Designers must be aware that the customer-supplied board outline shape isn’t always necessarily the shape that is to be delivered to the fabrication and assembly house for manufacturing. PCB’s must have two parallel sides (preferably the two longest sides) for processing them through the assembly equipment (conveyor transport).
The first episode of Outsourcing Things You Should Know, focusing on the oft-neglected subject of on-time delivery. Listen to Everett Frank and Sherri Hubbard of Optimum Design Associates discuss important metrics and methodologies you can utilize to help deliver on time, every time.
Choosing the right solder paste is like buying a new car: the options can seem endless, and it's really a matter of preference. In the end, however, it all comes down to three considerations: (1) Lead vs. lead-free, (2) Water-wash vs. no-clean, (3) Alloy ratio.
As pick-and-place machines become more precise, some assembly shops are doing away with local fiducials. Why take up real estate with non-functional markings when it's not absolutely necessary? Of course, it's never that black and white. Deciding whether local fiducials are necessary depends on a few different factors. Here they are.
With the growing popularity of SMT technology, through-hole technology is taking up less real estate on a PCB assembly. But through-hole pins are still a necessary for many boards, and they still need to be soldered. While this process can be cumbersome, many manufacturers have turned to selective soldering as a precise and cost effective way to solder through-hole technology.
When a PCB is thin, small, oddly shaped, or requires SMT components near its edges, chances are these kinds of boards won’t fit properly into your pick-and-place, reflow oven, or automated inspection machines. That's why many manufacturing engineers use fixtures to secure and support these kinds of PCBs. But the cost of fixtures can add up. A new, custom fixture must ordered for every new design, and there’s usually a 3-4 day wait for it arrive. It ends up costing more for the customer, without adding significant value to the end product.
For small to medium size CMs, the cost of RoHS compliance can be high—5.2% of annual revenue, by some estimates. This figure factors in the cost of higher priced materials (solder paste and laminates), higher cost of manufacturing, increased administration and testing, as well as a lengthier exemption process. But a growing number of CMs are now learning how to manage those costs and, in some cases, reduce it.
For mid-size EMS providers, costs of rework can add up quickly. By some estimates, rework alone could result in tens of thousands of dollars in annual losses. Yet these costs aren't as high as completely scrapping a board, which can be almost triple the annual costs of repair. In terms of cost, the question of whether to repair or scrap is relatively simple: It's almost always worth it to repair.
As we’ve covered in other posts on schematic symbols, one of the key goals of a librarian is to maintain consistency, both in terms of visual appearance of a symbol, and parity with a manufacturer’s data sheet. Establishing a set of standards which all schematic symbols must abide by allows for more timely part identification, and cleaner, easier to read schematics. With that in mind, let’s take a look at display settings for schematic symbols within Optimum’s library.
Base Symbol: adg1407-dil28.1 (dual inline IC, 28 pin)
Optimum’s symbol library makes extensive use of various abbreviations in symbol names. Our previous posts have dealt with the pins of schematic symbols, and the general theory behind some of our naming conventions. A look into our naming abbreviations could have been joined with our overarching naming convention post, but we feel the large number of different abbreviations warrant a standalone post.
Part Type Qualifier Abbreviations
