保存期限与烘烤条件.doc

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1、Shelf-LifeandDryBakingParameters.保存期限及烘烤条件Shelf-Life/保存期限Shelf-Lifeisafunctionofsolderability.Solderabilityofanyfinalfinishdegradesovertimeduetooxidationorintermetalliccompoundformationofdifferentfinishes.設定保存期限有助于確保護焊性。任何形式表面處理會隨著過期而產生氧化或形成金屬複雜化合物，從而護焊性也會下降。

2、PerIPC-4552ENIGshallremainsolderableforupto6monthsundercontrolledstorageconditions.依據IPC-4552化金板護焊性在受控條件下最多能維持6個月。PerIPC-4553ImAgshallremainsolderableforupto6monthsundercontrolledstorageconditions.依據IPC-4553化銀板護焊性在受控條件下最多能維持6個月。PertheIPCthesolderabilityofOSPs

3、hallbepertheprocurementdocumentation.OSPshelflifedependsupontheOSPvendorandgrade.ForexampleEntekCu-56hasashelfliferangeof3to6months.EntekPlus-HThasashelfliferangeof6to12months.依據IPC規範OSP板護焊性要參考購買資料，不同廠商、型號的護焊劑壽命不一，如：Cu-56型號的松香能儲存3-6個月，Plus-HT型號的松香能儲存6-12個月。Pe

4、rIPC-1601Tin/LeadHotAirSolderLevelinghasanacceptableshelfliferangingfrom6monthstoayear.依據IPC-1601噴錫板護焊性在壽命能維持6-12個月。Undercontrolledstorageconditionsthesolderabilityshelflifemaybeextendedto12monthsormore.Toverifysolderabilityofboardsheldinlongtermstorageitisad

5、visabletosacrificeoneboardfromthemanufacturedlotinquestionforuseasasoldersample.Asoldersampleprocessedthroughtheassemblyprocessverifiesnotonlysolderabilityofthefinalfinishbutcompatibilitywiththeoverallassemblyprocessaswell.Solderabilityshallbeinquestiononboar

6、dsthatarenotstoredproperly.在受控條件下儲存期限可能會延長，為驗證長期儲存下的PCB板的焊錫性，建議從疑似批號中取出一片作為實驗樣品測試，這不僅能反映焊錫性，也能體現与組裝流程可適性，對於未儲存好的板子焊錫性是存疑的。Moistureabsorption/吸濕性Printedcircuitboardsarehygroscopic.Theyshallabsorbmoisturetothepointofequilibrium.Whereasboardsreadilyabsorbmoistur

7、etheyrequirehelptoforcethemoisturebackout.IPC-1601“PrintedBoardHandlingandStorageGuidelines”specificationsection3.4andTable3-1providesguidanceonthedrybakingofprintedcircuitboards.PCB板具有吸濕性，鑒于此，有必要把這些濕氣赶出來，IPC-1601－PCB板處理与儲存指南規範3.4中的表3-1提供了建議如下：Table3-1Recomme

8、ndationsforPrintedBoardBakingProfilesPCB烘烤條件建議FinalFinishTemperatureTimecommentsTin/化錫105-125°C4-6hoursBakingmayreducesolderability.See3.4.1.5烘烤過度會使焊錫性下降Silver/化銀105–125°C4-6hoursSilverma