Your quality, production, purchasing, sales, shipping, legal, and IT departments can each provide compelling reasons why the tracking of individual parts through production -- and indeed throughout the entire product life cycle -- is fast becoming a no-brainer throughout industry. The reasons range from the need to quickly identify suspect parts, to being able to expedite work-in-process, speed distribution, prevent fraud, and control product liability.
Tracking substantially benefits the makers of virtually every component used in a vehicle, plane, or machine -- as well as virtually anything mechanical that comes in contact with the public. AIAG, ISO9000, and Spec 2000 requirements, and a burgeoning array of customer quality initiatives, are providing powerful impetus for individual parts tracking.
The tracking of individual parts is achieved most efficiently when the process is direct, that is, the parts -- rather than something separate that's hung on, radio-ed in, or labeled-on to them -- are what "does the talking." (The picture shows how John Deere uses Bumpy Bar Codes on connecting rods.) To achieve this, parts are marked with a Bumpy Bar Code. This unique technology, supplied by TraceAbility Systems (Ingomar, PA), uses a 3D mark which is expressed by highs and lows in surface height, rather than variations in black and white, as is the case with conventional bar coding.
The readers used with this system illuminate the bar code target with a laser, capturing the reflected image in a two-dimensional CCD. The angular displacement between the laser and CCD array allows detection of the differences in height, rather than contrast, to distinguish the bars and spaces of the code being read. This allows Bumpy Bar Codes to be read in the many situations where no contrast is available, for example, when the product is heat treated and the surface is dark, or where the product itself is dark. A complex algorithm provides redundant protection against mis-reading; an imperfect read will not process at all.
Parts that are marked with a BBC precisely identify themselves, generally by lot number, material, and date of manufacture. They can also express what processes have been applied to them (chemical baths, heat treating), what production machinery and work teams were involved, and for whom they were manufactured.
They can also express where they belong and where they're headed, so that if sequencing goes awry, production or shipping won't follow suit.
One interesting application of a Bumpy Bar Code system was the manufacture of injection molded parts, all of which were very similar in appearance. The manufacturer used dyes to distinguish them, and a sophisticated vision system to sort by color. The instrumentation was costly, but the ongoing cost of colorant was worse. The manufacturer subsequently discovered that he could, by making each individual part "tell its own story," eliminate the vision system and replace it with a simple, no-manual-action-required scanner. As a bonus, the manufacturer could upload and distribute this information, in its entirety, or selectively, to all of the diverse departments listed in the first sentence of this article.
Making parts able to communicate in this way can be accomplished using a range of methods. Simple indent marking equipment uses a pneumatically driven pair of styli to create a 3D "bumpy" bar code and its equivalent human-readable characters. One stylus has a chisel-like tip that creates a single bar; the other has a pointed tip that makes human-readable characters and dot peen matrices.
A 3D mark and its human-readable equivalent (if needed) can also be made using a CO2 (or YAG) focused-spot laser; this method is particularly well suited to high-volume part marking on metal, plastic, ceramic, and rubber. Die stamping, roll marking, and CNC machining can also create the Bumpy Bar Code mark, as can the direct molding and casting of code information intoplastic or metal. These latter two methods are ideal for marking part numbers, and are most beneficial where the conditions for reading the mark offer little or no contrast. (Tires, which are universally flat black, are an excellent example.)
Parts with Bumpy Bar Code data molded-in facilitate highly accurate automatic parts sortation, packaging, labeling, and shipping. The process is compatible with rubber and most plastics, and the high pressures used in these processes allow the creation of dimensional ("bumpy") bar codes with very small feature sizes.
The Bumpy Bar Code symbology pattern can be created by directly machining into a mold tool or by using an insert. One of the most persuasive advantages of what has come to be called "direct part marking," particularly for automakers and Tier 1s, is that the marking process itself can be made integral with production, adding little and often no extra time to the production cycle. This contrasts strikingly with the radio tags and printed labels, which must be made separately and attached or embedded mechanically. These "exterior" methods are also, for some applications, troubling in that full traceability is never possible, since the hangers-on aren't affixed until well into production, and is always interruptible, whether through deliberate or accidental means.
When parts carry their own data, true parts traceability can't be interrupted because the mark is a permanent feature of the part -- one that unlike radios or paper labels, will withstand heat treating, abrasive treatments, and being painted-over. Their readability is virtually impossible to destroy.
Parts that are permanently marked (and even thin gauge material can be marked successfully and without compromising material integrity) enhance the productivity of manufacturing plants, service centers, and distribution facilities, and make functions such as warranty fulfillment significantly easier and less subject to error. They are robust and flexible, and the equipment that makes them work integrates seamlessly with all the other automation marvels in today's factory
TraceAbility Systems manufactures and supplies markers and readers for indented Bumpy Bar Code, 2D Data Matrix and human-readable marks, including dot peen and laser systems. The company also specializes in custom software and engineering, and consulting for molding and machining the BBC mark into parts and material. Bumpy Bar Code is a trademark of TraceAbility Systems.
