Design for assembly is an essential steps for design process of electronic products. due to their high complexity and extensive use of professional technology. To accurately comprehend the potential impact of assembly . It is necessary to perform an analysis of assemblability at the design stage. to avoid issues such as unassemblability at the manufacturing stage. In the design for assembly , that can effectively test the effect of electronic products. thereby enabling the production of electronic products to better meet client’s needs.


PCB assembly is the process of combining a circuit board with other electronic components. (e.g. connectors, housings, heat sinks, etc.) to be embedded in the final product. Knowing its great significance, it is important to consider PCB assembly early . in the design for assembly process to get the best results. If not, then you may run into inadequate problems . such as limited board functionality, component conflicts, etc.




DFA, which refers to the design of products with good assembleability in the product design stage. ensures simple assembly process, high assembly efficiency, high assembly quality, low assembly defect rate and reduced assembly cost. Once design for assembly main function provides assembly analysis, support to check the hidden problems in component assembly, early analysis and check can avoid unnecessary losses caused by design during assembly.


There are two main stages of PCB design for the assembly process. One is prototype  assembly, and the other is production assembly. In the board design process, it is important to consider these two phases as part of the DFA.


Prototype Assembly:

In this step, a prototype board is assembled to ensure that all components are connected properly. The design should adhere to clearance and tolerance requirements. In addition to this, a number of other DFA measures should be observed during the design process. This may include adequate component spacing, precise component marking. proper solder resist application, etc.

Production Assembly:

The assembly follows all measures of prototype assembly and considers component reliability. mass production, component testability. The following DFA measures as followed in the prototype assembly.

  • Properly defined quality control
  • Component availability
  • Penalties allowed by the board
  • Layout that can withstand extreme conditions


The first PCB piece approval is the most important step.That towards effective PCB Layout for Assembly. An OEM approved first piece PCB. that is useful in answering all questions about manufacturing, assembly, and testing. It is the “proof of concept” before a PCB order production in mass, even if the quantities are small, such as 10 to 50. The first piece ensures a smooth transition into production volumes. with few to no questions unanswered. Furthermore, for the OEM, a smooth transition to production means meeting key market demands. such as time-to-market, quality, dependability, product delivery, and the critical time-to-revenue.GESP focus on PCB for 17 years ,we supply dependable design for assembly and other PCB services. Please contact us and let us help you to finish your project as soon as possible!


01 Device Analysis

Component spacing:

As we know ,device spacing is not enough to interfere with each other. there may be device welding difficulties to repaired. such as device to device height ratio, beyond a certain range there is uneven thermal wind waves. there may be poor welding, welding can not reworked. Device to the edge:

device to the edge of the board distance is not enough. milling or sub-board shear tool needs to set aside enough space. and mechanical processing with the risk of crashing the device. Insufficient distance from the device to the rail. SMT processing may exist when the equipment rail hit the risk of flying devices can not be welded.

Component screen printing:

Device contact characters, there may be characters by the device obscured. causing inconvenience to welding, rework. The character is too far from the device, can not identify the corresponding component bit number. there may be a risk of welding and paste the wrong components.

02 Pin Analysis

Pin number difference:

Inconsistency in the number of pins of SMD devices will lead to the inability to weld. need to confirm the model or package whether the wrong package is used. Inconsistency in the number of pins of the plug-in devices will lead to the inability to solder. That need to confirm whether the wrong package is used.

Bit number length:

bit number byte number length, ≥ 5 digits part of the device can not identify the longer bit number.

SMD pins:

The distance from the toe to the edge of the pad is not enough. there may be insufficient tin on the amount of false solder or the risk of poor soldering. Device pins to the edge of the disk width distance is not enough. there may be insufficient amount of tin on the risk of false solder or poor soldering.

Through-hole pins:

plug-in pin holes for NPTH properties. device pins have the risk of poor soldering and non-single-layer board electrical can not conduct. THT pins without through-hole, can not plug-in welding. Pitch of axial device for horizontal mounting is smaller than the body, and the device cannot be put in.

Crimp pins:

The diameter ratio of through-hole to crimp pins is too small for plug-in crimping. The diameter ratio of through-hole to crimp pin is too large, there may be components loose and not easy to weld.

03 Pad Analysis

Chip pad:

Firstly,chip component pad spacing is too small, there may be welding even tin short circuit. chip component pad spacing is too large, there may be a small contact surface soldering not risk. Then chip component pad length is not enough, there may be a small soldering surface on the tin amount is not enough. chip component pad length is too large, there may be welding offset and pull material standing monument risk.

Solder pad connection:

most of the package pads are connected with electrical networks. such as pads connected wirelessly, there is a risk of design errors open circuit.

Mark points:

That is the circuit board design PCB . applied to the automatic placement machine location identification point. mark point selection directly affects the automatic placement machine placement efficiency.

04 BOM Analysis Matching Sheet

BOM table check:

Check the before and after differences of bom document modification. Help users to check the correctness of the BOM table.

Coordinate collation:

Gerber file without coordinates, first need to load the coordinate file to identify the location of device welding. when the coordinate file has abnormal irregularities. collate coordinates to help users can use the correct coordinates to paste components.

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