![]() ![]() ![]() We welcome your questions you can contact us directly. IPG can assist you to improve the overall processing and manufacturability of your board as well as help lower its total applied cost. First, there are many excellent articles and tutorials on Paste-In-Hole processing, but one that we have found to be particularly helpful is PIHR (Paste In Hole Reflow) Technology by Bob WillisĪlso, Samtec’s Interconnect Processing Group (IPG) is an in-house staff of engineers to support your interconnect processing concerns. But instead of doing that, let me share some links to other web sites that may be of benefit. Therefore, depending on the connector geometry, some may not be suitable for paste in hole technology on boards thicker than 0.062″ (1.57 mm).Īt this point we could dive into a bunch of gory details about the specifics of PIH soldering. Please note that boards thicker than 0.062″ (1.57 mm) require larger stencil apertures to provide the needed solder volume. 0.062″ printed circuit board thickness, unless otherwise notedīelow is a typical PIH recommended stencil for 2mm pitch header strips.The nominal plated through-hole diameter found on the connector footprint.Samtec’s stencil aperture recommendations are calculated using: Samtec provides the recommended stencil aperture and plated through-hole sizes for most connector series capable of being processed using Paste-In-Hole technology on the connector footprint. This vertical and horizontal space is required to allow unobstructed transfer of the molten paste from the pcb surface into the plated through hole. PCB surface finishes must be able to withstand reflow temperatures without incurring warpage or other surface damage. Second, the vertical and horizontal clearance around the leads must be large enough to allow adequate printed solder paste volume. To be a candidate for paste in hole soldering, a connector must meet two requirements.įirst, the insulator body material must be capable of withstanding lead and/or lead-free reflow temperatures. PIH makes it easier to process double sided boards, especially with taller components.The strength of the PIH solder joint is comparable to those of traditional through hole solder joints.It also saves money because, again, there is only one process – reflow only. ![]() It saves time because it employs only one process – reflow only Typical solder pastes are suspensions of tiny balls of solder in flux that, when brought to the proper temperature, reflow and create a solder joint.The boards are run through a reflow soldering process, thus terminating both through-hole and SMT components in one reflow process. Very simply put, this is the process of screening solder paste into and around plated through-holes on a pcb, and placing the leads of through-hole components - like connectors - in these prepared through-holes. So, our reflow profile does match the solder paste specification.Many Samtec customers employ Paste-In-Hole (PIH) processing. The cooling ramp rate, from Figure 2, is (250-90)☌/(5.7-3.8) min = 160☌/(114 sec) = 1. 40☌/sec, which is within the acceptable rate of the solder paste spec. ![]() The peak temperature is 250☌, again within the specification recommended range as seen in Figure 1. Prices for their stencils start at about 5, and are based on the size of the stencil. One good supplier of polyimide solder paste stencils is OSH Stencils. There is no “soak” in this profile, so we can ignore this part of the solder paste spec.įrom Figure 2, the time above liquidus is 4.4 – 3.1 minutes (78 Seconds), right within the recommended range of the solder paste spec. Fortunately, there is another alternative: a material called polyimide (marketed by DuPont as Kapton) can be laser cut to produce solder paste stencils that are good for at least a couple of dozen boards, and the prices are surprisingly low. This result is just over the recommended spec, but within the acceptable spec as seen in Figure 1. Ramp Profile: From Figure 2, the oven goes from room temperature to liquidus in 3.1 minutes (186 seconds) this gives a slope of (219 – 25)☌/(186 - 0 ) sec = 194/186 = 1.04 ☌/sec. Now, let’s take each reflow profile requirement individually: The solder paste reflow specification is shown in Figure 1 below.įurthermore, let’s assume that we have a reflow profile that we have used in the past, as seen in Figure 2. Assume we want to start using Indium Corporation’s Indium8.9HF Pb-Free Solder paste. Matching a reflow profile to a solder paste spec is a required skill for an SMT process engineer.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |