i e 480w - final report

8/2/2019 I E 480W - Final Report

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PENNSTATEDepartment of Industrial Engineering

Rockland Manufacturing Team # 2Final Report

April 1, 2012

Team Members:Ronald ChanZachary DalePJ CliffordEric SegnerJeffrey Zub

Sponsor:Bo Pratt

Jim Hershberger

Adviser:Dr. Voigt


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Executive Summary

Rockland Manufacturing currently spends $90,000 on their grinding process using the PearlSilver nine inch grinding wheels. They are interested in finding a wheel that performs better thantheir current wheel to improve their grinding process and potentially yield monetary savings.

Rockland brought the Penn State team in to test different grinding wheels against their current wheelto understand the performance of their current wheel compared to that of different wheels available.The parameters of most interest to Rockland are the material removal rate, price, and wheel life. Theteam first did extensive research on grinding wheels and the grinding process to completelyunderstand the problem. The team found the main difference between nine inch grinding wheels isthe material of which they are manufactured and the manufacturer. The price also varied greatly, butthe team found the variation was a result of the manufacturer. The team developed a list of testwheels based on the two materials, aluminum oxide and zirconium, from seven different topmanufacturers; CARBO, CGW, DeWalt, SAIT, Westward, Norton, and Metabo which rangedgreatly in price. The wheels were obtained and three tests were performed. The first test was a weldtest where each wheel was used to grind off six 1 inch welds. This was done twice with each wheel,

using a new wheel for each test to obtain an average. The time was recorded and the weightdifference of the wheel was recorded. The time was testing the material removal rate as the eachwheel was grinding the same six welds. The wheel weight difference tested the wheel life. The bestperforming wheel was the Norton zirconium with a time of 149 seconds and the worst performingwheel was the Pearl Silver at 268 seconds. The next two tests developed tested grinding on baremetal; two different types of metals Rockland uses in their processes. Each type of metal was testedwith each wheel for two minutes. Two samples of these tests were taken to obtain an average. Thedifference in weight of the metal piece and the difference in weight of the wheel were recorded. Thedifference in weight tested material removal rate in two minutes and the difference in wheel weighttested wheel life. A jig was used to hold constant pressure on the grinder to avoid variability. Thesetwo tests had much less variability than the weld test as there was constant pressure and time wherethe weld test had different sized welds and operator fatigue that set in. The best performing wheel forthe harder metal was the CARBO Maxx Gold with a material removal of .132 lb. The bestperforming wheel for the harder metal was the CARBO Premier with a material removal of .144 lb.The worst wheel in both tests was the Pearl Silver wheel with a material removal of .0253 lb and.0231 lb. An employee evaluation was then performed by distributing forms to the employees withthe test wheel to rate the wheels compared to the current wheel. Because of the poor performance ofthe current wheel in each test, it was obvious that improvements could be made.

Analysis was completed using the data obtained in the two metal grinding tests. The wheellife and material removal rate was found and compared amongst the wheels. Then, this data alongwith the data of Rocklands current grinding costs and usage was used to make calculations andcomparisons regarding material costs for the wheels themselves and labor costs. Percentages werefound to compare each wheel to the current wheel. The zirconium wheels recommended are theCARBO Maxx Gold and CARBO Premier and the aluminum oxide wheels recommended are theCGW and DeWalt wheels which resulted in the most savings per wheel in grinding expenses whencompared to the current wheel. Also, the results from the analysis match the top performing wheelsin the user evaluation. The Pearl Silver wheel currently being used was the worst wheel in the batchof wheels tested, meaning there is much room for improvement and potentially a high monetarysavings when implementing one of the suggested wheels here. One of the four possible wheels listedhere should be implemented to replace the use of the Pearl Silver wheels.


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Table of Contents

1.0 Problem Statement .................................................................................. 41.1 Objectives/Goals ................................................................................... 4

2.0 Wheels Chosen to Test ............................................................................ 42.1 Reasons for Choosing Wheels .............................................................. 5

3.0 Experimental Approach ........................................................................... 53.1 Parameters Being Tested ...................................................................... 63.2 Metal Grinding Tests ............................................................................ 6

3.2.1 Jig .................................................................................................... 63.2.2 Metal Test Results ........................................................................... 7

3.3 Welding Test ....................................................................................... 103.3.1 Grinding Test Results .................................................................... 11

4.0 Analysis ................................................................................................. 13

4.1 Operator Feedback .............................................................................. 134.2 Wheel Retail Cost ............................................................................... 164.3 Material Removal Rate ....................................................................... 174.4 Wheel Life .......................................................................................... 174.5 Percent Better Wheel Life and Material Removal Rate ..................... 184.6 Percent Better Wheel Life and Material Removal Rate per $ ............ 194.7 Wheels Needed per Year .................................................................... 214.8 Cost per Year and Savings per Year in Wheel Costs ......................... 22

4.9 Labor Hours per Year and Savings per Year in Labor Costs ............. 244.10 Labor and Wheel Cost Results Combined........................................ 264.11 Assumptions ...................................................................................... 28

5.0 Recommendations ................................................................................. 286.0 Conclusion ............................................................................................. 297.0 Appendix ............................................................................................... 29


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1.0 Problem Statement

Our team worked with Rockland Manufacturing to evaluate a selection of 9 grinding wheelsin order to determine the best fit for the company. An improved grinding wheel from their PearlSilver wheel is desired to improve the performance of their grinding process and to potentially savemoney. Currently, Rockland uses air powered angle grinders for two main applications in the shoparea; after the plasma cutting process, and when bracing is removed the excess weld slag is groundoff. A combination of experiments was created to simulate each scenario and will be explainedfurther in this report.

A selection of grinding wheels was chosen by the team based on two main differences;brand/manufacturer and material type (aluminum oxide and zirconium). These various wheels weretested against Rocklands current 9 Pearl Silver Line grinding wheel. Each grinding wheel wastested with respect to cutting speed, cost, and wheel life. An economic analysis was conducted by

the team to determine the cost/benefit ratio of implementing new grinding wheels vs. Rocklandscurrent practices.

This report presents the findings of through the experiments held. The numerical results aswell as user results are provided and a comparison of these results is given to help understand whichwheel is optimal. Also, the recommendations to Rockland on the improved wheel choice will begiven.

1.1 Objectives/Goals

Obtain wheels of 2 material types from 8 different manufacturers and make comparisonsbased on tested parameters.

Receive operator feedback on the wheels Analyze test data via numerical and cost analysis Recommend best grinding wheel based on criteria being tested Report estimated savings and/or improved performance based on new wheel

recommendation

2.0 Wheels Chosen to Test

Manufacturer Material Retail Prices

Pearl Silver Line Aluminum Oxide $3.13

CARBO ZirconiumGold MAXX $6.85

CARBO Zirconium - Premier $13.01

CGW Aluminum Oxide $3.49

CGW Zirconium $9.40


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DeWalt Aluminum Oxide $6.71

DeWalt Zirconium $15.02

SAIT (United Abrasives) Aluminum Oxide $9.70

SAIT (United Abrasives) Zirconium $10.49

Westward Aluminum Oxide $6.01Westward Zirconium $12.29

Norton Aluminum Oxide $6.21

Norton Zirconium $12.81

Metabo Aluminum Oxide $4.25

Metabo Zirconium $74.80/10

Table 1: The wheels chosen to test for Rockland.

2.1 Reasons for Choosing Wheels

From the list above it can be seen that for each manufacturer, the two different materials;aluminum oxide and zirconium were chosen to test. During the initial research to find the parametersthat changed between different 9 wheels, it was found that the material, manufacturer, and pricewere the differences between grinding wheel choices and would be focused on to find the bestselection of test wheels. It was also found that the grit size of 24 was constant for the 9 X 7/8 X1/4 size of grinding wheel which took this variation out of the decision for different wheels. Next, itwas found that there are mainly three materials that make up this size of grinding wheel; aluminumoxide, zirconium, and ceramic. The ceramic wheels which had lofty claims were out of the budget ofthe experiment and seemed to be for more specialty metal jobs which took them out of the decision

of grinding wheels. This left the aluminum oxide and zirconium wheels to test. The team decided toacquire these two material wheels from many different main manufacturers of grinding wheelswhich covered a broad range of prices. This was done to find the effect of manufacturer as well asprice on the grinding wheel performance as different manufacturers offer the same material wheelsfor different prices. The manufacturers were chosen based on extensive research and phone calls tothe manufacturers regarding the wheels. Also, the teams budget, while already extended for wheel

purchases, had an effect on the amount of manufacturers to test leaving the larger, more prominentmanufacturers to test. The manufacturers chosen allow for the best wheel found to be easily obtainedfrom a local supplier while smaller manufacturers of wheels may be harder to gain the large amountsof wheels required by Rockland. Six samples of each wheel were obtained to have a new wheel foreach of the two samples of the three different experiments explained below.

3.0 Experimental Approach

The following describes the parameters that were tested to analyze the test wheels givenabove in Section 2.0. The parameters are then followed by a description of the three tests; twodifferent metal grinding tests and weld testing. These three tests were used to collect various dataregarding wheel performance used in the analysis section.


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3.1 Parameters Being Tested

There are three main parameters that the team tested in the experiments. The most importantparameter for the team tested for was how quickly material is removed when grinding (materialremoval rate). The team and Rockland was looking to maximize the amount of material beingremoved. This was measured in two different ways, depending on the experiment which will beexplained in the specific tests below. The second most important parameter that was tested with theexperiment is the cost of the wheel. This was based on the cheapest cost that each wheel can beobtained for in bulk from a local supplier of each manufacturer. There was a separate cost analysisdone once the experimentation was finished to determine which wheel makes the most financialsense once factoring in labor and other costs. The final parameter that the team was testing for waswheel life. This was tested for all of the experiments by weighing each wheel prior to performing thetest, and then weighing it again after the test was completed. Ideally we were looking to minimize

the difference between these two measurements so that the wheel will last as long as possible. Theoptimal combination of these parameters was found to recommend the best wheel choice.

3.2 Metal Grinding Tests

The metal grinding test was done in two different parts. This first part was to test 400 BrinellPlate and the second part was to test A572 Grade 50. Each test had two replications for each wheelthat was being tested, and there were 17 different wheels being tested which resulted in 34 tests foreach of the 2 types of metal; a total of 68 tests with 68 wheels. The two samples of each wheel werethen averaged to reduce variability. The test used a jig that is described in section 3.2.1 to minimize

the amount of variability between tests in order to gain accurate data. The jig helped to keep thegrinder at the same angle during each test, as well as to apply the same amount of pressure for eachtest. We used the weight of the grinder as the pressure. Some wheels required a slight amount ofpressure to be taken off the test piece because the wheel would slow down and stop because of theamount of pressure. For this test, the material removal was measured by weighing the sample ofmetal before the test, and then weighing it again after the piece was ground for 2 minutes each. Thescale used had a resolution of .002 pounds and we timed each wheel with a stopwatch. The teamlooked to maximize the difference in weights so that we know that the wheel is removing morematerial than other wheels in the same amount of time. These tests were held at Penn State.

3.2.1 Jig

The jig that was used for the grinding tests allowed the grinder to be firmly mounted so that itwould not move during the tests. Rockland machined and assembled the jig for the team. It washinged at the top so that it could be lifted off the sample to change test wheels without having to bedetached. The sample piece was pinned into a small sled that was slid back and forth on a track, tosimulate the movement of a grinder across a surface. This jig was taken back to Penn State fortesting. The jig was set up in a welding booth with a vent and a guard to stop the sparks. The jig willthen be presented in the final showcase. The jig is shown below in Figure 2.


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The original jig is shown below. The jig was brought back to Penn State and the grinder wasattached with U-bolts. It was seen that the grinder, at an angle of 45 degrees, would grind into themetal which was not how Rockland uses their grinders in their grinding process. The jig was takenback to Rockland to reduce the angle by moving the grinder closer to the base plate which resulted ina more accurate grinding test.

Figure 1: The first jig design to be used for the grinding tests

Figure 2: First Jig Figure 3: Jig after the modifications made

3.2.2 Metal Test Results

Figures 4 and 5 present the results of the metal testing. The weight difference in the metalpiece used to test is provided for each wheel in each test. The numbers given in the chart are theaverage of the two sample tests that were performed for each wheel. Metal 2 was the softer metalwhile metal 1 was the harder type of metal used in Rocklands products. From this chart, it can be


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seen that the CARBO wheel performed the best, removing the most weight in the two minutes. Thistranslates into these wheels having the fastest material removal rate. The SAIT and Nortonzirconium wheels also performed well. Also, it can be seen that the Pearl Silver wheel performed theworst, removing the least amount of material. The Westward wheels also performed poorly in thistest. The results from this test will be further analyzed below, providing a monetary value to the bestperforming wheels.

Figure 4: Average difference in weights of metal 1 from before the test to after the test per wheelused.

Best performing wheels metal 1:

CARBO Maxx Zirconium - .132 lbs CARBO Premier Zirconium - .111 lbs Norton Zirconium - .1045 lbs

Worst performing wheels metal 1:

Pearl Silver - .0253 lbs Westward Zirconium - .0325 lbs Norton Aluminum Oxide - .0418 lbs

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Metal 1 Difference (lbs)



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Figure 5: Average difference in weights of metal 2 from before the test to after the test per wheelused.

Best performing wheels metal 2:

CARBO Premier Zirconium - .144 lbs DeWalt Aluminum Oxide - .124 lbs CARBO Maxx Zirconium - .122 lbs

Worst performing wheels metal 2:

Pearl Silver - .0231 lbs Westward Zirconium - .0264 lbs Westward Aluminum Oxide - .0396 lbs

Figures 6 and 7 give the difference in wheel weight for the two metal tests. Thismeasurement relates to the life of the wheel. The resolution of the scale used was .002 lbs. The bestperforming wheel for Metal 1 test is the Norton aluminum oxide, DeWalt zirconium, and CARBOPremier as these wheels lost the least amount of weight. The worst performing wheel is again thePearl Silver wheel. The best performing wheels in the Metal 2 test are the Pearl Silver and CARBOwheels. The worst performing wheels in the Metal 2 test are the DeWalt aluminum Oxide, SAITzirconium, and Metabo wheels. The best performing wheels represent the wheels with the best life

while the worst have the shortest wheel life. The best wheel life will translate into less wheelsneeding changed and ultimately less wheels needing purchased.

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Metal 2 Difference (lb


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Figure 6: Average differences in wheel weights from before the metal 1 test to after the test

Figure 7: Average differences in wheel weights from before the metal 2 test to after the test

3.3 Welding Test

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For the welding test, the 17 wheels that were being tested were each tested twice; eachsample test used a new wheel similar to the metal grinding test. The idea of the welding test was totest how well the wheels removed a jagged weld after the bracing pieces have been removed fromthe main work piece. Unlike the metal grinding test, we were not able to weigh the sample piecesthat were being welded and grinded. Instead, we made consistent sized weld, and timed, using astopwatch, how long it took to completely remove the weld to make it smooth. Ideally, we were

trying to minimize the time it take to remove the weld. The welds were created by welding six 1 inchwelds in the corner of a piece of metal standing perpendicular to a metal table and then breaking thevertical piece off, simulating the broken welds that Rockland experiences. Each test consisted ofremoving three of the one inch welds two times. This resulted in two time measurements for eachindividual wheel which were then added. This was done twice for each type of wheel, resulting intwo time measurements for each type of wheel which were averaged to reduce variability. TheRockland employees created the grinds while the Penn State team performed the grinding, timing,and recording. Figure 6 illustrates the test. It was noticed that the size of the grinds were consistent atone inch each but the amount of metal in each grind differed greatly between the different weldswhich introduced some variability into the experiment. It was noted that this was acceptable as thegrinds that are currently being ground off in Rocklands processes are all different sizes and differentamounts of metal.

3.3.1 Grinding Test Results

Figure 8 gives the results from the weld test. These numbers are the average of the twosamples of grinding six 1 inch welds. These results directly relate to the material removal rate whilegrinding off jagged welds from the surface of the products. It can be seen here that the Pearl Silverwheels performed the worst as they took the longest to remove the welds from the metal surface. Thebest performing wheels were the CGW zirconium, Westward aluminum oxide, and Nortonzirconium wheels as they removed the welds the fastest. This translates to these wheels having the


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fastest material removal rate. This test introduced a large amount of variability as the welds were alldifferent sizes and operator fatigue was also a factor.

Best performing wheels:

Westward Aluminum Oxide136 Seconds CGW Zirconium139.5 Seconds Norton Zirconium149 SecondsWorst performing wheels: Pearl Silver268 seconds Norton Aluminum Oxide230.5 seconds CGW Aluminum Oxide211.5 seconds

Figure 8: Average of the total time to grind off six 1 inch welds per wheel

Figure 9 gives the difference in weights of the wheels for the weld test. Again these numbersare averages of the two samples of each wheel. These numbers relate directly to wheel life. Thewheels with the smaller difference in wheel weight will have the longer wheel life while largedifferences relate to short wheel life. From the results shown, the DeWalt aluminum oxide,Westward aluminum oxide, and Metabo zirconium wheels performed the worst with a large

difference in weights while the CGW zirconium. DeWalt zirconium, Westward zirconium, andNorton zirconium wheels performed the best with small difference in weights. These wheels willhave the best wheel life and require fewer wheel purchases and wheel changes on the job.

Best Performing Wheels - Wheel Difference

CGW Zirconium - .0055 lbs DeWalt Zirconium - .006 lbs Westward Zirconium.007 lbs

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Norton Zirconium .007 lbsWorst Performing Wheels - Wheel Difference

DeWalt Aluminum Oxide - .028 lbs Westward Aluminum Oxide.016 lbs

Current Wheel

Pearl Silver - .008 lbs

Figure 9: Average differences in wheel weights from before the metal test to after the test

4.0 Analysis

The team conducted three experimental analyses to test the data obtained from the abovedescribed tests. The team will first distribute operator feedback forms to get an understanding of howthe employees feel about the test wheels. Then a DOE will be conducted with the data as well as acost analysis to understand the optimal wheel choice for Rockland.

4.1 Operator Feedback

The operator feedback form shown in the figure below was given along with thecorresponding wheel to the operators to test and give feedback. This test was performed to comparethe results of the experimental test to an actual user evaluation to understand if the results weresimilar or different. The form distributed to the users compared the test wheel to the current PearlSilver wheel using three main ratings; grinding speed, wheel life, and overall comparison. The userswere to rank on a scale of one to five where one was the test wheel performing much worse than theoriginal wheel, three was the wheel performing the same as the current wheel, and five was thewheel performing much better than the current wheel. Also, as area for any general comments orconcerns was given. The wheels from the weld test were distributed with a corresponding form andthe results were recorded. The results can be seen below in Table 10.

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Wheel Difference (lbs)


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It can be seen that the current Pearl Silver wheel received the worst rating for wheel lifewhile the Metabo Zirconium, CARBO Gold Maxx, CGW zirconium, DeWalt aluminum oxide, SAITzirconium, and both Norton wheels received the highest ratings of four and five for wheel life. It alsocan be seen that in the overall category, the CRBO wheels, DeWalt wheels, Norton aluminum oxide,and Metabo Zirconium received the best ratings while the Westward wheels received the worstratings. In the speed of cutting category, the Pearl Silver, and Metabo zirconium received the best

ratings while all other wheels received ratings of four and five. There were a few concerns written inthe comments section for some of the wheels. The CGW aluminum oxide wheel broke while theDeWalt aluminum oxide wheel smelt bad. The Westward zirconium wheel did not take the slag offwell, the Norton zirconium wheels bent, and the Metabo zirconium wheels dug into the product ifthe user was not careful. From this test it can be seen that the wheels to focus on while makingfinancial decisions are; CARBO Maxx Gold, DeWalt aluminum oxide, SAIT zirconium, Nortonzirconium, and the CGW wheels. These results were compared with the results from the two othertests.

Best Performing Wheels

Metabo ZirconiumAverage = 4.67

CARBO MaxxAverage = 4.33 DeWalt Aluminum OxideAverage = 4.33 Norton Aluminum OxideAverage= 4.33

Worst Performing Wheels

Westward ZirconiumAverage = 2 Many WheelsAverage = 3

Current Wheel

Pearl SilverAverage = 3.33


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Figure 10: Operator evaluation form for the test wheels

Manufacturer Material Sample Speed Life Overall Comments

Pearl Silver Aluminum Oxide 2 5 1 4 Does not last

CARBO - GoldMAXX

Zirconium 1 4 4 5

2 4 4 4

CARBO -Premier

Zirconium 1 3 3 5

CGW Aluminum Oxide 1 3 3 3

2 4 N/A 4 Cut quicker. Broke.

CGW Zirconium 5 3 4 36 4 3 3

DeWalt Aluminum Oxide 1 4 4 5 Eats slag well. Smells bad.

DeWalt Zirconium 1 3 3 3

2 3 4 5 Pretty good

SAIT Aluminum Oxide 1 3 3 3

SAIT Zirconium 1 3 3 3


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$3.78 $4.37 $5.06$6.71 $6.75 $7.58 $7.90

$9.40 $10.18 $10.93$12.29 $13.01

$15.02 $15.85$20.12

Retail Cost per Wheel

Retail Cost per Wheel

Table 2: Operator feedback results

4.2 Wheel Retail Cost

The wheel costs that were used for the study were based on the retail prices for an evencomparison. These wheels will most likely be slightly cheaper when purchased in bulk from a localdistributor. It can be seen that the Pearl Silver wheel is the cheapest while the SAIT zirconium wheelwas the most expensive. These prices are used in the following analysis to analyze material costsavings.

Figure 11: Retail cost per wheel

2 4 4 4

Westward Aluminum Oxide 1 3 3 3

2 4 3 4

Westward Zirconium 1 3 1 2

2 3 2 2Wear too fast. Doesn't take sla

off/bevel well

Norton Aluminum Oxide 1 4 4 5 Grinds good and doesn't take as lo

2 3 3 4 Cuts good

Norton Zirconium 1 3 N/A 3Bevels well. Bends more but che

more

2 4 4 4

Metabo Aluminum Oxide 1 4 3 3

2 4 N/A 4

Metabo Zirconium 1 5 4 5 Gouge into product if not caref

2 5 5 5 Digs in


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4.3 Material Removal Rate

The material removal rate was calculated based off of what was recorded from theexperiments. An average removal rate was taken for each wheel based on the four replications of themetal grinding tests and then converted to pounds per hour so that it was a more meaningfulmeasurement. The material removal rate was converted from pounds per two minutes to pounds per

hour. The removal rates of each wheel are seen below in Figure 12.

Best Wheels

CARBO Premier3.825 CARBO MAXX3.81

Worst Wheels

Westward zirconium - .924 Pearl Silver .726

Figure 12: The material removal rate of each wheel in pounds removed per hour

4.4 Wheel Life

The wheel life of each wheel was also calculated by using the data from the experiments. Theweight removed off each wheel for each test was averaged for each wheel. This was also convertedto pounds per hour so that it was a more meaningful measurement. This is then used to represent thelife of the wheels. The fewer pounds per hour removed off the wheel, the longer the wheel wouldlast. An assumption was made for this part since not all of the wheels are exactly the same weight,

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but this is corrected in the next section with the percentages. Also, the wheel life was calculated thisway as it was out of the scope of the project to test the wheels to their completion.

Figure 13: The wheel life of each wheel given in pounds of wheel removed per wheel

4.5 Percent Better Wheel Life and Material Removal Rate

The two charts below simply take the data from the previous two sections and change theminto percentages so that they can be more accurately compared. The percent better wheel life was

calculated by taking the pounds per hour of the current wheel and subtracting it from the pounds perhour of the tested wheel, and dividing that by the pounds per hour of the current wheel. This gives agood comparison for the new wheels and how much longer they will last then the current wheel. Thepercent better grinding wheel efficiency simply takes the material removal rates and converts theminto percentages. This was done by taking the removal rate of the current wheel and subtracting itfrom the removal rate of the tested wheel, and then dividing that by the removal rate of the currentwheel. It can be seen in Figure 14 that the DeWalt zirconium has a much better percent wheel lifethat the current wheel. Also, the CARBO premier, Westward aluminum oxide, Westwardzirconium, and Norton aluminum oxide have much better wheel life when compared to the currentwheel. When looking at material removal rate, the two CARBO wheels, DeWalt wheels, and Nortonzirconium wheels have much better material removal rates when compared to the current wheel.

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Wheel Removal (lbs/hour)


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Figure 14: The percent better wheel life of each wheel when compared to the Pearl Silver wheel

Figure 15: The percent better grinding efficiency of each wheel when compared to the Pearl Silverwheel

4.6 Percent Better Wheel Life and Material Removal Rate per $

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This section shows the percentages of better wheel life and efficiency per dollar sincedifferent wheels cost different amounts. This was done by simply taking the data from the previoussection and dividing it by the cost of the respective wheel. This balances out the effects of theexpensive wheels compared to the cheaper wheels. From Figure 16, it can be seen that the Westwardaluminum oxide and CGW aluminum oxide wheels have a much better wheel life per dollar than thecurrent wheel. From Figure 17 it can be seen that the CGW aluminum oxide, Westward aluminum

oxide, and CARBO wheels have much better grinding efficiency than the current wheels.

Figure 16: The percent better wheel life of each wheel per dollar when compared to the Pearl Silver

wheel

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Figure 17: The percent better grinding efficiency of each wheel per dollar when compared to thePearl Silver wheel

4.7 Wheels Needed per Year

The wheels needed per year were calculated based of the efficiency percentages and data oncurrent wheel usage given by Rockland. Current usage is 1200 Pearl Silver wheels per year. Thepercent better efficiency percentages were then used to make a ratio between the number of current

wheels used and the approximate number of the new wheels that would be needed under the sameconditions. The results can be seen below in Figure 18 where it can be seen that more DeWaltaluminum oxide wheels would be needed than the current wheels while much fewer DeWaltzirconium, CARBO Premier, and Westward aluminum oxide wheels would be needed.

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Figure 18: The wheel used per year using the test data and the current wheel usage data fromRockland

4.8 Cost per Year and Savings per Year in Wheel Costs

The costs for wheels per year was calculated by taking the estimated number of wheelsneeded per year from the previous section and multiplying it by the retail costs of each respectivewheel which is given in Figure 19. Then to calculate the savings in wheel costs per year, the cost peryear of the tested wheel was subtracted from the costs per year of the current wheel, which resulted

in either a savings or added expense per year given in Figure 20. The percent savings per year forwheel costs was calculated by taking the total cost per year for the current wheel a dividing it by theamount of savings per year for each wheel which is given in Figure 21. From the three charts, it canbe seen that the Westward aluminum oxide, DeWalt zirconium, and CGW aluminum oxide wheelswill result in much less material costs per year while the more expensive wheels; DeWalt aluminumoxide, SAIT zirconium, Norton zirconium, and Metabo zirconium will result in greater materialcosts than Rockland currently has.

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Figure 19: The material cost per year for each wheel using the wheels needed per year and the retailcost of each wheel

Figure 20: The savings in wheel costs per year for each wheel

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Figure 21: The percent savings of each wheel when compared to the Pearl Silver wheel

4.9 Labor Hours per Year and Savings per Year in Labor Costs

The labor hours per year was calculated using the percent better efficiency data and datasupplied by Rockland. Rockland reported spending of $90,000 a year on 4160 hours of labor. Thepercentages of better efficiency were used to make a ratio to estimate how many hours of laborwould be needed to accomplish the same amount of grinding. These hours were then multiplied bytheir labor cost per hour which was calculated by dividing the $90,000 a year by the 4160 hours ayear to get cost per hour. This gave the estimated cost of labor per year for each wheel. The savings

per year was then calculated by taking the labor costs per year and subtracting it from the labor costsper year of the current wheel. A percentage was then calculated by taking the cost per year of thecurrent wheel and dividing it by the savings per year of each tested wheel. From Figure 22, 23, and24 it can be seen that the CARBO wheels, Norton and DeWalt zirconium, and DeWalt aluminumoxide wheels require less labor to accomplish the same amount of grinding; therefore reducing costs.While all wheels require less labor as the Pearl Silver wheels, the Westward wheels and Nortonaluminum oxide wheels will save less than the other test wheels.

-100%

-50%

0%

50%

100%

150%

200%

250%

300%

350%

% Savings per Year in Wheel Cost

% Savings per Year in Wheel Cos


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Figure 22: The labor hours used per year for each wheel using data from the current grinding usageand labor costs

Figure 23: The labor costs of each wheel using the current grinding usage and labor costs

0

500

1000

1500

2000

25003000

3500

4000

4500

Labor Hours per Year

Labor Hours per Year

$0

$10,000

$20,000

$30,000

$40,000

$50,000$60,000

$70,000

$80,000

$90,000

Labor Cost per Year

Labor Cost per Year


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Figure 24: The savings per year in labor costs for each year when compared to the Pearl Silverwheel

Figure 25: The percent savings per year in labor costs for each year when compared to the PearlSilver wheel

4.10 Labor and Wheel Cost Results Combined

$0.00

$10,000.00

$20,000.00

$30,000.00

$40,000.00

$50,000.00

$60,000.00

$70,000.00

$80,000.00

Savings per Year

Savings per Year

0%

10%

20%

30%

40%

50%

60%70%

80%

90%

% Savings per Year

% Savings per Year


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Combined costs per year were then calculated by taking the wheels costs per year and addingit to the labor costs per year for each wheel shown in Figure 26. The combined savings per year ofeach wheel was calculated by taking the cost of each wheel per year and subtracting it from thecombined cost per year of the current wheel. This was converted into a percentage by taking the totalcombined cost per year of the current wheel and dividing it by the savings per year of each wheelwhich is shown in Figure 27. From these results it can be seen that the CARBO wheels, DeWalt

zirconium, Norton zirconium, CGW aluminum oxide, and DeWalt aluminum oxide wheels willresult in the lowest costs per year which results in the highest savings per year.

Figure 26: The combined labor and wheel costs per year for each wheel

$0

$10,000

$20,000

$30,000

$40,000

$50,000

$60,000

$70,000

$80,000

$90,000

$100,000

Combined Costs per Year

Combined Costs per Year


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Figure 27: The combined percent savings in costs for each wheel when compared to the Pearl Silverwheel

4.11 Assumptions

Assumptions were made when calculating the above analysis. First, the two minute timeperiod used was assumed to be constant over the life of the wheel as it was out of the scope of the

project to test the wheels to their completion. Also, by calculating percentage relating to the datagiven to the team regarding the current grinding process resulted in other assumptions relating tolabor costs. Also, averages from the experiments were used in the data analysis. The dollar amountin costs and savings given here are extrapolated from the test data to show relative performance andsavings for the wheels. These results reveal the best wheels but the exact dollar amounts cannot beguaranteed as the wheels would have to be tested on the job at Rockland. From the analysis givenhere, it can easily be seen which wheels are the best performing while the Pearl Silver wheel is theworst performing.

5.0 Recommendations

Based on all of the data that was collected on the grinding wheels, the best two wheels werethe CARBO Premier wheel and the CARBO MAXX wheel. These wheels both have the mostsavings per year in time and money for the grinding operation. These wheels are zirconium wheelswhich may be difficult to order in large quantities. If this is the case, the aluminum oxide wheelswould be desired. The best performing aluminum oxide wheels were the CGW aluminum oxide orDeWalt aluminum oxide wheels. The results and recommendations given here correspond to topperforming wheels in the user evaluation test.

0%

10%

20%

30%

40%

50%60%

70%

80%

% Combined Savings per Year

% Combined Savings per Year


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6.0 Conclusion

The team began the grinding wheel project by first completely understanding the problem;testing a variety of grinding wheels to make a recommendation to Rockland regarding an improvedwheel from their current wheel to reduce costs in labor and wheel costs and improve performance.

The team performed extensive research regarding wheels and found that two materials; aluminumoxide and zirconium would be tested from a seven different main manufacturers. The manufacturerstested were CARBO, Norton, DeWalt, SAIT, CGW, Metabo, and Westward. The budget limited thenumber of manufacturers to test which is why the top manufacturers were chosen. The team thendesigned and performed three experiments. The first experiment consisted of grinding off 6 one inchwelds and timing the grinding. Also, the difference in weight of the wheels before and after the testwas recorded. Then, two grinding tests were completed. A jig was designed, manufactured, and usedto reduce variability. In this test, the grinder was mounted to a jig was applied constant pressure tothe metal piece which was ground for two minutes. The difference in weight of the metal pieces wasrecorded as well as the difference in weight of the wheel. This test was done for the two typed ofmetals used by Rockland; a harder metal and a softer metal. Then, a use evaluation form was

distributed along with the test wheels to the employees to test the wheels on the job. The results fromthis test were again recorded. The current Pearl Silver wheel was the worst performing wheel in theexperiments which proved the room for improvement in Rocklands grinding process.

Analysis was completed with the data from the experiments. The experimental data was usedalong with the data regarding Rocklands current cost to find wheel life, material removal rates,material costs, and labor costs with respect to each wheel. Savings were also calculated and apercentage relating to how much better each wheel was compared to the current wheel. It was foundthat the current wheel resulted in the highest grinding costs and there was much room forimprovement with an improved wheel. From the analysis, it is recommended that Rockland useCARBO Gold MAXX or CARBO Premier wheels if looking for a zirconium wheel to use. TheCGW and DeWalt aluminum oxide wheels are recommended if looking for an easier to obtain

wheel. These wheels will result I a better wheel life and material removal rate which translates intodecreased costs and increased savings when compared to the current wheel.

7.0 Appendix

OVERALL Weld Test Metal 1 Test Metal 2 Test

Manufacturer Material Time WeightDiff.

MetalDiff.

WheelDiff.

MetalDiff.

WheelDiff.

Pearl Silver AO 268 0.008 0.0253 0.016 0.0231 0

CARBO -MAXX Zirconium197 0.008 0.132 0.004 0.122 0.001

CARBO Zirconium 201 0.009 0.111 0.001 0.144 0.001

CGW AO 211.5 0.014 0.073 0.002 0.078 0.002

CGW Zirconium 139.5 0.0055 0.0649 0.002 0.0462 0.002


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DeWalt AO 203.5 0.028 0.067 0.002 0.124 0.015

DeWalt Zirconium 166 0.006 0.089 0.001 0.11 0

SAIT AO 165 0.009 0.0682 0.003 0.0495 0.002

SAIT Zirconium 154 0.011 0.0902 0.002 0.0847 0.005

Westward AO 136 0.016 0.0451 0.002 0.0396 0

Westward Zirconium 176 0.007 0.0352 0 0.0264 0.002

Norton AO 230.5 0.009 0.0418 0 0.0407 0.002

Norton Zirconium 149 0.007 0.1045 0.002 0.0977 0.002

Metabo AO 185.5 0.014 0.0472 0.004 0.0528 0.004

Metabo Zirconium 211 0.018 0.0806 0.004 0.0704 0.004

Table 3: Overall results of the three tests


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Manufacturer Material Sample Weight Total Time Weight Difference Total Time Weight Difference Average Time Average Weight

Pearl Silver AO Sample Weight

5 1.30 lb 257 0.012

6 1.308 lb 279 0.004 268 0.008

CARBO Zirconium Sample Weight

1 1.438 lb 167 0.008

2 1.444 lb 227 0.008 197 0.008


1 1.578 lb 86 0.01

2 1.578 lb 316 0.008 201 0.009

CGW AO Sample Weight

1 1.428 lb 117 0.014

2 1.428 lb 306 0.014 211.5 0.014

CGW Zirconium Sample Weight

5 1.394 lb 111 0.001

6 1.406 lb 168 0.01 139.5 0.0055

DeWalt AO Sample Weight

1 1.382 lb 256 0.034

2 1.382 lb 151 0.022 203.5 0.028

DeWalt Zirconium Sample Weight

1 1.486 lb 148 0.006

2 1.484 lb 184 0.006 166 0.006

SAIT AO Sample Weight

1 1.574 lb 133 0.01

2 1.562 lb 197 0.008 165 0.009

SAIT Zirconium Sample Weight

1 1.638 lb 165 0.012

2 1.642 lb 143 0.01 154 0.011

Westward AO Sample Weight

1 1.294 lb 111 0.022

2 1.296 lb 161 0.01 136 0.016

Westward Zirconium Sample Weight

1 1.420 lb 157 0.008

2 1.418 lb 195 0.006 176 0.007

Norton AO Sample Weight

1 1.502 lb 166 0.01

2 1.506 lb 295 0.008 230.5 0.009

Norton Zirconium Sample Weight

1 1.484 lb 164 0.008

2 1.492 lb 134 0.006 149 0.007

Metabo AO Sample Weight

1 1.356 lb 214 0.014

2 1.344 lb 157 0.014 185.5 0.014

Metabo Zirconium Sample Weight1 1.670 lb 196 0.018

2 1.648 lb 226 0.018 211 0.018

WELD TEST - Welds 1"-5/16" high (3 in a row)

WELD TEST - SAMPLE 1 WELD TEST - SAMPLE 2

Figure 28: Raw data for the weld test


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Figure 29: Raw data for the metal 1 test

Manufacturer Material Sample Weight Metal Diff. Wheel Diff. Metal Diff. Wheel Diff. Average Metal Diff. Average Wheel D


1 1.3024 lb 0.0286 0

2 1.320 lb 0.022 0.032 0.0253 0.016


3 1.448 lb 0.134 0.006

4 1.450 lb 0.13 0.002 0.132 0.004


3 1.596 lb 0.108 0.002

4 1.582 lb 0.114 0 0.111 0.001


3 1.424 lb 0.078 0.004

4 1.372 lb 0.068 0 0.073 0.002


1 1.604 lb 0.0616 0.002

2 1.610 lb 0.0682 0.002 0.0649 0.002


3 1.426 lb 0.066 0.002

4 1.404 lb 0.068 0.002 0.067 0.002

DeWalt Zirconium Sample Weight3 1.480 lb 0.09 0.002

4 1.446 lb 0.088 0 0.089 0.001


3 1.566 lb 0.0858 0.004

help 4 1.580 lb 0.0506 0.002 0.0682 0.003


3 1.668 lb 0.0792 0.002

4 1.654 lb 0.1012 0.002 0.0902 0.002

Westward AO Sample Weight

3 1.294 lb 0.044 0.002

4 1.300 lb 0.0462 0.002 0.0451 0.002


3 1.406 lb 0.0506 0

help 4 1.408 lb 0.0198 0 0.0352 0


3 1.540 lb 0.0418 0

4 1.542 lb 0.0418 0 0.0418 0


3 1.484 lb 0.0726 0.002

4 1.480 lb 0.1364 0.002 0.1045


3 1.356 lb 0.044 0.004

4 1.362 lb 0.0504 0.004 0.0472 0.004

Metabo Zirconium Sample Weight

3 1.666 lb 0.0682 0.004

4 1.630 lb 0.093 0.004 0.0806 0.004

Metal 1 Test

SAMPLE 1 SAMPLE 2


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Manufacturer Material Sample Weight Metal Diff. Wheel Diff. Metal Diff. Wheel Diff. Average Metal Diff. Average Wheel D


3 1.312 lb 0.0264 0

4 1.310 lb 0.0198 0 0.0231 0


5 1.438 lb 0.116 0.002

6 1.442 lb 0.128 0 0.122 0.001


5 1.596 lb 0.14 0

6 1.588 lb 0.148 0.002 0.144 0.001


5 1.294 lb 0.082 0.004

6 1.382 lb 0.074 0 0.078 0.002


3 1.614 lb 0.0484 0.002

4 1.514 lb 0.044 0.002 0.0462 0.002


5 1.45 lb 0.192 0.028

6 1.400 lb 0.056 0.002 0.124 0.015

DeWalt Zirconium Sample Weight

5 1.448 lb 0.1 0

6 1.472 lb 0.12 0 0.11 0


5 1.580 lb 0.0506 0.002

6 1.558 lb 0.0484 0.002 0.0495 0.002


5 1.644 lb 0.0792 0.004

6 1.610 lb 0.0902 0.006 0.0847 0.005

Westward AO Sample Weight5 1.296 lb 0.044 0

6 1.302 lb 0.0352 0 0.0396 0


5 1.410 lb 0.0242 0.002

6 1.412 lb 0.0286 0.002 0.0264 0.002


5 1.386 lb 0.0308 0.002

6 1.534 lb 0.0506 0.002 0.0407 0.002


5 1.486 lb 0.0682 0.002

6 1.484 lb 0.1272 0.002 0.0977 0.002


5 1.360 lb 0.0484 0.004

6 1.362 lb 0.0572 0.004 0.0528 0.004

Metabo Zirconium Sample Weight

5 1.678 lb 0.0726 0.004

6 1.656 lb 0.0682 0.004 0.0704 0.004

Metal 2 Test

SAMPLE 1 SAMPLE 2

Figure 31: Raw data for the metal 2 test


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Figure 32: Raw data from the analysis



Wheel Brand Wheel Type Metal Removed (lbs/2 mins) Wheel Removed (lbs/2 mins) Material Removal (lbs/hour)

Pearl Silver AO 0.0242 0.008 0.726

CARBO - MAXX Zirconium 0.127 0.0025 3.81

CARBO - Premier Zirconium 0.1275 0.001 3.825

CGW - AO AO 0.0755 0.002 2.265

CGW - Zirconium Zirconium 0.05555 0.002 1.6665

DeWalt - AO AO 0.0955 0.0085 2.865

DeWalt - Zirconium Zirconium 0.0995 0.0005 2.985

SAIT - AO AO 0.05885 0.0025 1.7655

SAIT - Zirconium Zirconium 0.08745 0.0035 2.6235

Westward - AO AO 0.04235 0.001 1.2705

Westward - Zirconium Zirconium 0.0308 0.001 0.924

Norton - AO AO 0.04125 0.001 1.2375

Norton - Zirconium Zirconium 0.1011 0.002 3.033

Metabo - AO AO 0.05 0.004 1.5

Metabo - Zirconium Zirconium 0.0755 0.004 2.265

Wheel Brand Wheel Type Wheel Removal (lbs/hour) Cost per Wheel % Better Wheel Life % Better Grinding Efficiency

Pearl Silver AO 0.24 $3.78 0% 0%

CARBO - MAXX Zirconium 0.075 $7.90 220% 425%

CARBO - Premier Zirconium 0.03 $13.01 700% 427%

CGW - AO AO 0.06 $5.06 300% 212%CGW - Zirconium Zirconium 0.06 $9.40 300% 130%

DeWalt - AO AO 0.255 $6.71 -6% 295%

DeWalt - Zirconium Zirconium 0.015 $15.02 1500% 311%

SAIT - AO AO 0.075 $10.18 220% 143%

SAIT - Zirconium Zirconium 0.105 $20.12 129% 261%

Westward - AO AO 0.03 $6.75 700% 75%

Westward - Zirconium Zirconium 0.03 $12.29 700% 27%

Norton - AO AO 0.03 $10.93 700% 70%

Norton - Zirconium Zirconium 0.06 $15.85 300% 318%

Metabo - AO AO 0.12 $4.37 100% 107%

Metabo - Zirconium Zirconium 0.12 $7.58 100% 212%

Wheel Brand Wheel Type % Better Wheel Life per $ % Better Efficiency per $ Wheels per Year Cost per Year

Pearl Silver AO 1200 $4,536

CARBO - MAXX Zirconium 53% 103% 375 $2,963

CARBO - Premier Zirconium 76% 46% 150 $1,952

CGW - AO AO 234% 166% 300 $1,518

CGW - Zirconium Zirconium 53% 23% 300 $2,820

DeWalt - AO AO -2% 101% 1275 $8,555

DeWalt - Zirconium Zirconium 133% 28% 75 $1,127

SAIT - AO AO 34% 22% 375 $3,818

SAIT - Zirconium Zirconium 8% 16% 525 $10,563

Westward - AO AO 236% 25% 150 $1,013

Westward - Zirconium Zirconium 82% 3% 150 $1,844

Norton - AO AO 98% 10% 150 $1,640

Norton - Zirconium Zirconium 25% 26% 300 $4,755

Metabo - AO AO 169% 181% 600 $2,622

Metabo - Zirconium Zirconium 26% 56% 600 $4,548


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Wheel Brand Wheel Type Savings per Year % Savings per Year in Wheel Cost Labor Hours per Year Labor Cost per Year

Pearl Silver AO $0 0% 4160 $89,981

CARBO - MAXX Zirconium $1,574 53% 793 $17,146

CARBO - Premier Zirconium $2,585 132% 790 $17,079

CGW - AO AO $3,018 199% 1333 $28,842

CGW - Zirconium Zirconium $1,716 61% 1812 $39,200

DeWalt - AO AO ($4,019) -47% 1054 $22,801

DeWalt - Zirconium Zirconium $3,410 303% 1012 $21,885

SAIT - AO AO $719 19% 1711 $37,001SAIT - Zirconium Zirconium ($6,027) -57% 1151 $24,900

Westward - AO AO $3,524 348% 2377 $51,418

Westward - Zirconium Zirconium $2,693 146% 3269 $70,699

Norton - AO AO $2,897 177% 2441 $52,789

Norton - Zirconium Zirconium ($219) -5% 996 $21,538

Metabo - AO AO $1,914 73% 2013 $43,551

Metabo - Zirconium Zirconium ($12) 0% 1333 $28,842

Wheel Brand Wheel Type Savings per Year % Savings per Year Combined Costs per Year % Combined Savings per Year

Pearl Silver AO $0.00 0% $94,517 0%

CARBO - MAXX Zirconium $72,834.85 81% $20,108 79%

CARBO - Premier Zirconium $72,902.09 81% $19,030 80%CGW - AO AO $61,139.27 68% $30,360 68%

CGW - Zirconium Zirconium $50,781.24 56% $42,020 56%

DeWalt - AO AO $67,179.38 75% $31,357 67%

DeWalt - Zirconium Zirconium $68,096.02 76% $23,011 76%

SAIT - AO AO $52,979.35 59% $40,819 57%

SAIT - Zirconium Zirconium $65,080.45 72% $35,463 62%

Westward - AO AO $38,563.20 43% $52,430 45%

Westward - Zirconium Zirconium $19,281.60 21% $72,543 23%

Norton - AO AO $37,192.06 41% $54,428 42%

Norton - Zirconium Zirconium $68,442.37 76% $26,293 72%

Metabo - AO AO $46,430.09 52% $46,173 51%

Metabo - Zirconium Zirconium $61,139.27 68% $33,390 65%

i e 480w - final report

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