abrasive technology TECHVIEW GRANITE & MARBLE EDGE POLISHING WITH DIAMOND TOOLS: THE ONLY WAY TO GO Robert W. Evans, Jr. VP Engineering and Quality

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1 abrasive technology TECHVIEW GRANITE & MARBLE EDGE POLISHING WITH TOOLS: THE ONLY WAY TO GO Robert W. Evans, Jr. VP Engineering and Quality Presented at ITSE, Anaheim, CA. June 2, 199

2 Granite & Marble Edge Polishing Abstract Conventional polishing of granite and marble edges has been done by hand. While this has changed somewhat with the advent of automatic finishing machines, it is still very much a hand finishing technology. The addition of power tools to aid the finisher has made the job less fatiguing but still very much a hands-on art form like process. Further, the control of the operating parameters varies widely between technicians. Surface finish quality also varies considerably between individuals and their selected tools. Today, craftsmanship continues to reign supreme in the area of edge polishing. The relatively recent addition of diamond pads for power hand tools has made the job easier, particularly for granite edge polishing. However, finish quality, while easier to achieve, still varies a lot because of inconsistency in operator techniques. Also there is a general lack of working at the optimum levels of feeds and speeds for the diamond-granite polishing interface. This paper presents the results of two years of work focused upon the diamond-stone polishing system with a particular focus upon power edge polishing by hand. The data was collected across a wide variety of stone fabrication shops and their operators. This was a field based study that was quite revealing. Practical suggestions are given to assist the practitioner in producing a higher quality finish in less time. This is done by focusing upon operating more closely to the optimum parameters for diamond tools. Conclusions Following the optimum operating parameters can result in over a % increase in productivity above current field practices (1. times current). Annual sales revenue increases from a single operator can exceed $6, in over half the cases when switching from typical current practices to more optimum levels. Following the optimum operating parameters can result in an improved finish and minimize reworks. Following the optimum operating parameters can result in less operator fatigue and thereby improve output. Both granite and marble can be effectively polished with diamond tools. Polishing marble with diamonds and water reduces respiratory dust concerns for both the polisher and those in the work area.. Shops doing /" and thicker edges on a regular basis would do well to select inch diameter tools. They need to maintain their current force level on / inch edges and press harder on 11/2 inch edges (from. pounds up to near 1 pounds). Current hand polishing practices can be easily modified to achieve the optimum levels. Following the optimum parameters can result in significantly faster delivery times without additional work hours. FAST FORWARD?»» If you are in a hurry, you can skip the next sections and get right to the recommendations starting with the paragraph labeled "Traverse Speed" on p.6. 8 Green Meadows Dr. Lewis Center, OH USA Fax:

3 Discussion Abrasive Technology, Inc. is a major manufacturer of superabrasive tools for a wide range of industries. In an effort to assist its customers and the stone fabrication industry, it has conducted a product development program focused upon the polishing of stone using diamond tools. An earlier paper entitled, Granite and Marble Polishing With Diamond Tools - The Ultimate In Efficiency and Finish, was presented at Stone Expo in March 199. It discussed the use of diamond tools to polish large flat surfaces. The, then current, industry practices were examined and the test results from both laboratory testing and field validation runs were presented. It was shown that more detailed attention to operating parameters can result in an outstanding finish in less time and with more productivity than had been possible before. Practical field guides were presented for setting up the polishing system to achieve the correct contact pressures, surface speeds, water flow rates, traversing velocities and head overlaps. This paper expands upon the previous work and addresses the issue of correct application of diamond tools when performing edge polishing of granite and marble stones. The approach taken was to design and build a special polishing platform. This platform would need to measure and record the forces and times being used by an operator for each grit, over a variety of stone types. This platform had to be portable since all the data was to be collected from polishing professionals in their own shops, on their own stones, and using their own tools. A three axis Kistler dynamometer was procured. Its high frequency capability made it especially suitable for this work. The dynamometer was attached to two square plates (one above the dyno and one below). In this way, the bottom plate could be fastened easily to a bench top. The stone could then be placed on the top plate and clamped in place (ref photo A). Any forces applied to the stone would then have to be transmitted through the dynamometer, thereby producing an electrical signal proportional to the actual force being applied to the edge of the stone. Photo B The special platform and data acquisition system were transported to a number of stone shops. Each available operator was asked to polish a granite edge and a marble edge using his normal tools and techniques (ref photo C). Photo C No attempt was made to influence each person s style and technique. Each stone was their selection from their own yard. The stones polished are shown in Table 1. STONE TYPES EVALUATED Photo A The electrical signals were sent to amplifiers and then into a two pen strip chart recorder (ref. Photo B). The entire system was quite portable and the strip chart records provided adequate resolution over the anticipated operating range (approximately. pounds resolution). GRANITES: BLUE PEARL MARBLES: WHITE CARERRA VERDI ALPI BOTTICINO Table 1 The power tool was their own choice and from their own equipment inventory. A list of the power tools used in shown in Table 2. 8 Green Meadows Dr. Lewis Center, OH USA Fax:

4 BRAND TYPE EDGE POLISHING TOOLS USED DURING EVALUATIONS TOOL SPINDLE TYPE STONE POWER DIAMETER (in.) SPEED USED ON SOURCE 1 BOSCH BELT SANDER N/A 2, FPM MARBLE ELECTRIC 2 PORTER CABLE BELT SANDER N/A 1, FPM MARBLE ELECTRIC MAKITA 9218-PB 2, RPM ANY, BUFF ELECTRIC FLE ORIGINAL LW1, RPM GRANITE ELECTRIC NIKKEN WS- 2, RPM GRANITE AIR 6 NAT.DETROIT DSQ 1, RPM MARBLE AIR NIKKEN WS-, RPM GRANITE AIR ADJUSTABLE 8 MALTABO, RPM MARBLE ELECTRIC ADJUSTABLE 9 ALPHA 2, RPM GRANITE ELECTRIC Table 2 The abrasive tools they used were theirs to choose, and again, from their own inventory. All machine settings such as RPM and water flow rate were their choice. Consequently, there should not have been any issues regarding lack of familiarity with how to perform the work successfully. Most operators chose to have the stone laying horizontal and to polish the vertically oriented edge by pushing in lightly. This orientation is shown in photo # A, above. One shop chose to place the slab vertically and to polish the horizontally oriented edge with a slight downward pressure (ref. Photo D and E). This seemed to provide some advantage to the operator in consistency of loading and minimization of fatigue. Further, he avoided water in the face with this setup. Photo E their time with their best people. Due to the production focus and the art or craft orientation toward edge polishing, there has been a general lack of data collection and virtually no systematic testing for better methods and a more complete understanding of the polishing process. This is in spite of the fact that most of the companies visited could benefit in a significant financial way from a more optimized and consistent approach to edge polishing. Data format The forces from the dynamometer were output as lines on a moving strip chart. A typical sample of the strip chart record is shown in Figure 1. The upper line, labeled grinding contact force, is the force being applied to press the tool into the stone. The lower line, labeled tangential force, is the force being produced from dragging the tool across the stone. It is in the same plane as the edge being polished. SINGLE GRIT GRANITE AND TOOLS OPERATOR TECHNIQUE AS OBSERVED Photo D General observations The average operator had.9 years of experience in edge polishing and nearly half had over years of experience. One operator evaluated had 16 years of experience. There were wide differences in technique, choice of operating parameters and finished product appearance. There were also large differences in the time to perform a polishing sequence. The majority of the granite edges had to be redone because of cosmetic appearance issues. This has to be very costly in both time and materials. There was a surprisingly strong reliance upon post polish finishing techniques other than buffing. Chemical coatings of many types are in use. Levels of commercial acceptability varied widely. Some operators were much more skilled with one stone than another. Years of experience did not seem to completely predict polishing skill. It seems that training efforts could be strengthened with a focus on consistency of technique and selection of more optimum operating parameters. Most companies were quite open and willing to give of GRINDING CONTACT (INTO STONE) TANGENTAL (ALONG EDGE) CONTACT STONE TANGENTAL Figure 1 8 Green Meadows Dr. Lewis Center, OH USA Fax:

5 A graphical analysis of the data is shown in Figure 2. The average value was taken from an "eyeballed" best fit line drawn over the data. The max and min values were similarly taken for each trace. The values were recorded in tabular form across each operator, on each stone, and for each grit used. GRINDING CONTACT (INTO STONE) SIDEWAYS (ALONG EDGE) CONTACT STONE SINGLE GRIT GRANITE AND TOOLS OPERATOR TECHNIQUE AS OBSERVED 1. SIDEWAYS Figure 2 Field testing summary. RANGE = 1. or + 6. lbs... AVG. = 2. lbs. RANGE = 2.6 or + 1. lbs. AVG. = 11. lbs. Table below shows some summary statistics from the field work we conducted on granite. The values shown are brought into practical focus in the section Implications For Edge Polishing. Previous work key relationships It is important to compare this current round of field data with the previous work. This comparison will assist in achieving a more complete understanding of where the current practice of edge polishing resides and where it needs to go in order to be at a more optimum level. To that end, this section is a series of brief excerpts from the previous work by the same author on the use of diamonds in the polishing of both marbles and granites. This excerpted paper is titled Granite & Marble Polishing With Diamond Tools - The Ultimate in Efficiency and Finish and is also available from Abrasive Technology, Inc. For White Cherokee marble and both Charcoal Black and Mahogany granites, a test plan was developed using statistically based Designed Experiments. Variables evaluated included abrasive types, bond systems and associated characteristics, and operating parameters. The output characteristics were stone reflectance, depth of color, overall appearance, and tool wear. Tests were conducted almost continuously over a 2 month period. The tooling formulations were developed in response to the output characteristics initially measured. Progressive improvement was incorporated into each succeeding level of tool design and testing. The various stones finish sensitivities to both small and large changes in the operating parameters were also quantified. Each of the variables, surface speed (SFPM), load (LB), water flow rate (GPM), traverse speed (FPM), pass overlap and the number of passes required were varied over a considerable range during the test program. A table of optimum values was published which, when used, produced significantly better results than any other levels tested. We recognize that field conditions are often less than optimal. Also, production equipment often lacks the adjustment and control features necessary to obtain the table values exactly. However, three things can be stated definitely. First, deviation from the table values detracted from the optimum finish and productivity numbers we achieved during testing on the specific pieces of White Cherokee marble, Charcoal Black and Mahogany granites that we used. Second, no one is using THE exact pieces of stone that we used. Consequently, some changes in operating parameters may be useful. However, the table values represent a well tested and proven set of parameters for a starting point when polishing stones in this range. Third, care must be taken when changing parameters. We found interactions between parameters that significantly affected finish. An interaction between load and water flow rate, for example, would mean that at light loads, water flow should be low for optimum finish, but that at heavier load water flow should be high to maximize reflectance, a reversal or interaction. The reflectance values obtained during testing are shown in Figures and. FIELD TESTING - GRANITE DATA - /" THICK, 12" EDGES OPER. ID A B C D E F G H I J AVG: MA: MIN: YEARS EP GRANITE BLUE PEARL BLUE PEARL BLUE PEARL TOOL TYPE MIED MIED TOOL DIAMETER (in.) / / RP 2, 2, 2,2, 1,/, 1,/2, 2,,,, PERIPHERY SPEED (sfpm) 2,9 2,9 2,9 2,9 1,9/29 1,9/11 1,1,8,8,8 AVERAGE LOAD APPLIED (lbs) MA LOAD MIN LOAD LOAD RANGE TOTAL POLISH TIME (sec) AVERAGE TIME PERGRIT (sec) TOP HALF AVG NUM. GRIT STEPS 11 8 EDGE STYLE DEMI BULL Table 8 Green Meadows Dr. Lewis Center, OH USA Fax:

6 REFLECTANCE REFLECTANCE WHITE CHEROKEE MARBLE TECH SHINE PADS & DIAGLO M COMPOUND m Buff GRIT SIZE Figure CHARCOAL BLACK & MAHOGANY GRANITE with TECH SHINE PADS & DIAGLO COMPOUND m Buff Amb.Temp. GRIT SIZE Figure We have found that the two most significant variables for controlling polishing results are the contact pressure on the stone and the tool rotational velocity. Water flow is important. Further, it is clear that the number of passes the tool makes over a single spot on the stone is important. Of course, the proper values will be different for different tools from different sources. Also, we know that stone varies widely. However, for a given stone, the two key variables that the producer can control are the load on the stone and its resultant contact pressure and the surface feet per minute being produced by the motor RPM and the diameter of the tools. The optimum contact pressure for both marble and granite was found to be 9. psi. The optimum surface speed for marble was found to be 8 SFPM and for granite it was 1 SFPM. The optimum water flow rate was found to be. GPM. The optimum traverse speed was found to be FPM. The optimum number of passes for marble was found to be 2 passes while for granite the optimum was passes. The diamond grit sequence commonly used in the field for granite is, 12, 22, 6, 8, 18, and. For marble, the sequence is, 12, 22, and. Implications for edge polishing The differences in technique and associated times to polish, along with the high frequency of reworks greatly reduces productivity. We estimate that in half the cases, over a % increase in output per operator can be achieved if techniques are optimized for first time acceptance and standardized for consistency between operators. This % increase number initially came about when we decided to attempt to train a polishing technician to more closely duplicate the practices that had worked so well in the large flat surface work we had previously conducted. Our original plan was just to observe current practices and quantify operational parameters. However, after several shop visits, we just could not resist trying to help improve their practices. After the operator had polished an edge in Black Absolute granite, we showed him the strip chart graphs of his work (ref. Figures 1 & 2).We explained that a smoother, more steady motion would help eliminate the somewhat wavy appearance he had produced. While it was not severe enough to reject the stone from a commercial standpoint, it was noticeable under a reasonable examination. Also, the edge had some lightness (lack of depth of color) in a streak running over a good portion of the length of the edge. We suggested that a closer examination of the stone after the 12 grit would help prevent this problem in the end. He agreed to use an air gun to dry the stone after the 12 grit and to not advance to the next grit until all of the grit scratch pattern had been removed. Finally, we suggested that he was spending too much time and not getting the higher quality results possible from spending less time at more optimum levels. Specifically, an increase in contact pressure and a decrease in traverse speed across the stone with fewer passes should help achieve the optimum finish in the minimum time. He agreed to try this approach on the adjacent side of the same stone he had just polished. The change in method is shown for the same operator, grit and stone in Figure. GRINDING CONTACT (INTO STONE) TANGENTAL (ALONG EDGE) SINGLE GRIT GRANITE AND TOOLS OPERATOR TECHNIQUE AFTER TRAINING Figure The analysis of the data is shown in Figure 6. The dramatic change in technique was achieved after a brief five minute discussion. The quality of the final finish was significantly improved to a level well above just commercial. This shows that a little training can be quite effective when properly focused and delivered. 8 Green Meadows Dr. Lewis Center, OH USA Fax:

7 GRINDING CONTACT (INTO STONE) SIDEWAYS (ALONG EDGE) SINGLE GRIT GRANITE AND TOOLS OPERATOR TECHNIQUE AFTER TRAINING 1. RANGE =. or + 2. lbs AVG. = 1.8 lbs. RANGE = 1. or +. lbs.. AVG. = 1. lbs. mating purposes, we used a six foot counter,. inches thick, of granite, with a flat polished edge being sold for $. Using the productivity numbers above, the improved method would yield additional counters out the door per person per shift. That translates into $2 per day in increased sales revenue or $6, per year per person! The benefits from this change in productivity are in three areas. First, more sales mean more profits. Second, increased output per labor hour means a more competitive shop, getting more jobs and winning the jobs it really wants to win. Finally, and perhaps most importantly today, an optimized operation can promise quicker delivery times and meet its commitments more easily. Of course, each stone is different, and each operator s current practices are different. These numbers do not include the additional operator setup times that go with this increased output. Also, the favorable impact of reduced or eliminated reworks has not been included in the estimates. Our data suggests that elimination of reworks may yield another % improvement! In any case, savings per operator will vary. However, the data and field experience clearly show that a tremendous gain in productivity is possible when using diamond tools properly. Figure 6 A comparison of the as found method and the after training method is shown in Figure. START START 1.9 cm = 81.8 sec CYCLE TIME COMPARISON TWO METHODS - ONE GRIT GRANITE 1. cm = 112. sec FINISH AS FOUND AFTER TRAINING FINISH Smoother motions More consistant pressure Less total time Figure The charts were run at the same speed during the tests. Therefore the difference in lengths of the two lines represents the time saved per grit when converting to the more optimal method. This saving represents a % increase in finished edge footage for this one operator! This operator was still using too much time to achieve the optimum polish. We found that half of the operators tested can produce an average of. lineal feet of polished granite edges per shift using their current methods when excluding setup times. The same operators can each produce lineal feet of polished granite edges per shift using the after training optimized method. For esti- Traverse speed: The optimum traverse speed is feet per minute (FPM). For practical purposes, an operator should be moving the power tool across the stone edge in a smooth motion that covers 1 foot every 12 seconds. It may be helpful to mark off 1 foot sections with masking tape and counting one thousand and one, one thousand and two,...one thousand and twelve for a while to help get the correct idea of an appropriate traverse rate. Number of passes: Granite requires four passes and marble only two passes. A pass is defined as moving from one end to the other. The operator would then move at the same speed back to the starting point. This would be the completion of two passes. When polishing granite this sequence would be repeated again (a total of passes). Surface speed: This parameter is somewhat more difficult to manage. Each operator seems to have his/her own power tool preference and each manufacturer s power tools operate at different speeds. Some tools are speed selectable while others are of a fixed RPM design. The other variable that effects surface speed is the diameter of the polishing disk. Most shops are operating with either or inch disks. Considering the importance of surface speed, it will pay big dividends to the operator that takes a little time to optimize this parameter. From the previous work, the optimum value for granite is 1 sfpm while that of marble is 8 sfpm. The nomograph below (Figure 8) shows the interplay between the diameter and the spindle speed and their effect upon surface speed. While it may not be possible to hit the optimum values exactly, the closer you get to the optimum the better the results. Knowing the tool diameter and the handpiece RPM, draw a straight line connecting the two values. Where the line crosses the surface speed line is the speed this set up will produce. An operator can either adjust the RPM via the manufacturer provided dial 8 Green Meadows Dr. Lewis Center, OH USA Fax:

8 or select another power tool with a more favorable RPM in order to achieve a more optimal surface speed. Of course, changing the tool diameter selection can also be an effective way to optimize surface speed. In some cases, changes in selection of both the hand tool and the disk diameter may be required to obtain optimum levels. INCH DIAMETER TOOLS CONTACT AREA ANALYSIS CENTERED ON STONE NOMOGRAPH FOR OPTIMIZATION OF SURFACE SPEED (SFPM) HAND EDGE POLISHING /" 1 1/2" OFFSET ON STONE 6 2 /" 1 1/2" OPTIMUM FOR GRANITE 2 19 TOOL DIAMETER (IN) SURFACE SPEED (SFPM) OPTIMUM FOR MARBLE 1 1 HAND TOOL SPEED (RPM) 1 11 Figure 9 mond tool s bond prematurely and tool life suffers. Table summarizes the contact area and force considerations for three tool sizes. Contact pressure: Figure 8 The issue of contact pressure relates to four variables. The first variable is how hard the tool is pressed onto the stone. This is expressed in pounds of force. The second variable is the gross contact area over which the load is distributed. This is measured in square inches. The third is the percentage of the contact area that is actually resin and diamond touching the stone. Finally, because the edge is a narrow line and the polishing disk has a larger diameter than the edge width, the geometry of the pad orientation to the edge must also be considered. Figures 9 shows some of these considerations graphically. Stone is polished by the contact pressure between it and the diamond tool. Imagine a 1 pound weight 1 inch square resting upon your hand. The weight does not cause you pain because the contact area is relatively broad (1 square inch) and the load is relatively light (1 pounds). This translates into 1 pounds per square inch or 1 psi. If however, you then turn the weight up on edge so that the entire weight is pressing onto your hand over a.1 square inch area, your level of comfort just deteriorated significantly. It is still the same 1 pounds but the contact area through which it is pressing on your hand is now just 1% of what is was previously. This new arrangement translates into 1 pounds per square inch (1 psi). It is the high contact pressures that break down the stone piece by piece. If the stresses are not high enough, the stone does not become scratched and it never becomes polished. If the stresses are too high, the excess pressure helps to break the dia- TOOL FORMULA TOOL DIAMETER (in.) SUPER-DIASHINE : PRO-DIASHINE : EDGE THICKNESS (in.) / 1 1/2 / 1 1/2 / 1 1/2 / 1 1/2 / 1 1/2 CONTACT PRESSURES AND APPLIED S FOR SELECTED TECHNIQUES CONTACT AREA CENTERED (sq.in.) REQUIRED FOR 9. PSI CENTERED (lbs.) CONTACT AREA OFFSET (sq.in.) REQUIRED FOR 9. PSI OFFSET (lbs.) Table Figures 1 and 11 show this data graphically for the two most common edge thicknesses and for the two styles of tool positioning (centered and offset). Based upon the field data,. pounds of load on the stone is commonly achieved. In Figure 1, we see that tool to stone centering and offset techniques on / inch edges produce little difference for the inch Pro- Diashine (p) and inch Super-Diashine (s) (around a 1-1% change). However, the inch Pro-Diashine (p) and inch Pro-Diashine (p) produce a substantial difference in contact load requirements depending upon technique (up to a % change). This seems to suggest that an operator should select one approach or the other and stay with it to enhance his/her consistency of load and resultant contact pressure. The inch tools seem to be close to optimum contact pressures at the commonly achieved load. The inch tools need an increase in contact load for either tool orientation, cen Green Meadows Dr. Lewis Center, OH USA Fax:

9 LOAD (lbs) OPTIMUM LOAD FOR / INCH EDGE POLISHING 6/9 rwe COMMONLY ACHIEVED LOAD cent / offset / tion of his/her feel for the correct loading. One simple and inexpensive way to accomplish this would be to obtain a bathroom scale. This scale could be placed in the shop in a standard and convenient location for a painless check on a scheduled basis. The human memory for correct feel is somewhat weak and in need of frequent reinforcement. A "start of shift" habit could be just enough to emphasize the importance of correct loading and frequent enough to become ingrained. Figure 1 tered or offset (between 2 and 6 pounds increase). In Figure 11, the tool to stone centering and offset techniques on 1 1/2 inch edges produced little differences for any of the tools surveyed. LOAD (lbs) Figure 11 However, the optimum contact loads required are well above what is typically used by skilled operators. Further, as the tool diameter gets larger the required forces increase significantly. For 1 1/2 inch edges, the case for inch tools seems clear. The operators need to increase their contact force by nearly 1% to get to optimum productivity levels. They need to nearly triple their current load when using the " Pro-Diashine (p). For these reasons, a shop doing both thicknesses of edges on a regular basis would do well to select inch diameter tools. They should maintain their current. lb. load on / inch edges and press harder on the 1 1/2 inch edges (from. pounds up to 1 pounds). Figure 12 shows this for the centered technique for both edge thicknesses across the family of tool sizes and types. LOAD (lbs) S -P -S -P -P TOOL DIAMETER AND TYPE OPTIMUM LOAD FOR CENTERED TOOL AT / & 1 1/2 INCH EDGE THICKNESSES 6/9 rwe OPTIMUM LOAD FOR 1 1/2 INCH EDGE POLISHING 6/9 rwe COMMONLY USED LOAD -S -P -S -P -P TOOL DIAMETER AND TYPE cent / cent 1-1/2 CURRENTLY ACHIEVED LOAD -S -P -S -P -P TOOL DIAMETER AND TYPE Figure 12 With loading being so important, the efficient shops need a method to assist the polishing technician in periodic calibra- cent 1-1/2 offset 1-1/2 Water flow rate: Water flow rates are generally uncontrolled beyond full on and full off flow levels. Because the water tends to run off an edge much more so than off a slab, more water is needed in edge polishing. Too little water translates into shortened tool life and unwanted scratches from the stone swarf as a secondary abrasive. Too much water can cause tool hydroplaning and poor surface finish or at least require a longer time to achieve a good polish. We did not conduct a full investigation into the optimum water flow rate required when edge polishing. However, it seems apparent that some level would be more optimum than others. Further, it is nearly impossible to determine what level is optimum if there is no way to repeatedly obtain a given flow rate. Also, there is a need to identify relative flow rates in order to be able to arrive at statements such as higher is better. For these reasons and to assist all operators in setting up to the same levels, we recommend that the water flow rate be set by a control valve and gage placed before the hand tool. The valve on the hand tool should only be used for full on and full off switching. We have had good success with a relatively inexpensive flow meter and control valve assembly that is easy to set, gives numerical flow values and is consistent. The cost of the system is around $1 and it would be well worth the investment. Summary There are several key lessons to be learned from this work. 1. Major productivity improvements (over %) can be achieved from a more disciplined and informed approach to edge polishing. 2. Annual sales revenue increases from a single operator can exceed $6, per year in over half the cases we observed when switching from typical practices to more optimum levels.. Rework can be greatly reduced by following a more consistent and optimum approach. A % increase in productivity is possible in over half the cases we observed.. Current hand polishing techniques can be easily modified to achieve optimum levels.. Shops doing /" and thicker edges on a regular basis would do well to select inch diameter tools. They should maintain their current. pounds of force on the /" edges and press harder on the 1 1/2 inch edges (from. pounds up to 1 pounds). 6. Following the optimum parameters can result in significantly faster delivery times because of the large increases in productivity. Special thanks I want to extend my heartfelt appreciation to all those who so willingly helped to make this project a success. None of this would have been possible without the enthusiastic support of all who participated. Thanks team! 8 Green Meadows Dr. Lewis Center, OH USA Fax:

10 World headquarters - Lewis Center, Ohio USA abrasive technology WORLD HEADQUARTERS EUROPEAN HEADQUARTERS ASIAN HEADQUARTERS Abrasive Technology, Inc. Abrasive Technology Ltd. Abrasive Technology Asia Pacific Pte. Ltd. 8 Green Meadows Dr. Roxby Place Fulham, London Blk 19 Lower Delta Rd. -11/1 P.O. Box SW6 1RT United Kingdom Tiong Bahru Industrial Estate Lewis Center, Ohio USA Ph: Singapore 1692 Ph: Fax: Ph: Fax: Fax: