Small foundry can gain efficiency by computerizing operations.
Smaller foundries often have greater difficulty than their larger counterparts in maintaining control over production and quality. Typically, such foundries are owner-managed, with several clerical tasks critical to the running of the business falling directly upon the owner.
These tasks include: * order processing * production planning * work flow monitoring * quality assurance * product traceability
Repetitive, tedious and time consuming, these tasks tie up management for considerable periods. Properly designed, computer-assisted production management (CAPM) systems can provide the facilities needed by small foundries to reduce this administrative workload by 50-60%.
This is possible, however, only if tested and supported packaged software is employed. Internally written programs have a distinctly unsatisfactory track record in these applications.
Until recently, production control and quality assurance in foundries have been viewed as separate disciplines. Increases in supplier quality programs and new quality standards, plus the relative ease of creating foundrywide computer data bases, have been responsible for computer merging of the two functions.
Integrated production and quality control encompasses: * pattern, die, tool and gage control; * order processing; * work in process management; * production scheduling; * creation of "work to" lists; * production monitoring and work booking; * scrap recording and analysis; * creation of shop floor process layouts and quality assurance documents; * historical traceability; * creation of test certificates and documents of conformity; * generation of shipping documents and invoices; * generation of information for management control.
There is, of course, a great degree of commonality within the data required for each of these areas. This makes the computer an ideal tool to help streamline the work effort involved in extracting and organizing data useful to production management and control.
Most small foundries are jobbing shops making products to order, not to stock. This means that most production software currently available will not work in the foundry environment. Foundries, however, do share with other industries ever-increasing quality assurance demands. Generally, while the quality itself presents little problem, its assurance emphatically does. As a result, a specialized type of CAPM system is needed for foundries.
The objective of foundry production and quality control is to maximize profitability by converting customer orders into finished castings delivered on time and as ordered.
The foundry CAPM system must cope with a number of demands, but in principle it is of very simple structure as illustrated in Fig. 1. The computer serves as a central information bank, or data base, holding details of parts, orders, history, etc. It must be fed order changes, new orders and details of work completed, materials requirements, shipments, labor and scrap, usually on a daily basis.
Once such data input has been made, all other computer functions are available. On-screen customer order status can be made in seconds, suggested production schedules can be created by the computer and confirmed by the operator, shop floor/quality documents can be printed and a full range of management information reports can be prepared (overdue orders, jobs on hold, sales-to-date in month, value of shipments and the like).
To manage production effectively, a foundry CAPM system must be capable of the following major functions: * store summary processing data on all castings to facilitate production planning; * maintain process layout information in sufficient detail to produce route cards for quality assurance purposes; * hold full details of customer orders and delivery schedules, updating as necessary and having the facility (for the 1990s) to communicate with various electronic data interchange (EDI) protocols; * automatically compute and present suggested production schedules; * allow manual intervention in scheduling routines; * print customer acknowledgement letters when schedules are determined; * provide rapid "look-up" facilities to answer order status queries; * print necessary workshop process layouts in the form of route cards, operation tickets, pattern or die release notes and material requisitions; * facilitate the easy and rapid updating of work in process (WIP) information on individual jobs, implying in some cases bar-code reading or even real-time machine monitoring; * retain current job data on work progress and associated scrap returns and reject data; * produce management and exception reports appropriate to a particular foundry's control needs; * retain historical information such as batches cast, scrap reports, operator performance and shipping dates; * print necessary certificates, letters and other documents to satisfy quality assurance needs.
Data Base Requirements
Computer operations in a small foundry also need a strong data base. Such a data base would include:
Pattern/Die Records - All types of foundries share many common requirements for their parts data base: part number, customer name, metal type, number of cavities per mold or die, weight and price, plus a number of monitoring or counting stages. Figure 2 is a typical, widely applicable data form.
It is unwise to define too many audit points. Sand foundries typically record at mold/cast and shipping stages, later adding cleaning/finishing, heat treatment and inspection. Some foundries may require additional points such as machining and other post-casting operations.
Routing & Quality Assurance Data - Many foundries will eventually require that all detailed manufacturing information currently held in various forms be transferred to the CAPM system. For instance, a routing card printed by the system could be a second level of computerization after the basic scheduling and control are in place.
Order Entry and Maintenance - Customer delivery requirements with their associated WIP details are the "order information" in a foundry control system. An order in this context is a specific request to deliver a given quantity of castings on a given date.
Normally a separate record is kept for each order by a foundry control system. In the case of customer schedules, each release should be allocated a unique code number for reference purposes.
Minimum data required to enter orders would be: * customer order number * pattern or die number * delivery quantity * date required
In the case of schedules, the last two items are repeated for each release.
Customer delivery requirements, schedules and samples will be adjusted as soon as revisions have been accepted by the foundry. Since new or revised customer schedules may be the output of their own computers, they may not include the foundry's latest deliveries.
The advent of EDI systems, such as "FORD-NET," have added a new information dimension by narrowing the time delay problem, but they place greater demands on the foundry control systems.
Some systems have an archive capability that allows specific items of "transaction" information to be stored in computer files for reference purposes, and limited only by the amount of data that can be stored live on the computer.
Eventually, downloading of older data to a secondary storage medium, such as magnetic tapes, floppy disks or printed paper, may be desirable.
Many foundries will require two archive records:
For manufacturing - quantity cast, quantity scrapped, batch or heat number (where required) and manufacturing date.
For shipping - date, memo number, quantity and total shipped.
Data should be automatically "posted" to the appropriate archive records file as the information is entered to record WIP movements (at the cast stage) and shipping. There should be no need to duplicate data entry.
The objective of scheduling is to produce a loading of jobs on key work centers (normally casting) within the manufacturing capacity, while at the same time satisfying customer delivery date requirements.
These demands often conflict and ideal solutions are rarely possible. Since entirely computerized solutions do not work in the foundry environment, manual intervention (the so-called "man-in-the-loop") is essential. What the computer does effectively is search, sort and do the calculations that are so pervasive in any scheduling activity.
Simple Scheduling - This produces a listing of production requirements for all parts on order, showing weekly quantities in production as a means of tracking on-time customer delivery.
Simple scheduling takes the computed production requirements for all parts and schedules the casting operation by subtracting the lead time (in weeks) from the required delivery date. No attempt is made to batch production runs into economic quantities, nor is consideration given to the resulting loads on the various work centers. This technique is probably the optimum for the smallest foundries with fewer than 15 employees.
Man-in-the-Loop Scheduling - This produces feasible production programs that load work centers to a finite capacity using the man/computer partnership.
As a first stage, the computer scans its data base and loads the various work centers to ensure that requested customer delivery dates can be met. Since the computer is employing infinite capacity scheduling techniques, overloads are bound to occur on some sections during certain weeks.
Section loads can be broken into weekly periods and subtotaled to indicate committed resources in terms of: * molding or casting time * number of molds or number of shots * total coremaking time * total poured or shot weight * total value of orders
Manual intervention (man-in-the-loop) then reschedules jobs that are causing overloads and are moveable in the scheduler's opinion.
This system also offers a compromise between computer scheduling and the human ability to sit back and consider matters. The computer takes care of all sorting, number crunching and purely logical activities. This leaves the production planner free to exercise his judgment and experience to override or accept the computer's indications.
Graphics techniques like those shown in Fig. 3 can be used in a more interactive approach to scheduling. Schedulers can then visualize where and when production bottlenecks will occur.
When an acceptable schedule has been created, the computer can print "work-to" lists for necessary work centers. The release of work to the shop floor can be controlled by specifying a definite planning horizon that programs the next five to 10 working days.
It should be noted that planned jobs not completed could be included in the work-to lists. This would make it impossible to forget overdue jobs because the computer automatically includes them at the top of the list unless they have been rescheduled.
Properly employed, a computerized foundry scheduling system will provide significant improvement in both speed and quality of information flow and analysis.
Next month: production monitoring and data capture, quality and system implementation.
PHOTO : Fig. 1. Computerization of foundry operations can cope with many tasks to relieve information bottlenecks affecting profitability.
PHOTO : Fig. 2. The author, seated, shows a prospect the efficiency and effectiveness of the foundry record-keeping and management support software programs available through AFS.
PHOTO : Fig. 3. Computer graphics techniques of AFS software can allow users to visualize quickly a wide variety of specific foundry management and production parameters.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||part 1|
|Date:||Aug 1, 1990|
|Previous Article:||Getting more from your ceramic shell slurry.|
|Next Article:||Mechanization of Cleveland West facility bolsters Ashland's commitment to quality.|