tiêu chuẩn thiết kế xưởng may

Sổ tay tiêu chuẩn thiết kế máy P1 doc

... and professional reputa-tions. By themselves, these concerns may cause faulty decision making.The decision maker may operate in one of the following ways (Janis and Mann[1.15a] ... decision, and it may becompromised by time constraints.The basic ingredients for a good, effective decision are listed in Table 1.10, alongwith substitutions that may have to be ... weightingfunction may be established using factors developed from experience or opinion toaid in estimating the utility value for various solutions.Decision matrices may be used to...

Sổ tay tiêu chuẩn thiết kế máy P2 pptx

Danh mục: Kĩ thuật Viễn thông

... assemblies in which fluid leakage may bedetrimental to performance may have a specification for a pressure test to evaluateleakage. A pressure vessel may have a specification for ... plating thatis to be applied.Weight limits may also be specified on drawings. Pistons for internal combustionengines, for example, may have provisions for metal removal to ... A simple part, such as a right-circular cylinder, may require only one view. A complex part, such as an engine cylinder block, may require several views and many sections for an...

Sổ tay tiêu chuẩn thiết kế máy P3 pptx

Danh mục: Kĩ thuật Viễn thông

... call it 0.5 because it is notknown to three significant digits. Indeed, the digit 5 may not be correct. Dispersionin the mean is addressed by the standard deviation of 0.070. ... onlypositive values, and so the normal cannot be the true distribution. However, a nor-mal fit may be robust and therefore useful. The lognormal does not admit variatevalues which ... theexpected value (mean), and the variance (standard deviation squared). A frequency histogram may be plotted with the ordinate AnI (n AJC), where An isthe class frequency, n is the...

Sổ tay tiêu chuẩn thiết kế máy P4 pot

Danh mục: Kĩ thuật Viễn thông

... output may bein the form of an indicated reading (e.g., from the dial of a pressure gauge), or it may be in the form of a strip-chart recording, or the output signal may be ... particular standard used determines the accuracy of the mea-sured variable. The measurement may be accomplished by direct comparison withthe defined standard or by use of an intermediate ... example, a purevoltage source of 10 V (Op) must be capable of supplying any number (this may approach infinity) of charges (Os) in order to maintain a voltage level of 10 V....

Sổ tay tiêu chuẩn thiết kế máy P6 ppsx

Danh mục: Kĩ thuật Viễn thông

... approximate a real number by aspecified number of digits. For some cases, significant numbers may be useful, andthe following relates to the obtainable degree of precision.Degree ... considerations of accuracy in manufacturing and opera-tion. For example, a dimension of a part may be expressed by four significant digitsas 3.876 in, indicating for this number that ... expressed in thousandths of an inch. As another example,the weight density of steel may be used as 0.283 lbm/in3, indicating a level of accu-racy associated with control...

Sổ tay tiêu chuẩn thiết kế máy P7 doc

Danh mục: Kĩ thuật Viễn thông

... 0.95 confidence level, the left two digits are correct; the third may be corrector rounded.Alternatively, one may use Eq. (5.5) to find the bilateral tolerance:e2 = 1.96 JMX^^M ... of which no commercial programming is available. The designer or his orher assistants may have to create or supervise the creation of such programs. Thebasis for this programming ... use proprietary pro-gramming. They are sometimes called "turnkey" systems. They may be used interac-tively by technically competent people without programming knowledge...

Sổ tay tiêu chuẩn thiết kế máy P8 ppt

Danh mục: Kĩ thuật Viễn thông

... surface fatigue. However, in someapplications corrosive conditions may seriously accelerate fatigue failure. This may !Materials of high hardness or strength usually have decreased ... Furthermore, there may be a limitation on the sur-face finish available or the skill of the personnel to manufacture or assemble theproduct. Finally, there may be considerations ... rise due tosliding may have a larger influence. For a quick view of the factors that influencetemperature rise A T of asperities on rubbing surfaces, we may reproduce one...

Sổ tay tiêu chuẩn thiết kế máy P9 pps

Danh mục: Kĩ thuật Viễn thông

... of carbon, hydrogen, and oxygen to whichother elements such as chlorine or fluorine may be added. They cover a wide rangeof structural arrangements, with resulting variations ... without the need to machine aspecial test specimen. In other words, a hardness test may be a nondestructive test inthat it can be performed on the actual part without affecting ... both sides of thedefect is normal. For example, the normal FCC stacking of planes may be inter-rupted by one layer of a hexagonal close-packed (HCP) plane, since both are...

Sổ tay tiêu chuẩn thiết kế máy P10 pps

Danh mục: Kĩ thuật Viễn thông

... causes the part to elongate or creep. The failure point may be whenthe part stretches to some specified length, or it may be when the part completelyfractures.The creep strength ... temperaturethat results in 50 percent cleavage fracture and 50 percent shear fracture, or it may be defined as the temperature at which the impact strength shows a marked drop.The ... temperature. A = nil-ductility tem-perature; B = transition temperature.7.73 CREEPSTRENGTHA part may fail with a load that induced stresses in it that lie between the yieldstrength...

Sổ tay tiêu chuẩn thiết kế máy P11 potx

Danh mục: Kĩ thuật Viễn thông

... Publishing Ltd.,London.)available. However, for heat-treated low-alloy steels, the Jominy test may be replacedby an estimate based on the multiplication method of Grossmann and Fields ... obtained by equating the preceding pair of equations isRQ = 29.9. The Jominy curve may be corrected for tempering. Table 8.13 shows thetempered hardness and ultimate strength ... standardJominy specimen. The tempered hardness after 2 hours (at 100O0F, for example) may be predicted fromRT= (RQ-D -B)f+ B + "LA RT<RQ-D (8.1)RT=RQ-D RT>RQ-D...

Sổ tay tiêu chuẩn thiết kế máy P12 potx

Danh mục: Kĩ thuật Viễn thông

... stronglyaffect the worker; if just one element is badly placed, the resulting system condition may be unacceptable. Recommendations for the design of ergonomically acceptablecomputer ... [9.11], [9.12], [9.13], and [9.14].Thus, for new types of controls and tasks, tradition may not apply.9.5.1 Control SelectionIn general, controls shall be selected for their functional ... obstacles; use of platforms to stand on should be avoided,if possible, because the operator may stumble over the edge. While movements ofthe body associated with dynamic work are, basically,...

Sổ tay tiêu chuẩn thiết kế máy P13 docx

Danh mục: Kĩ thuật Viễn thông

... example, a power saw, a lawnmower, or similar powered equipmentthat may be "safe" for an adult user may not be "safe" in the hands of a child.Lowrance's ... probability, and magnitude of the hazard. This additional informa-tion may be within the user's memory or may be provided by other sources external tothe user. Much of the ... signs.Auditory Warnings. Auditory warnings may have a shorter range of effective-ness than visual warnings, but their effectiveness may be greater in that short range.Auditory...

Sổ tay tiêu chuẩn thiết kế máy P14 potx

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... convergence monitor printout is desired. The neces-sary number of function evaluations may be predicted fromN = 1 + 2.08 In —when the fractional reduction in interval of ... mean and Does the result make good sense?what is its interpretationin common terms?How may the results have beenaffected by my assumptions?Is the result good enough toact on ... learnand generalize steps are to be woven into the first three, and are the last ones. • How may my results have been affected by my assumptions (decisions)?ã Is the result good enough...

Sổ tay tiêu chuẩn thiết kế máy P15 pot

Danh mục: Kĩ thuật Viễn thông

... and consequently, the various copper alloys may have widely differing properties. The primary consideration in selecting a copperalloy may be the machinability, ductility, hardness, ... or whatever material is being considered for thedesign. Properties used by a designer may come not from an actual test, but from his-torical experience, since parts are sometimes ... specifications of a part.8. Uncertainty as to the intensity and dispersion of loads that may or will beimposed on a machine member and as to the understanding of the effect of...

Sổ tay tiêu chuẩn thiết kế máy P16 pptx

Danh mục: Kĩ thuật Viễn thông

... coefficient of variation. Coefficientsof variation of engineering steel endurance limits may range from 0.03 to 0.10 indi-vidually, and the coefficient of variation of the fatigue ... eyebolt.The increase in yield strength and endurance limit due to cold work, whilepresent, may not be helpful. Consider the strip spring formed from bar stock to thegeometry of ... curve.When the presentation is made on logarithmic scales, some piecewise rectification may be present, which forms the basis of useful curve fits. Some ferrous materialsexhibit...