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SMT electronics assembly manufacturing forum.


Informations about Traceability

Mario Schaarschmidt

#24509

Informations about Traceability | 16 May, 2003

Hello everyone! My first day as a registered user and the first post in the forum. I�m a student and I�m going to write my diploma thesis about traceability in microelectronic productions. At the moment I�m collecting every information about this topic. From some posts in the forum i got the impression, that there is a number of people here in this forum with a lot knowledge and experience about it. I know that it�s not the best way to post such a general request on informations, but I�m really interested in every piece of information about traceability. For example documents in the web concerning this topic (i already found some informations, but you can get stuck in the www). I would greatly appreciate it if someone finds the time to tell me his experiences in introducing a traceability system in his company, where are pitfalls, what are things you have to take care of and so on. I think there are a lot of articles in journals, but not many "real books"(or did i missed some fundamentals?) so i�m going to talk to people who "use" traceability to get a grip on this topic. Thanking you all in advance for your help, comments etc. Best regards Mario Schaarschmidt

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#24512

Informations about Traceability | 16 May, 2003

Traceability of raw material, personnel and equipment performance during product manufacture:

Tracing raw material is done by recording the material mfg.�s batch-code that they assign during the material�s manufacture. This is everything from the fluxes and solders used to make the circuit board interconnections to the actual electronics components and bare boards. This is accomplished by bar-code scanning, RF scanning or manual data entry into an MRPII or ERP system. The raw material mfg.�s batch codes must be assigned to a given product�s production batch code or lot number for future traceability.

Tracing personnel is done by recording what specific operators perform the various tasks associated with the work instruction for assembly of a given production lot nr. Automated equipment such as stencil printers, placement systems, etc�. have event logs where operators actions are recorded. The manual method is by using route cards or production logs to record who did what when.

Equipment traceability requires that the automation have some method of storing data associated with the production batch. The printing process data for a given production batch can be stored if the printing system has inspection capability or a separate dedicated inspection machine is used. This way data for post-print inspections are recorded and saved. Pick and place systems are not so critical for traceability unless they have on-line electrical component testers or on-line post-placement or pre-pick component inspection cameras. Those with electrical testers have the ability to record and store component electrical test data for a given production batch. Reflow ovens can be fitted with a system whereby the oven heating and cooling zones are monitored 24/7. These systems can record and store the reflow oven�s heating and cooling performance for a given production batch. Pre and post solder AOI (automatic optical inspection) systems that are used to inspection component identifications, orientation, position, solder joints, as well as AXI (automatic X-ray inspection) systems checking solder joints, and in-circuit electrical test systems, can record and store all inspection & electrical test results data associated with a given production batch.

The purpose of all this is that if a product fails, we can trace back��. �.what solder and flux we used to go back to the mfg for report and analysis. �.what components were used to go back to the mfg for report and analysis. �.who performed each of the operations to assemble that product, did anyone screw up. �.what the solderpaste measurement data and reflow oven temperatures for that lot. �..what the component inspection/test results data were for that lot.

The main purpose for tracing all this is that if a product failure occurs in the field, the data provided from traceability is essential in determining if the cause is raw material, personnel or equipment. If none of those, then product design may be suspect.

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blnorman

#24513

Informations about Traceability | 16 May, 2003

In addition to the information provided above, we put a bar code label on each of our PCB's, and on 4 lines we burn in the bar code with a laser. That way we have traceability on that board throughout our process. At the end of the line another bar code label is generated to transfer the info to the outside of the module (we pot some of our modules so you can't read the PCB label). Again, if a module is returned we can scan it, find out what day/shift/time it was built and the history of the process surrounding that specific module.

As a materials person, we also impose traceability on our material suppliers. When solder paste comes in the plant ita has a batch code from which the vendor has to be able to go back to their records and show us what "lot" of raw materials were used on that batch, and what the pedigree of the raw materials was.

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#24514

Informations about Traceability | 16 May, 2003

In agreeance with the previous postings I would like to add one more thing, in event of a automotive recall a lot of money can be saved by knowing which lot code is bad and tracing the data back to a specific group of vehicles instead of recalling several months worth.

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Mario Schaarschmidt

#24561

Informations about Traceability | 22 May, 2003

First of all thanks to everyone who has replied, especially Pete C for his long article :-). My question is, do you have any special software to collect all the needed data? Cause data isn�t equal to information , i guess a "stupid database" (and a huge one, there is lot of data to store I�m afraid) alone can�t be called traceability system or am I wrong? Of course it�s a question of definition, but there must be more (I hope, it�s going to be my diploma ;-)). Cause if there is a problem and someone claims that it�s your fault and you should pay, you have to proof that it was someone�s else fault i think. And then you�ll have to fight yourself through all the log�s of the placement systems(are they all stored?) and the other stuff. And another question, does anyone store all the informations from the AOI (or AXI)? Must be a huge data volume i guess. Isn�t that a problem? Cause it costs to store it and it�s hard do calculate what the profit of this is in case of errors. For example I should consider the Return on Invest of the introduction of a complete system and I think this means a lot of trouble for me cause it�s really hard to quantify the pay back of the system.

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#24566

Informations about Traceability | 22 May, 2003

The following are some companies that supply MRPII / ERP programs for the manufacturing industry. These programs have the ability to store traceablity information from factory automated systems with LAN connections and to receive manual data entry or bar-code & RF scanning from computers stationed at workcells and stratigic locations throughout the factory- and link it to product production lot codes:

www.qad.com www.adonix.com www.sap.com www.oracle.com www.microsoft.com www.tecnomatix.com www.aiscorp.com

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iman

#24590

Informations about Traceability | 24 May, 2003

Good Points made. Keen observation. Work-life is mainly about covering Ye arse and keeping the air smelling full of roses.

most traceability systems that do cover arse, comprise elements such as :

1) Lot no. control - link to production schedule / model qty / dates 2) first article inspection process - content varies company to company, and determines "cost of quality" budgets 3) measurement readings of critical processes to produce Ye product 4) records (electronic/hardcopy storage) of these measurement readings 5) good library on process technology and industrial standards to enable the engineers to establish inhouse "acceptance" standards, and make sure the measurement readings fall in between the tolerance of those "acceptance" standards 6) get a good engineer who knows where is what, when the customer bangs on the table (try to avoid this scenario at all costs) 7) show data/measurement readings Ye process is in control 8) show Lot no. records that show links to those "accepted" data/measurement readings 9) good engineers push the envelope further by suggesting to the customer where else the customer should "investigate" in the other culprit's production line *grinz, hey its a real world...* 10) always do Ye homework, and dun just copy blindly techniques from the others, the great masters "steal"...

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iman

#24612

Informations about Traceability | 28 May, 2003

Mario, Hi,

basic point about all quality systems, is the cost justified? Traceability is just one aspect coverage in the quality system.

As a pointer, is your diploma project research might focus and narrow down into tracability in high-end product industries (eg. Aerospace, military, medical) applications where cost of quality (ie. traceability requirement) can be swayed into the mindset of top management that "long-winded" procedure gates imposed are needed and beneficial to the company in the long-run.

In such high-end arena, traceability can be as fine-comb as to item-serial no. traceability that includes info such as individual datecodes of IC, PCB, etc...and other components that went into the manufacture of this said high-end product.

On the otherhand, for large-scale commercial products such as handphones and TV sets, traceability for electronic modules can be linked to batches' traceability. We might even expect to see only serial-no. in the very end-end-end-product handphone/TV set. Supposed this reason is why (from my experience) the electronic board is usually just swapped for a new board when the functional verification (by the repair guy) confirms the set as faulty.

Bottom line, any business in manufacturing of a product can dream up all sort of traceability and quality gates to produce a world class quality product, with full-proof traceability right down to the individual screw, nut and bolt purchased and built-into the product. However at what cost???

Its a realistic world and even us engineers these days get dragged from our ivory towers away from our fun-gadgets and electric-toys to answer "financial reduction schemes" questions by the top boss(es). It is just called by different names in the search to improve quality.

My advise, traceability is linked to cost. Cost must be kept minimal; else if it hasn't yet been transfer to customer in the sales quotation, then it becomes a financial burden to the company itself. Either way it has to be resolved in the continual improvement program to improve the lives of everyone involved.

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