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Precision 3D Laser & CT Scanning Bring “Big Data” Directly To The Top Floor From The Shop Floor

Industry 4.0 Through The “Eyes” Of Metrology

Industry 4.0 – Big data – The Internet of Things (IoT) – We’ve all heard these phrases a hundred times in the last few years. What do they mean? How can they impact your business on a daily basis? Metrology company, Exact Metrology co-owners Steve Young and Dean Solberg, bring a slightly different perspective to these questions, and in this article share their thoughts on the growing interconnection between, as they say, “the Shop Floor and the Top Floor.”

Production management has always relied on data as its driver. Whether at a large OEM, a contract manufacturer or a job shop, there’s always been the need to review the information on production. From analyzing the piece part consistency across a batch run to the taking of CMM measurements (high-tech descendant of the caliper and go/no-go gauge) and the comparison of part dimensions to the drawing or CAD file, with subsequent adjustment on the machine tool control, this function has always been a necessary and vital component of the machine tool world, whether those machines were making nuts and bolts, tool/die sets, mold components or turbine blades for a jet engine.

Those adjustments on the machine tool were once made by master craftsmen with handwheels, then NC punch tapes through a DRO and now on the heart of the modern machine tool, the computer numerical control (CNC). Until just a decade ago at most shops, the production data would be read and compared to the design, the manager would jump out of his chair, run out into the shop and stop the machine operator, bringing along the programmer to reset the parameters, check the tooling, re-calibrate the zero point, load the next blank and hit cycle start. Meanwhile, a lot of product went into the scrap bin. In today’s competitive and highly automated machine shop world, this must read like ancient history to many of you, of course.

The last decade has seen everything from the emergence of PLM software, which seamlessly blends the design and production software with the actual output data, to the latest CNC, which can integrate all the data in both directions and make the instant algorithmic adjustments to the cutting parameters of the cycle to keep production as consistent as possible, taking into account all the tool data, thermal expansion and machine kinematic information, because it ALL impacts quality on the produced part runs in your shops.

Enter Metrology  

This idea, for those who don’t know the term too well, simply refers to the systematic and highly precise gathering of data in time and space. A part can be fixtured, scanned and swapped out on a work table next to the machine or, in the most advanced production machining centers, in-process on the actual work table of the machine tool, using highly controlled robots for both part articulation and metrology sensor. Today’s CNC can even run these robotics on a second channel of the control, from a remote pendant, so the operator becomes both machinist and CMM operator simultaneously.

Now, The Real Fun Begins….

All these data points, which are gathered by the reflection of the light beam and captured in the software of the scanner, can be instantly sent over a communication bus to a host computer in the QC department. There, the points are compared to the CAD file, the CAM file is recalculated or the CNC can do it on the machine in-process (very new technology there) and the machine makes the very next part to the correct specification, altering the cutting parameters to offset the thermal or tool wear conditions or even the machine kinematics.

CT Scan of Automotive Component

The very latest advancement in our world is the introduction of the industrial CT scanner, where the internal geometry of a metal casting or forging, injection molded plastic or autoclaved composite part is examined, as well.  The data points here render an image many may recognize from the medical world, when you’ve had a CT scan. By examining the internal conformation of a part, additional data can be gathered on why an identical tool might make radically different impact on a material surface. Information overload? Not at 38,000 feet with a turbine blade in today’s jet engine.

Industry 4.0, to encapsulate the concept, seeks to fundamentally alter the interaction between worker and machine. The integration of manufacturing, IT and cybersystems, including security, plays an ever-growing and evolving role in the manufacturing world at all machine shops today, whether they be a family-run mold shop, a 100-person contract manufacturer or the production department at a major transmission builder.

Metrology doesn’t seek to alter the data, rather it seeks to enhance it, speed its collection (as in light speed!) and, most importantly perhaps, reduce and eventually eliminate the scrap and downtime in a process by gathering the information and acting upon its significance in the most effective, efficient manner possible.

Let’s look at an example:

Volume Graphics CT Scan Topographical Error Report

The parts shown above is an automotive components.  The 3D scan can produce a dense point analysis for comparison of an “as machined” image to the pristine “as designed” CAD file. The scanning software can also render the 3D CAD comparison and deviation plot, which are significant steps up from the CMM or optical gauge capability.  Conventional first-article inspection reports are also possible output from the scanning software technology today.  Using the latter, also known as a 3D color map, which immediately visualizes the scanned object against the nominal design and is available almost immediately post-scan.

Over time, SPC data can be developed as color maps or simply detailed, tabular data to track the performance of your machines in a preventive or predictive maintenance mode, as well as for OEE indexing.

Portable Arm CMM Laser Scanning

Scanning modes vary and are as detailed below:

Laser scanners are typically mounted on a robotic arm with an optical scanning system; can work in an area up to 18 feet in diameter and produce data at a rate of nearly 500,000 points per second

White/blue light scanners, mounted on a tripod or robot, capture more than 18,000,000 points per second; in a single shot, white light scanning can take measurements in an area from less then a square inch to several square feet

CT scanning allows the measurement of internal structures of parts by generating a voxel cloud from a number of two-dimensional x-ray pictures which can be converted to point cloud data

Resolution on all these technologies is today as tight as 0.0127 mm (0.0005”). Combined with the accuracy, which rivals all current CMM technologies, laser and white light scanning are perfect for micro to large machined parts. When the advantages of a portable CMM (PCMM) are needed, the laser scanner is simply replaced with a touch probe on the robot arm with optical trackers. This gives the shop the benefits of both high-density scanning and high-precision point measurement on the same part.

A last consideration in the rapidly advancing world of Industry 4.0 is cybersecurity. As the manufacturing world transitions from the open cloud to the closed cloud, the protection of your shop’s intellectual property will be vital and those of us in the metrology business remain watchful for the trends in this area, so we respond with the proper safeguards on the big data our technology produces for you.

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