Silkscreen is usually white and human readable letters, normally used to identify components, test points, PCB and PCBA part numbers, warning symbols, company logos, date codes and manufacturer marks.
Silk-screening requires specially formulated inks. The standard colour is white, but you can also select red, blue, black, yellow, etc.
At any given time 60% of our PCB manufacturing at Omni is producing multilayer circuit boards, so understanding the process is important. Layers of copper foil, pre-preg and core material are sandwiched together under high temperature and pressure to produce multilayer assemblies. Pressure is needed to squeeze out air while heat is required to melt and cure the thermosetting “pre-preg” adhesive which holds the multilayer PCB together.
Holes are drilled in PCBs for two main reasons:
Customer requirements.- PTH component mounting and to promote conductivity between Cu layers (vias)
Manufacturing requirements.- To ensure precise registration and to help the operator ensure each drill has successfully completed the tool path.
Given that we are leaders in Immersion White Tin PCB fabrication here at Omni, it goes without saying that we are heavily in favor of its use.
To understand why, you first have to understand the reason behind our preference for white tin in the first place.
Traditionally, printed circuit boards have been finished with a coating of material to protect them from oxidation and allow for components to be soldered onto them in a reliable consistent way, this is usually specified to as "PCB Finish" and requires the use of Lead (HASL) and vast amounts of water during processing (All other PCB finish types).
For short runs, the flexibility of quick set-up ensures cost effective Flying Probe tests outperform the lead-time, cost and fixed designs of dedicated test beds.
With Flying Probe tests, no fixtures need to be prepared, only data files.
Flying Probe tests are able to reveal not only shorts and opens produced by the manufacturing process but have also been known to expose design errors.
They may not feel comfortable down mouthing the competition in public but a process? Well that’s fair game. What the salespeople don’t know or won’t tell you is the Immersion Tin used as a finish for circuit boards completely dissolves in the solder used in the circuit board assembly process.