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Process/production monitoring systems: today's shortcut to CIM.

Process/Production Monitoring Systems: Today's Shortcut to CIM

Not just cycle counters any more, they've grown up into real-time SPC tools and scheduling aids. Here's a guide to what's available.

As recently as two years ago, production monitoring systems for injection molding were pretty much just that: relatively simple computer setups that kept an eye on a few basic production indicators such as cycle time (absolute and relative to standard), which machines were up or down, and the number of parts produced and still to be molded to finish a job.

Today, there are plenty of systems available that do that and much, much more. For little or no more cost than production-only monitoring systems cost a few years ago, many of the latest offerings will keep track of both production and process variables in real time. These moderately priced systems now perform many of the functions of sophisticated microcomputer machine controllers and central plant "host" computers:

* Besides up-to-the-minute job production status, they'll give you all the statistical process-control (SPC) documentation you need for customer quality assurance, process analysis, or determining which machines will run a certain job most efficiently.

* They'll monitor materials utilization, deducting automatically for reground sprues and bad parts.

* They'll keep track of labor utilization for accurate job costing.

* They provide real-time scheduling for each machine and the whole plant.

* And they're no longer just passive monitors, but can take action when necessary--typically as automatic q-c inspectors, kicking out "bad" parts when process conditions stray beyond preset limits.

Thanks to advanced software and more powerful personal computers, yesterday's "bean counters" have evolved into computer-integrated manufacturing (CIM) networks. However, the basic hardware layout of these new systems has not changed much since the first monitoring packages were introduced more than a decade ago. The standard configuration is still a data collection unit (DCU) of some sort on or near each injection machine that monitors production and process data and feeds it to a central computer terminal for analysis.

What has changed though, is the systems' level of sophistication and the number of companies now competing for a share of this quickly expanding market. While many of these new systems come from suppliers of just controls and/or monitoring systems, a growing number of injection machine manufacturers are building machine controllers capable of monitoring every aspect of the production process and transmitting the data to a personal-computer terminal for analysis and reports generation. These systems eliminate the need for separate data-collection boxes at each machine, since the information is tapped directly from machine controllers. However, some sources claim that these OEM systems are more limited in the amount of information they provide and are usually only able to monitor newer-model molding machines of that particular make.

A NEW BALLGAME

Suppliers and users of the latest generation of production and process monitoring systems feel so strongly about their worth that many predict that molders without an up-to-date system will soon be squeezed out of business or restricted to low-end manufacturing jobs. Currently, they say, only about 20% of the injection molding shops across the country have installed such systems.

"In the past two or three years there has been a big push for quality from plastics end users," says Ed Hansen, national sales manager for the PlantStar Div. of Syscon International, South Bend, Ind. "The molder has had to keep up with that demand for quality and the only way he can do that is to keep a close eye on his entire production process."

Many molders already using the computerized monitoring systems agree with Hansen's assessment. They say a growing number of their large-volume customers are requiring that SPC/SQC reports be shipped with their completed order to ensure the parts meet predetermined specifications. "In the next five years, if you don't have a system like this, you're not going to be in the ballgame," says Ray Pelle, president of DJ Inc., a 50-press custom molding operation in Louisville, Ky. "You might run knives, forks and spoons, but you won't be doing any work for the big guys."

About a year ago, Pelle ended a two-year-long search by purchasing a monitoring system from CAMIS Systems Inc., Erie, Pa. The search was a lengthy and sometimes difficult one. "On the surface, a lot of systems look alike," says DJ vice president Harry Pelle. "You really have to search for the one that suits your needs."

The bottom line on these systems, users and suppliers say, is that they can increase productivity so much that their basic $30,000-$60,000 a cost (for a typical 10-machine system) can usually be recovered within a year. "If you can monitor the process, you can improve productivity," says Mick Thiel, president of Mattec Corp., Loveland, Ohio. "Probably the biggest advantage of these systems is that they allow molders to be better managers."

WHAT'S IMPORTANT?

It's generally agreed by both suppliers and molders that there is no single most important factor to consider when buying a plantwide information system. Many do say, however, that the ability to integrate process and production monitoring systems with higher-level computer management information systems (MIS), ease of operation, expandability, and the ability for the user to custom-tailor his information into displays and charts that suit his particular needs are important aspects to look for when choosing a system.

But suppliers often disagree on the importance of certain other aspects of their products. Denes Hunkar, president of Hunkar Laboratories Inc., Cincinnati, says that an industrial-grade "hardened" computer is vital to prevent accidental data loss. Hunkar and William Bird, president of Control Process Inc., E. Berlin, Conn., are among a group of suppliers who feel sensors that are calibrated and SPI certified are essential if one is to obtain meaningful data. Others argue that while the forementioned items are important, they certainly do not provide a basis for comparison of various systems.

"Philosophically, they all do the same thing," says PlantStar's Hansen. "But it's in the way it's done that the systems differ."

One area in which the systems differ is in their data collection units that are mounted on or near the molding machines. Control Process' Midas 3000 uses two separate pieces of hardware to collect data. The system consists of a data acquisition unit, a real-time unit capable of interfacing with hundreds of sensors and digital I/O poins; and an operator interface--a serial I/O device that permits the operator to send and receive information to and from the central computer terminal.

This unit, like most of those from manufacturers dedicated to control and/or monitoring systems, collect data from sensors as well as various makes of machine controllers.

The data collection units in many systems act as a sort of a built-in security system, preventing machine operators from tinkering with job parameters and preventing other operators from running another person's machine unless he enters a user code unique to that DCU. The designers of PlantStar's Focus 100 have taken that security factor a step further by requiring a user identification code, usually known only by the plant's production manager, to be entered on a computer terminal before any job specifications are entered or changed.

Most systems have DCU's that permit operators' manual input of numerically coded downtime reasons and number of bad parts made. DCU's typically have small message screens, frequently limited to one line of 40 characters. Suppliers say they designed their units this way in order to keep their use as simple as possible and not scare machine operators into thinking they are being replaced by a computer. But control manufacturers such as Barber-Colman Co., Loves Park, Ill, and injection molding machine makers such as Battenfeld of America, West Warwick, R.I., have opted to have their controls send data directly to a personal computer terminal, providing operators with larger message screens and eliminating the need for conventional DCUs.

Most DCU's now come with RS232 ports so a personal computer can be rolled up to the side of a machine so SPC data on that particular press can be monitored locally and parameter changes can be made if necessary. Serial ports also can be used to allow manual or automatic input of parts-quality data from electronic scales or gauges.

Other systems, like the one from CAMIS, provide the bulk of their data right at the DCU. The CAMIS units have a 5-in. CRT screen at each machine, giving the operator a closer look at what he or she is doing and more room to explain any problems that may arise. The units, which are actually tiny personal computers, can even provide the machine operator with graphs and SPC data. For some, this is a major selling point.

"We saw the simple units as a Big Brother approach," says DJ's Harry Pelle about the alternative approach of having smaller DCU displays and a central command terminal. He said the systems that would give his operators more control over their machines were the ones he considered buying. "Some guru in a remote control tower doesn't have to yell down, `Hey Joe, you're messin' up.'"

The majority of differences between systems are in the details of software features--e.g., for SPC, reports generation, and such things as mold-change scheduling. A number of system suppliers are even offering foreign-language options.

But suppliers say that the basic computer hardware and software architecture is the most important element of a system. "Anyone can write a program," says Denes Hunkar, "but if you don't have the database and you don't have the architecture, those programs won't be any good to you." Standard architectures for many of the systems are quite similar. Almost all the systems use IBM or IBM-compatible personal computers and almost all the systems have at least one hard-disk drive for permanent data storage. All of the latest systems allow users to design their own reports and all have the ability to capture data from every cycle of every machine.

MORE TO COME

Mattec's Thiel and many other suppliers say the ever-shrinking cost of computer power will allow the systems to perform new functions previously considered too costly. Already, processors can acquire SPC monitoring capability and automatic good/bad parts qualification without needing a sophisticated machine controller. Some of them are finding the automatic, real-time updating of machine job queues to be more valuable in some ways than expensive plant scheduling systems running on minicomputers.

"We're just scraping the tip of the iceberg here," says Mattec's Thiel. "The cost of these systems is so small compared with the cost of running a molding plant. The sky's the limit as to where we can go." Suppliers' forecasts include more sophisticated materials requirement planning (MRP) functions; systems branching out to monitor auxiliary equipment like dryers and robots (some already do); and monitoring of other cyclical processes such as blow and compression molding (some systems can already be applied to other processes with little or no modification).

In an effort to bring even higher levels of sophistication to their systems, several suppliers have entered into cooperative arrangements with other suppliers or purchased smaller companies to expand their capabilities. Some examples:

* Data Technical Research, Jacksonville, Fla., has struck a deal with Production Process, Londonderry, N.H., that will give DTR a complete production and process monitoring system. In the past, DTR offered only a production monitoring and accounting system.

* Mattec Corp., recently acquired Madeira Computer Systems, Inc., Cincinnati. Mattec thus obtains the rights to Madeira's Feature Plus software, which includes a complete manufacturing system and an accounting system. Mattec plans to tailor the software to meet the needs of plastics molders. Feature Plus will be integrated with Mattec's ProHelp system, giving processors the ability to monitor quality and production from their machines while immediately updating inventory control.

* CAMIS Systems entered into a cooperate marketing agreement with IBM Corp., Armonk, N.Y., in January that will see the computer giant market CAMIS' products through its network of direct sales representatives and business partners. The agreement went into effect in late January.

* In a similar move, IBM last month also agreed to work with Control Process Inc. to have its sales representatives market Control Process products.

* A year ago, Hunkar Laboratories was named a partner in IBM's Systems Integration Complementary Marketing Program, based in Boca Raton, Fla. This makes it easier to integrate Hunkar's systems with higher-level IBM plant computers and IBM shop-floor tools for networking with non-IBM devices from Allen-Bradley, Fisher Controls, and so on (see PT, April '89).

WHAT TO LOOK FOR

Accompanying this article is a chart itemizing many important features of available production and process monitoring systems, divided into two groups--those from control and monitoring system suppliers, and injection machine suppliers. Shown here are only systems designed for injection molding, though some of them can be used for other cyclic processes as well. While we attempted to make this chart as complete as possible, some may have been inadvertently omitted, because not every company responded to our request for information.

While most systems do about the same things, the frequency and the way they do it often differs. Here are some factors to consider when choosing a system:

What type of display does the data collection unit have? Depending on how much responsibility you want to put on your machine operators, the display type of the machine-mounted data collection units is important. A numeric display limits the input of the operator to entering coded messages without any explanation. An alphanumeric display allows the operator to explain in more detail reasons for downtime or rejected parts. Some systems, like the one from CAMIS have gone as far as incorporating a 5-in. CRT into their machine units, giving the operator a wealth of information and greater flexibility in his communication with the command terminals.

Number of parameters monitored by the data-collection unit. It probably goes without saying that the more parameters the DCU can monitor, the more insight the molder will have into his process. The systems built into molding machines by machine manufacturers typically monitor eight to 12 analog parameters and the same number of digital parameters. Systems such as Plant-Star's Focus 100 can monitor up to 48 digital and 48 analog parameters.

Number of machines monitored. Depending on how big your shop is, you'll want to select a system that can accommodate all of your machines as well as a few extra for when you grow. Some systems can monitor as few as 16 injection presses with one personal computer while others can handle up to 128 machines. Suppliers such as Barco Industries, Charlotte, N.C., manufacture several versions of their systems, each designed to monitor a certain sized plant. The BarcoCim 200 can monitor up to 50 machines. The company's BarcoCim 300, can handle up to 64 machines; and the BarcoCim 400, is capable to monitoring as many as 1024 machines.

Third-party interface. Can the system you're looking at interface with other manufacturing and office software such as Lotus 1-2-3, D-Base III, Data-Myte FAN, Supercalc IV, or special SPC programs? Many, but not all, systems allow you this flexibility in data-analysis tools.

Is a modem available for customer support? No matter how good you may be with computers, you probably won't learn everything about your new system immediately and you may have to call your supplier with questions. A modem, which many system manufacturers now offer as a standard feature, will make those calls easier by allowing an expert technician at the supplier's plant to monitor your system and work through the problem with you.

Number of computer terminals that have simultaneous access to machine data. In many cases you will probably choose to have more than one computer terminal in your plant. The production manager, plant manager or company president, and q-c manager may each want a terminal, not to mention the shipping, maintenance or tool-room departments, and some users have found it a valuable morale-builder to have at least a video monitor visible by machine operators on the shop floor. Frequently, several persons within the plant may want to view the same information at the same time. So if the system you are considering doesn't allow simultaneous access to machine data, you may be limited in who can review what and when.

Can the computer terminal collect data from machine controllers rather than a DCU? If so, and your injection machines are equipped with sophisticated sensors, you may not need a DCU at each press. This will hold down the cost of the system, since each DCU costs an average of about $1000.

Is there a job-scheduling database? Most of today's systems offer provisions for scheduling jobs, calculating how long the job will take to run, telling the user how long until the job is completed, how much material is going to be needed and how much has been used, and then calculating all that information into an efficiency quotient to determine which machine is best suited for a particular job. Most will also store that information for future reference that can be easily called up again when a job is rerun. What a buyer should look for is how long a job queue can be scheduled for each machine. Some systems can only schedule three or four jobs per machine but an infinite number plantwide. Others can schedule as many jobs per machine as the user desires.

Does the same manufacturer make both the system's hardware and software Valid arguments for both approaches can be made. Proponents of a single-source system such as Mattec's Thiel say that since all the equipment comes from one place, a user doesn't have to contact a different supplier every time he has a problem with one part of the system. Supporters of the off-the-shelf hardware approach, such as the Control Process' Bird say that a system whose user can purchase DCU's and computer terminals "off the shelf" eases expandability and gives the user more choice when designing his system. "However," Bird warns, "you want to be sure you're on an industry-standard operating system and have industry-standard hardware."

At the end of this issue, our Processors' Page details a case history of the benefits one molder has been able to achieve with a new-generation process and production monitoring system. (See also PT, March '89).

PHOTO : Process/production monitoring systems provide a wealth of information, scrutinizing every

PHOTO : aspect of the molding process from cycle times and injection pressures to numbers of

PHOTO : rejected parts and machine efficiency.

PHOTO : Data-collection units come in a variety of sizes and shapes. One of the DCU's available

PHOTO : with Mattec's ProHelp system (top, left) features a numeric input keypad and a 16-line

PHOTO : display. The DAT from Hunkar Labs' (above) has an alpha-numeric keypad, allowing expanded

PHOTO : operator entries, and the DCU on the CAMIS I system (left) uses a 5-in. CRT that can

PHOTO : provide operators with graphs and charts.

PHOTO : The software in today's process/production monitoring systems can be tailored to give

PHOTO : users dozens of charts and graphs, mapping out every portion of their molding process.

PHOTO : X-bar and R charts (left) show the average and range of variables taken over a

PHOTO : predetermined time period. Production screens (right) provide a portrait of the status of

PHOTO : jobs in progress.
COPYRIGHT 1990 Gardner Publications, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1990, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

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Title Annotation:computer-integrated manufacturing
Author:Monks, Richard
Publication:Plastics Technology
Article Type:buyers guide
Date:Apr 1, 1990
Words:3217
Previous Article:How to process LCP's.
Next Article:A new way to evaluate injection machine performance.
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