What is statistical process control or SPC for short??

Question

I keep hearing engineers talk about it all the time in big factories but what is it really?? Help, I'm a janitor who works at one of those places, but I'm just curious to learn.

Answer 1

Statistical process control :

1.The ongoing measurement of a production process by providing charts, maps and other displays of specified key attributes. Observed data is compared with preset control limits and other parameters to designate process output as acceptable or not.
www.bridgefieldgroup.com/glos8.htm

2.A method of analysing quality and other parameters to identify causes of variation and enable improvements in performance.
www.dti.gov.uk/actt/technology/glossary.html

3.Statistical process control is the use of statistical techniques and tools to measure an ongoing process for change or stability.
strategis.ic.gc.ca/epic/internet/instco-levc.nsf/en/h_qw00037e.html

4.The continuous monitoring and charting of a process while it is operating, to warn when the process is moving away from predetermined limits. Typically the upper and lower control limits will be three standard deviations away from the mean. All points outside the control limits should be investigated and corrected.
www.bpic.co.uk/jargon.htm

5.A phenomenon will be said to be controlled when, through the use of past experience, we can predict, at least within limits, how the phenomenon may be expected to vary in the future.
www.cs.wpi.edu/~gpollice/cs562-s03/ExamDefinitions.html

6.A method to ensure consistent manufacturing results. Machines are used to analyze variation in tablets. If a tablet does not fall within an acceptable range, it is automatically rejected.
www.nutrilite.com/english/public/GeneralInfo/Glossary/doc3565r.asp

7.Statistical process control, or SPC is a method for achieving quality control in manufacturing processes. It was pioneered by Walter A. Shewhart and taken up by W. Edwards Deming with significant effect by the Americans during the World War II to improve aircraft production. Deming was also instrumental in introducing SPC techniques into Japanese industry after that war.
en.wikipedia.org/wiki/Statistical_process_control

Answer 2

in conserving with N.Shaviv & R. Pielke the contributions of AGHG to interior sight climate commerce is about 20% and some thing is subsequently of uncomplicated forcings. Correlations frame of mind has many susceptible aspect as stated by technique of R. Grumbine. One very last piece. solid your eyes again as a lot because the graph, and perchance click on on it to get the entire length version. contained in the route of the right hand end, you observe a dot it is far above the instantly line more beneficial healthy. you at the instantaneous are not any further surprised that it is 1998 -- the twelve months of the biggest El-Nino that develop into concurrent with a time of severe solar project. The bit farthest less than the curve round 357 ppm CO2 is 1992-3 -- cooling consequences of Mount Pinatubo. Even in the route of a statistically sturdy style, there are nevertheless diverse consequences contained in the gadget that would provide some tenths of a level climate adjustments. there are multiple motives climatologists do no longer technique interior sight climate this way, and so they're ideas-blowing ones. I perfect did it considering that i have been encountering resources that say that the correlation is 0 (nonexistent). those places are incorrect.

Answer 3

Statistics in general is a way to estimate something about an entire population just by examining a few items as a sample.

With SPC, the idea is that you don't have to inspect every single manufacturer component, but rather if you inspect a sample, then finding no defects in that sample gives you confidence that the enitre batch will be ok.

Answer 4

i take it that you have no background in statistics....essentially, in all processes there is variation in outcomes. statistical process control is essentially a quality control. a simple example might be of a potato chip manufacturer. the product is a 16 oz bag of potato chips. it is reasonable to assume that not every bag produced contains exactly 16 oz of chips. therefore, there will be parameters set, let's say, 15.2 ounces to 16.8 ounces. while quality control will not weigh every bag, that would be redundant, they will randomly sample and weigh a small number of bags to see if they are within the prescribed parameters. Statistical methods are used to determine whether or not, "the sample" falls within the parameters. if it does, they can be reasonably sure, generally 95% confident, that the processes of filling the potato chips in bags at or around 16 oz. this is just a simple example of one of the many uses of statistical process control. this might help i hope. but you might have a better understanding if you understood the basic tenants of statistics, the normal distribution.
the normal distribution is a probability distribution. using the binomial distribution, for example, if you flip a coin with a friend and he bets on heads and he gives you tails. after ten flips he won six times on heads and you won 4 times on tails, the statistical probabilities of heads coming up 6 times in 10 flips is not that unusual. However, if after 100 flips he wins 60 and losses 40, (this is the exact same percentage 60%) you can be 97.2 % certain that he has a weighted coin and he is cheating you. i hope this helps..................

Answer 5

It's a way to monitor and control the variability of a manufacturing process over time so that its probability of going out of bounds is kept to an acceptably low level. It doesn't wait until the process actually /does/ go out of bounds (i.e., starts making out-of-spec--"bad"--parts) before making a correction. It relies on inspecting a certain fraction, or statistical "sample," of the parts coming out of a process.

Or something like that. :P