Issue link: https://iconnect007.uberflip.com/i/1398328
32 SMT007 MAGAZINE I AUGUST 2021 BOM e bill of materials should include item numbers, quantities, reference designators, part manufacturer, manufacturer's part num- ber, and part or package description. Excel format is the preferred format and allows an easy way to import into a multitude of differ- ent systems. Output Data Although there are several options, Gerber data still seems to be the industry standard that everyone gravitates toward. e problem with Gerber data is that it does not contain any use- ful intelligent information. Intelligent data out- puts include ODB++, and IPC-2581. Fabrication and Assembly Drawings e key to a successful build is documenta- tion. Include notes, surface finish, materials, build instructions, visual details, labeling and marking formats, etc. Test Requirements is could be as simple as stating if flying probe or bed-of-nails/ICT test is required or a full set of instructions for functional test. Also state if a functional test set or a test fixture will be provided to the supplier. Project Notes Although notes should be included in the fab and assembly drawings, some prefer to pro- vide additional notes not found on the draw- ings. Notes can be a vital part in conveying specific assembly details such as solder/flux type, labeling format, serial numbering, wash instructions, and so on. Other Items to Consider Specifications I am a huge fan of industry specifications. IPC and SMTA provide a plethora of infor- mation from PCB layout to bare board fabri- cation and final board assembly. An experi- enced layout expert will study and understand best practices for completing a design that allows the fabricator and the EMS provider to complete the subsequent processes once the design phase is complete. Unfortunately, many engineers and designers do not understand the details and processes involved in getting a design from the CAD system to a finished prod- uct. A truly good designer must know a little bit about chemistry, physics, thermodynam- ics, materials, etc. Any competent EMS com- pany will be able to build product that adheres to the industry standards. Avoid Making Changes During the Assembly Cycle On-the-fly changes cost time and money and can sometimes cause a lot of unnecessary con- fusion. Plan ahead to avoid making component or circuit changes during the assembly phase. With the current supply chain constraints, make sure the materials you choose for the project are readily available or have a list of alternate part numbers available to choose from. Last minute changes create schedule delays and increased costs associated with the project. What that means to an EMS provider is an interruption in the normal production flow and having to re-organize other project schedules to accommodate the new manufac- turing criteria. Pre-production Meetings If the luxury of time is on your side, then pre- production meetings are a great idea. ese meetings will allow everyone involved to voice any concerns or questions, review documen- tation, and discuss the overall scope of the project. Remote group meetings can easily be arranged via Zoom, Teams, or some other plat- form of your choosing. Put Everything in Writing EMS providers work on hundreds of projects each year, so giving any type of verbal instruc- tion or direction to the salesperson or program manager could be devastating. It's always best