Longer reading distances and faster transfer times give engine maker an edge.
Monitoring materials and products as they move through high speed manufacturing facilities has become increasingly more important as evolving concepts like lean and flexible manufacturing alter production facilities. Radio frequency identification (RFID) is also evolving, with technologies like ultra high frequency (UHF) RFID emerging to provide reliable contactless monitoring.
UHF RFID is on its way to becoming the new standard for identification and tracking in automated facilities. Startup costs can give some plant managers sticker shock, but there are many benefits that make it easier to justify the cost of adopting UHF RFID. For example, an engine manufacturing plant switched from HF RFID to UHF RFID, reducing downtime to provide a 50% return on investment in the first year.
There are strong technical rationales for those considering RFID tracking. UHF RFID operates at 915 MHz, giving it a longer reading range and faster data transfer speeds compared to HF RFID, which operates at 13.5 MHz. On the financial side, UHF tag costs can reduce cost by up to five times compared to HF tags.
There are also intangible returns on investment that are valuable to an organization. A UHF system can improve traceability and inventory management, especially compared to bar codes and manual tracking, helping companies get more efficient and lean. Companies working towards Industry 4.0 or IIoT will find the additional data extremely valuable.
For example, an engine-production plant realized significant benefits when it converted to UHF RFID. The seven-year-old facility, which typically makes 150 or more engines per day, had a problem in an engine test area. The HF RFID system embedded in the floor often failed to pick up engines when their carriers rolled over the checkpoint. Readers were often damaged by collisions or when oil and coolant spills seeped into packages.
Often, at least one of the 18 readers in the facility was problematic, leading to over 200 lost production hours annually, costing over $200,000 per year. Sometimes, data had to be entered manually. Other times, maintenance personnel were called in to fix problems.
Plant managers turned to a trusted partner that had helped with other automation challenges, Patti Engineering. The 40-person company specializes in heavy equipment manufacturing and RFID, among other technologies. Ian Mogab, one of Patti Engineering’s controls engineers, explains that the first step of any successful UHF RFID installation is a comprehensive site survey in an e-book, Your Guide to Implementing UHF RFID.
That survey should always bring in the actual readers, antennas and tags and performing tests in some of the worst-case locations. This will give a very good understanding of how the system will perform in a production environment. The layout is critical because UHF RFID signals have a long range, so they can interact with their surroundings more so than other RFID systems. Fields should not overlap, or problems can occur.
Integrators must also account for smaller secondary fields that are on the sides or back of the UHF antenna. The manufacturer’s specifications for spacing between readers provide information that helps installers avoid interference from these secondary fields. Interference from other readers can cause phase-shifts and cancellations, causing mysterious problems if reads or writes are triggered from both antennas simultaneously.
In most industrial sites, planners must consider the impact of large metal objects, which can create reflected fields that can cause readings of tags that are outside the desired main field. Additionally, metal objects can cause phase-shifts or cancellations, creating numerous issues. Liquid tends to absorb waves, creating holes or weak zones in a field. These factors should be noted and mitigated as much as possible during the project’s design phase.
Antenna and tag selection are also key elements that impact UHF RFID system performance, Mogab writes. Different tags have varying read distances based on the antenna that they are paired with, and each pair will have different characteristics. Picking the correct combination of tag and antenna is critical for success. The tag and antenna manufacturer’s documentation can be used to determine which pairing works best in an application. Patti engineers are also experienced in choosing the correct components for any system and can assist in making the decision.
Correct tuning and filtering of the RFID reader is decisive for system reliability. Using the Siemens RF600 web interface, read points can be easily tuned individually to optimize performance. Correct tuning will reduce bad reads, overshoots, reflections, and no-reads. Filtering helps remove any false reads from extraneous tags. The combination of proper tuning and filter implementation will make for a reliable, error-free system.
This technology provides huge potential for manufacturers looking to get on board with the industrial internet of things (IIoT) or Industry 4.0. UHF systems can be used for anything from lot-traceability systems to item-level tagging. For an assembly with thousands of parts, this level of tracking is now possible because the costs of UHF tags have been sharply reduced. This could allow a manufacturer to positively identify each and every part that is assembled.
Upfront planning is an absolute must when implementing a large-scale UHF project. A well-thought-out strategy can be the difference between a very reliable and successful system or one constantly plagued with issues.
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