Bob Croslin
Nielsen Media Research
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From: Morse, Carrie [mailto:[log in to unmask]]
Sent: Thursday, August 28, 2003 11:04 AM
To: [log in to unmask]
Subject: Re: [TN] Cracking Ceramic SMT CapacitorsVictor,We build our assemblies in panel format. This allows us to minimize handling, decreasecycle type, and optimize throughput by performing one process on all boards on the panelat the same time. Specific processes for which this is applicable include but are notlimited to: Screen Printing, Reflow, Wave, and Test. Since we can only place componentson one board at a time we do not see a huge savings at that step, but, we do have a savingsby not having to handle as many boards. In addition, we may simply add "rails" to boardsthat we build 1-up simply for ease of handling through the SMT and Wave processes.-Carrie--------------------------------------------------------Original Message-----
From: Victor Hernandez [mailto:[log in to unmask]]
Sent: Thursday, August 28, 2003 10:59 AM
To: [log in to unmask]
Subject: Re: [TN] Cracking Ceramic SMT CapacitorsCarrie,I have experience in PCB mfg. and Component Assembly. The depaneling was always done at the PCB levelnot after Component Placement. Please provide more details.Victor,--------------------------------------------------------Original Message-----
From: Morse, Carrie [mailto:[log in to unmask]]
Sent: Thursday, August 28, 2003 8:54 AM
To: [log in to unmask]
Subject: Re: [TN] Cracking Ceramic SMT CapacitorsWe have seen an increase in cracking.The root cause for us is depanelizing using a rotary style blade cutter.Caps and some filters too close to the edge are most subject to damagedue to the forces imparted on the board when depanelizing. Often wecan eliminate the problem by flipping the board over during depanelize, but,that does not always work and since we do not have the tools to analyze theforces during the depanelize process, any changes like flipping the boardover is essentially a bit of a gamble.-Carrie--------------------------------------------------------Original Message-----
From: Bob Perkins [mailto:[log in to unmask]]
Sent: Wednesday, August 27, 2003 7:42 PM
To: [log in to unmask]
Subject: [TN] Cracking Ceramic SMT CapacitorsCracking Ceramic SMT Capacitors" Is anyone else seeing an increase in the number of cracked and shorting ceramic chip capacitors? In our experience as a contract manufacturer we have, in the past, seen the occasional instance of ceramic capacitors cracking and shorting out. The cause of this problem is generally obvious, as it is isolated to components situated in areas of the PCB that are subject to flexing.Recently however we have seen more frequent instances of this problem; very often in areas of the board that should not be experiencing any appreciable flex. Our process has not changed and neither have our sources of these components. Have chip capacitors themselves become more fragile?"Rod LafondManager, Quality Assurance and Technical TrainingAPEX-Micro Manufacturing Corporation---------------------------------------------------
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