There are many approaches to producing electronic circuits and one of the most popular is low volume PCB assembly. As the name suggests, this form of circuit board assembly involves the production of a small quantity of PCB assemblies, and which follows design-for-manufacturing (DFM) and Design-for-testing (DFT) procedures. This form of assembly is normally procured as a turnkey service and it involves parts procurement, PCB fabrication, and the final assembly.
In DFM consideration for low volume PCB assembly the customer sends the requisite documentation (for the circuit board to be created) to the turnkey company, and which in turn reviews its Gerber files for engineering concerns, problems with circuit diagrams and assembly drawings, and BOM (bill of materials). Effective turnkey solution providers always look into ways of lowering the panelizing costs and facilitating the assembly process. A recommended way of doing this is through using the solder mask opening process as it is a high yield rate procedure which is also effective for preventing solder bridging. Part lists then need to be checked against PCB files and a clarification for any differences is made before placing the order for the components. These measures are geared to prevent money wastage and delayed delivery due to non corresponding circuit components.
Shifting focus to the design-for-testing role in low volume board assembly, it should be appreciated that there are a couple of fixture styles, probe models and tester limitations which are involved. Turnkey firms can on reviewing your test procedure offer professional expertise advice on how the test points can best be distributed over the circuit board. Circuit board assembly companies worth their salt should also be ready to fulfill the customer-prescribed troubleshooting procedures requirements, diagnostic tests, and indeed any other associated guidelines for getting the board fully tested for compliance and function.
Experienced circuit board assembly companies normally have in place different ways of how to get low volume PCB assembly jobs done risk-free. Dependable turnkey service firms ordinarily follow a protocol whereby all the printed circuit boards they create must be electrically-tested and that a few of the assembled boards must be shipped to the client for approval before actual production of the entire batch commences. It has also become a somewhat standard procedure that assembled boards must be inspected using X-ray to assess BGA and the quality of leadless assemblies. These procedures should be adequate to detect and resolve any fabrication problems before shipment.
Low volume PCB assembly jobs do not carry economies of scale but this does not mean that the costs should be exorbitant. Approaches that can be used to address this include waiving NRE and stencil charges for repeat jobs, shopping for parts from major distributors, and choosing quantities with lowest per part prices. These companies also build strong relationships with major component suppliers so as to keep costs competitive without sacrificing quality.
Low Volume PCB Assembly – what it entails