Ken,
Excellent discussion!!!
I've also seen this problem. Spent and am still spending significant time policing. I don't think it is just a buyer issue though. There are many dimensions to the problem. Suppliers, Engineering, Manufacturing, and Purchasing all play a role. Yes, communication will help, but utimatly management chooses the path of direction. Especially when a schedule is involved. The processes you put in place must be followed. Otherwise, results can be less favorable. Let me share some brief history with my exoerience with this problem and what we've done to resolve:
We traced some excessive attrition rates to specific smt components. The probelm was verified by observing a build in action. After the build we measured the embossed tape cavities and component dimensions for the problem parts and determined the way they were packaged was not conducive for ideal placement. Comparision was made to EIA-481 standard. Talked with the buyer(s) and insisted conformance to EIA-481. (Note: EIA-481 does give suppliers some flexibility) Buyer(s) aggreed to list EIA-481 in PO flow down note codes. Later the vendor responded and claimed they already conformed to EIA-481. For info on EIA-481 see the following URL... http://global.ihs.com/search_res.cfm?customer_id=%21%25K%5D%5C%0A&shopping_cart_id=%27%25X%5B%28J0LLZ%20%20%28%0A&country_code=US〈_code=ENGL&input_doc_number=EIA%2D481∨g_code=EIA
Then asked QA to inspect to EIA-481. Was told by QA Director to pound sand. Too much time and labor would be required to inspect conformance to EIA-481. After escalation to management, the issue abruptly became dead on arrival. Not accepting defeat I started pushing from another angle. Asked for common inventory. The idea was to force Engineering to use common parts (where feasible) across all new products. This in turn would make the buyer's job easier managing component procurement. The result after implmentation was larger part buys thereby eliminating the 'middle man' or distributor, lower part cost, and increased machine capacity. Now we deal directly with component manufacturers. As a result we are now less likely to require a repackage and schedules are not impacted.
We also were seeing an excessive rate of components being place with incorect position or polarity. After an exhasuting investigation I identified several areas of weakness in the process. Here they are:
1. Package media was not specified by Manufacturing. Shame on us. It gave Purchasing an open door to buy anything under the sun.
2. Expected BOM component became obsolete. Those darn Enginese failed to close the loop with Manufacturing on obsolescence. As a result alternate received in different media. Problem not forseen and downtime results.
3. 1st, 2nd, 3rd, and so on suppliers all package differently. Hence when alternates are used package media changes. I found this mostly applies to diodes and transistor suppliers.
4. Matrix trays are not consitently loaded by supplier or distributor. I found that many times we are having to change the orientation of the parts in the tray so our placement machine places the part in the correct postion.
5. Purchasing could order the wrong package media by mistake due to poor communication, or could not get the specfied media order to fit in the lead time.
6. Small incremental buys put us in a bad negotiating position. The result was poor responsiveness and inability to hold vendors to requirements.
7. Distributor/Supplier not aware of EIA-481 standard. The result was incorrect media or loading of the media.
8. Engineering is not consistent with component orientation when creating CAD symbol libraries. The Gerber position files which are extracted from the CAD layout files are used as placment data. If the orienation is not consitent with what's coming in the receiving door the placement program will have to be changed at the time of the first build. Recommend pushing them towards EIA-481 to reduce or alleviate this problem.
I'm sure there are many more possibilities but the point is that unluss you have a process which can either accomodate all the possibilities (unlikely) or you agree to adhear to it you'll never guaranteed success.
If your organization is not buying common inventory try suggesting it. If so try weighing the cost of the attrition, machine downtime, and production delays with the cost of imposing a minimum buy on the parts procured. This may be enough get you out of the hands of the distributors or repackageing houses.
Good Luck, Gregster
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