| | We are changing from through-hole to SMT, wondering what pitch requirements would an 8 pin SOAC require for pick and place? We think that this would be our finest pitch part. | | | | | | | John: Never heard of an "SOAC." SO packages are 50 ptch (50 mil, 1.27 mm). | | | | I think you should anticipate that your pitch requirement will become more stringent as you become more involved in SMT and your requirements change. | | | | Plus, with good 50 mil pad design, reasonable solder paste deposits, and an OK reflow oven; you don't need to be concerned about placement accuracy. Getting a 50 pitch component somewhat on the pad is all you need to do. The capiplulsive force of the solder will snap that puppy in position, like blam!!! | | | | I think you should be asking yourself "what kind of production mix will we be assembling 2-3 years down the road?" | | | | We'll help | | | | Good luck | | | | Dave F | | | | Thanks a lot,, so assuming we are using standard parts, with nothing out of the ordinary we could safely assume that a machine capable of 20 mil would be more than able to meet our needs down the road. | Yes, but also think about:
OTHER MACHINE CAPABILITY REQUIREMENTS: BGA inspection and placement, board size, CAD download, product change-over time, and peculiarities of your (assumed to be) wacky operation. PRODUCT MIX: I mentioned that didn�t I? SUPPLIER: Ability meet your short and long term support requirements. PREVIOUS CUSTOMER SATISFACTION: Does what the cheerleaders say mean more to you than what the whiners say? VALUE COMPARED TO SIMILAR MACHINES: Placement rate is a small piece of this equation.
Each January "Circuits Assembly" publishes a flawed, but useful comparison of placement machine suppliers� machines. It also is at their site. Look at "SMT" magazine�s "10 Steps" at their site.
Push on
Dave F
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