PROJECT PROFILE #1

In the summer of 2003 Control Electric was called on to design, build and install a large material handling control system for a Northern Ohio Consumer Products Manufacturer. The control system controlled a large conveyor system that was used for both replenishment and order picking within the warehouse.

Conveyor Stem with Overhead Antenna (above)

This Customer operates both a manufacturing facility and a distribution center under the same roof. The conveyor system moves newly manu-factured products into the warehouse and at the same time orders are picked for shipment. The system consisted of over 110 conveyor motors, 44 sortation lanes, 16 UBT transfers used in product replenishment, 3 pick-to-light/put-to-light carousels, and many merges and diverters.

All manufactured goods are placed into standard sized totes and conveyed into the warehouse. Because the totes are used for both replenishment and picking, it was necessary to assign each tote a unique ID number for tracking purposes. Because the totes were square in shape and it would be difficult to maintain orientation throughout the conveyor system, we decided against using barcode labels for the tote ID's. We would have needed to install these barcode labels on all four tote sides and install expensive barcode scanners at 14 locations throughout the warehouse. Instead, we installed 14 RFID readers each with approximately a 14" read range. The readers were mounted on frames over the centerline of the 24" wide conveyors. Each tote had one RFID tag installed near the top edge of the tote. Using RFID products saved the Customer over $45,000 when compared to using barcode scanners. Because there are no moving parts or optics used in RFID, we anticipate a longer operating life with RFID products compared to barcode scanners.

Regardless of tote orientation, using RFID readers, we are able to read 99.99% of all totes and sort accordingly. Because RFID readers do not require line of sight, tote orientation is not required. Tote tags are printed with a barcode and then laminated. The tote ID is also human readable. This makes the totes very versatile in that each tote can be read by RFID readers, handheld barcode readers and humans looking at the totes.

Our software engineers designed and programmed an extensive C++ application for tracking and sorting totes, and maintaining an inventory location database. The custom program also interfaced with the PLC control system. We used distributed I/O throughout the conveyor system to minimize wiring.

PROJECT PROFILE #2

A Customer of ours recently asked us to come up with a solution for tracking metal assemblies through-out their manufacturing operation. Each assembly is mounted to a special fixture that looks much like a metal skid. These fixtures are conveyed throughout their manufacturing department from one process to another. Their manufacturing department is made up of 16 work cells. Each work cell performs specific tasks. Fixtured assemblies need only to go to certain work cells depending on its build instructions.

Our solution was to install a RFID tag on each fixture and when the fixture is first introduced to the conveyor system, an operator, using a series of pushbuttons, selects which work cells the assembly needs to report to. Once the work cells are determined by reviewing the work order, the info is automatically written to the TAG and the fixture is released onto the conveyor system. The conveyor system has a diverter that diverts the fixtures into each work cell. At each diverter we installed a RFID reader. When the fixture arrives at each reader, the tag is read and it is determined whether or not that fixture needs to go to that cell. If not, the fixture continues down the conveyor system to the next work cell. The tags are read while in motion and the main sorter conveyor does not need to stop.

RFID proved to be a very cost effective solution. No software was required to track each fixture and no data base's was needed to determine which fixtures need to go to specific work cells. Because the Customer only has 400 fixtures in use, we only needed to purchase and install 400 tags. The cost of the RFID system was significantly less than a barcode system.