Are Local Fiducials Necessary?

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.  


What is Selective Soldering?

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.


Fixturing vs. Paneling in SMT


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.


Reducing the Cost of RoHS Compliance


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. 


When Do You Repair and When Do You Scrap PCBs?

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. 


Schematic Symbol Properties for DxDesigner

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)


DxDesigner Tutorial: Pin Name Abbreviations

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


DxDesigner Tutorial: Schematic Symbol Pins

While having appropriate labeling and naming for schematic symbols is the most critical aspect of organizing your symbol library, ensuring that pins for all symbols are consistent is equally critical. This maintains visual consistency on the schematic, and consistent connection points within DxDesigner. All of the pin settings must be considered: visual aspects such as length and orientation, as well as technical considerations such as inverted pins and location of connection points. Optimum maintains rigorous standards for pins on schematic symbols, let's take a more in depth look. 


DxDesigner Tutorial: Schematic Symbol Naming Conventions

Much like your library of footprints or cells, proper naming conventions are critical for easy identification and utilization of schematic symbols. This can be complicated by the fact that generic symbols can be utilized for certain component types, whereas more intricate components, such as connectors or ICs, will require unique symbols with different naming conventions. In this series of DxDesigner tutorials we’ll take a look at the organizational methods of Optimum librarians, beginning with symbol naming, and moving on to pin considerations, and overall symbol library structure.

Symbol Name Prefixes


Mentor Expedition Library Tutorial: Renumber Pins Referenced by Parts

At various points in your design process it may be necessary to modify the pin naming or numbering of components in your design. Be it an error in the part’s original creation, pin or gate swapping for placement and layout concerns, any number of reasons. Modifying symbol pin names or cell pin numbers after the elements are associated with a part will invalidate the part. Fortunately, Library Manager has built in utilities to assist with modifying pin labeling in these instances.