TPi July 2017

products & developments Pipe and tube marking and measuring By Walter N Arth, Jr, director of automation and engineering, InfoSight Corporation, USA

There are many different needs for marking and measuring pipes and tubes for the OCTG industry. These needs continue to grow as API, customer and internal requirements become more demanding for proper identification, tracking and improved quality. Fortunately, the various technologies implemented to meet these changing needs also continue to evolve and can be used to reduce initial investment as well as downtime and maintenance costs. Specifically, advancements in lasers, robotics, sensors, machinery and automated stencil equipment as well as barcode marking and reading can improve accuracy and simplify implementation. To save on equipment cost, in-line equipment can be used. Length measurement and stencil marking are easily accomplished ‘on the fly’ (Figure 1), while weight can be measured on approaching ‘roll-by’ gravity transfer rails. Alternatively, if conveyor space is limited and/or cycle time is critical, cross-transfer equipment can be implemented to perform various functions simultaneously in a small footprint (Figure 2). The above are only examples. In either case, the equipment is used to first measure the pipe, and then perform tolerance checks, followed by marking as needed, and then finally to report the information on a per-pipe or per-order basis. Measurements include both length and weight, followed with associated

Figure 2: Cross-transfer weigh, measure, stamp and stencil

thread engagement verification ( 3 / 8 " triangle) is also growing. The specific marking processes can be performed in a number of automatic or manual methods, including stencilling, stamping, application of labels/tags, and line/band spraying. OD and ID stencilling can be on just one end of the pipe, both ends or even full-length, and can be achieved with in-line, cross transfer or overhead beam equipment. Variations of the above methods and requirements can often be combined into a single integrated machine commonly referred to as weigh measure stencil (WMS) equipment that utilises a multi-station cross-transfer machine to process multiple pipes at once. For example, the first station can process weigh and length measure functions, the second station can stamp, and the third station can stencil. The specific designs generated vary greatly based on needs and plant geometry. For example, equipment can include cross-transfer walking beams to move the pipe from station to station, or robots may be better suited for the variability of pipe dimensions associated with both ID and OD marking needs of stationary pipes. Individual requirements along with ingenuity and technology will drive the specific solution. InfoSight Corp – USA

tolerance checks and calculations to meet various API or customer-driven requirements. Length measuring methods including lasers, photo- eyes, proximity sensors, encoders, etc easily meet the API required ±0.1 foot accuracy, with typical actual length accuracies approaching ±0.03 foot (0.375"), and can be accomplished with contact or non-contact distance measuring devices. Accurate weight measurement can be performed via lift-and-weigh devices, cross-transfer equipment or even roll-by methods by installing the load cells beneath the support structure. The measurements are then used to validate, and report (tally) each specific pipe by performing weight-to-length calculations and comparing those to the API acceptable tolerances. Once the specific pipe measurement information is gathered and combined with the remaining message that has been downloaded from the host, the markings can be applied to a large variety of locations via numerous methods. The two most common methods are OD stencil and/or OD stamp marking of man-readable text and/or logos, followed by the need for OD colour bands. Additionally, barcodes (either 1D or 2D) can be utilised, not just to meet customer or end-user requirements, but also for manufacturers’ own internal tracking and traceability needs. Beyond that, interest in defect marking and

Figure 1: In-line length measure and stencil

sales@infosight.com www.infosight.com

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TUBE PRODUCTS INTERNATIONAL July 2017

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