According to the customer's BOM list, the purchasing department of the processing firm will make an inquiry, including PCB bare board, electronic parts, etc. Sometimes, PCB assembly costs and engineering costs will be included in purchasing quotation. It needs to cover about 5% of the material loss when purchasing the components, due to the reason of material loss, like resistance and capacitance disk loading material and SMT chip. For the small batch of PCBA, engineering costs are usually covered in quotation, including the costs of processing file, stencil, Changing SMT line etc.

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In this passage, we are going to tell you all about automated assembly in PCB manufacturing. If you are going to learn more about automated assembly in PCB manufacturing, please check and read the content below.

What are the causes to affect PCB assembly quality?

The overall process of SMT assembly mainly covers solder paste printing, placement, soldering and inspection among which solder paste printing, placement and soldering top the list.

Defects Caused in Solder Paste Printing Process

As the beginning of SMT assembly process, solder paste printing plays a direct role in determining the quality of both PCB and end product. If rigorous control isn’t applied during solder paste printing, soldering balls will possibly be caused in later procedure of SMT assembly. For example, unwetting will cause metallic particles to be oxidized or metallic particles will possibly suffer from irregular shapes due to insufficient solder paste. Else, soldering balls will be possibly aroused due to solvent flashing or metallic particle oxidization.

Defects Caused in Placement Process

Placement, also called chip mounting, is regarded as the most complicated manufacturing step as far as SMT assembly is concerned so that the level of placement indicates the performance of SMT assembly manufacturing. Therefore, the quality of chip mounting stands for the level of SMT. However, defects tend to be caused mostly in this step, leading to the highest defect rate of manufacturing equipment. For example, missing components possibly occur due to badly-performed nuzzle; component’s wrong orientation may be aroused due to the errors taking place on component suppliers; or, misplacement may be caused due to incorrect alignment.

Defects Caused in Soldering Process

Soldering refers to a process during which devices are stuck to PCB board through melting metallic solder that will be cooled down and become hardened with adhesion completed. Soldering affects the performance of electronics products to the largest extent so soldering quality improvement lays a basis to product performance guarantee. When it comes to the overall process of soldering, all essential elements have to taken into serious considerations including surface cleanness, soldering temperature setting and solder quality. The top defect caused in reflow soldering process during SMT assembly manufacturing procedure is soldering balls that are small metallic particles caused on component surface through reflow soldering. Soldering balls possibly make ICs (Integrated Circuits) shorts, directly leading assembled circuits to failure. Furthermore, if smaller PCBs have to go through second soldering, shorts will be also aroused on circuit board due to rolling soldering balls or the whole board or product will be burned down.

Apart from the aforementioned defects causes during SMT assembly process, cost control or insufficient cleaning will also lead PCBs to be degraded in performance. Too many residues on the board surface will tend to make soldering joints far from being full and bright.

What are the benefits of PCB assembly?

These are some benefits of Automation PCB Assembly:

Lower total cost

Using automated PCB assembly means you can expect lower overall costs. Many SMT assemblers use the exclusive circuit board assembly program before actual production. This is to reduce the risk of errors and delays.

Short product development cycle

The time invested in manual assembly may vary depending on the circuit board that produces inconsistent time frames for completion. Hand-assembled PCBs may take longer to develop, which can be counterproductive if you have several other operations that you could complete at the same time.

Consistent quality

As an automated machine is designed and programmed to perform the same task repeatedly, the precision and quality of the circuit boards can be better and more consistent than manual assembly.