12 votes

How can Pareto Analysis help solve engineering problems?

This gives you the starting point for a return on investment calculation. It tells you the value in fixing each issue in terms of how many defects would be prevented. The idea is that the curve shows ...
  • 5,960
9 votes

How can the vendor be approved/disapproved based on validation test data?

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, ...
6 votes

How does measurement uncertainty combine with tolerances?

There are two different aspects in your measurement. On the one hand, you are dealing with tolerances. On the other hand, you cover probabilities in measurement systems. Just for a rough calculation: ...
  • 215
5 votes

How do I properly compute mean time to failure?

First off, always remember that garbage in = garbage out; so if your data is garbage then your statistics will be garbage. In this situation your optimal data would be something like Run Hours Until ...
4 votes

How does measurement uncertainty combine with tolerances?

Measurement variations are very common and should be taken in to consideration when engineering systems. In most cases high precision equipment is available but might be cost prohibitive to justify ...
4 votes

How do I properly compute mean time to failure?

If you don't have hard data, making assumptions (preferably "reasonable" ones) is the only option you have. (Maybe that's why engineers used to call their slide rules "guessing sticks...") You can't ...
  • 12.5k
4 votes
Accepted

What is the best graph type to show a comparison value between two cases?

Based on the discussion in comments, you probably want to use a bar chart combined with a line for the error. Have a look at Create a combination chart for more details. In your case, and using dummy ...
  • 1,816
4 votes

accurate measurements with less accurate tools

If you know that the errors in your measurements are truly random and have a normal distribution then you can improve the resolution of a measurement by taking several measurements and averaging them. ...
4 votes
Accepted

System identification of a simple motor with only position measurements

The process of system identification consists of the following steps: Choose an appropriate input for the system. The input should definitely satisfy the Persistence of Excitation condition and ...
3 votes

How do you determine the accuracy of a measurement device?

The only way to determine the accuracy to which any measuring device provides measurements is to calibrate it against a device of known accuracy and known errors for measurements. You technique is ...
  • 9,527
3 votes

How to display data with three degrees of freedom on a chart?

Per @Dan's suggestion, I googled "nomography" and found an article titled "The Lost Art of Nomography" by Ron Doerfler, published in the UMAP Journal 30.4 (2009). The article describes a compound-...
  • 2,989
3 votes

How to identify low quality electronic components early?

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 ...
3 votes

How can the vendor be approved/disapproved based on validation test data?

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$_{...
  • 1,044
3 votes
Accepted

How do I include statistical significant index in bar chart in excel?

Quite seriously: Friend Don't Let Friends Use Excel. Learn to use Matlab/Octave, or python, or R, or just plain Gnuplot. No matter what tool you use, since "significance" is a separate variable, ...
3 votes

What does (a) the input of the activation function mean?

Just a quick summary of my concluding thoughts on this step in your research. I understand that you have been advised to use the Sigmoidal Function, so this discussion will try to explain it's ...
  • 652
3 votes
Accepted

Double interpolation for a large set of data in Excel

It appears that your dataset has integer row and column header values starting at 0. You can try the following code. Turn on Excel's Developer ribbon if it's not already on. Click the Visual Basic ...
  • 8,794
3 votes
Accepted

Talking in terms of 6 sigma, why 4 ppm would be very costlier than 1 ppm (part per milion)?

If we talk about quality and 6-sigma (which roughly means 1 ppm defects), the 1 ppm refers to test escapes, not test rejects. Even if a part only costs \$1, if testing fails to catch a bad part and ...
2 votes

How can the vendor be approved/disapproved based on validation test data?

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 ...
  • 11.3k
2 votes
Accepted

Estimating maximum lift or strength

This actually isn't as much of an engineering question as it is a physiology question. There are actually a number of widely used estimates to predict your one-rep maximum, aka "1RM", if you know how ...
2 votes

How to compare utilization rates?

I don't know of any mathematical or statistical techniques that would help you analyse machine utlization data. From the additional information you've given in the comments, my understanding is that ...
  • 9,527
2 votes

How to identify low quality electronic components early?

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 ...
  • 1,044
2 votes
Accepted

How to identify low quality electronic components early?

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 ...
  • 5,323
2 votes
Accepted

How do you determine the accuracy of a measurement device?

Your approach is broadly correct. If you are only interested in the accuracy of your system you probably want to use something like the maximum error. Your accuracy is then +/- Max error with the ...
  • 1,025
2 votes

How do I properly compute mean time to failure?

The statistical tool Weibull as suggested by the previous two responded is the tool of choice for Mean Time To Failure (MTTF) calculations. Based on your comment as capture below, it appears that ...
2 votes

Guidelines to develop quality engineering training content and select a trainer

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 (...
  • 1,044
2 votes

Guidelines to develop quality engineering training content and select a trainer

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 ...
2 votes

Moments of inertia, rods mechanism

The point where center of mass lies so the center of gravity. So, for center of mass For rod AC. B is the mid point of AC.So,let us take A as origin So coordinates of B($\frac{l}{2}$,0).Similarly for ...
2 votes

How to find raw data sets for engineering?

Search for daily maximum and minimum temperatures for your local region. If there is a river nearby, search for river level or river gauge height. If it rains, search for annual rainfall in your ...
2 votes
Accepted

Usage of the three-sigma limits in calculating minimum force

Data is data. This is the capability of the design and manufacturing process. Trust the data. If there is a need to improve the quality of the data one could take for example 3 measurements for each ...

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