2019cnc4-5

CNC WEST April/May 2019 www.CNC-West.com 57 Microchip manufacturing is rife with opportunities for auto- mated measurement. A seed crystal of silicon is grown into an ingot, then trimmed, dimensionally ground, flat ground, sliced, edge-rounded, lapped, etched, and polished. Up to 6,000 chips can be placed on a single 6-inch square of silicon, and the pathways can be as thin as 1/5000th of a human hair. Microchip inspection can include checking these path- ways for continuity. Microchip inspection is also a great ex- ample where it is impossible for humans to conduct without automation. Specialized equipment such as X-ray computed tomography (CT) machines also offer a way to examine in- ternal structures without destroying a part in the process. Ro- botic material handling and machine loading and unloading is one example of automating the inspection process. For parts of larger volumes, such as automobile bodies in white (BIW) or airplane fuselages, Laser Radar offers anoth- er automated inspection option. First of all, the Laser Radar measures three-dimensionally by measuring range using pro- prietary technology. Combined with vertical and horizontal angles we are able to measure objects in 3D. You can also think of it as a hybrid between a programmable CMM taking single points with high precision and a scanner taking up to 500 points per seconds or more. The first attribute is being non-contact. We literally bounce a focused infrared light beam off a surface to measure range. By contrast, laser trackers, which have been around awhile, require a cooperative retroreflector typically housed in a spherical mount called an SMR (spherically mounted retroreflector). This mirror corner-cube retroreflector must be hand carried or held in place by some mechanical or mag- netic means. The second attribute is automation. Since we don’t re- quire someone or something to move a sensor, we can au- tomatically direct the system to measure pre-determined or previously measured features. There are existing Laser Ra- dar applications that function in a “lights-out” or unattended manner. We do require a line of sight to the features, so vari- ous instrument positions may be required. But this can also be automated by using a robot or other positioning system to move the Laser Radar to any required viewing location. Alignment to the object is typically maintained with tooling balls. As a result, it is possible to completely orchestrate a mea- surement task by automating Laser Radar positioning and grouping viewable features for each position. We have con- ducted tests Laser Radar completed in six minutes what it took a coordinate measuring machine with horizontal arm 40 minutes to measure. Recipe for Forming the Future The following is offered as a set of guidelines for thinking about automating measurement. 1. Measure where it’s needed according to the custom- er’s vision and requirements. 2. Select your hardware partners according to compo- nent size and volume, the requirements for contact or non- contact, and to what degree automating the process adds value. 3. Select software that supports your metrology solu- tion, ability to automate, and clarity of the resulting reports. 4. Select integration partners by their familiarity with your industry and production requirements and their ability to coordinate and provide complete solutions. To recap, necessity will always be the mother of inven- tion. To risk providing another medical analogy, focus on your pain points. Better yet, focus on solutions that avoid creating the pain points. Try not to limit your thinking to conventional and familiar technologies and processes. At the same time, don’t let barriers get in the way. In production, as in life, to measure is to know, and knowing is better than hoping. Compared to laser scanners, Laser Radar does not need probes on the parts being measured, meaning it can be used in-line and not offline. Automating not only loading and unloading but between various means of measuring is an emerging metrology application.