fill for the through-hole apertures. If you are unable to use ProFlow, then a 45 degree squeegee can increase the paste pressure. But, if the board is thicker than 1mm, several print stokes will be required, which could degrade the SMT deposits.Standard solder paste should be used for this application. Clive AshmoreGlobal Process ManagerDek Printing MachineMr. Ashmore is responsible for the Global Applied Process Engineering group for DEK. Clive specializes in all aspects of manufacturing engineering, with special emphasis on mass imaging technologies.Same paste should work. You can calculate amount of paste required knowing 4 items: pin dimension, board thickness, hole size, and annular ring size. Paste to solder shrinkage is usually about50%. Paste volume can be achieved in 3 ways: Overprint, Step-up Stencil, through-hole paste fill.Good reference paper is in SMT Magazine Nov and Dec 2006 "Intrusive Reflow for Lead Free paste." Bill ColemanVice President TechnologyPhoto StencilFor over 18 years, Dr. Coleman has been the vice president of technology for Photo Stencil, working closely with customers to understand their printing requirements. Hisefforts have resulted in several new stencil products. The use of an off-line x-ray inspection system post paste that offers oblique angle views without tilting of the actual board to inspect a representative sample of boards will allow you to seethe amount of paste that is located down the holes prior to reflow, non-destructively. The same test can also be used post reflow to quickly confirm that the resultant pin-in-paste hole fill meets the IPC 610D recommendations of a minimum of 75% fill. Dr. David BernardProduct ManagerDage Precision IndustriesMr. Bernard has been the X-ray Systems Product Manager at Dage for over 5 years and have been involved in all aspects of x-ray inspection and test for printed circuit board assembly applications. Priorto this, Dr. Bernard was working with radiation measurement instrumentation. There are numerous tradeoffs to consider when pin in paste hole fill is the goal. First, overprinting can be problematic due to the possibility of mid chip solder balls. Step stencils are more expensive than standard stencils, and willlikely result in reduced throughput and material expense due to the need to increase underwipe frequency.One technology which is becoming very popular is the use of solder preforms in tape and reel packaging. The preforms come in standard sizes, such as 0402, 0603 and 0805 to name a few. They are packaged exactly like chip capacitors and resistors.Placement is done after paste printing. Only 20-25% of the preform needs to contact the solder paste. Since the preform is solid metal, a preform as large as four times the volume of the paste volume can be added and still achieve perfect reflow results. Paul J. KoepGlobal Product ManagerAlphaMr. Koep is responsible for product planning and technical marketing for the Preform Products at Alpha. He is the co-author of several patents in the areas of soldering applications focusing on reflowand alternative methods. Reader CommentReaders may be interested in the free ebook on "Pin In Hole Intrusive Reflow Design and Assembly" at http://www.pihrtechnology.com The most common problem with the process isthe hole to lead