Micrometer Accuracy: Drunken Threads and Slip-sticks With the number of micrometers on the shop floor and in inspection areas these days, it’s important to understand the degree of confidence that one can expect from these instruments. Whether it’s a screw thread or digital micrometer, the level of precision depends on two factors: the inherent accuracy of the reference (the screw thread or the digital scale) and process errors. With a screw micrometer, accuracy relies on the lead of the screw built into the micrometer barrel. As with any screw-based movement, error in this type of micrometer tends to be cumulative and increases with the length of the spindle travel. This is one reason micrometers come in 1 in. (25 mm) measuring ranges. Apart from the difficulty of making long, fine threads, the error generated over the longer lengths may not be acceptable enough to meet performance requirements. One approach that sometimes improves the overall performance of the measurement is to tune the micrometer to the range where it is most likely to be used. For example, if a 0 – 1 in. (0 – 25 mm) micrometer is to be used on parts towards the largest size, the micrometer could be calibrated and set up so that the optimum accuracy is at some point in its travel other than at its starting point. You could choose the middle to balance any errors at the end points, or elsewhere to maximize performance at any particular point of travel.To read the remainder of this article CLICK HERE. Micrometer with Integrated Wireless Data Transmission Simplifies Measuring — Mahr’s Micromar 40 EWRi digital micrometer with Integrated Wireless improves speed and quality assurance, eliminating cumbersome cables and external transmitters. Mahr’s wireless data transmission capability is integrated within its Micromar 40 EWRi digital micrometer. The 40 EWRi is the latest addition to Mahr’s Integrated Wireless family of products including digital calipers, indicators, and depth gages, which allow users to measure faster, more easily, and more reliably. Measurement data is transferred to an i-Stick on a computer without any interfering data cables, and MarCom Software makes data acquisition simple: just take a measurement and transmit measuring data directly into MS Excel or via a keyboard code into any Windows program or existing SPC application. Micromar 40 EWRi is the first digital micrometer with large, 10 mm digits on a high contrast digital display, making for safe, fatigue-free reading of the measured values. It offers an easy to understand tolerance display and additionally displays warning limits. The reference system in the Micromar 40 EWRi makes handling the micrometer very simple since the zero position is only set once. This setting remains stored for all further measurements. Also, a ‘Hold’ function (digital lock) allows measured values to be ‘frozen’ so they can be easily read. The highly precise Micromar 40 EWRi micrometer is equipped with a state-of-the-art inductive measuring system that exceeds international standards. Class IP65 protection against dust, coolants and lubricants makes the Micromar 40 EWRi ideally suited for use in difficult environments in the manufacturing industry. The MarConnect Integrated Wireless interface is active as soon as the i-Stick is plugged in. Once connected, each micrometer/caliper/indicator is identified by signal coding in the MarCom Software so there is no confusion as to which instrument is transmitting the data. The micrometer confirms whether the transmitted data was transferred correctly or whether the operator is in the receiving area of the i-Stick receiver. Since the wireless data transmitters are built into the micrometer/caliper/indicator, no interface boxes or additional batteries are required. Plus, integrating the transmitters into the gage electronics makes the units extremely energy efficient and can extend battery life up to 50% longer than competitive systems. To learn more about Mahr’s Wireless tools, CLICK HERE. Have a Gaging Tip question or success story? Send an email to the Gaging Guru at: george.schuetz@mahr.com |
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