7/1/2001 | 7 MINUTE READ


Facebook Share Icon LinkedIn Share Icon Twitter Share Icon Share by EMail icon Print Icon

Keeping track of assets—be they parts or entire vehicles—can be more readily done in the largest production plants and associated parking lots through the implementation of a radio-frequency-based system.


Facebook Share Icon LinkedIn Share Icon Twitter Share Icon Share by EMail icon Print Icon

Knowing where things are—physical, actual things, like vehicles, not computer information about things—is certainly helpful for operating an efficient supply chain: Or, more to the point, a physical link in said chain, as in a factory. Which is a large part of the functionality of the technologies proffered by WhereNet Technologies (Santa Clara, CA). This is wireless technology. This is technology that is said to provide "real-time location" of products. The company, which was established in 1997, has numerous applications in numerous industries in numerous countries; one of the prime areas they've identified for implementation is automotive.

Case in point: at Ford. This is no trivial application: the implementation received one of a handful of Henry Ford Technology Awards in 2000.

High-tech Kanban.
This is the "WhereCall Parts Replenishment System," which works in conjunction with Ford's SMART parts replacement program. A key element is the WhereCall tag, a transmitter. In an assembly operation, when an operator needs more parts, she pushes a button on the tag, which then sends a signal (it uses low-power, spread-spectrum radio frequency technology), which is picked up by antennas, location processors, and then processed by software. The result of which is that the materials replenishment people get the alert that there is a request for parts. (There is even a timer so that the operator can determine whether or not the request is being honored in a timely manner.)

This is said to provide several benefits for Ford (given that it has been installed in 20 Ford plants and is scheduled to be used in many more, there must be a good return being realized). For one thing, compared to wired call systems, it is faster to set up (operators can simply affix the tags in their workstations) and a whole lot less expensive (no running reels of cable is required). And when there is a change to the line, due to either rebalancing of existing processes or because of a new product, the tags can be reused, simply associated with new parts. In addition, because there is that timing function, there is the ability to use the data to make determinations for process engineering, noting, for example, how long it really takes for deliveries.

In a very real sense, it is kanban gone high tech.

Where Did I Park It...?
Ford has also installed a different type of system from WhereNet, this called the "WhereSoft Vehicle" application. Once again, there are the elements of the transponder tags, antennas, location processors, and software. But this time, instead of parts, the tags are placed in vehicles when they are in final assembly. The benefit here is that there is certainty of precisely where that vehicle is. For one thing, it makes it possible to determine if there are assembly bottlenecks. But it is especially important when the vehicle is complete and it is parked on a lot outside of the factory in the shipping yard. When it is necessary to find a particular vehicle, it can be located to within 10 feet. It isn't necessary for people to be wandering through the lot looking for just the right vehicle for, say, a custom dealer order or in case there is a quality control hold being placed on a particular group of vehicles. Apparently the ability to quickly locate vehicles means huge dollar savings through superior inventory control.

(By the way: before the vehicles are rolled off on trains or trucks, the tags are removed for re-use.)

Technology, Briefly.
From a technical standpoint, the WhereNet engineers have developed a system that uses direct sequence spread spectrum radio frequency (DSSS RF) technology. It's not Bluetooth. It's not GPS. What you simply need to know is that the WhereTags send out low-power signals that are spread across 60 MHz. Because they are low power transmitters, the lithium batteries within them can last for years Because of the spectrum spread, there is minimal RF pollution.

So there is a beacon, sending out a signal at a set period of time. The signal is received by antennas that are installed in a known grid pattern. What happens is that the signal is received by three different antennas at slightly different times. It is known when the signal was sent. It is known where each of those antennas is located. As a result of comparing the time with the known place, the system is able to calculate where the beacon is located.

In addition to which, along with the "here I am" signal, there is as much as 96 bits of telemetry information sent, which allows additional information about what is where (e.g., what the VIN number is).

Not only does this all facilitate simple location on the screen of a PC, but it also permits displaying the information across the Web—for extensive supply chain visibility.

There are additional applications developed for this technology. For example, there is container management: permanently tag a container and keep track of where it is and what it contains. And there is yard management, which permits knowing where trailers, tractors and tugs are at all times when they roll into a plant site.

on-line parts replenishment
Here's how the technology is used at Ford for on-line parts replenishment.

Zeiss Launches Linux
2001 SAMC

Linux for metrology
Linux for metrology: Zeiss offers the capability from moving UMESS from a workstation to a PC.

Linux-based PCs can now be used to run UMESS-UX-based metrology programs for coordinate measuring machines–heretofore run only on Unix workstations–through a new offering from Carl Zeiss IMT Corp. (Minneapolis). According to the folks from Zeiss, Linux (they're providing a Red Hat distribution of the platform) provides a "reliable platform to run UMESS-generated programs." Apparently, just minor "low-cost" modifications need to be made to the UMESS-UX programs; functionality is not lost. The Zeiss people suggest that people can run Linux and Windows NT on the same machine, using NT for CALYPSO measuring programs and Linux for the UMESS-directed measurements. Lest there be some concern about UMESS Linux: Zeiss tested it using test data records from the Physikalisch-Technische Bundesanstalt.

Industrial Strength
2001 SAMC

Looks like a mill
Looks like a mill. Measures to microns.

One of the more striking aspects of the HoloVision HV3000 3D measuring system from coherix (Ann Arbor, MI), which is described in its literature as "an advanced process analysis and measurement instrument," a device that uses tunable laser light to obtain accurate (a resolution to 0.002 mm on a part measuring 900 x 1,200 x 600 mm) measurements of parts that can include things such as ABS and fuel injector components or wheel hub assemblies (this is 3D measurement), is that it resembles something else entirely. A knee mill. A Bridgeport knee mill, which is probably the quintessential machine tool design of the 20th century. Peter Ackroyd, the firm's vp of Sale and Marketing, explains that when they were developing the product, they spent time in factories, where the tool is to be deployed. "We wanted something solid—like a Bridgeport," Ackroyd remarks. So the industrial designers set out to develop the new unit... and came back saying that the Bridgeport base casting and table are ideal. And so that's what they're using. The real thing.

Another aspect of the system—and this as up-to-the-moment as the knee mill design is classic—is the use of the XactCOM metrology architecture, which sits on top of a Microsoft platform. XactCOM is from Xygent Inc., (North Kingstown, RI) which was recently spun off from Brown & Sharpe Manufacturing Co. An objective of XactCOM (and the applications below it) is to provide a simple-but-powerful means by which any inspection device can be programmed and deployed. One of the hallmarks is the simplicity of the front end (vide Microsoft Windows), and as the HV3000 is capable of capturing one million points per minute, ease-of-use of the software is certainly a valuable virtue.

Portable & Accurate
2001 SAMC

non-contact inspection
By using non-contact inspection, large manufactured parts can be compared with their CAD models.

The name says it all: Optigo. As in optical (it is a non-contact 3D measuring machine) and go (i.e., it is portable, actually rolled around like one of those cameras used in TV studios). The latest in the lineup from CogniTens (Ramat Hasharon, Israel) is the Optigo 100E, which has an optical head that employs three high-resolution CCD cameras. Fundamentally, a sequence of 2D images is obtained by the optical head; the view size is up to 450 x 670 mm (a density of 400,000 points per view can be obtained), so by taking a sequence of views, large parts (one example shown is a car door) can be handled. Based on the 2D images, computer algorithms calculate 3D measurements; features that are measured include holes, slots and edges. This measurement information can then be used for comparison with the CAD model; this can be performed automatically. The accuracy is in the 30 to 100 micron range.

The system is designed to operate in the factory environment so parts can be measured at the production line (say for auditing purposes). Optigo runs on a native Windows NT platform.

Thanks for considering a subscription to Automotive Design & Production. We’re sorry to see you go, but if you change your mind, we’d still love to have you as a reader. Just click here.