# Tag Info

9

TL;DR: It depends, but probably not You might argue that "all 15 samples are within spec, so the supplier should be approved". Not so fast: depending on the parameters of your full production run, the 15 samples may or may not be statistically significant. There are numerous calculators online to do these calculations; I used this one. A good resource for ...

9

The work history and temperature history of any metal can make a big difference in the final shape after machining. If the material was cold worked (e.g. rolled) there may be significant residual stresses within the material. When you start selectively removing material, those stresses may cause the part to warp into a new shape. Cast metals and ones that ...

3

Indicators to warn that brakes need repair do exist. They are on many cars, but not all and are called pad wear indicators. These are small (usually copper or brass) metal studs held in an insulator that put a warning light on when they come into contact with the disc or rotor as the pads wears. This usually happens when the pad has about 3 or 4mm left so ...

3

The average and standard deviation from the above sample set are: Average ($\mu$): 4.754V Standard Deviation ($\sigma$): 0.142368 Mean: 4.74 USL: 5.5 LSL: 4.5 C$_{p}$ : 1.1706 C$_{pl}$: 0.5947 C$_{pu}$: 1.7466 C$_{pk}$: 0.5947 Equations $\text{Pr}(\mu - \sigma \leq x \leq \mu + \sigma) \approx 0.6827$ \$\text{Pr}(\mu - 2\sigma \leq x \leq \mu + 2\sigma) ...

3

You do not say what sort of capacitors are involved. Tests will vary with capacitor type. Electrolytics can be tested for eg leakage, ESR, behaviour as they approach rated voltage, ... . Ceramic capacitors that are "of unknown origin" may well exhibit temperature dependant variations not matched to they specifications. [Tantalum capacitors may explode with ...

2

Looking for good and reliable suppliers might be one of best solutions. Vendors such as Digi-key, mouser, Newark always supply high quality electronic components. But understandably they come at a higher cost. If directly purchased from a manufacture it might be good idea to request for test data from suppliers to validate that product is meets specification....

2

In the mechanical world, if you have a million bars, and pull on them until they yield, you'll get a wide variety of failures. These failures, if you counted them with how many failed at what strength, you usually end up with a normal distribution, though to make the math easy we usually fit it into a log-normal distribution. When dealing with a part who ...

2

In the first order the most commonly used quality engineering tools are average, standard deviation, histograms, pareto charts, control charts. In the second order tool such as Design for Experiments (DOE), ANOVA, student t-test, z-test, confidence testing, gauge R&R, Ishikawa diagram most likely are next set of tools that are most used. From software ...

2

Get an ASQ certificate: ASQ certification is a formal recognition by ASQ that an individual has demonstrated a proficiency within, and comprehension of, a specific body of knowledge. They have a bunch of different certificates that are applicable to the different engineers/techs you guys have: Certified Quality Engineer (CQE) Certified Quality ...

2

Remember that a rule of thumb is just that, a rule of thumb. It is not a hard specification, so in some sense there really is no right answer here. It is a good starting point, but to determine what is acceptable for your system you need to balance three things 1) What is the cost of a false positive? i.e. what is the consequence if a perfectly ...

2

In most organizations, how you refer to a test in the report depends on the purpose of the test and in turn that will be reflected in the established document naming system. For example if the purpose of your test is validation, the report template would be named something like Validation Report - (Project XYZ) or something like that. Typically all of this ...

2

You could take an over or between pins measurements if it's the male or female part. Take 2 measurements using 2 different diameter pair of pins. Assuming the edges are fairly straight you should be able to deduce the dovetail angle.

2

I agree with What Trevor said in a comment. You specified 5V ±10% (4.5-5.5 V) and that's what you got. I don't see the problem here. All the samples you got are within spec. There may be other reasons to not use this vendor, but samples failing to meet specs is not one of them. However, first article samples don't tell you that the vendor is OK, ...

1

I assume measuring the depth of the dovetail is not an issue. The classic manual technique is what jko describes, using two pairs of gage pins (or just one pair if the angle is known to be good a-priori). When doing this, you should also account for any difference in depth on the two sides, by the way. If the CMM machine has some kind of spherical probe you ...

1

The best metric of confidence in making measurements is the overall relative uncertainty of the measurement. Two factors contribute to uncertainty for a measuring device. One is the calibration uncertainty. This is an offset or bias. The other is the device or scale uncertainty (precision). Consider a force-gauge with a spring. The spring constant depends ...

1

There is no good reason to think that Qualcomm's QC people did not detect the problem. It's what you do about it that is the problem. That there is or ever was a problem is denied by Qualcomm, some users and some independent testers. But at least one reasonably well documented test set indicates that when running benchmark programs the processors tend to ...

1

Correct. The rule of thumb is multiply your tolerance range by 10% (or divide by 10) to get the minumum resolution of your measuring device. Regarding the 12.96 tolerance range because more precision is applied to the dimension, two decimal places, or .01mm precision, you need a measuring device 10x that precision to be accurate. So a device with .001mm ...

1

I have procured "active harmonic filters" for an engineering project. We needed them to compensate for the harmonics caused by a large number of variable speed drives. Active harmonic filters are not a consumer product, so you won't find them on Amazon. Try looking in the catalogues of Danfoss or Siemens, who are two manufacturers of these type of units. ...

1

Ask these questions: What is the industrial application High/lo speed? Hi torque? Is it a continuous load? Shock loading? Direction changes? Actual gear teeth amount? What gear tooth size standard? Those are needed to provide an actual estimate to gear life. What 3D printing process?? FDM? SLS? Etc. Is it feasible? Possibly, with a SLS printed gear set, ...

1

Out of desperation, I got in contact with some very nice statisticians at NIST. They walked me through the answer to my question, which boils down to: control charts are an empirically derived chart with strong statistical backing. However, because of this by its very nature, there is no one right answer. It depends on how historically stable your process is,...

1

Apart from current answers, I think a quality engineer must also be aware of the FMEA processes (DFMEA as well as PFMEA in general)... In fact , for a Mfcg company, (if it is not designing the product), PFMEA (along with the relevant other processes like control plans) are essential too.... SQC is also important.... If inspection is being done on sampling ...

1

With out a cost benefit analysis it is hard to tell with method will bring the best financial value to your organization. I am assuming that the analysis suggest that using a test automation will bring the best value for your organization. Base on the current industry standard test automation will bring you the best value in almost all cases. In one of my ...

1

Have you looked at NI Test Stand? When I worked in the medical device industry that's what was used at every step along the way. The devices weren't built completely and then tested, but tested after each stage of production with a final programming and validation at the end. The devices were serialized by a ROM, which was tied to an engraved s/n on the ...

1

One has to recall, on this question, the capacitor plague problem that the computer industry experienced for a number of years. The issue with this is I'm not sure if there was ever a way to discover these effects prior to failure, and the main mitigation method was a supply-chain change. However, it does give perspective. As Aravinthkumar (answerer here) ...

1

Check some component randomly, low quality components produce heat immediately. As you can imagine, the liquid inside the capacitor will only dry out if the capacitor isn’t perfectly sealed and/or if the capacitor is exposed to high temperatures the definition of “high temperature” for us is any temperature above the standard room temperature of 25° C or 77°...

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Ive been cutting, plating ,sawing, drilling aluminium and castings for over 30 years Alumininium alloys cool rapidly after the material is poured and rolled to form a standard plate thickness and depending upon the cooling rate a "grain" structural size variation is formed within the material . larger grains form at the outer layer and reduce in size ...

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