01005 is not a dramatic departure but there are some basic guidelines that can be helpful:- Stencil cannot be too thick or paste deposition will be inconsistent. A general rule is that the width of the aperture should be greater than 1.5 x the thickness of the stencil.
- Paste should be printed within pad boundaries and the component should be centered on the pads. This is to help prevent tombstoning.
- A low mounting force of approx. 1 N is recommended.
- The type 4 and type 5 paste that is used with these smaller parts has a huge surface to volume ratio. In other words, the smaller solder balls have more surface area and less flux to reduce the oxygen�so protecting the flux is critical. The typical ramp and soak profile for reflow can deplete the flux. So it is recommended to use the "tent" or straight ramp profile and get the parts and paste into reflow as quickly as possible without depleting the flux.
- Nitrogen can actually INCREASE the likelihood of tombstoning in smaller parts. When using nitrogen, the wetting forces go up and any problem with paste deposition or component placement will be magnified and manifested in the form of a tombstone. So it is recommended to use an air environment or a very high PPM of oxygen � Approximately 500-1000 PPM.
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Marc Peo
President, Heller Industries Inc.
Mr. Peo has been with Heller Industries for over 20 years and has been President for the past 8 years. Marc has authored several industry articles on Soldering, Flux collection, nitrogen use and Lead Free conversion.
From the placement side, you need a machine with high accuracy, an accurate feeder design, and a precision 01005 nozzle. We at Juki have placed millions of 01005's in the past 2 years, and we have found that screen printing is the most critical step in the process. If the printing is good, the placement process is rather routine. As we demonstrated live at APEX, printing, placing and reflowing 01005's is so routine, we built 100's of boards in our booth during the show and passed them out to visitors.
Bob Black
North America Sales Manager, Essegi Automation
Mr. Black was the President and Co-Founder of Zevatech in 1977 and introduced first Pick and Place System at Nepcon West 1980. Bob is now the President, CEO and Co-Founder of Juki Automation Systems. He is also a Co-Founder of the SMEMA Council of IPC. He serves as a member of SMTA and SEMI..
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