May 24, 201016 yr Yes, may it be any industry, control charts are very helpful to know the limitation of the process or the product you are working on as per the specified limits.It also depends upon problem, if the control chart shows that the process is in control, then you will have to use some other tool to check the variation.I am new to six sigma, s please let me know if im incorrect. Thanks!
May 28, 201016 yr Control Charts helps to understand process variations , depends upon the area of implementation , these quality control / Statistical tools can be implemented .
June 10, 201015 yr with help of process chart u can find valueadding or non value adding time so by reducing them or minimizing them u can simply reduce variation
June 10, 201015 yr If the control chart shows that the process is in control, then are there any other tools use to check the variation? Please share your thoughts.
June 10, 201015 yr Dear Friends, Control chart is the final step in the process omptimisation, before that their lot of study ot be carried out like : What are the CTQ's of Bussiness than from CTQ's we need to find the process which are significant for CTQ's for that process or process parameters we need to have stability study done and once process is stable than need ot go for Capability study. In capability study we also defined the Index which is desired not necessary always 1.33 or 1.67 or 2.00 it totally depends upon the criticality of the parametrs. Once the desired capability achived than once should go for implementation of Process control chart. for sustainance of achived capability. Hence contorl chart is only for to monitor th sustainance of achived process capability. That's what I am thinking, incase anybody has different opinion pls share.
June 11, 201015 yr Control chart is the best tool to monitor the process performance against the set limits (LCL & UCL), It gives us early warning before product of service get defective. So if we want to see the performance of any process. Control chart is the best tool.
June 12, 201015 yr Control chart tells at what point test fails. which is due to special cause variation, one can see and go back to see what different happened at that particular opbservation. for failing. Then you can attend the problem and agin run the control chart so that all the points on the graph will lie between LCL & UCL. also see the moving range chart(I-MR) also hepfull to study the process
June 15, 201015 yr Yes, Control Charts play an important role in the regular monitoring of Quality products & services and should invite feedbacks from directly concerned & connected personals to improve with first hand information.Regards.N.J.Cassad.
June 15, 201015 yr If control charts showing that process is under control, But there is some variation in the process, How can special causes and normal causes be found or identified to control these variations. Ramesh Rangera
June 15, 201015 yr Based on the pattern of data , we can find either special cause or common cause .Data's falling outside the Upper control limit (UCL) and Lower control Limit (LCL) are called outliers.Outlier's are special causes.
June 15, 201015 yr Hello All, Lets go to the basics of control charts , controls charts are prelimary designed to monitor continous process & data schwart charts are introduced initially ,Control charts displays the total variation of the process so it can be monitored & Kept in control ( within its operating capability of course) ,so we can easily identify random & Non random variation of the process . Control charts deal with the analysis of the process to judge whether the product under study is acceptable or not, it should be used when poka yoke cannot be done on to the process overall Control Charts are Monitoring Instrument. So if we satisfy any of the above criteria we can use control charts irrespective of the Domain function. Correct please if wrong Regards Mahi
June 17, 201015 yr Hello All, I have a different opinion. Control chart does not depend on the Company/Type of Business. It depends on Type of Project. Please look at the below scenario a) Defect reduction Project and the root cause was eliminated with a Mistake proofing. In this case Control chart is not applicable at all for Productivity Improvemnt Project by 15%. After implementation the productivity targets are revised by additional 15%. How do we apply Control charts Thanks, Srinivas MBB
June 17, 201015 yr Hello Mr. Srinivas, your point no (a) is 100 % correct, now point number ( control charts can be modified as they are dependent only upon the given specified limits under which control limits are drawn, So lets take an example if the productivity is at 100 % control limits are set to a mean value -(minus) 3 Sigma of sample observation, if after improvement project target is at 115%, observations will cross earlier target value of 100% so as the sample mean will be up by a certain values , u just made new ;mean -(minus) 3 sigma ; control limits for new target, it is very clear that the control chart is dependent only on specified limits, control limits we set as per the process requirements ......... correct me if wrong ..... Regards Mahi
June 20, 201015 yr Hello Mahi, Your input needs some more explanation.Control chart is not dependent on specification limits at all. It only uses real process data.You have mentioned "productivity is at 100%"? Is this the average productivity?Control charts are mostly used for raw data and not for converted data (productivity is a ratio and therefore is converted data. You might need the raw data for plotting control charts.)
June 21, 201015 yr Hello Sir , Quite correct that 100% productivity is the target productivity we are looking for ( also in addition productivity can go beyond 100% as productivity iis the time taken to complete a task with respect to standard time we calculate producivity % age = (Task performed x Standard time) / (Total time worked - Diverted time) Control Charts are not dependent upon specification limits is also true , but at the starting of any process , specification limits are required gradually we develop control limits on the observations we obtain from the process... Please clarify if not in line Regards Mahi
April 29, 201115 yr I would like to disagree politely to your point Mahendra.... Control limits are derived through operating range of the process and specification limits are set by the customer.... Control limits can change whenever there is a process shift, or we have eliminated special cause variation (thereby eliminating the spl. variation points and recalculating the control limits)
April 30, 201115 yr Dear Mr VenkatI fully agree with your explanation ogf control chart. control limits are depending on sigma and not customers LSL & USLRegards
May 4, 201115 yr Dear Sir 1)What is difference between control chart and pre control chart. 2)which we have to do first regards anil gupta
May 5, 201115 yr How Can special cause & Commom cause can be identified by controll charts , what is mathod of identification.Thanks Ramesh Rangera
May 5, 201115 yr Special cause variation can be identified in a continous control chart through the following methods: 1 points > 3 standard deviations from center line9 points in a row on same side of center line6 points in a row all decreasing or all decreasing14 points in a row, alternating up or down2 out of 3 point > 2 standard deviations from center line (same side)4 out of 5 points > 1 standard deviation from center line (same side)15 points in a row within 1 standard deviation of center line (either side)8 points in a row > 1 standard deviation from center line (either side)If none of the above anomalies are available then we will use common cause variation
May 16, 201115 yr Control charts may find their use most suited for a manufacturing sector of operation. But to find a more practical use for control charts in IT can be in log file verification. In production server log file verification is a painful job. Support team has to verify it on hourly basis. To analyze is whether everything under control (which is the key functionality of control charts) support team can use the help of X-bar or R-bar charts. Regards Sabari
September 4, 201114 yr Pre-control chart is used as an initial tool when no process data is available. Have a look at this external link for useful guidance.
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