As a separate topic im also thinking about explaining. Process capability analysis and process analytical technology. If pp and ppk are approximately equal, then the process is centered between the specification limits. Im not entirely sure what citation style youre using, but this convention is used in the mla citation style, as well as some other citation styles that i cant remember off the top of my head.
We strive for 100% accuracy and only publish information about file formats that we have tested and validated. Resolving the process capability index issues of cp, cpk, pp, and ppk is very important for organizations. Even if they were priced the same, id still choose the bersa. Walther tph operator instruction manual genuine interarms 1991 vg. Quickly find an in stock walther ppk for sale at over 1600 stores, auctions, and classifieds in one click. I guess ill have to get a copy of dieter marschalls walther pistols models 1 through p99 after all. I sent a job to dpos yesterday and one of the points had a fixed solution for both the rtk and ppk solution. Agenda introduction to capability what is capability histograms. The truth is that these statistical indices are much more than that, and it is important to understand what process and capability statistics really mean. Cp cpk template calculates cp, cpk and pp, ppk on multiple sets of data. If you continue browsing the site, you agree to the use of cookies on this website. It has excellent photos and very good descriptions of the various pistols and how they are different. The result is a direct increase in bottomline profitability.
For regions of stability, process capability indices can be used to describe how the process is performing relative to specification limits. The value of cp helps to better understand process performance. Introduction a process capability index is a numerical summary that compares the behavior of a product. The ppks, though, is very familiar and about to get a lot better. Generally you use this when a process is under statistical control. Either one of these books will contain an index of serial numbers for walther guns. It differs from process capability in that process performance only applies to a specific batch of material. Sigma or standard deviation is a statistical measure of dispersion in data.
Ppk is a good measure when the process is not exactly centered in the middle of usl and lsl. Interpret the key results for normal capability sixpack. Process capability explained, tobin, emmet, cooper. Process capability cp, cpk and process performance pp, ppk what is the. Cp, cpk, pp and ppk are all parameters indices that can help us to understand how our process is operating relative to the specifications, or in other words, they measure how close our process is running to its specification limits. Cp and cpk are related to the longterm predictive performance of the process. When we speak about the capability of processes we often refer to a couple indices called cp and cpk. Overall capability for betweenwithin capability analysis.
Cp, cpk, pp and ppk are all parameters indices that can help us to understand how our process is operating relative to the specifications, or in other words. Resolving process capability index issues for cp, cpk, pp, ppk. It is a measure which uses the characteristic of past data to make judgements about how the process will perform in the future. Make offer original oem walther model ppppk ppks pistol instructionowners manual 1987.
Best, concise explanation of process variation indexes i have ever read. Examination of the origin and development of the individual extensions of man should be preceded by a look at some general aspects of the media, or extensions of man, beginning with the neverexplained numbness that each extension brings about in. Looks like your supplier is really performing for you. Process capability cp, cpk and process performance pp, ppk. Attribute data measurements is collected from products as they are being produced. Using the tools only gets one so far if theres not an understanding of why one needs to understand capability. These two indices, used together, can tell us how capable our process is and whether or not we have a centering issue. Process capability uses the process sigma value determined from either the moving range, range or sigma control charts. Cpk vs ppk cp cpk versus pp ppk compare to sigma qi macros. This act has banned or barred other pistol classes that do not meet the standard guidelines for pistols.
Process capability compares the output of an incontrol process to the specification limits. The putty private key file type, file format description, and windows programs listed on this page have been individually researched and verified by the fileinfo team. Understanding process capability indices stefan steiner, bovas abraham and jock mackay institute for improvement of quality and productivity department of statistics and actuarial science university of waterloo waterloo, ontario n2l 3g1 1. Chapter 255 capability analysis introduction this procedure summarizes the performance of a process based on userspecified specification limits. Process capability cp, cpk and process performance pp. Well have to do some checking to see if this new work will be released in an english edition. May 2014 your supplier has sent you the process capability charts you requested. Difference between ppk and ppks difference between.
Process capability explained, tobin, emmet, cooper, brendan. I have a german ulm made pp no import marked 32 that i have not fired yet, it is the nds marked one brought back from germany. There are several variants of the walther pp pistols, and keeping up with them can get confusing real fast. The ppk s is a newer gun model compared to the ppk. Download it once and read it on your kindle device, pc, phones or tablets. The supplier has produced some very nice charts, obviously generated with some fancy software package and, of course, with all those accompanying statistics. Cpk and ppk are two commonly used measures of process capability.
Walther ppk for sale best price in stock walther ppk deal. We can see from the examples above that cpk only tells us part of the story, so the next time you examine process capability, consider both your cpk and. But the statistical measurements of cp, cpk, pp, and ppk may provide more insight into the process. This often happens with a mature process that has been around for a while. Ppppk serials table jan balcars books waltherforums. Keep in mind hoffschmidts book was written circa 1975, so it will have information that is more dated. Therefore, these indices represent only one side of the process curve, and do not measure how the process performs on the other side of the process curve.
Capability studies, confirming that the pp and ppk indices can be used only. How to find where a walther gun was made by the serial number. Any whitepaper or book can be customized to reflect a companys improvement process. Understanding process capability indices statistics and actuarial. The observed performance as well as the performance relative to the normal distribution are output. For a normal distribution, the mean equals median, which is 50th percentile, and. The ppk s passed the import point test required in the u. Now you should be able to explain process capability to anyone who is new to the concept. Get the best deals on gun manuals for walther when you shop the largest online selection at. My understanding of this is because ppk is a measure of process performance, and cpk is a measure of process capability. There are plenty of walther enthusiasts who can decode the details for you, but the basic story is that the pp has a longer slide and barrel, and a metal backstrap.
The real truth behind cpk and ppk capability and potential. Reading it, understanding it and utilizing the information therein has helped many collectors to discover previously unknown ssrsha guns. Epochss rtk 331110 ppk 864940 i am not sure how to evaluate and compare the solutions because i am not sure i have a feel for what ppk really means. Issues with cp, cpk, pp, ppk process capability indices. It was developed at a later time than both the pp and ppk. Process capability is a relatively simple statistical measure which provides an estimate on the level of process outputs which will be within permitted specification limits. A ppk of 1 means that there is half of a bell curve between the center of the process and the nearest specification limit. Capability suite creates six charts including histogram, control charts, probability plot, values plot and capability plot.
The described process capability cp, cpk, pp, ppk issues and resolution approach to process performance reporting provides improved process understanding. For requirements we measure the process specifications. Most people have at least heard of cp or cpk, but few people really understand the concepts behind the calculations. Your customer has asked you to report the cpk of the product you are sending. Dec 04, 2017 however, the real value of process capability analysis comes from the strategic, bigpicture approach that it takes to quality improvement. Yes, different booksarticlespeople handle s and sigma differently or call them both s as you said. Cp cpk formulas versus pp ppk formulas whats the difference.
Process capability is also the ability of the combination of people, machine, methods, material, and measurements to produce a product that will consistently meet the design requirements or customer expectation. Chapter of my book, robust process development and scientific molding, also carries this information. However, there are issues with traditional process capability indices reporting. Six sigma process performance is reported in terms of sigma. In this video, i explain the concepts of process capability and process capability index.
Learn the difference between cp cpk and pp ppk formulas and the different methods for calculating sigma estimator. Learn the definitions, interpretations and calculations for cp, cpk, pp and ppk. The book is relevant for the first time user as it does not go into firering details and faultfidings etc. Interpret the key results for normal capability sixpack minitab. You know, things like cpk, ppk, sigma level, ppm out of spec and so on. P pk min p pl,p pu for a capable process, these values should be equal to or greater than 1. Interpreting pp, ppk process performance index basically tries to verify if the sample that you have generated from the process is capable to meet customer ctqs requirements. Received my copy of know your walther pp and ppk pistols and have been reading thru it. This book is an excellent reference book for anyone interested in walther models pp and ppk pistols.
The full sized police pistol pp is hard to find these days, outside of an auction house. In the broader sense, studying process capability is more than just measuring cp and cpk. This resolution is easily accomplished with 30,000footlevel reporting. But the statistical measurements of cp, cpk, pp, and ppk may provide more. Marshall mcluhan understanding media the extensions of man. The cpk and ppk indices measure the capability of the process in relation only to the specification limit that is closest to the process mean. Our goal is to help you understand what a file with a. The main difference between pp and cp on one side and ppk and cpk on the other side is whether we use complete set of data for calculation pp and ppk where we calculate real performance of the system, or we use sample preproduction, batch, logical subgroups where we calculate capability of the process. Jan 02, 2017 i dont have the same understanding of ppk. With this in mind, i welcome the release of process capability analysis. I have a ww2 made ppk in 32 and it shoots just fine and is a very well made pistol. Although not necessarily written with beginners in mind, polhemus work is nevertheless accessible to rankandfile qaqc professionals with an abiding interest in the inner workings of process.
For information, call, write, or email to the address above. There are four terms that are defined based on the spread, the tolerances and the possibility of molding acceptable parts. Pp and cp are the ability of the process to produce acceptable parts if the average of the parts was centered at nominal. Cpk is the shortterm capability of a process, and ppk is the longterm. And here is where the danger lies in only reporting cpk and forgetting about ppk like its george michaels lesserknown bandmate no offense to whoever he may be. Compare ppk to a benchmark value that represents the minimum value that is acceptable for your process. Variability can be stated as either shortterm or longterm. And until you introduce all the different sources of variation such as component lot to lot, operator, changeover. Reading it, understanding it and utilizing the information therein has helped many. The ppk was the wondergun of its day, but the bersa is a better choice. It was made after the ratification of the 1968 gun control act u. The statistics assume that the population of data values is normally distributed.
After approval, begin production and follow the approved. The ppk s, though, is very familiar and about to get a lot better. Its good information, and the chart should be of interest to all ppppk owners. Where x is the individual values for a sample of size n. If a given set of data has normal probability distribution then the number of defects that will. Hence, the ppk was one of those types which were slowly being wiped out. Apr 27, 2018 there are four terms that are defined based on the spread, the tolerances and the possibility of molding acceptable parts.
Process capability explained kindle edition by tobin, emmet, cooper, brendan. I suspect all those issued one believed that they needed to. If the system is centered on its target value, ppk should be used in conjunction with the pp. Most importantly, it means understanding what causes variation within the process, under what conditions, and how these variables interact. What is important to know before we will explain the definitions of the indices is that the definitions in the past have changed. I give it 5 stars for the overall excellence of the text and the photos. Data, properly understood and put into context, has much to teach the quality professional.
Statistical process control spc is an industrystandard methodology for measuring and controlling quality during the manufacturing process. As you gather the information, someone asks, which sigma do they want. And remember to center your processes, reduce your variation and increase your process capabilities. The book was written in 1975 and could need an upgrade therefore 3 stars rather than 4 read more. You know that to compute the cpk, you need to have the product specifications, and that you need to have the mean and sigma. Process capability cp, cpk and process performance pp, ppk what is the difference. These are anecdotal and related to the particular run or experiment. Sep 25, 2016 in this video, i explain the concepts of process capability and process capability index. Interpret the key results for normal capability analysis.
Ppk can be determined by diving the z score by three. The new walther ppk is made in the usa the mag life. Histogram calculates cp, cpk, pp, ppk, sigma and twenty other metrics using your data and spec limits. Process capability ratios such as c p and c pk are produced. I also have a interarms ppks in 380 that has not been fired yet so i could not tell you if it jams but its a very nice pistol. Use features like bookmarks, note taking and highlighting while reading process capability explained. Free shipping on many items browse your favorite brands. If ppk is lower than your benchmark, consider ways to improve your process.