CIM helps compounder keep its colors true.
The eleven divisions of PMS Consolidated, the color concentrate giant, share pigment information and product formulations about as easily as if they occupied the same building. Though in fact, the company has manufacturing facilities spread out from coast to coast, and each uses nearly endless combinations of colorants and resins. Yet thanks to a sophisticated color-control system, PMS has achieved an impressive level of computer integration among its far-flung manufacturing plants, its technical center in Coral Springs, Fla., and corporate headquarters in Suwannee, Ga. In so doing, the company says it has gained the all-important ability to quickly produce consistent, reproducible colors regardless of plant location, mixing process or polymer. "We don't have to reinvent the wheel 11 times," says project engineer Tracy Phillips at the Florida technical center.
Given the nature of PMS' products, the company's computer-integrated manufacturing (CIM) plan necessarily hinges on color management. At its heart, a commercial software package helps match and then formulate colors based on customer samples. But PMS goes a step further by linking all its divisions via modem and electronic bulletin board, enabling each to dip easily into a vast, standardized database of colorant information. Equally important, PMS makes use of an IBM AS/400 midrange computer for formulation storage and production management, though not directly for color-matching applications.
When it comes to color information, this companywide practice of share and share alike translates into some real benefits from the standpoints of quality and customer service. "Integration and standardization of color-control technologies across resins, markets, processes and manufacturing plants were determined to be keys to quality and service," explains Leo Valdiserri, v.p. of corporate technical development.
Now colors matched at one plant or at the Corporate Technical Center (CTC) can be reproduced more easily and accurately at another location. And even small delays, like those associated with sending formulas or other colorant information through the mail, disappear with modern use. The company says this increased "formula portability" becomes especially attractive for national customers favoring a regional manufacturing approach. This way, geographically separated facilities making the same product still can purchase their colors locally.
Despite the benefits, PMS' experience also underscores some of the difficulties in adopting a CIM plan. "Some of the system's capabilities haven't filtered down to the division level yet," concedes Phillips. But that won't be true for long, she says.
COMMUNICATION IS KEY
Far from arriving at its current approach overnight, PMS has a 20-year history of computerized color management. It previously relied on both the minicomputer- and PC-based forebears of its current software package, Chroma-Calc 2.0 from Datacolor International Inc. of Lawrenceville, N.J. But in adopting its current system, PMS has truly embraced the information age. According to Datacolor International president Terry Downes, the high degree of integration among the PMS sites may be unrivaled right now, even though there are many other users of the latest Chroma-Calc.
At each PMS manufacturing facility, as well as the CTC, the matching process begins with what is best considered a "color workstation." Like standalone color-matching systems, each color workstation on the PMS network uses a spectrophotometer to measure the light reflectance or transmittance patterns associated with a given color. If shown graphically, this information appears as a distinct spectral curve for each color. The instrument's readings of a sample are then analyzed by the Chroma-Calc 2.0 PC-based software, which has been designed specifically for plastics applications. Using the CTC's database of pigment and resin characterizations, the software helps an operator come up with the best pigment formulation for matching a customer's sample color.
Here the similarity with standalone setups ends, and the PMS system's communication capabilities enter the picture. Rick Johnston, color systems specialist at PMS, explains that the system has been built on a "hub concept." Colorant information radiates to the divisions from the CTC, where the ongoing work of characterizing the color behavior of the various pigments and resin systems takes place. The divisions can tap into this colorant database with a modem. They simply dial up the company's electronic bulletin board, known as the Technical Access Bulletin Service, or TABS. "By setting up the CTC as the hub for data transfer, all divisions can call TABS and pick up the latest technical information," says Johnston.
This flow of information through TABS isn't solely devoted to empirical data either; it can also include subjective comments such as processing observations from the manufacturing staff--sort of like an electronic roundtable discussion. Or, Phillips notes, lab managers often send in requests for the CTC to add a new pigment or resin to the database. "Everything can go through TABS," Phillips says.
Within the technical center, a local "token ring" network connects the staff there to one another. Its file server links the facility's two color workstations to numerous other on-site PCs, some of which serve as workstations for the company's AS/400 midrange computer. The network does not connect directly to TABS.
Instead, a floppy disk carries information from the network server to the bulletin board. Phillips says this separation of TABS from the network, as well as password protection, keeps any would-be "hackers" from getting into the company's colorant files.
Having its own private bulletin board pays off for PMS in several ways. For one, it lets the divisions take advantage of a companywide standardized colorant database rather than relying on individual ones. And because the database evolves continuously, TABS also allows the divisions to stay current. Regular updates spring from the CTC's ongoing work to characterize new colorants and resins as they pop up. In just a few hours, the CTC can offer the divisions an updated colorant file containing the new pigment characterizations, says Johnston.
And TABS allows the company to husband its resources more efficiently by spreading out the color-matching chores. Sometimes, for instance, a divisional lab might become swamped with quality-control work, leaving little time for color matching and formulation. "Now the division can take spectral readings on its spectrophotometer and transfer the spectral data to the CTC for color-matching assistance," says Johnston.
Perhaps the biggest continuing challenge, though, came with the company's software upgrade to Chroma-Calc 2.0 earlier this year. This latest package offers two types of colorant files. According to Phillips, newer "absolute files" can now provide more flexibility and precision than the Chroma-Calc 1.0's "relative files." Contrasting the two types of colorant files, Phillips explains that the older "relative" ones each contain the spectral characteristics of a pigment and given resin mixed with a black and with a white. Since changes in scattering behavior or pigment hue can accompany a switch in resins, the relative-file approach in theory called for individual characterizations of every pigment in every resin system. The newer "absolute" files, however, can store spectral information about the resins themselves along with that of the pigments. Here, each characterization consists of stored data for a mix with a black as well as one to five more mixes with whites. Phillips says this ability "provides the software with spectral data at various levels of white, resulting in more precise formulations."
It also saves time. As an example, Phillips says, you might previously have characterized a certain red pigment in a polyolefin carrier and done the same all over again in a styrenic carrier. Now, you can characterize the pigment, but the software will add in previously stored info about the resins' color behavior. "It minimizes the number of colorant files and pigment characterizations that have to be made," says Phillips.
This expanded database is especially timely because the ability to characterize the color contributions of the resins themselves has become crucial. Owing to the market's swing away from traditional heavy-metal-based pigments, Phillips says, "We're forced to use organics more and more. And they tend to shift hue in different resins and at different white levels more than inorganics do."
Conversion software does render the relative files from Chroma-Calc 1.0 compatible with the upgrade. But the CTC staff still must build absolute files in order to take advantage of the new software's full range of features. In terms of lab work, such colorant file changes mean fabricating more "working masters," or pigmented plastic chips, and characterizing them in the new absolute database.
Though more work remains in creating the absolute files, the upgrade has not stood in the way of the company's goal of standardization. "With all the divisions using the same software package, we ensure that all data are compatible so duplication of effort is eliminated," Johnston says. Just as the new software hasn't rendered the old database useless, it allows the company to continue using multiple generations of Datacolor spectrophotometers, from the first generation Spectro-Sensor I right through the latest Chroma Sensor CS-5.
ROSIER FUTURE FOR MATCHING
Once PMS finishes the switchover from old colorant files to new, it can then take fullest advantage of the Chroma-Calc 2.0 software's abilities--ones that, for the time being, PMS employs on a more limited basis. "We're not doing everything right now," says Phillips, "but we're working toward it."
Right now, PMS uses the software to analyze spectral data and come up with a formula. From that, PMS molds a color chip. If it doesn't meet the customer's match requirements, the color matcher then applies a correction to arrive at the true formula. So, the technician usually makes up at least one intermediate chip before matching a sample color. The software automatically scales any formulas to user-specified letdown ratios.
PMS also uses the software for regular quality-control checks of production runs to reveal any deviations from color tolerance. As an added benefit, the system indicates any equipment contamination or misweighs. "The spectral curve that is the fingerprint of a color shifts with contamination or misweighs," explains Norwalk, Ohio, plant manager Jim Mongiardo.
While work on the absolute files continues, PMS makes only limited use of one of Chroma-Calc 2.0's most attractive features. Called the "palette file," it could often save the company that intermediate step of making up a color chip, according to Phillips. "There will be fewer shots to get there," she says.
When trying to match a new sample, the software can automatically search the palette file's stock of proven formulas first and determine if one of those would do the trick. Chroma-Calc 2.0 can also apply any needed corrections to the closest previous matches to arrive at the sample color. Otherwise, the software would start from scratch, performing the conventional combinatorial tries until finding the right match. It also lets users prioritize multiple formulas based on individual production standards such as cost or pigment availability. Users can likewise select those matches least affected by metamerism--a problematic phenomena where colors appear to match under some light sources but not others.
Another feature PMS plans to employ in the near future helps eliminate waste and cut raw-material costs by storing color information on leftover batches and then treating them as colorants for future production runs. Also, the company will implement a feature that uses contrast ratio to determine the loading requirements for matching a standard's opacity.
Some software features for which PMS doesn't have a need right now also fit into the overall package. Chroma-Vue, for one, allows users to view color samples and their matches on specially calibrated video screens as they would appear under a variety of light sources. Since PMS still checks all matches visually, the monitors would not eliminate any steps. Phillips says such a feature "would be nice" as a visual aid for customers or as a teaching device for novice color matchers, but for PMS it's not "critical enough at this time" to send the monitors out for calibration.
Color management takes the front seat in this company's CIM setup, but computers may transform the less specialized tasks as well. Its IBM AS/400, for instance, sees increasing use collecting and storing data for production management, according to MIS manager Gaylen Wisdom. It already stores all the production formulations since these relate to both pigment inventory and customer ordering.
Perhaps more important, the AS/400 makes formulations portable. A typical formula includes the specific colorants, their proportions scalable to batch size, and their cost for a given production run. Johnston points out that the AS/400 is now the only method for transferring finished production formulas between divisions for those times when multiple plants make a single product.
This midrange computer's growing contribution to data collection also helps improve the company's batch ticketing procedures and order tracking. "Data collection allows us to make on-line changes to batch tickets and make sure they always show the correct pigment and weight," Wisdom says. Such on-line changes let the company respond instantly to inventory deficiencies or last-minute formula revisions. To further boost data-collection efforts, PMS has also started to bar code raw materials and finished batches at its Fort Worth, Texas, plant with the others to follow suit over the coming year. And yet another capability of the AS/400, electronic data interchange (EDI), allows customers to place orders directly into the central computer system.
By contrast, statistical process control and statistical quality control (SPC/SQC) will likely remain at the division level. "There aren't any plans to collect this sort of data to put it all on the AS/400," says Wisdom.
Still, SPC has been widely adopted out in the field as part of the company's quality program. Ohio plant manager Mongiardo notes that much of the SPC charting at the divisional level relates to the less "colorful" processing variables. "What we sell are pellets," he says. So concerns like pellet size and bulk density loom large.
THE EYES STILL HAVE IT
CIM may have helped PMS get one step ahead of the curve when it comes to color management, but it hasn't been all that easy. "People get in the habit of doing things the old way," says Phillips. "You have to help them realize the potential of a new system." But even that considerable potential has its limits, and CIM doesn't provide an answer to every color ill. For example, PMS must do visual checks because iridescent pearls, fluorescent pigments, and other special-effect colorants may not be handled properly by a standard spectrophotometer.
More profoundly, it seems that computer tools just can't substitute completely for the human perception of color. "A computer is only a numeric backup to what we're seeing," Phillips says. "Our customers still look at everything visually and so do we."
So computers must share the color watching with human eyes for the foreseeable future. "We still develop color matchers here," says Phillips, "not just pairs of hands to punch a keyboard."
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|Title Annotation:||computer integrated manufacturing in PMS Consolidated|
|Date:||Nov 1, 1992|
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