement services,, nanomeasurements

Nano measurements: 3 basic factors for determining the value of your measurement data

Posted by Mike Knicker on Nov 4, 2016 12:29:05 PM

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With the rapid development of technology comes the greater need for the increased accuracy in measurement capabilities that are able to keep up with the pace of products being manufactured at the nano level. For precise accuracy up to the micrometer, such as 3D measurement data of a needle tip or surface roughness measured to extreme accuracy, nano measurement is the logical solution for these intricate measurements. But how do you know if it is worth your time to invest in this specific measurement solution for your application?

Of course, every measurement technique has its challenges, and with the various methods of nano measurement, there are generally three things to consider when choosing the best method for your application; specifically measurement accuracy, speed, and cost. While there are two main methods of acquiring nano measurement data, optical-based and contact-based, you will need to examine these three basic criteria when you are weighing your decision on which type of method to implement.

Accuracy of measurement

What benefit will this measurement data provide your application? To measure in the nano realm, there are two types of methods. One way is via contact-based methods of nano measurement which can give very high resolution measurements with high accuracy. This is due to the fact that they come in contact with the surface of the part being measured, so that certain features the probe comes in contact with can more easily be distinguish, and thereby measured accurately. However, parts that may become compromised if they come into direct contact with the measuring device would not be suited for this particular form of measurement.

This is only a general rule of thumb, however, as white light interferometry, a type of optical-based measurement, is one of the most accurate methods possible even though it does not come in contact with the measured unit.

Speed of measurement

If you are looking for a faster measurement solution, an optical-based method of nano measurement may be the best option, because this method uses light to take the measurement and does not physically come into contact with the surface that it is measuring. This process speeds up the collection of measurement data without the risk of surface damage, unlike what can be experienced with a probe used in the contact-based methods.

One drawback of these faster methods of measurement may be the loss of some resolution on surfaces with high aspect ratios; such as a surface with features such as steps, slopes, holes or sharp edges. These can be much more accurately measured with a contact-based method, but this will be more time consuming in order to protect the surface of the piece being measured.

Cost to measure

Of course different measurement systems will have different financial costs associated with them, and this will have to be weighed when choosing the right system to meet your needs. When making your decision on accuracy, precision, and speed you will need to keep in mind how much the measurement data will cost. Along these lines, the following are some things to consider:

  1. Will it be more cost efficient to purchase the equipment to perform your measurements in-house; or would it be better to outsource this activity to a lab that specializes in these measurements? If you manufacture a part in-house and need to perform repeated measurements, then it might be in your best interest to invest in the equipment and training necessary to do the measurements yourself.

  2. A major benefit of going to a lab for your measurement needs is the specialization that they have in performing these measurements with the appropriate training, experience and equipment to give you the data you need. Labs are fairly flexible and can be great assets for measurements of one-off parts as well as large ongoing jobs.

While you can make some adjustments to reduce the cost per part, such as reducing the sample frequency of measurements, ensuring that you get exactly the type of measurements for the data you are looking for is one of the best ways to reduce your cost overall.

Having difficulty getting started on your measurement project? Since 1987, Q-PLUS Labs has provided a one stop solution for precision measurements to our customers. As a leading dimensional measurement laboratory, we have been able to not only supply measurement services and calibrations as needed but also consult on, specify, integrate, and sell in-house measurement solutions to meet the many and varying needs of the manufacturing industry. As a lab registered to ISO 9001 and accredited to ISO 17025, we've built our reputation on providing objective, unbiased information whether it be from our lab services department or our metrology products division.

Nano Measurement Ebook

 

 
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Topics: dimensional measurement, dimensional inspection, dimensional inspection equipment, dimensional measurement services, nano, measurement services,, nanomeasurements

Q-PLUS Labs' Case Study: Extreme Components, LP's Surface Finish Analysis of DAT Mold Interlocks

Posted by Mike Knicker on Aug 12, 2016 12:47:02 PM

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Extreme Components, LP is known for designing and creating cost-saving, effective alignment/positioning devices for the Injection Mold Industry that are durable, reliable, and high precision. Their molding alignment locks are manufactured using dynamic alignment technology or DAT, which is a revolutionary method for self-aligning locks that involves minimal friction and wear, even at high speeds. Using Q-PLUS Labs’ nano measurement expertise, Extreme Components, LP wanted to use the surface finish analysis results to find out precisely how well their DAT locks held up against the wear of daily use versus the traditional friction-fit locks.

Introduction

Extreme Components, LP's unique product was designed using DAT which consists of rollers constrained in a cage, and moving in a prescribed manner due to the kinematic relationship between the rollers. The tongue is moved relative to the housing without direct mechanical contact between the tongue and the housing. Because there is very minimal friction between parts, the process decreases the amount of wear that would normally be experienced using methods such as those used with traditional friction-fit locks.

Our Process

Color_Map.jpgTo analyze the exact amount of wear, Q-PLUS Labs performed a surface roughness analysis to confirm the wear on the unused surface of a traditional friction-fit lock versus the wear experienced by Extreme Components LP’s DAT locks after multiple uses. This was accomplished using white light profilometry from CyberTechnologies’ CT 300. The subsequent data from the unused surface of a friction-fit lock revealed an average roughness of 10.6 micro inches. There was major deviation from the level surface while the actual tongue contact surface was too rough to measure using conventional high precision instruments due to galling, or wear caused by adhesion between sliding surfaces, which could be observed from visual inspection.

Color_Map_EC.jpgIn comparison to the friction-fit lock, Extreme Components’ DAT lock that had been used by a multinational medical device manufacturer for 4 years of near continuous service, cycling every seven seconds with a 2,300 pound load yielding more than 10 million cycles, was measured to have a surface roughness of only 5.7 micro inches. The data of the surface map displays better uniformity than the friction-fit lock, and visual inspection shows the DAT lock’s mirror-like surface and no galling.

Usually, this measurement was done using far less accurate and time consuming means. However, with the rapid and accurate surface finish analysis data Q-PLUS Lab’s provided, Extreme Components was not only able to effectively compare their DAT locks to traditional friction-fit locks, but visually show customers the value of how their product holds up in real use scenarios.

 
Nano Measurement Ebook

 

 
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Topics: manufacturing, 3D scanners, 3D Scanning, 3D scanning equipment, case studies, nano measurement,, CT300, nano