外文翻譯--尺寸和量規(guī)的公差 英文版

423Chapter 22Dimensioning and Tolerancing of Gagesper the ASME Y14.43-2003 Dimensioning and Tolerancing Principles for Gages and Fixtures StandardSteps for Writing a Dimensional Inspection PlanChapter ObjectivesReaders will learn；1. To design, dimension and tolerance GO gages for MMC, NOGO gages for LMC and Functional gages for geometric tolerances per ASME Y14.43-2003.2. How to calculate whether the gage is likely to accept borderline out-of-tolerance parts, reject borderline parts that are in-tolerance, or if the possibility exists that the gage might do either.3. The ramifications of using different modifiers (MMC, LMC or RFS implied) on gage tolerances.4. The differences between Absolute, Practical Absolute, Optimistic and Tolerant gages and which policies are preferred per ASME Y 14.43.5. The steps necessary in writing a Dimensional Inspection PlanDownloaded From: / on 04/11/2014 Terms of Use: /terms424Chapter Twenty-TwoDimensioning and Tolerancing of Gagesper ASME Y14.43-2003In 2003, an ASME standard was approved called ASME Yl4.43-2003 Dimensioning and Tolerancing Principles for Gages and Fixtures. It marked the first time a nation had issued a standard (ANSI and Department of Defense approved) on the proper design, dimensioning and tolerancing of gages and fixtures for the inspection of geometric tolerances. This standard not only governs the principles for the appropriate procedures for the creation of gages for geometric tolerances (called functional gages) but also continues the practices to measure maximum material conditions with GO gages and least material conditions with NOGO gages that were originally shown in ANSI B4.4. B4.4 has been retired, but its principles were absorbed into Y14.43 and extended to apply to the more difficult Functional Gages (to inspect geometric tolerances).The basic premise of all gaging is to reject all bad parts (those that violate the tolerances) and to accept all of the good parts (those parts that are in compliance with specified tolerances).But since all gages need to be toleranced, it is understood that they will fail to achieve these lofty goals. They will either reject a small percentage of technically in-tolerance parts or they will accept a small percentage of technically out-of-tolerance parts. The parts that are on the borderline of exceeding their tolerances (whether just barely exceeding tolerances or just barely in tolerance) are the ones in question.What is critical is that companies decide which side they would rather error on. Would you rather buy a few bad parts or reject a few good ones? This is the question whose answer will determine whether gage pins will have a plus tolerance or a minus tolerance. It will also determine whether gage holes are toleranced on the plus or the minus side of their acceptable boundaries.For example, if a GO gage pin designed to check a maximum material condition is dimensioned at the MMC of the hole to be gaged, but then toleranced with a plus only tolerance, the plus only tolerance will infringe on and, therefore, subtract from the tolerance assigned to the hole being gaged. Therefore, some of the borderline, but in-tolerance, holes being gaged could be rejected. This could have the effect of increasing manufacturing costs for the parts containing the holes, but increase the quality of the parts.Conversely, if the GO gage pins are sized at MMC and then toleranced with a minus only tolerance, some of the borderline, but technically out-of-tolerance, holes being gaged could be accepted. This could have the effect of decreasing manufacturing costs but also decreasing the quality of the parts.Downloaded From: / on 04/11/2014 Terms of Use: /terms425Dimensioning and Tolerancing of GagesSo, a company must choose which they will do-take the risk of rejecting a few borderline good parts or accepting a few borderline bad parts. Their decision will commonly set the course for all gages and fixtures the company designs (or has designed for them) in the future.The ASME Y14.43 standard has taken as its preferred practice two policies on gage and fixture tolerancing. These policies are called Absolute (also called pessimistic) Gage Tolerancing and Practical Absolute Gage Tolerancing.For GO gages that inspect the maximum material condition sizes of features, the Absolute Gage Tolerancing policy is preferred. It sets as the goal never to accept an out-of-tolerance part. Therefore, all GO gage pins are designed at the MMC and toleranced to have only a plus tolerance on the size (no minus tolerance). All GO gage holes are dimensioned at the MMC of the pins being gaged and then toleranced so that the gage hole may only be produced at that size or smaller (all minus tolerance, no plus tolerance). This has the effect of never accepting features (holes, shafts, slots and tabs) that are outside of their tolerance range. It also has the effect of rejecting a small percentage of technically in-tolerance parts. For example:FIGURE 22-1 Part with HoleFIGURE 22-2 GO Gage pin with Absolute TolerancingThis gage is shown using 10% of the part tolerance.Downloaded From: / on 04/11/2014 Terms of Use: /terms426Chapter Twenty-TwoBoth the GO gage and the NOGO gage have been toleranced so as to subtract tolerance from the hole being gaged. The GO gage pin is all plus tolerance, to accept no parts that are outside of the MMC size limit. This has the effect of also rejecting a very small percentage of in-tolerance holes. The NOGO gage also accepts no bad parts, but may reject a small percentage of borderline, but technically good, parts. Remember, the job of the NOGO gage is to not go into the hole. By reducing the size of the gage (from the 051mm LMC) with a minus only tolerance, the gage is more likely to go into the hole and, therefore, reject the hole as being too large (in violation of the least material condition).FIGURE 22-3 NOGO Gage This gage uses 10% of the part tolerance.FIGURE 22-4 Detail Drawing of a Workpiece to be GagedDownloaded From: / on 04/11/2014 Terms of Use: /terms427Dimensioning and Tolerancing of GagesFor the workpiece shown in FIGURE 22-4, a gage is constructed using 10% of the part tolerance for each element being represented on the gage-for example, 10% of the flatness tolerance, each perpendicularity tolerance, position tolerance and hole size tolerance. This gage is called a Functional Gage and is toleranced with the Practical Absolute Gage Tolerancing methodology.FIGURE 22-5 Functional Gage using the Practical Absolute Gage ToleranceGAGEDownloaded From: / on 04/11/2014 Terms of Use: /terms428Chapter Twenty-TwoAs you can see, datum feature simulators are constructed to represent datum features A, B and C. Datum feature A is a portion of the entire surface, so the datum feature simulator is that large (70.5 x 100). It is assigned a flatness tolerance of 0.01 (10% of the 0.1 flatness tolerance on the workpiece). The gagemakers tolerance ideally ranges from 5% to 10% of the workpiece features tolerance that is being simulated.Datum features B and C both have a tolerance on the workpiece of perpendicularity, so the datum feature simulators on the gage have been assigned perpendicularity tolerances of 10% of these tolerances. Datum feature simulator B references only datum A in its perpendicularity control, but datum feature simulator C references both datums A and B.The holes on the workpiece are represented by gage pins on the gage. These gage pins are sized at the virtual condition of the holes on the workpiece that are being gaged.15.0 = MMC Holes- 0.2 = Geometric Tolerance at MMC14.8 = Virtual Condition of HolesFunctional gage pins are dimensioned to be the virtual condition of the holes being gaged. So, the two gage pins are sized at 14.8. With Absolute and Practical Absolute Gage Tolerancing methods, the gage pin tolerance is all on the plus side of the 14.8 virtual condition boundary size. Since the holes have a size tolerance of 0.2, the gage pins will have a plus only size tolerance of 10% of that, which is 0.02. The gage pins will be:14.8 +0.02 0The gage pins are given a position tolerance. Since this gage is shown with fixed pins, the pins are given a position tolerance directly that is 10% of the position tolerance on the holes being gaged. The holes being gaged have a position tolerance of 0.2 at MMC, so the gage pins are given a position tolerance of 10%) of 0.2 at MMC, which is 0.02 at MMC. Now the control reads:2X 14.8 +0.02 0s 1 0.02 M A B CIf this gage used push pins that are to be shown separate from the gage base, the gage pins would be dimensioned as2X 14.8 +0.02 0for the portion of the pin diameter doing the gaging. Then the holes in the base of the gage that the pins would be pushed in to (once the workpiece was mounted onto datum feature simulators A, B and C appropriately) would be given a position tolerance of:s 1 0.02 M A B CDownloaded From: / on 04/11/2014 Terms of Use: /terms429Dimensioning and Tolerancing of GagesThis position tolerance would govern the allowed movement of the holes in the base of the gage. The fit between the gage pins and these holes in the gage base is to be a Sliding Fit as governed by ANSI B4.2 on Preferred Metric Limits and Fits. Had the workpiece and accompanying push pin gage been dimensioned and toleranced in inches, the fit between the gage pins and the holes in the base of the gage would have been a Sliding Fit per ANSI B4.1.The way to determine the likelihood of a good part being rejected by this gage or a bad part being accepted is to construct a chart of the holes (being gaged) virtual condition boundary and the gage pins inner and outer boundaries. The virtual condition of the holes being gaged is 14.8. Any gage pin outer boundary larger than 14.8 runs the risk of rejecting good parts. Any gage pin inner boundary smaller than 14.8 runs the risk of accepting bad parts. The risk of rejecting good (but borderline) parts is very real. The risk of accepting bad parts is mostly theoretical in that the physical gage pin diameter is a minimum of 14.8. Any reduction of this number is caused by the position tolerance allowing the pin to move away from its perfect location (as shown by the basic dimensions on the gage drawing. But wherever the gage pin ends up in its location, it is still at least 14.8 in size.Also, remember that for every action, there is an equal and opposite reaction. So, as the gage pin moves in on one side (acting smaller on that side), it moves out on the opposite side (acting larger on that side). This means that even though this movement may generate an inner boundary smaller than 14.8, it will (because of its movement) simultaneously generate an outer boundary larger than 14.8.Think of yourself (as the gage pin) trying to walk through a door (the hole being gaged). If you center yourself to the middle of the door, you walk easily through it. But if you move a step to the right of center, your left shoulder easily clears the left side of the door. You are acting as though you are smaller on the left side of your body. But at the same time, your right shoulder bangs into the door frame and you dont fit through the door.While your left side might be occupying less than its half of the door entrance, your right side is occupying more than its half of the door entrance (acting as though you have grown on your right side). So, you are really the same size as you always were, but because you have moved to the right, the left side of your body acts smaller and the right side of your body acts bigger.Now the important part. You dont fit through the door. And, likewise, the gage pin doesnt fit into the hole being gaged. If the gage pin moves, it is more likely to reject a good part than accept a bad one.When could it accept a bad one in this scenario? .when the door (hole) moves in the same direction, by the same amount, as you (gage pin) move. This, in a practical sense, is most unlikely to happen. That is why this type of gage tolerancing is called Practical Absolute Gage Tolerancing. It means that a gage toleranced in this manner will practically absolutely not accept a bad part. Now that the practicality has been explained, we can look at the numbers and not panic when we see them wander down into the accepts bad parts range.Downloaded From: / on 04/11/2014 Terms of Use: /terms430Chapter Twenty-TwoOuter Boundary of the Gage Pins 14.82 = MMCPins +0.02 = Geometric Tolerance at MMC 14.84 = Outer Boundary Gage PinsInner Boundary of the Gage Pins 14.80 = LMCPins - 0.04 = Geometric Tolerance at LMC 14.76 = Inner Boundary Gage PinsFIGURE 22-6 GraphThe graph would seem to imply that there was just as much of a possibility of accepting bad parts as rejecting good ones, until we remember that the physical diameter of the gage pins are a minimum of 14.8 and a maximum diameter of 14.82. The rest is movement. Moving the pin to the left or right is rarely going to allow a 14.80-14.82 gage pin to fit into a hole acting smaller than that. You will probably reject a very small percentage of technically good, but borderline, parts. You will absolutely, practically never accept any bad parts using this gage tolerancing policy.The pin gage dimension and its tolerances can be manipulated to get any result you desire. For example, if I wanted an Absolute Gage (instead of Practical Absolute) where, even in theory, no bad parts would be accepted, we could increase both gage pin size limits by the difference between them and the position tolerance. Since the difference between the gage pin MMC of 14.82 and the LMC of 14.80 is 0.02, we would take that 0.02 and add it to the position tolerance, which is also 0.02 at MMC for a total of 0.04.This 0.04 would then be added to the size limits as follows: 14.82 = MMC Gage Pins + 0.04 = Increase Factor 14.86 = New Gage Pin MMCDownloaded From: / on 04/11/2014 Terms of Use: /terms431Dimensioning and Tolerancing of Gagesand 14.80 = LMC Gage Pins + 0.04 = Increase Factor 14.84 = New Gage Pin LMCThese new gage pins would be as follows: LMC MMC 2X 14.84-14.86 Gage Pins 0.02 A B C%MThis would generate new boundaries: 14.86 = MMC + 0.02 = Geometric Tolerance at MMC 14.88 = Outer Boundary Gage Pinsand 14.84 = LMC - 0.04 = Geometric Tolerance at LMC 14.80 = Inner Boundary Gage PinsSo, our new graph would be as follows. FIGURE 22-7 GraphThis graph shows that we cant buy a bad part with these new gage pins, even in theory. However, it also shows that the chance of rejecting good parts is much greater. With the original gage drawing, we had only wandered into the rejects good parts range to 14.84. Now, with the new gage pin dimensions, we have gone twice as deep into that range to 14.88. This potentially raises the cost of the workpiece being gaged, with more technically good parts being rejected.Downloaded From: / on 04/11/2014 Terms of Use: /terms432Chapter Twenty-TwoAnother possibility that gives similar results is the use of the LMC modifier on the gage pins in the position control. For example: LMC MMC 2X 14.82-14.84 Gage Pins 0.02 A B C%LAs you can see, the MMC and LMC of the gage pins have been increased by the 0.02 position tolerance. This is to keep us out of the accepts bad parts (in theory) range. If the position tolerance had been zero, instead of 0.02, the gage pin MMC (14.82) and LMC (14.8) would have remained the same. But, with the MMC raised to 14.84 and the LMC raised to 14.82, the outer and inner boundaries are as follows: 14.84 = MMC Gage Pins + 0.04 = Geometric Tolerance at MMC (0.02 Geo. Tol. plus 0.02. Bunos Tol.) 14.88 = Outer Boundary Gage Pinsand 14.82 = LMC Gage Pins - 0.02 = Geometric Tolerance at MMC 14.80 = Outer Boundary Gage PinsAs calculated, it becomes apparent that these boundaries are the same for both possibilities that follow. 2X 14.84-14.86 Gage Pins 0.02 A B C%Mand 2X 14.82-14.84 Gage Pins 0.02 A B C%LBoth generate gages categorized as Absolute and will never, even in theory, accept bad parts. But both run the risk of rejecting more in-tolerance parts than the original ASME Y14.43 favored method of Practical Absolute Gages toleranced as: 2X 14.80-14.82 Gage Pins 0.02 A B C%MFIGURE 22-8 is another example that uses the Practical Absolute Gage Tolerancing method.Downloaded From: / on 04/11/2014 Terms of Use: /terms433Dimensioning and Tolerancing of GagesFIGURE 22-8Downloaded From: / on 04/11/2014 Terms of Use: /terms434Chapter Twenty-TwoFIGURE 22-9 Functional Gage for the 4-HoIe Pattern Position ToleranceGAGEWORKPIECE APPLIED TO GAGEAll gages in this section have used either the Absolute Tolerancing Method (shown on the GO and NOGO gages) or the Practical Absolute Tolerancing Methods (shown on both Functional Gages). These gaging practices use as the premise that all gage pins have plus tolerances and all gage holes have minus tolerances for all GO gages and Functional Gages. For NOGO gages, all gage pins have minus tolerances and all gage holes have plus tolerances. This is to achieve a gage that does not accept parts that are out of their tolerance ranges.Downloaded From: / on 04/11/2014 Terms of Use: /terms435Dimensioning and Tolerancing of GagesThere are two other gage tolerancing practices that are NOT RECOMMENDED by the ASME Y14.43- 2003 standard on Dimensioning and Tolerancing Principles for Gages and Fixtures. One of these is called Optimistic Gage Tolerancing. This policy tolerances gages in ways that are the opposite of those described in this unit. GO gage pins and functional gage pins would begin at the same sizes shown in this unit but would have no plus tolerances. These gage pins would be tolerancing entirely in the minus direction. The 5% to 10% policy would still apply, just in the opposite direction as shown for Absolute and Practical Absolute Gage Tolerancing.For gage holes on Go gages and Functional Gages, the Optimistic Gage Tolerancing would be all plus and no minus. For NOGO gage pins, the Optimistic gage would have a plus tolerance and the Optimistic gage holes would have a minus tolerance. Optimistic Gage Tolerancing risks buying a small percentage of out-of-tolerance parts. Optimistic gages buy all parts within tolerance and also a few that are not. This is generally perceived as lowering production costs of parts but sacrificing a small portion of quality and the parts ability to function or mate with other parts in the assemblies.The third policy NOT RECOMMENDED by ASME Y14.43 is known as Tolerant Gaging. Tolerant Gaging sizes GO gages at MMC, NOGO gages at LMC and Functional Gages at virtual condition, just as do the Absolute, Practical Absolute and Optimistic methods. But instead of just tolerancing to either the plus or to the minus side only, the Tolerant Gaging policy gives gage pins and gage holes both a plus and a minus tolerance. The problem with this non- recommended practice is that it does not take a stance as to a companys policy. It does not decide to reject a few good parts and not buy any bad ones (Absolute), and it does not decide to buy all good parts and also to accept a few bad ones (Optimistic). They do not know whether their gages will buy a few bad parts or reject a few good ones.The ASME Y14.43 standard suggests making the decision up front and, therefore, using one of the other gage tolerancing policies explained in this unit or in the ASME Y14.43 standard.Downloaded From: / on 04/11/2014 Terms of Use: /terms436Chapter Twenty-TwoSteps in the Development of a Dimensional Inspection PlanThe concept of a dimensional inspection process designer creating a Dimensional Inspection Plan is recommended for the verification of most, if not all, product designs. Times when design needs for part functionality are abandoned because of inferior, ill-conceived inspection plans and a lack of knowledge of equipment potential belong in the past. This unit leads one through a process for the creation of a Dimensional Inspection Plan. It shows some of the items worthy of consideration when writing the step-by-step process a part must go through to assess tolerance and cosmetic compliance and assure functionality. It explores the uncertainties common to the inspection processes and what uncertainties are and are not permissible. It raises the point of what to do with information gained from the inspection process to improve the manufacturing procedure and quality of parts produced from that time on. A step-by-step example is given for one possible Dimensional Inspection Plan for a part to be produced.For each workpiece design, the measurement process designer may prepare a Dimensional Inspection Plan. The plan should include a list of measurements to be made, what gage to use for each measurement, the procedure for each measurement and the gaging limits for each measurement. It is recommended that the measurement process designer document logic for the plan. The Dimensional Inspection Plan may be developed in the following steps:1) For every part to be inspected:a) Learn how the part functions.b) Decide which dimensions will be inspected and which dimensions will not be inspected.c) Determine the ramifications of approving a dimension that is not within its tolerance and of rejecting a dimension that is within its tolerance.2) For every dimension that is to be put under test:a) Determine if an inspection plan already exists that will suffice if minor modifications are introduced. If one exists, tailor it to the new part as needed, and go to Step 2 (e). Otherwise,b) Find out how the part is produced and what errors of geometric perfection are common to that manufacturing procedure.c) Determine the best inspection approach/scheme to follow. Decide the most appropriate tools, gages and major equipment neededd) Discover which measurement uncertainties will be introduced. Does your measurement approach/scheme contain inherent uncertainties? Do the gages and/or inspection equipment and/or inspector know-ledge have uncertainties that need to be considered?Does the environment within which the part will be inspected have the capability ofintroducing uncertainty?e) Decide on the acceptable probabilities of accepting a bad feature or rejecting a good feature.f) Analyze the most likely distribution of measurement data.g) Calculate/analyze the gaging limits.Downloaded From: / on 04/11/2014 Terms of Use: /terms437Dimensioning and Tolerancing of Gages3) Create a Dimensional Inspection Plan for every part design.The Dimensional Inspection Plan FormatA Dimensional Inspection Plan should be created for each part design. Among the items to be considered are:1) Which characteristics of which part features will be measured.2) The tools needed for the measurement of each feature characteristic.3) When in the best interest of the feature, the position and number of points on the surfaces where sample data will be taken may be specified.4) The steps to be followed in the measurement procedure.5) How collected data will be analyzed.6) What to do with the collected data to improve the manufacturing process.The inspection planner may consider it wise to document the reasoning behind each decision in the plan. This may explain to those scrutinizing the plan the logic behind the decisions made by the planner.Plan DevelopmentTo determine the best possible plan for the inspection of any part, the designer of the measurement process should know:1) How the part functions.2) Which characteristics of which features must be inspected in order to insure the parts functionality.He or she will also need to determine how lots will be measured and what type of sampling is necessary to insure optimization of inspection time and collection of the most valuable data. Whether the information is used merely to insure the functionality of that one part or is to be used as variable data for the continued production of parts within geometric tolerances, the inspection plan is a vital piece of the process. It can help insure functionality, interchangeability and a product produced at the lowest possible costs.Each MeasurementThe portion of the Dimensional Inspection Plan that deals with how each measurement should be taken should consider:1) Has a previous plan been developed either for this part or for this type of part? If so, it may be used as a guide to rewrite the plan, or to create the plan.2) Should the feature be measured? Sometimes measurement of a feature is not necessary. For example:a) If the dimension is controlled by a proven die or mold.b) If attribute can be verified by a means other than measurement. For example: strength vs. diameter.Downloaded From: / on 04/11/2014 Terms of Use: /terms438Chapter Twenty-Twoc) If dimension is unimportant to workpiece function and is known to be not a factor worth consideration in the batch or part under test.d) If a feature can be either accepted or rejected at a lower cost by simply seeing if it will fit into the assembly, it is sometimes better to do so (for example, if interchangeability is not a factor).What Is Being Verified?In the case of geometric controls applied per the ASME Y14.5 Standard, if the feature is to be inspected, verification of either boundaries or tolerances zones is required. When the designer specifies a positional MMC control, for example, the surface of the feature may not lie outside a boundary of virtual condition or else it often will infringe on space supposed to be occupied by the surface of the mating feature. Position of the virtual condition boundary may be fixed or movable (as in the case of features controlled to datum features of size at MMC).In some controls, line elements are to reside within tolerance zones. In others, centerplanes, surfaces, axes or points must reside within the specified tolerance zone. In most instances where a centerplane or axis is being controlled, verification of either the tolerance zone or the virtual condition boundary it generates is acceptable. Verification of both is rarely necessary. Although it is generally understood that the verification of tolerance zones or boundaries is appropriate, and considered to be roughly equivalent, these two concepts are not always mathematically equivalent. Where there is considered to be a conflict between the two concepts for verification, the virtual condition boundary concept is given greater weight. It is considered that the MMC concept virtual condition boundary is usually more descriptive of the space needed for assembly in mating situations.The intent of the designer should always be clear and interpretable per the ASME Y14.5 Standard. Where intent is not clear, the designer should be contacted for clarification whenever possible.Hard vs. Soft GagesIn order to verify feature compliance with size or geometric tolerance, we may use either hard or soft gages. Hard gages are mechanical in nature, like for example Coordinate Measuring Machines, micrometers, vernier calipers, ring gages and snap gages. Depending on the situations, these gages are capable of taking either direct measurements or comparative (to a standard) measurements.Hard gages are often used to determine coordinates of a set of points on a feature surface to estimate the true shape of the feature surface. This information is sometimes then compared to mathematical soft gages in computer software. The comparison can be either direct (measured values to the ideal values) or comparative (measured quantity determined to be either larger than, equal to, or less than the standard). If the information fed to the computers involved in this method is correct, soft gages can perform verification techniques for geometric controls quite well. Remember, however, that the verification is only as good as the procedures followed during the collection of data. Hard gage measurements can be compared directly with gaging limits to determine acceptance or rejection.Downloaded From: / on 04/11/2014 Terms of Use: /terms439Dimensioning and Tolerancing of GagesSoft gages can use knowledge of the manufacturing process for features to be able to augment data that is represented by the part configuration. For example, in terms of deviations which generate smooth profiles, these deviations from geometric perfection may be caused by thermal bending of the machine or workpiece during machining, clamping distortion or bad fixturing. Deviations which tend to form a trend like a periodic pattern over the workpiece may be caused by machine tool feed, tool form errors-as in rolling components, tool stiffness, cutter form errors, or cutter alignment problems.Dividing these errors from one another and analyzing their causes can allow one to take action that will prevent them from reoccurring.Cho osing Gag esThe choice of appropriate gages should be based on:1) Capability2) Availability3) Cost EffectivenessWe would all like to check our parts in the most accurate manner available without spending more inspector time and machine time than the part can warrant. For this purpose, the Dimensional Inspection Plan designer should know:1) How many parts are being made from this design?a) In this run.b) In future runs.2) What gages do I have available from other inspection procedures that could be used?3) How long will set-ups take using the various gages available?4) How valuable is the machine time needed to inspect this part in relation to its importance?5) What is the cost of investment of acquiring the use of gages not currently available?6) Is training of personnel a factor in the implementation of this inspection plan?7) Is the environment required available for use during inspection?Determine UncertaintyA) Uncertainty of the Measurement Plan Has every piece of important information concerning this part and its measurement been used to create the plan?B) Uncertainty of the Gages What is the quality of the gages that have been chosen? What is the repeatability and the accuracy of the gages to be used? Softwa re errorsWith the advent of computer analysis of collected information about part features, we were faced with telling the computerized mechanisms how to collect data, how much data to collect and what to do with the data that was collected. Sometimes this was done by those with skills in one area of expertise, such as computer programming and/or mathematics, but that were not knowledgeable in the guidelines that existed in the standards for what was being inspected forDownloaded From: / on 04/11/2014 Terms of Use: /terms440Chapter Twenty-Two(or what uncertainties were introduced by real world mechanisms and environments), not to mention operator error. Standards are now being written worldwide t