Top common mistakes to avoid while placing PCB assembly order!

By | Date posted: | Last updated: May 23, 2023
PCB Assembly Order

In the fast-paced electronics industry, new products and features are added to the market every day. To stay ahead of the competition, you have to launch your PCB products on time. Avoiding common mistakes while placing the PCB assembly order is crucial in maintaining the delivery schedules. Several checkpoints in the PCB design process can ensure a high production yield. You have to follow design specifications, place components strategically, implement Design for Manufacturability (DFM) guidelines, and share the latest Bill of Materials (BoM) with your Contract Manufacturer (CM). Building trust with your CM is a key aspect during the PCB fabrication and assembly process.

You can generate quotes from different vendors and compare the pricing before finalizing the right CM for your product manufacturing. The PCB fabrication cost depends on details like board dimension, the number of layers, surface finish, and design complexity. Do you need PCB fabrication along with assembly? Will you procure the components or the CM has to source from your BoM list? What is your lead time for getting assembled PCBs? All these questions have to be answered before going ahead with the order placement and collaboration with a contract manufacturer.

Small mistakes in PCB assembly, especially during bulk orders can cause significant time delays and budget overflows. The degraded performance of the product will also affect the brand’s reputation. Hence, it is important to avoid these common mistakes while placing PCB assembly orders.

Common mistakes to avoid while placing a PCB assembly order:

1. Do not choose a CM without evaluating their competence

There are many contract manufacturers available in the PCB industry today. Without rushing to place an order, you have to explore the services and pricing offered by multiple CMs (Contract Manufacturer). You can visit the assembly house to understand their process quality and technical capabilities. Based on your product market, choose a contract manufacturer with relevant industry certifications. An experienced CM can effectively perform component analysis, review designs, and check for product integration. Take time to compare and then decide the best service provider for your PCB assembly.

2. Do not share partial or inaccurate BoM

If you are asking your contract manufacturer to source the components for PCB assembly, then double-check the BoM before sharing. It has to be complete and up-to-date. If you have missed any component details in the BoM then the CM may procure a wrong part, affecting the board performance. The longer lead-time components used in the design should be highlighted for early ordering. Check for obsolete or ‘End of Life’ components in the BoM and replace them with ‘in-production’ parts. Do not forget to share your approved vendor list with the CM. This will avoid sourcing counterfeit parts.

Also checkout: Why Bill of Materials (BOM) is important in PCB manufacturing process?

3. Do not skip PCB design reviews which are essential for high-yield optimization

Along with the functionality review of the circuit design, check if the Design for Testing (DFT) and Design for Assembly (DFA) guidelines are implemented. Missing these recommendations during PCB design will reduce the assembly output. Silkscreen should be readable on both sides of the PCB. Include fiducial markers on the board to assist the pick and place machine during component assembly. Provide edge clearance on the PCB for mounting equipment to get enough grip. This is mandatory for a successful PCB assembly.

4. Do not provide incompatible design output files

Communicating clearly with your CM is highly essential to avoid confusion or delay in the PCB manufacturing services. There are different design output files like Gerber files, IPC 2581, and ODB++ used for PCB fabrication. For Assembly, BoM and X-Y placement files are required. BoMs (Bill of Materials) should be reviewed and shared in standard templates. Schematics and assembly drawings are also part of the design output bundle. It is necessary to provide these files in the formats accepted by your CM.

5. Do not handover ambiguous assembly instructions and testing documents

Provide clear PCB assembly instructions for component mounting sequence, orientation, and soldering techniques. If special components are used in the design, then add associated handling procedures to the document. For example, including the details of EMI-sensitive components and their shielding circuits can save component failures post-assembly.

The PCB assembly document package consists of test specifications and regulatory requirements. Test procedures and expected results must be clearly explained in the test documents. All the assembly documents should be revision controlled for traceability.

6. Do not miss to verify the PCB assembly quality before reordering

Do not opt for low-cost services. It is a common mistake to overlook quality over cost. But this will backfire in the long run. Assess the PCB assembly quality after the first batch output. The PCB assembly should pass the required tests and conform to industry standards. PCB assemblies of inferior quality will result in performance failure. This will add to the debug and rework costs, along with a delay in the delivery.

There are ways to reduce the PCB assembly cost through prior planning. If you are looking for a shorter lead time, then the price will shoot up. Also, the quantity of PCB ordered will impact the assembly cost. CMs will charge for creating soldering stencils, programming devices, preparing test setups, and board inspection. Choosing standard PCB sizes and common materials can help to reduce fabrication and assembly costs. While generating a PCB assembly quote, you must consider all the above aspects. Once you decide on the contract manufacturer, go through the quote in detail and understand the pricing and services offered.


To achieve maximum assembly output, you have to plan and then place the PCB assembly order. Avoiding the common mistakes listed in this article guarantees a smooth and efficient run of the PCB assembly process. The key factor is to evaluate and choose the right service provider. Keep in mind to share the complete and updated BoM. Review your circuit design thoroughly and implement DFM guidelines. As you focus on cost-reduction methods, do not forget to verify the assembly quality before placing your next PCB order.

We have 40 years of expertise in providing PCB assembly services. We use surface mount (SMT), through hole and mixed technology to manufacture consigned printed circuit board assembly, turnkeys, board types with metal cores, etc. as per your requirements. Get a quick PCB assembly quote or email us on or call us on 714/630-9200 to ask your queries related to our custom PCB services.

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