CIM on a large scale.

Few U.S. injection molding plants have implemented real-time process and production monitoring on the scale ot 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 Tupperware's central plant computer for manufacturing recourse 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, which directs a fleet of automated guided vehicles (AGVs) that carry totes full of parts to an elaborate automated warehouse.

The plant's MRP-II system permits significantly reduced inventories and faster product development cycles, according to plant manager Tony Ackroyd. The system, which runs on an IBM 3090 mainframe, has modules for forecasting, master scheduling, bills of materials, routing, capacity planning, inventory, purchasing and material requirements planning.

In 1989, Tupperware management decided to replace its PC-based production monitoring system with a new production and process monitoring system from Barco Automation, Inc., Charlotte, N.C. This BarcoCIM system utilizes a DEC Micro VAX supervisory computer to collect production information from a small data unit on each molding machine. It provides real-time production information on current machine status, total plant efficiencies, cycle history, and individual machine efficiency. Historical reporting identifies machine downtime, scrap, and job and mold history.

REAL-TIME SCHEDULING

IS KEY

By use of real-time production scheduling, jobs can be defined by a number of parameters: product number, quantity requested, or deadline for completion. 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.

Once a job starts, the BarcoCIM system follows all events automatically, showing corresponding reports on request or at predefined times. Individual job status can be requested at any time on 12 CRTs placed strategically throughout the production are. All machine downtime information is logged for historical anaylsis, and the BarcoCIM system continuously monitors production rates.

The microprocessor-based DU5P data unit on every injection press provides bi-directional communications between the presses and the MicroVAX supervisory computer, which collects all the production information and stores it in a database management system. The DU5P automatically measures cycle time or production speeds, detects machine stoppages, and tracks process parameters including plasticating and injection time, pressures and temperatures.

Information from the monitoring system can be brought wherever it's needed via a network of CRT monitors located in Tupperware's production and production planning offices and at key locations in each zone of the molding room. The system provides color-coded graphics for operators to check on machine performance.

ROBOTS REMOVE PARTS

The presses have Automated Assemblies parts-removal robots, which are regulated via 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 warehouse. The AGVs are guided by a wire buried in the floor with responders identifying its position. Finished products in totes are picked up from the press area and then delivered to the automated warehouse. Empty totes and bulk items are delivered to the molding cells as required.

All AGV movement is controlled by a HEwlett-Packard 1000 computer system currently capable of controlling 16 AGVs and four AGV wire tracks embedded in the plant floor. Stopping of the AGV at individual molding machines and the delivery of totes are controlled by Allen-Bradley PLCs. The PLCs and the HP 1000 have a communication link to two HP 1000s controlling the automated warehouse. 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.

AUTOMATED WAREHOUSE

The Tupperware Express automatic storage and retrieval system (AS/RS) employs robots and conveyors to move 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.

Two Robo Pick systems work in the automated warehouse with computer-controlled product dispensers to fill tote bins on a main-line conveyor. Totes on the main-line conveyor are directed underneath the product dispensers, where individual customer orders are fd 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 sot that the Robo Pick controller's card reads and fills the order.

Each Robo system has 448 storage lanes located behind the dispensers and three cranes to deliver totes to the storage lanes. Each lane can hold up to seven totes of products. 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.