Enhanced SPC and production data.

Enhanced SPC and Production Data An expanded statistical process control (SPC) analysis and charting software package called QA/S is now being offered as an optional addition to the Focus 100 process and production monitoring system from PlantStar, a div. of Syscon International, Inc., South Bend, Ind.

The QA/S, developed in conjunction with Paul Hertzler & Co. Inc., Goshen, Ind., has been customized by PlantStar to integrate directly with its Focus 100 system.

The standard Focus 100 software includes graphing of X-bar and R charts on 17 process variables over the last 50 machine cycles, and of Pareto-type bar charts of reasons for downtime or rejects. The QA/S package greatly extends these SPC capabilities. For example, it can draw histograms of the data distribution on one to 10 variables simultaneously--e.g., different variables on the same machine, or the same variable from different machines running the same job or different operators on the same machine during different shifts. It can also fit a curve to the data, calculate percent of data above and below specification limits, calculate capability indexes (Cpk), and perform correlation analyses on pairs of variables.

The QA/S package consists of two modules, one for analyzing process variables, and the other for product attributes, such as weights and dimensions. Each module costs $3750. PlantStar spokesmen say most new Focus 100 customers are buying at least one of the modules, and about half choose both.

Integrating the QA/S software with the Focus 100 system is just one of several new features in PlantStar's Focus 100 Version 6.3, introduced last October. The improved system more fully intergrates SQC and SPC with the system's production monitoring functions. Here are some of the new standard features:

* Cycle time is now a 17th chartable SPC variable.

* SPC sample frequency and sample size can now be specified individually for each machine, instead of all the same, and it's now easier to change those parameters "on the fly"--for example, to sample more frequently during startup and less frequently during startup and less frequently after the machine is running smoothly.

* Operators can now change the cavity multiplier on the fly at the machine, rather than at the central computer station. Thus, if a cavity becomes blocked, the production part counts can be corrected immediately.

* The Focus 100 "high-speed graphing" capability, which draws real-time charts of two variables such as injection pressure and screw position, has been enhanced with a feature PlantStar calls "Signature Analysis." These charts can be saved on a hard disk, along with tolerance bands around the curve of a "good" cycle. The software can superimpose the curves of the two variables or of a standard and current actual curve for a single variable. The horizontal (time) axis can be scaled by the user so that all 500 data points can be concentrated in the portion of the cycle of greatest interest.

* New labor and material lot tracking feature lets you keep track of, for example, how reject rates compare from one material lot to another or one operator to another, PlantStar says.

* New plantwide scheduling capability supplements the reports of job queues that were previously available only on a machine-by-machine basis. Now the job queue for the whole plant is visible in one display, continuously updated in real time. This can be done automatically at the end of a shift, or other interval, showing jobs waiting and currently active jobs with numbers of pieces left to go and current actual cycle rate (from which it is simple to estimate a job-completion time).

* Multitasking capability--allowing two Focus programs to run simultaneously--is now available through an interface to Desqview software.

* Plants running Unix-based software on a host computer can now run Focus 100 on a version of Xenix, a Unix lookalike.

For the future, PlantStar is developing a mold-change setup display that will show real-time updated scheduling of upcoming mold changes at each machine in the plant.