Cory and Lise, Following up on my colleagues reply, and to elaborate a little further: 1 Answered by David Greenman. Note however: A Conformal Coating should be applied to a flat unencumbered substrate at a cured thickness of 0.003 inch plus/minus 0.002 inch. However, Acrylics (AR) and Urethanes (UR) may be applied at 0.002 plus/minus 0.001. It is understood that the film thickness around components will be typically, x 3 or x 4 the flat land thickness. Obviously, (please note Duane!) to achieve the desired protective effect, the coating should be UNDER as well as over, the components. The most efficient and cost effective method of acheiving this, is by dip coating and you will coat both sides simultaneously. You can acheive >> 500 assemblies per hour from equipment costing 50% less than selective systems. The only issue is that of masking. When we have customers needing to process at this level, then design for manufacture becomes much more easily acheived. In other words, design the assembly with all components that should not be coated, on one edge of the assembly, the dip to that point and no further. Total process cost including capital, labor and materials will be << $0.05 per assembly. You cannot get these economics with selective coating systems. 2 Bubbles As previously given, this will most probably be due to the coating being applied too thick. This causes solvent entrapment by the surface skinning over before the solvent has due time to escape. It converts to gas and hey presto - bubbles. The bubbles, in this senario, will most probably be around the components rather than over them. If they are over them, then your problem may be related to drying too fast. 3 Dipping equipment We specialise from lab units to +500 bph (boards per hour) systems. Your request would suggest that you have been trying to dip by hand. So, for the benefit of those who are interested - wake up at the back! - dip in at < 12 inches per minute so you don't trap air under the components. Come out at < 6 inches per minute or slower than the cascade effect of the material. This permits the surface tension of the material to pull off the excess. In other words, the faster you withdraw, the greater the film build the slower out, the thinner the build. By the way, these speeds are almost impossible to achieve by hand - you really need a machine - and don't use an electric motor above the tank, the solvents in the coating are generally highly flammable and we don't want you to fry! Regards, Graham Naisbitt [log in to unmask] ---------- From: Cory and Lise Steeby[SMTP:[log in to unmask]] Sent: 09 June 1998 11:24 To: [log in to unmask] Subject: [TN] dip conformal coating We are using a manual DIP conformal coating method with an acrylic coating and building assemblies to the IPC-610 specification. 1. Are there other specifications which apply to conformal coating? 610 is brief on the subject. 2. Our biggest defect is bubbles in the coating. We are finding that dip angle, insertion rate and extraction rates all effect the amount of bubbles on the finished assembly. Does anyone have similar experience or advice? 3. Does anyone know of available dipping equipment and / or drying equipment? Our goal is to be able to dip 250 assemblies per day (1000 assemblies per day panelized 4 up). Thank You Cory Steeby ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################