Quality control systems for small foundries.

Regardless of its size, any foundry committed to quality improvement can implement an effective quality program.

When this article was planned, the goal was to determine (what quality systems) worked well in small foundries. It was believed that most smaller foundries (50 people or fewer) did not or were not using many of the more sophisticated quality methods adopted by many larger foundries.

But, like their larger counterparts, smaller shops are facing increasing pressure to supply their customers with consistently higher levels of good castings and to manage quality in some fashion.

To get a better idea of the types of quality programs in use at small foundries, tours of nine ferrous sand foundries in the Chicago area were conducted in the belief that short-run shops have common quality problems. By visiting a sampling of small shops, it was hoped a pattern could be found that other small foundries could use to compare their programs. Each plant employed fewer than 50 people, cast either iron and/or steel, and specialized in short-run and prototype work.

Common traits shared by each of the foundries included:

* their customers are usually small and relatively unsophisticated;

* much of their tooling is old, in poor condition, and their customers resist repairing it;

* their customers tend to buy on price;

* production runs are short, ranging from 1-200 castings;

* most blueprints are sketchy. They often do not specify the alloy or hardness range, and are often no more than machining prints;

* most of the foundries maintain a large volume of part numbers. It is common for some of the older shops to have more than 4000 patterns.

Table 1 provides a brief operations synopsis of each of the nine foundries. In addition, it characterizes each foundry by its level of "commitment" to quality. This rating was based on personnel and equipment dedicated to the task of quality control (QC).

The foundries broke down into two basic groups: those that had made a philosophical and monetary commitment to quality systems, and those that had not. Plants 6, 7, 8 and 9 demonstrated the highest level of commitment to establishing and maintaining a QC program. Each of these plants had the following in common:

* QC manager;

* spectrometer;

* carbon equivalent (CE) meter;

* hardness tester;

* written job control instructions;

* QC manuals.

Some of the foundries with quality programs also had invested in:

* coordinate measuring machines;

* ultrasonic inspection machines;

* SPC programs;

* tensile testing machines;

* calibration programs;

* final inspection instructions;

* incoming material inspections;

* written process instructions.

None of the foundries with demonstrated quality programs was doing military or aerospace work. When one foundry owner was asked what he did differently than big foundries, he said, "You have to have a first-class QC system to survive. We do everything the big shops do." Despite this enlightened statement, none of the shops visited had the following programs in place:

* written raw material specifications;

* vendor rating and auditing programs;

* machinery QC maintenance programs;

* cost of quality reports;

* failure mode evaluation & analysis programs;

* design of experiment programs;

* auditing of QC/operational methods;

* gage R&R studies;

* written tool inspection programs;

* casting tagging systems;

* just-in-time systems;

* total quality management systems;

* locked QC hold areas;

* formal QC planning;

* process flow charts;

* zero defects programs;

* quality circles programs;

* written department process specifications;

* ISO 9000 quality systems.

This last set of QC programs is vital in moving toward a total quality management system. However, even many larger plants do not have all these systems in place. All of the foundries with a demonstrated QC system tended to be inspection based. Their programs were not directed toward eliminating defects, but in finding them.

The difference in the amount of investment between the plants with formal QC programs and those without them was striking. This is not meant to render a value judgment on those that have chosen not to invest their resources in quality equipment and systems.

Each of the foundries makes good parts and all are profitable. Their owners and management were clever, highly experienced and proud of their reputations. However, they are not convinced an investment in QC training, personnel or equipment is justified.

One foundry owner explained he maintained quality by buying first-quality materials, respecting his employees and being loyal to his suppliers. These goals are good ones and eminently sensible. All the owners without quality programs felt they did not need formal systems because their employees were highly experienced and as owners, they spend large amounts of time on the shop floor supervising and working.

Arguments that the shop is small enough so everything is controllable, the workers are experienced and the owner is "hands on" are typically heard in shops without formal quality systems. They are often used to convince customers that formal quality systems are not needed, but are rarely accepted by increasingly sophisticated customers.

While operating a small foundry, an experienced work force and an involved owner all help in reducing scrap. However, they are not as effective as an ongoing, organized QC system. In shops without a formal quality system, scrap may remain low for a period of time, but then jump to intolerable levels for no discernible reason. Upon investigation, the rise will be traced to a failure, which a formal quality system is designed to prevent. Effective quality systems are merely the codification of expensively learned lessons.

Another observation was the plants with formal or semiformal quality programs tended to practice better housekeeping than those without. These operations were cleaner, more brightly lit, and had more modern and up-to-date equipment. This also seemed to translate into improved profitability.

One theory is that companies with high levels of commitment to product quality have more resources available for internal investment. This might be because customers are willing to pay higher prices for more consistent, higher quality castings. Quality experts also may add that effective quality systems reduce costs, so profit margins are higher.

Practical Quality Systems

An effective quality system makes good financial sense regardless of the size of the operation because it reduces scrap and waste, while attracting better paying customers. But how does a small operation with limited resources implement a system to accomplish this within a limited budget and without adding to the already growing mass of paperwork?

In many cases, information on quality programs is written and developed by quality professionals working for high-production operations. Too often the programs appear time consuming, confusing, complex and costly to the TABULAR DATA OMITTED operator of the small plant.

Fortunately, many small operations already have demonstrated that effective quality systems can be implemented with existing personnel and equipment. One thing the foundry manager must understand at the onset of a quality program is that the initial workload will be significant. At the same time, once it is up and running, an effective system will actually reduce the time and effort previously devoted to quality problems. It is much like installing new labor-saving equipment. The installation and learning period involve additional work, but after it's in and people are accustomed to it, you wonder how you ever lived without it.

A quality system has seven basic parts, all of which must be present for the system to work. While they all serve to eliminate scrap in their areas, if one part is neglected, sooner or later it will lead to problems in other areas. The major parts of an effective quality program include: raw materials, job controls, process controls, machinery maintenance, pattern control, instrument calibration and final casting inspection standards.

Raw Materials--Good, consistent raw materials are needed to make consistent high-quality castings. "Good" quality means they must be serviceable. Ensuring this is not difficult. Keys are:

* buy from reputable suppliers. These should be firms you trust with a good track record.

* document what qualities must be present in your important raw materials. Your supplier can help eliminate items that aren't vital.

* check each new load against the inspection sheet. Whoever checks the material should log it into a book and initial the entry.

* take a sample and compare it with the last two samples. If it isn't the same, question the supplier. Keep samples from the last three batches.

The costs involved include a logbook and the time to document the inspection standards. Essentially, the inspection itself is free because someone should already be checking in shipments. The samples can be stored in almost any practical container, including used baby food jars.

Job Controls--Job controls provide a record of the lessons learned each time a job is run. This can be as simple as using an 8 x 11 in. sheet printed on card stock. It includes important variable information like sprue size, alloy and pouring weight. Detail is what makes the card useful. Record scrap on it and what actions were taken or should be the next time to reduce scrap.

These cards are stored in the office to keep them handy and safe. A copy is sent out on the floor in a plastic sheet protector and the operator posts the card at his station. As the job is run, any special problems that occur during production should be noted on it.

The card is then passed on to the next area as each operation is completed. When the entire job is finished, the card goes back to the office, where updates and new information are added to the master card.

Costs associated with job controls include the printing of the cards, plastic sheet protectors, some photocopying and the time to update the cards. When the initial samples are being taken, fill out the card.

Process Controls--Process control indicates each step of how a process is operated, not a specific part number. Good process control assures that a task is done the same way every day. A new employee, for example, must learn each step of an operation to be productive. The most effective way to train new workers and provide a thorough review for experienced employees is with a video camera. Each step in the operation should be taped in sequence.

Videotaping is not necessary for every operation, only the ones that you deem important. Determining which processes are directly affected by individual skills will help you to prioritize which operations should be recorded.

In addition to the tape, these tasks also should be documented and posted in the immediate work area. In any case, both the tapes and documentation will need to be updated when the operation changes in any way.

The video camera, tapes, TV and VCR represent the most significant cost in this area. But in addition to documenting the process, taping also serves as an effective training tool.

Machinery Maintenance--Equipment like flask pins and bushings, muller plows and jackets require regular maintenance or quality suffers. Simply create a list of the critical equipment that requires regular, routine maintenance and develop a mandatory inspection schedule (daily, weekly, monthly, etc.). The main cost is the time to create the list of equipment, required maintenance and inspection schedule.

Pattern Control--It goes without saying that pattern quality has a direct effect on casting quality. Therefore, a regular inspection and repair schedule are required. A good, practical way to start is to print two sets of tags--one green and the other red.

When a casting run is completed, the foreman checks the pattern before storing it. Patterns not requiring repair are labeled with a green tag. Patters needing repair get a red tag indicating that the next step is to send them to the patternshop for maintenance. These patterns should not be allowed back into production until they receive green tag from the patternshop.

The cost for printing the tags is minimal and the foreman should already be inspecting the patterns immediately after a production run.

Instrument Calibration--If a gage is not calibrated, there is no way to know if it is accurate. Yon have to know that today's 187 Brinell means the same as a 187 Brinell hardness a month ago.

First, make a list of important gages. If anyone reads a gage and uses the reading to adjust a process or to inspect castings, it is important. You then determine the best way to calibrate each gage. This does not need to be complex. Make a set weight for each scale or purchase hardness test bars. Outside services should be used to calibrate sensitive gages every three months.

A logbook should be placed by each gage. At the start of each shift, the operator checks the gage. If it is OK, he initials and dates the logbook. If not, the operator must be required to calibrate the instrument and indicate in the logbook what was done. The costs involved include the time to develop the list, purchasing the logbooks, and, if needed, the services of an outside instrument calibration firm.

Inspection Standards--Each casting and customer has special problems and requirements. Written records help prevent making the same mistake twice. One of the most effective ways to document inspection standards is to take a photograph of the problem, glue the picture onto a card and write down on the card the problem and the defect size or conditions that are allowable.

These cards should be kept in the finishing room. The finishing room foreman should be required to check the cards and the castings for each job prior to shipment. Costs include the camera, film and card stock. No additional inspection time is required, since someone normally checks the castings before shipping.