<quote>Sounds to me that each manufacturer is building his own system and that often it is ERP capable dependant, and that it also has some depth where each one is more or less performant and accurate.</quote> Yep. As you identified, there are methodologies for measuring defects of products or services in general, but I am unsure as to the value in having a standard on how best to measure defects specifically for PCBs. Many factors to consider. Data collection and analysis efficiency and effectiveness is a major one. Another is the resources available to do something with the information. Performing a root cause analysis and corrective action on each defect when you have a hundred a month is not feasible, but if it only ten, go for it. As I have mentioned here before, I am currently using the three metrics of total work orders with at least one defect, total PCBs defect and "impact". The first two are simple to understand. For the latter, I use the term "impact" because to say cost is misleading. I do use the financial value calculated as a percentage of the price (for a rough gross cost) factored from where it was taken from the process. Some would say the result is the cost of the scrap, plus an administration factor for each instance. I say so what. While the end result of Quality is a control to reduce cost and improve performance, I personally am not concerned about the dollars unless I am going for a pay raise and need to justify my existence based on a common value that relates to my paycheck. What I do care about is the impact that quality has on the company. PCBs are priced based on impact. Higher technology (additional processes, tighter design parameters, additional layers, etc.), quicker turn around and less standard processing (lower volume, infrequent orders) increase the impact on the company. Best-case, defects are the last resort as an indicator of a process deviation, with process control parameters and techniques akin to SPC in place to detect variations before defect. Yeah, so anyway, using PCB defects as an indicator of process deviation, I want to focus on the areas of the most impact, hence using the cost factor. I have 11 instances of 2 PCBs each with poor legend, the impact is $2,000. I have 2 instances of multilayer pressing issues, the impact is $20,000. The dollar symbol introduces unnecessary emotions. All that is important is that one number is a lot bigger than the other. In the same manner, I am not so much concerned about initially capturing one multilayer issue was a result of operator error (sorry, training) and the other from equipment malfunction (oops, preventative maintenance). The impact itself will trigger an investigation, root cause, remedial and corrective action cycle which will raise those issues so as to try and stop the problem from impacting the company again. I am using manual logs and excel and then linking it to our MRP to perform the calculations. Not the most sophisticated system, but it is appropriate for our current needs. The amount of time I have to focus on what is wrong is balanced by the amount of time I have to fix the problems. And the fact that I just drolled on about it maybe says I should get back to either one or the other. ;) Cheers, Chad Renando Quality Manager Precision Circuits Pty Ltd Ph: +61 3 9877 3222 Mo: 0417 593 337 Fax: +61 3 9877 5079 www.precisioncircuits.com.au CAUTION - This message (including any attachments) may contain privileged and confidential information intended only for use of the addressee named above. If you are not the intended recipient of this message you are hereby notified that any use, distribution or reproduction of this message is prohibited. If you have received this message in error please notify the sender. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Roland Jaquet Sent: Thursday, 8 June 2006 1:13 AM To: [log in to unmask] Subject: Re: [TN] How are PCB & Assembly manufacturers measuring scrap? Thank you fro the info, but yes this is for PBA only I may sound old fashioned, but I am looking for a management standard / industry recognized system for Rejects and Defects for Bare PCBs. I know the subject has been raised before and as most things, it is coming back. The way PCB manufacturers are calculating Rejects & Defects from what I seen and used for many years, is not at all consistent. Companies are more aiming on First pass Yield, but below that it is getting blurry as for others: Some are talking in Rejects, and not considering defects, even so we know often the number of Defects could be double the number of Rejects. There is Internal Defects, Customer Defects, Internal Rejects and Customer Rejects. From what I seen, internal to Customer ratio is of about 10 to 100 times. I.e. If PCB manufacturer says he has 0.1% rejects at the customer side, it could mean 1 to 10% Defect in production. Now, regarding the way to value those rejects, some people are accounting in finished product value (sold price) at any given stage of manufacturing, and/or calculated at cost of production and material.. Now some will eventually consider the fact that during the time they were manufacturing a reject, they could have done a good board! Adding the re-make cost! Same for defects, and reworks costs and so on.. Isn't there someone who was able to put some order of logic into all this? What about reject forecasting? - i.e. by process such as Panel Plating versus Pattern? - Additive / semi-Additive? - Positive / Negative Photoresist? - Liquid versus Dry Film Resist? - ... Sounds to me that each manufacturer is building his own system and that often it is ERP capable dependant, and that it also has some depth where each one is more or less performant and accurate. Meilleures salutations Very Best Regards Rol@nd www.PCBspecialist.com Roland Jaquet 14 Champ Budin 1258 Perly, GENEVA Switzerland Tel +41-22-880-0405 Fax +41-22-880-0409 Mobile +41-79-203-3723 There are three constants in life... Change, Choice and Principles. Stephen R. Covey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Franklin D Asbell Sent: Wednesday, June 07, 2006 4:17 PM To: [log in to unmask] Subject: Re: [TN] How are PCB & Assembly manufacturers measuring scrap? The work and documents seem more focused on assembly rather than bare board calculations. Is there work being done on bare board rejects? Franklin -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski Sent: Wednesday, June 07, 2006 9:01 AM To: [log in to unmask] Subject: Re: [TN] How are PCB & Assembly manufacturers measuring scrap? See the link http://www.ipc.org/committeedetail.asp?Committee=5-22G Rich K / KEDS 260.925.8719 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Franklin D Asbell Sent: Tuesday, June 06, 2006 2:53 PM To: [log in to unmask] Subject: Re: [TN] How are PCB & Assembly manufacturers measuring scrap? Technical Committee 5-22G??? Which one is this? Franklin -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Roland Jaquet Sent: Tuesday, June 06, 2006 12:14 PM To: [log in to unmask] Subject: Re: [TN] How are PCB & Assembly manufacturers measuring scrap? Dear Jack, Thanks to Denny I learn there is an IPC committee 5-22G in regards to Production scrap (Rejects) and this subject is of acute interest to me as I believe there is some major flows in Bare Board Manufacturing measurement of Defect and Rejects. I do not know how to get information on what has been done and what I could read in order to follow the path of the wise men.. I seek to make measurements of Rejects and Defects at the Electrical Test level (keeping in mind we are on Bare Boards). I would appreciate your help as I would appreciate anyone's input as well. Thank you very much PS I am a member of EIPC Regards to Denny, and thank you. Meilleures salutations Very Best Regards Rol@nd www.PCBspecialist.com Roland Jaquet 14 Champ Budin 1258 Perly, GENEVA Switzerland Tel +41-22-880-0405 Fax +41-22-880-0409 Mobile +41-79-203-3723 There are three constants in life... Change, Choice and Principles. Stephen R. Covey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dennis Fritz Sent: Thursday, April 20, 2006 4:18 AM To: [log in to unmask] Subject: Re: [TN] How are PCB & Assembly manufacturers measuring scrap? The assembly side PWB manufacture has worked hard to quanify yield in terms of "defects per million opportunities - DPMO". While this is not actually a measure of scrap, this does even out differences between simple and complex assemblies Recently, the same group has started to try to quanify board fab in some similar terms to DPMO. Board fabrication is not so easy to quantify as it is harder to define an individual "opportunity". At Apex/Expo time, this group was collecting the defect codes from several board fabrication shops to try to get a feel for some metrics the committee could track. Anyone interested should contact IPC Committee 5-22G under Greg Hurst of BAE Systems or IPC Technical Staff LIason Jack Crawford, as a start. Denny Fritz MacDermid, Inc --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the 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