Hi Rod, I hope you could reach to the following papers. Regards ilknur Baylakoglu Author(s): Scheer, F.; Crane, L. Corp Source: McCurdy Circuits, Orange, CA, USA Title: The advantages of electrostatically sprayed LPI solder mask for the fabrication and assembly of high density SMT boards Source: Surface Mount International, Conference and Exposition. Proceedings of the Technical Program p. 2 vol. 1306, 922-5 vol.2 Publication: USA Language: English Publisher: Surface Mount Int; Edina, MN, USA Conference Loc: San Jose, CA, USA; 27-29 Aug. 1991 Year: 1991 Treatment: P Practical Record Type: Conference Paper Abstract: While the use of dry film solder mask has allowed for the increased use of SMD technology there are still areas of issue from both a fabrication and a board assembly standpoint. While dry film solder mask has improved the fabricators yield it is in fact the requirements of the assembly house, which are further driving the search for improved, solder mask technology. The search for improved assembly and fabrication yields has led to the use of liquid photoimagable solder masks (LPI). The main focus of this paper is on the advantages of LPI technology over dry film and the advantages of electrostatically spraying the LPI over other methods of application and what these advantages mean for both the fabricator and the assembler/end user (0 Refs.) ---------------------------------------------------------------------------------------------------------------- Author: McGregor, D.R.; Hull, R.B., Jr.; Petersen, R.N. Corp Source: Du Pont Electronics, Research Triangle Park, NC, USA Title: Solder mask and SMT solderability Source: Printed Circuit Fabrication, vol.15, no.12 p. 30, 32, 36-7 ISSN: 0274-8096 CODEN: PCFAE6 Publication: USA Language: English Year: Dec. 1992 Treatment: P Practical; X Experimental Record Type:Journal Paper Abstract: The major difference between dry film and liquid photoimageable (LPI) soldering yields has been ascribed to the difference between the height of solder dams and that of SMT pads. Dry films have solder dams higher than pads while LPIs have dams lower than pads. To study the effect of solder dam height on soldering performance, nine solder masks were benchmarked for reflow and wave soldering. The benchmark test included high-conformation dry-film, liquid- dry, and LPI solder masks, which provided a range of mask thicknesses adjacent to SMT pads. This article presents the test vehicle, methodology, data, and conclusions (0 Refs.) On 30 Oct 00, at 15:07, IPCsm840 Rod Simon wrote: > I am looking for some information on dry film soldermask vs. LPI > soldermask. > > Manufacturing wants to change all boards to dry film mask and tent all via > holes so that when conformal coating is applied to the boards the coating > does not drip through the holes. > > About 2-3 years ago I remember reading an article on problems with dry film > and alternatives to using dry film. Since I had only used dry film once or > twice a long time ago I did not save the information and can' > > t find it in > any back issues of Printed Circuit Design or SMT that I have. > > It is my understanding that our main supplier has the facilities to dry > film and is encouraging the dry film solution. (In my opinion more $ and > less Competition) Cost is not a big issue since we do not produce large > quantities of our products. > > Any help would be greatly appreciated. > > Rod Simon > > [log in to unmask] Flight Vision Inc. Sugar Grove IL 60554 > 630-466-2119 > > --------------------------------------------------------------------------------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------