Polishing Success for Prime Automotive


Mike Shappell, Senior Application Engineer, Norton | Saint-Gobain Abrasives


Craig Chaffee, Product Manager, Norton | Saint-Gobain Abrasives

This article appears in GlobalSpec's Engineering360. Reproduced with permission.



utomotive buffs are likely to be associated with aftermarket polishing, an aspect of car detailing or autobody repair by which surface imperfections can be removed and the glossy finish of a car’s original paint can be dramatically restored. This labor-intensive, one-car-at-a-time process is merely a microcosm of what happens in the prime automotive space — the manufacturing production lines producing hundreds or even thousands of vehicles daily. There, teams of skilled workers are tasked with addressing even the smallest flaws, to avoid allowing end products to roll off the line with scratches, spots, or other markings that make for a dull finish.


The challenges inherent to that environment are many. Defects can be introduced from the presence of dust or other contaminants in the painting area, paint applied too quickly or too thickly, overspray from adjacent areas, and other production line pitfalls. Moreover, although such defects can be the size of quarter-dollar coins, they are difficult to spot without inspection performed under specialized bright lights designed to simulate outdoor conditions.


Once they are spotted, the team can get to work on addressing them through sanding and buffing. Typically, one person is stationed on each end of the vehicle, front and back, with two more on each side of the roof. All must work quickly, to maintain plant throughput, and efficiently, to reduce the need for rework. Pitfalls nevertheless remain. Too much time spent sanding can cut through the clear coat. Too much time spent buffing with filler-based compounds can alter the areas being worked on, leaving spots that will become visible when the car heats up outdoors. Rotary buffers run too quickly over a vehicle surface can leave trails or “hologram” patterns; temporarily invisible under a coating of wax or glaze, they will eventually be revealed as the coating degrades. Dirty polishing pads can create minute scratches that mar the painted base beneath the clear coat finish, an example of the type of “below surface” defect that is more difficult to address than those which are topical.


The labor-intensive, one-car-at-a-time process of aftermarket polishing is merely a microcosm of what happens in the prime automotive space.


It is during the buffing stage that a surface finishing system incorporating Farécla compounds may be brought into play. A new member of the Saint-Gobain Abrasives portfolio, Farécla compounds and pads can be used together to proactively address the more challenging aspects of the polishing process: the rate at which end products need to be completed to keep pace with demand, also known as takt time; the effectiveness of materials; and overall cost, particularly in terms of the number of pads expended. Tests of the Farécla compound and pad combination have shown highly promising results at multiple plants in the prime automotive space.


Takt time


One baseline benchmark for prime automotive is keeping per-unit takt time under one minute — in other words, no more than a minute spent by the team on a single car. That is an ambitious goal that can only be met by highly skilled workers and finishing systems tuned for speed and efficiency.


To avoid damage to the finish, only a few seconds of sanding can be allowed. Areas where the vehicle is sanded will show as milky spots in the clear coat, which must then be buffed with orbital or rotary buffers, buffing compounds, and pads. There are preset buff times, which are useful not only for maintaining plant efficiency and throughput, but also for allowing operators time to rest between units. This is critical, given the labor-intensive nature of the process — yet it also presents the drawback of limiting operators’ ability to do a thorough job.


Fortunately, tests of the Farécla system have consistently shown an ability to meet or exceed the one-minute takt time goal. This produces several key benefits. Less time needed for buffing allows operators more time to thoroughly inspect and complete their work. It also affords operators more time to rest between vehicles, creating an ergonomic advantage with a significant positive impact on productivity. The overall net result is that labor hours are cut in half.


Buffing compounds


Many buffing compounds include petroleum-distillate fillers and silicones that provide a “quick fix” for surfaces, with less abrasion. Visually, these present well — but only initially. After washing, filled-in flaws can reappear. If noticed before the cars leave the plant, this can mean devoting time and resources into rework; worse, defects may also not be noticed until after the dealership has already received the cars. As mentioned above, filler-based compounds can also be overused, altering vehicle surfaces; they are also difficult to clean up if they spill accidentally on adjacent surfaces.


Farécla compounds, by contrast, contain no fillers or silicones and, as water-based products, are easy to clean up. Each spot to be buffed requires just a dime-sized dollop, resulting in cost savings. Their semi-transparent nature also offers a more viewable work area, with greater potential for gauging the success of defect removal. In prime automotive settings, this can be demonstrated by wiping down the buffed area with alcohol, underscoring their qualification within the preferred product class of “what you see is what you get.”


Buffing pads


The prime automotive world tends to prefer buffing with foam pads. Though well-suited for the tasks at hand, they begin to break down during use and are treated as disposable and non-reusable. When used with compounds containing fillers, they become hot — further shortening their life. A typical per-operator pad use rate for two-hour quarter-shift periods is six to eight pads per period. This adds up quickly, with some manufacturers using as many as 40,000 to 50,000 pads per year; pad cost is often double or triple that of compounds.


Testing, however, is bearing out the efficacy of the Farécla system. Because the compound is both more effective on automotive surfaces and less destructive on buffing pads than competitive compounds, operators are finding that pads will last twice as long. Half as many pads are getting them through the same quarter-shift time periods.


The Farécla system includes a wide variety of compounds and applicator pads.


Farécla makes pads in various materials and configurations that can be used with different Farécla compounds, as illustrated in the industrial brochure. For prime automotive, trial runs both in the field and on painted panels in Norton’s labs have identified the best results from a specific combination: the Farécla 3.25 in orange dimple pad used in conjunction with Farécla Profile Advanced Plus compound. The pad features a single-sided, collapsed cell structure (CCS) design for cutting and polishing; the compound offers the highest level of cut and gloss on painted surfaces, removing sanding marks of P1500 grit and finer.


Success for prime automotive


All things considered, Farécla is proving to be a winner. It offers both increased efficiency and cost savings in the prime automotive space. With labor time cut in half, operators gain time for performing inspections and finishing while also benefiting from increased rest periods between units. Thanks to a long-lasting, easy-to-work-with compound, cleanup is simplified and the need for rework is reduced. Manufacturers are also liable to realize dramatic savings in terms of pad use, particularly when pairing Farécla compounds and pads.


In the final analysis, Farécla is more than just a compound - it is part of an advanced surface finishing system that can be thought of as a “1-2 punch.” For more information, visit the Farécla page.