error proof Archives - AUTOMATION INSIGHTS

More and more, retailer sellers are starting to require that manufacturers place RFID tags on their products before they leave the production facility and are shipped to those retail locations. From high-end electronics all the way down to socks and underwear are being tagged.

These tags are normally supplied by the retailer or through a contracted third party. Typically disposable UHF paper tags, they are only printed with a TID number and a unique EPC that may or may not correspond to the UPC and barcode that was used in the past. Most cases I have seen require that the UPC and a barcode be printed on these RFID tags so there is information available to the human eye and a barcode scanner when used.

While this is being asked for by the retailers, manufacturers can use these tags to their own advantage to track what products are going out to their shipping departments and in what quantities. This eliminates human error in the tracking process, something that has been a problem in the past, while also reducing workload as boxes of finished goods no longer must be opened, counted and inspected for accuracy.

A well-designed RFID portal for these items to pass through can scan for quantities and variances in types of items in boxes as they pass through the portal. Boxes that do not pass the scan criteria are then directed off to another area for rework and reevaluation. Using human inspection for just the boxes that do not pass the RFID scan greatly reduces the labor effort and expedites the shipping process.

I recently assisted with a manufacturer in the garment industry who was having to tag his garments for a major retailer with RFID tags that had the UPC and a barcode printed on them. The tags were supplied through the retailer and the EPCs on the tags were quite different then the UPC numbers printed on them.

The manufacturer wanted to know how many garments of each type were in each box. Testing showed that this could be done by creating a check point on his conveyor system and placing UHF RFID antennas in appropriate locations to ensure that all the garments in the box were detected and identified.

In this case, the manufacturer wanted was a simple stand-alone system that would display a count of different types of garments. An operator reviewed the results on a display and decided based on the results whether to accept the box and let the conveyor forward it to shipping or reject it and divert it to another conveyor line for inspection and adjustment.

While this system proved to be relatively simple and inexpensive, it satisfied the desires of the manufacturer. It is, however, possible to connect an RFID inspection station to a manufacturing information system that would know what to expect in each box and could automatically accept or reject boxes based on the results of the scans without human intervention and/or human error.

We have all gotten that dreaded phone call or email…the customer received their order, but there was a significant problem:

Missing part
Wrong color
Leaking seal
Improper assembly
Too lose…or too tight
Incomplete processing, e.g. missing threads
Something is damaged
Missing fluids or fluids at wrong level
…and so on

Assuming that we have reliable suppliers delivering quality parts that meet the required specifications…everything else that can (and often does) go wrong happens inside our own facilities. That means that solving the issues is our responsibility, but it also means that the solutions are completely under our control.

During the initial quality response meetings, at some point the subjects of “better worker training” and “more attention to detail and self-inspection” may come up. They are valid subjects that need to be addressed, but let’s face it: not every manufacturing and assembly problem can be solved by increased worker vigilance and dedication to workmanship. Nor, for that matter, is there the luxury of time or capacity for each worker to spend the extra time needed to ensure zero defects through inspection.

It is often more effective to eliminate errors at their source before they occur, so that further human intervention isn’t required or expected.

Some things to look for when searching for manufacturing trouble spots:

Are all fasteners present and properly tightened, in the proper torque sequence
Correct machine setup: is the right tool or fixture in place for the product being produced?
Manual data entry: does the process rely on human accuracy to input machine or product data?
Incorrect part: is it simply too hard to determine small differences by visual means alone?
Sequencing error: were the parts correct but came together in the wrong sequence?
Mislabeled component: would the operator realize that part is wrong if it was labeled incorrectly in the first place? Sometimes where the error has impact and where it actually occurred are in two different places.
Part not seated correctly: is everything is correct, but sometimes the part doesn’t sit properly in the assembly fixture?
Critical fluids: is the right fluid installed? Is it filled to the proper level?

Once the trouble spots have been identified, the next step is to implement a detection and/or prevention strategy. More information on the error proofing process is available on the Balluff website at www.balluff.us/errorproofing