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A CIM showcase in South Carolina.

Real-time process and production monitoring may have penetrated as much as a third of U.S. injection molding plants today, but few have implemented it on the scale of Tupperware's Hemingway, S.C., facility. Its supervisory computer network makes manufacturing data from 95 injection presses available at a dozen PC terminals throughout the plant for production reporting, scheduling, and statistical quality-control (SQC) analysis. That computer system interfaces with a central Plant computer for manufacturing resource Planning (MRP II), and with a corporate computer in another location that instructs the plant on how much of what products to make and when.

Equally interesting is the Hemingway Plant's automated Product handling system. A group of dedicated computers directs a fleet of automated guided vehicles (AGVs) that carry totes full of parts to an elaborate automated warehouse.

Ironically, all these high-tech systems are built around 15-year-old presses, which have been remanufactured with new controls, hydraulics and robotics. It Proves that making the transition to computer-integrated manufacturing (CIM) does not require starting over from scratch with a "grass-roots" facility.

A corporate-wide emphasis on quality drove Tupperware Hemingway to rapidly update its technology and information systems. The plant, with more than 850,000 sq ft, began production in 1976. In the late 1980s, new management and new technologies were brought in as part of a program designed to enhance and improve the 'total quality" of the manufacturing process. Tony Ackroyd, a Tupperware veteran with 18 years of experience managing its European operations, was appointed plant manager.

Ackroyd's approach to total quality is simple, yet comprehensive. His first step for Hemingway was the implementation of a strategic plan focusing on organizational improvements, human- resource development, and technology upgrading. As part of the plan, Ackroyd asked each department manager to develop departmental goals. Some of the goals Tupperware set for itself included replacing inspection of finished parts with a program for continual quality improvement; zero customer defects; and getting better control of the process through precise operational definitions.

PLANNING COMES FIRST

When Ackroyd arrived, the implementation of a new manufacturing resource planning, or MRP II, system, had already been accomplished. Ackroyd says it has significantly reduced inventories and speeded product development cycles. The MRP II system is designed to "plan what should happen and react to what does," he says. It has modules for forecasting, master scheduling, bills of materials, routing, capacity planning, inventory, purchasing and material requirements planning. Because of the massive data manipulation required, it runs on an IBM 3090 mainframe computer.

In 1989, Ackroyd and other Tupperware management decided to replace its PC-based production monitoring system, which had problems with speed, data integrity and vendor support. The PC-based system strained to keep up with monitoring 24 injection machines per PC and was "crashing" more often than Tupperware could tolerate. And Tupperware had to deal with four different suppliers for support, all of which had provided different components of the system.

In place of this, a new production and process monitoring system from Barco Automation, Inc., Charlotte, N.C., was brought in to aid the molding department in identifying and correcting problems. Running on DEC VAX computers, this BarcoCIM system provides production management using a data unit outfitted on the molding machines called the DU5P, and a supervisory MicroVAX computer housing a relational database management system. BarcoCIM uses information from the MRP II system to assist in selecting appropriate molds, machines and molding parameters. It then provides real-time production information on current machine status, total plant efficiencies, cycle history, and individual machine efficiency. Historical reporting identifies machine downtime and reason code, scrap and reason code, job and mold history.

REAL-TIME SCHEDULING IS KEY

One of the most important applications of the system is for real-time production scheduling. Jobs can be defined by a number of parameters: product number, quantity requested, or deadline for completion. This information can be keyed into the system, but more often it is provided by Tupperware's corporate IBM mainframe in Orlando, Fla., and Hemingway's on-site MRP II system, both of which communicate with the BarcoCIM system. The planning systems tell the BarcoCIM supervisory computer how much of which products need to be molded, and the BarcoCIM computer provides information back to the planning systems about what has actually taken place. Integration of the MRP II and BarcoCIM systems was handled for Tupperware by Barco.

BarcoCIM's production-scheduling software then assists in selecting the appropriate molds, machines and molding parameters. The system calculates all production times, taking into account shift schedules, maintenance plans and other information. Production planners still have the freedom to reschedule orders or to shift them in time: the planning software calculates the consequences.

Once a job starts, the BarcoCIM system follows all events automatically, showing corresponding reports on request or at predefined times, such as the end of the day or shift Individual job status can be requested at any time on 12 CRTs placed strategically throughout the production area, providing actual production times, rejects and job-end forecasts. At any time, a production manager can have a complete overview of current machine status. Color-coded graphics show the production overview on a "map" of the physical layout of the machines. Reports on production rates and scrap can also be offered in terms of the same graphic plant layout.

All machine downtime information is logged for historical analysis, providing necessary information for process optimization. For example, a type of bar graph called a Pareto analysis shows the major downtime reasons responsible for 80-90% of total downtime. Calculations of efficiencies-based on data on production rates, machine idle times, set-up times and scrap-can be provided per shift, day, week or month; and per order, machine or machine group. Report formats have been customized by Barco to Tupperware's needs, with bar and pie charts of plant efficiencies. This graphic representation of plant performance is a feature highly appreciated by Tupperware production managers and supervisors.

The BarcoCIM system continuously monitors production rates, checking them against standards, to help plant personnel keep them running at a constant and optimal speed. At any time, reports can be generated comparing actual to standard cycle times.

BI-DIRECTIONAL

COMMUNICATIONS

One of the most important components of the monitoring system is the DU5P, a microprocessor-based data unit with numeric keypad, function keys and a four-line, 20-character LCD display. Every injection press at Tupperware is outfitted with a DU5P to provide bi-directional communication capability between the presses and the DEC MicroVAX supervisory computer, housed in a computer room adjacent to the molding area, which collects all the production information gathered from the presses and stores it in a database management system that was tailored for Tupperware by Barco.

The DU5P automatically measures cycle time or production speeds, detects machine stoppages, and tracks process parameters including plasticating and injection time, pressures and temperatures. Other information, such as on rejects and reject codes, mold and color changes, and numbers of parts containers filled, are entered into the system manually via the keypad on the DU5P data-collection unit.

Ackroyd likes the DU5P's bi-directional communication capability. "Not only can it transfer information from the machine to the computer system, but it can also send information back to each injection press," he says. Bi-directional communications permit Tupperware to shut down a machine directly from the supervisory computer; to actuate a signal fight in the machine's "lighttree"; to transmit a message to the data unit's display; and to transmit machine set-up data.

The DU5P also can function as a backup. If the supervisory computer is down for maintenance or another reason, process and production information are held in the DU5P's on-board memory and transferred to the BarcoCIM system as soon as the computer is restarted.

COLOR GRAPHICS & SPC/SQC

Information from the monitoring system can be brought wherever ifs required via a network of CRT monitors located in Tupperware's production and production planning offices as well as key locations in each zone of the molding room, allowing easy access to a host of production information by molding and quality assurance personnel. The system provides color-coded graphics for operators to check on machine performance-e.g., red for problem or alarm conditions and green for normal conditions. Ackroyd says the color-coded screens allow for easy reading and help plant operators understand the message and respond a lot faster.

Quality-assurance personnel have implemented a statistical quality-control (SQC) system using the BarcoCIM system. Parts are weighed and measured and the data are entered into the system manually. We measure part weigh% examine any deviation from standards, and indicate whether ifs acceptable or not. We're also able to create our own SPC charts manually using that information " says Ackroyd. For the future, Ackroyd plans to implement a computerized statistical process-control (SPC) system. "We can't do everything at once, but SPC is one of our priorities for the future."

REMANUFACTURED PRESSES

As noted previously, Hemingway's presses average about 15 years old. The collection of Impco toggle machines was remanufactured internally by Tupperware and equipped with new controls and Vickers proportional hydraulics. The controls and hydraulics, which were provided and installed by Cross Sales and Engineering Co., a North Charleston, S.C., Vickers distributor, can be set up from digital data stored on cassette tapes or data cards. The presses also have been outfitted with Automated Assemblies robots. These help keep the process consistent and allow press operators to devote greater attention to the quality of the products being molded. The robots are regulated through an interface with the injection machine controls.

Parts are removed from the presses by the robots and placed on conveyors. As they reach the end of the conveyor they are manually loaded onto Mannesmann Demag AGVs, which pick up and deliver finished products to the "Tupperware Express" automated storage and retrieval system. The AGVs are guided by a buried wire in the floor with responders identifying its position. Finished products in totes are picked up from the press area and delivered to the Tupperware Express automated warehouse (described below). Empty totes and bulk items are delivered to the molding cells as required.

All AGV movements are controlled by a Hewlett-Packard 1000 computer system currently capable of controlling 16 AGVs and four AGV wire tracks embedded in the plant floor. The stopping of the AGV at individual molding machines and the delivery of totes is controlled by Allen-Bradley PLCs. The PLCs and the HP 1000 have a communication link to two HP 1000s controlling the automated warehouse. The AGVs and their control software were provided by Logitech, Inc., Grove City, Ohio. The control software provides for vehicle scheduling and monitoring, workstation configuration, and the pickup of parts for specific products which are later assembled into finished products.

AUTONLATED WAREHOUSE

Another impressive feature at the Hemingway plant is the multimillion-dollar Tupperware Express automatic storage and retrieval system. It's a system of robots and conveyors that moves product from Tupperware's 202,000-sq ft Dense Storage Warehouse through packing and shipping. All movements of products are controlled by a computerized custom-order system originating from the corporate mainframe in Orlando.

Two Robo Pick systems, provided by Republic Storage System Co., Canton, Ohio, work in the automated warehouse with computer-controlled product dispensers to fill tote bins on a mainline conveyor. Totes on the main-line conveyor are directed underneath the product dispensers, where individual customer orders are fed into each tote. Each product dispenser is interfaced to an IBM PC-AT computer, which receives customer orders from the mainframe in Orlando. Orders from Tupperware distributors are analyzed by the PC-AT and formatted in such a manner that the Robo Pick controller's card reads and fills the order.

Each Robo system has 448 storage lanes located behind the dispensers. Each lane can bold up to seven totes of products. Each Robo system has three cranes to deliver totes to the storage lanes. As the tote exits the Robo line, it is conveyed to one of 32 pack stations, where an operator places the order and documents into the shipping carton.

The Dense Storage Warehouse has storage capacity for 250,000 totes. Eleven cranes are used to store and retrieve products in totes. Identification of product and inventory control is achieved by scanning a seven-digit barcode label.

CMM & CAM IN THE TOOL ROOM

Tupperware Hemingway has also brought new high-tech equipment into its expanded tool room. A new area for major repairs, which were previously fanned out has been built and new computer numerical control (CNC) equipment installed. Mold repairs are accomplished with the aid of a SmartCAM system from Point Control Co., Eugene, Ore. Tupperware is using an unusual "reverse engineering" process. When a mold needs major repairs, Tupperware uses the CMM to digitize the surface of a production part from that mold, in order to acquire a mesh of points that can be broken down into a mathematical definition, generating a program for the machine tool or CAD drawings. SmartCAM receives this information from the CMM. SmartCAM's software has the capability to edit or revise the basic digitized data. Once all the information has been manipulated and corrected, SmartCAM generates a CNC program for Tupperware's Okuma machining center to repair the mold. The machining center will then produce the desired tool with positioning accuracy within 0.20 mil and repeatability within 0.8 mil.

One further interesting detail about the Hemingway plant Ifs the new home for Tupperware's Color Concentrate Lab, which was moved there from a Rbode Island facility. Not only does this molding plant make its own color concentrate, but it also supplies other Tupperware plants.
COPYRIGHT 1991 Gardner Publications, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1991, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

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Title Annotation:computer-integrated manufacturing in Tupperware's Hemingway, S.C. plant
Author:Fallon, Michael R.
Publication:Plastics Technology
Date:Jul 1, 1991
Words:2250
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