March 2005

Some Audits Can Be Good

Abrasives testing and auditing are key to lowering production costs and improving finish quality.

By Douglas Jensen
Douglas Jensen, senior product engineer at Saint-Gobain Abrasives, suggests testing abrasives often and never replace an abrasive with an untested one.

When a woodworking company's finishing costs increase, or its competition wins out with better quality products or lower prices, it may be time to call in the engineers from its abrasive supplier for a consultation.

Leading abrasives manufacturers can offer suggestions and recommendations for changes in abrasives, equipment or production processes that might turn things around.

At the very least, an engineer knowledgeable of abrasives and production processes might suggest a new abrasive product for an area or operation plant management has pinpointed as problematic.

Companies interested in a more systematic or plant-wide assessment may want an abrasives audit - a detailed assessment of all of a plant's sanding and finishing operations.

Testing: Sound Strategy Anytime

Generally speaking, a woodworking company should never replace an abrasive without testing and comparing the new one to the old one. Testing will save time and money by matching products to applications, reducing sanding time and helping to determine the best abrasive value for a particular finishing procedure.

To accomplish these goals, however, it is necessary to quantify the performance of competing abrasives by asking:

  • How long does each last or how many pieces will each satisfactorily finish?
  • How well does each perform its required task measured in removal rate, finish or other relevant parameters?
  • Overall, which presents the most cost-effective solution?

    These questions are based on some often-overlooked facts:
  • Not all abrasives are the same;
  • It is not always best to use the lowest-cost abrasive or the highest-cost

    product; and
  • Abrasive life is not the only thing that matters.

Actual production situations also can include factors that testing may not take into account. For example, what if an operator typically changes out an abrasive product at the end of his or her shift, regardless of how many more parts it could have successfully sanded on the next shift? Or, what if the operator simply removes abrasive products with no regard for finish, when finish is a quality factor? What if the sanding equipment is out of adjustment? What if different wood species are run on the same sanding equipment?

Such considerations point to reasons why management teams that are serious about productivity or quality improvements - or want to enter into an ongoing continuous improvement program - often choose to do a comprehensive abrasives audit.

Preparing and Performing an Audit

An abrasives audit investigates the cost and consumption of every abrasive product used at a site and determines exactly how each is used. As noted, engineers from leading abrasives manufacturers are prepared to help their customers with abrasive audits, but there are many things any company can do on its own to prepare for an audit.

The company's purchasing and production personnel need to produce a list of all abrasives purchased at a site along with an account of how much of each is purchased annually, and where each is used and for what part of the process it is specifically used. Also helpful will be current production figures for each product produced at the site.

Using this information, production personnel can answer the following questions:

  • Which abrasive products/applications are used on each piece produced?
  • What is the abrasives cost per unit produced?
  • How many pieces of each product are produced on each abrasive


With advice from management, supervisors, engineers, operators and abrasives suppliers, responsible site personnel can then select a period of time over which to conduct the audit and pick the members of the audit team.

In doing the audit, auditors, who may include personnel from the company's abrasives supplier, will confirm by direct observation information already gathered about where and on what product each abrasive is used. They will record for each product and/or workstation quantities, uses and operating parameters of the abrasives. They also will confirm that the abrasive is the right one for the sanding equipment and the application. And whether the abrasive product in use utilizes the correct grit size, abrasive mineral, backing (i.e. paper vs. cloth), etc. In other words, the auditors will thoroughly investigate the sequence of operations and pinpoint areas that might cause costs to increase or product quality to suffer.

As management and the audit team begin to understand where problem areas are, goals for corrective action are formed. Examples might include the elimination of a bottleneck, a decrease in overall abrasives consumption by a certain percentage and/or a decrease in the number of rejects by a fixed percentage. It is important that management be involved in this goal-setting exercise because it should not occur in a vacuum. The goals should be in line with the company's business objectives.

During the audit, auditors will spend time with operators and their sanding equipment. They will investigate whether machinery is in spec and being maintained properly and on schedule. A representative of the company's abrasives supplier can be of particular help in reviewing the system and taking into account, for example, a sanding machine's characteristics (belt tension, etc.), workpiece characteristics, as well as operating pressure, force, power, vibration, displacement, deflection, etc.

None of these factors can be analyzed in isolation because each affects the others. Therefore, leading abrasives suppliers invest in special troubleshooting tools to assist in evaluating the entire process.

Auditors must also look at all plant equipment, not just sanding equipment. Any equipment that interfaces with the sanding equipment can affect production costs and quality; any change in a production facility can affect downstream sanding costs and quality.

Putting an Audit to Work

Some examples of how audits have led to recovered productivity and quality will help illustrate how important a system's approach to auditing is.

Consider this example: At a company producing engineered panels, production rates dropped because belts in the sanding process loaded faster than before. Auditors looked at the total process and determined the company added more resin to the panels in order to speed upstream production.

However, it was the resin that was prematurely loading the belts. A return to lower resin levels put overall production back to its original rate, demonstrating how upstream changes can create downstream problems.

In another audit, a woodworking company discovered that its widebelt sander operators used only the center area of the conveyor feed belt, losing about 14 inches of the sanding width. However, if the operators used the entire width of the belt, it burned the workpiece.

A thorough inspection revealed the problem was maintenance related. The sander's conveyor belt had significantly more wear in the center than on the outside edges. This put more sanding pressure on the parts when they were run through the outside area, causing the burn.

This condition drove up sanding costs for some time and clearly demonstrates the importance of maintenance, as well as the fact that auditors must deal with whole systems, not just individual components.

Sometimes, a woodworker's raw materials supplier is the source of finishing problems, reinforcing the notion that upstream changes can cause downstream problems and demonstrating that the audited "system" is sometimes bigger than the facility in which the audit occurs.

For example, a cabinet manufacturing facility having problems with the finish on some of its panels thought inconsistent coating on the anti-loading agent applied to the surface of the discs was causing the finish issue.

The disc's supplier used a scanning electron microscope (SEM) in an effort to determine the cause of the finish problem. Using the SEM's elemental analysis capability, they discovered no trace of zinc stearate - the primary ingredient in the anti-loading agent - on the wood samples exhibiting the finish problem. This analysis eliminated the abrasive disc as a cause and indicated there could be an issue with the consistency of finishing materials.

In a large facility, chances are an audit will reveal so many areas for potential improvement that site management will need to identify one or two problems or issues for initial testing and improvement.

The team might isolate a starting point for improvements by focusing on products that produce the highest abrasives costs. Or, perhaps, the best place to start implementation of audit results is where there are production bottlenecks. Of course, any situation requiring safety or ergonomic improvements should be addressed immediately; correcting them is likely to improve productivity.

If a starting place is not evident, one might become evident by answering questions like these:

  • Does one operator or operation consistently consume more abrasives than another?
  • Does one area have higher abrasives usage than others?
  • Has there been a recent evaluation of specific abrasive products for specific applications?
  • Have there been changes in abrasive technology that might help improve production or product quality?

Leading abrasives suppliers can help an audit team evaluate products for specific applications and recommend new technologies that might help lower costs and improve throughput or product quality. In such cases, testing, as described, is necessary before the adoption of any new technology.

When the most pressing problems at a site are dealt with, the audit team, which by then might be known as the "continuous improvement team," will already have the data required to address the most critical problems or situations remaining.

Douglas Jensen is the senior product engineer at Saint-Gobain Abrasives of Watervliet, NY. He can be reached by phone at (518) 266-2340 or by visiting or


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