A manufacturer of sub-surface oil well pump barrels needed a better way to check the inside of their barrels for wear. The barrels, some up to 30 feet long, must be periodically removed from the well and checked for excessive wear due to constant plunger motion.
The challenge has long been familiar: Every day a variety of parts, similar in size and shape, are manufactured, and they need to be inspected for conformance. What is different in today’s manufacturing environment is that long runs of the same parts are becoming rare.
The term “shaft measurement system” is standard industry parlance today, but to think of these gages as measuring only shafts is too limiting. For the most part, anything created as a turned part on a lathe is probably well suited for these devices. If there are features such as diameters, lengths, groove widths, fillet radii or chamfers on the part then it is well suited for measurement by a shaft measurement system.
A manufacturer of orthopedic implants needed to improve measurement and documentation proficiency of parts with literally hundreds of configurations. Air gaging was desired because it can quickly and accurately measure precision tapers.
The science of physics has a whole branch of study-fluid dynamics-devoted to understanding how fluids (liquids and gases) behave upon encountering various surfaces under differing conditions. In the dimensional metrology world, we look at things from the other side, and try to understand how part surfaces behave when encountering their counterparts and fulfilling their various functions.
System integration may seem complex. But the basic process is one that has been ongoing and evolving since a cave man first thought to attach a handle to a rock. The world of dimensional metrology has been undergoing a process of system integration in recent years that is significantly enhancing our ability to measure complex parts accurately and efficiently, and paving the way toward other, even more significant advances in the future.
When a gaging system is not performing as expected, the human tendency is to blame the gage or instrument for incorrect results. However, more times than not, the trouble lies elsewhere.
The characteristics on the surface of a part whether it’s dull or reflective, rough, smooth or even slippery can often affect the function of the part. For example, although it is counterintuitive, a surface that is too smooth can actually be ‘sticky.’
Apple Computer recently introduced its next generation iPad. Soon after, some media outlets said that this new technology might cause the laptop, a technology introduced 20 years earlier, to become obsolete. In April, the 20th anniversary of the column “Gaging Tips,” I reflected on how part measurement strategies, process and equipment have also evolved over the past 20 years.
Considerations for Measuring Large Precision Bearings
Mechanical bearings, including ball, roller, taper roller, needle, spherical and cylindrical, to mention a few, have been in use for hundreds of years, with countless designs, applications and sizes, and just as many measurement requirements that need to be defined and verified.
High precision orthopedic components can only meet high quality standards when the individual manufacturing steps starting with cutting and ending with final machining are consistently stable. This requires process oriented inspection of characteristics, along with fast feedback when tolerances have been exceeded, and documentation of all process data.
Convenience is one of the reasons the caliper is often the measurement tool of choice. The basic caliper provides direct size information, has relatively high resolution and is easily adaptable to different measurement applications. Beyond the basics, there are various caliper styles that extend these advantages to special measurement applications.
What do you do when you are doing everything right and it is still coming out all wrong? There are many times when dimensional gaging just does not seem to work, especially when part tolerances get tight.
Improve Surface Finish Measurement for Aerospace Manufacturing
In aerospace production, surface measurement often is used for many components, including high pressure hydraulic systems and fuel injection systems. The surfaces on these com-ponents often are narrow and difficult to access, frequently residing in small o-ring grooves or at odd angles on the ends of small, difficult-to-orient parts.
Engineered surfaces need specific characteristics in order to perform as desired. Surface measurement evaluates those characteristics and helps control the manufacturing processes to ensure that the surface will func-tion as desired.
Moving gaging to the point of manufacture is the process engineer’s dream. It is what drives productivity on the shop floor, puts quality in the hands of the machinist and quickly weeds out process problems before they become catastrophic.
Measuring calipers have been around for nearly 150 years. In that time they have evolved into fullfeatured digital measuring systems. But it is a testament to the simplicity and versatility of the original design that the evolution has been so slow and that so few changes have been required to produce the instruments we are familiar with today.
The subject is complex and there is no one-size-fits-all solution, even for the same dimension on the same type of part, measured under similar condi-tions but in different shops. There are, however, some broad distinctions that can be made in terms of levels of preci-sion, speed and throughput required that can help make the gage selection and mea-surement process easier.
During his recent presentation at the 2009 Quality Measurement Conference, Ted Dorion of NIST called gage blocks, “a zombie technology.” His point was that gage blocks represent calibration standards of the past—indeed, of the 19th century.
The Adjustable Snap Gage is a Versatile Tool for Taking OD Measurements on the Shop Floor.
There are many ways to measure an outside diameter (OD), including scales, micrometers, calipers, coordinate measuring machines (CMMs), optical beams and vision systems. The choice depends on many factors including tolerance, run size, operator skill, part size and, of course, budget.
Six Heads Better Than Two for Large Bearing Measurement
Producers of large, thin-walled bearings are faced with two key challenges. They need high precision, and they usually must produce many different bearing configurations in small volumes.
No matter whether you are interested in a machine tool, a metrology system or another precision device that relies on mechanical motion, what errors of mechanical motion are compensated for and how they are compensated directly impacts that system’s ability to operate at the highest level of capability.
There are many applications where custom tailoring a gage for an application can speed things up, improve accuracy, incorporate multiple measurements, generate sophisticated analysis or otherwise add value to the process.
Since the introduction of optical surface measurement systems some years ago, proponents have lauded the superiority of this technology, and predicted the imminent demise of more traditional tactile-based systems.
History of the Mahr Federal Precision Measurement Center
Much about the origins of the Mahr Federal Precision Measurement Center has settled into legend, as have any number of other stories about the uniqueness of its structure and the incredible precision of its instruments.
Split screen enables the user to view two features on the analog display screen at the same time. The digital display can also output two features at once.
Understanding the role frequency plays in the measurement process and why it needs to be specified on part prints is critical to making reliable quality checks on manufactured parts.
All calibration equipment should be periodically certified and documented with evidence of conformity to help ensure that parts get measured accurately.
CX 1 Height Gage From Mahr Federal Outpaces CMM For Quality Inspection At Gerhardt Gear
The Digimar CX1 is part of a family of motorized, programmable height measuring systems which offer a combination of features and performance previously available only in higher priced equipment.
Currently there are no standards for multisensor machines. How can we use our best knowledge of the measurement process and related conditions to estimate uncertainty values?
Whenever operators ask,“What is the accuracy of your multisensor machine?” Technically, an accu-rate answer is, “Excellent.” This surprises many people who are expecting a quan-titative “±X-type” answer.
Digimar® Height Gage Improves Efficiency And Throughput At NSK Steering Systems America Labs
The Digimar CX2 is part of a family of motorized, programmable height measuring systems which offer a combination of features and performance previously available only in higher priced equipment.
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