Practical Tips To Save Money On PCB Manufacturing

Minimize Your PCB Dimensions

Strive to reduce the size of your PCB as much as possible. Larger boards inevitably incur greater material expenses. Nevertheless, it's critical to find a balance; making your PCB too small may necessitate the use of highly specialized machinery by manufacturers, which can drive up costs. Therefore, it’s essential to strike a balance between board dimensions and manufacturing complexity.

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Opt for High-Quality Materials

Cutting corners on material quality can lead to increased costs down the road. Always select standard, high-quality materials for your PCB layers to ensure durability and reliability.

Design Using Standard PCB Shapes

When possible, stick to conventional rectangular or square designs for your PCB. Irregular shapes can substantially increase production expenses. Avoid creating unnecessary internal cutouts unless absolutely necessary.

Adhere to Minimum Spacing Guidelines

As the gaps between copper features like pads and traces shrink, production costs escalate. Crowding more features into a smaller space demands precision machinery, thus increasing expenses. Most manufacturers maintain minimum spacing criteria, often around 8-10 mils between pads and traces. It’s wise to consult with your fabricator about their particular spacing standards and incorporate these rules into your PCB design software to alleviate design-related stress.

Maximize Hole Diameter

Tiny holes and narrow annular rings lead to elevated manufacturing costs. Similarly to spacing requirements, smaller features necessitate more sophisticated fabrication techniques.

Choose Appropriate Vias

There are three main types of vias you may consider:

• through-hole
• blind
• buried

Blind and buried vias should be reserved for specific high density and high-frequency PCBs where absolutely necessary.

Limit the Number of Layers

Before opting for additional layers to create more routing space or power planes, reconsider your design. The cost difference between a two-layer PCB and a four-layer PCB can be significant. Use the needed number of layers judiciously, even if it requires slightly increasing the board's size.

Design for Efficient Panelization

PCBs are usually fabricated on large panels alongside similar boards. By utilizing the largest panel size offered by your PCBA supplier, you can save money. Increasing the number of PCBs on a production panel allows pick-and-place machines to work more efficiently, reducing setup time and labor costs.

Stick to Industry Standard Sizes and Components

The electronics industry relies on standard sizes and components for a reason: it enhances operational efficiency and supports automation in advanced manufacturing technologies. To avoid unnecessary costs, opt for widely accepted components and sizes.

Favor Surface Mount Technology (SMT)

Utilizing surface mount components can dramatically cut down the number of drilled holes needed on your PCB, streamlining the assembly process. However, if you decide to mix surface mount and through-hole components, be prepared for increased costs due to the necessary additional handling and processing.

Below are strategies to help you save money when fabricating your next PCB.

In this article, we will focus solely on PCBA (Printed Circuit Board Assembly) and its implications. Some businesses merge PCBA sourcing with housing integration into a single role, which can obscure their understanding of PCBA's specific costs. The primary cost drivers in PCBA are BOM (Bill of Materials) costs (excluding PCB costs), PCB manufacturing expenses, assembly costs, and tooling fees, if amortized into unit costs rather than categorized as non-recurring engineering (NRE). In some cases, like server motherboards, the BOM represents over 95% of the total PCBA expense. Thus, a significant effort should focus on optimizing BOM costs, followed by PCB and assembly costs. In previous discussions on PCB cost modeling (more details can be found at: link), I elaborated on various strategies for assessing PCB costs. Therefore, this discussion will primarily highlight BOM and assembly-cost consideration.     

Suppose you operate within a competitive industry, selling a price-sensitive product, and lack the resources to manage PCB design and assembly costs effectively. To address this, identify multiple potential PCBA suppliers, considering factors like company size, capabilities, and geographic location. After allowing selected suppliers to submit quotes for their services, a procurement manager should analyze these offers. However, two critical questions arise: Q1. What should suppliers be asked to quote? Q2. How should the received quotes be analyzed? 

The process of producing circuit boards generally includes two phases: PCB fabrication and component assembly/testing. PCB manufacturing is typically outsourced to one vendor while PCBA may be handled by a different entity. Another arrangement is employing a contract manufacturer (CM), responsible for both PCB production and assembly (sometimes even component sourcing). It’s often preferable to work with CMs, particularly in OEM business models. Conversely, in ODM models where the design is not owned, obtaining precise BOM and component-level pricing can be challenging. Business model type (CM/OEM/ODM/JV), alongside dedicated resources for management, significantly impacts the accuracy and detail of quotations received, including BOM (cBOM) insights. Strategies to acquire a cBOM are included in Appendix A. 

If you don't possess a cBOM, you can still perform RFQ (Request for Quotation). Comparing multiple suppliers’ estimates offers invaluable insights into leveraging supply competition and crafting a better sourcing strategy. Next, cherry-pick from the various RFQs, selecting the lowest quotes in each field to establish a final budget. Despite aiming for the best price, remember that a lack of detailed information could hinder effective cost management, even if the quote appears favorable. It's highly advisable to maintain a comprehensive cBOM updated to reflect the latest quotes and engineering changes.

Having established a reasonable BOM or cBOM, the next step is to perform a BOM scrub for component pricing analysis. This ensures that every component has a valid and competitive source. A structured BOM should include critical details like BOM levels, customer/vendor part numbers, usage quantities, lead-time, minimum order quantities, cancellation windows, and product lifecycle statuses. Below presents a simplified example of a BOM.  

BOM example

BOM example (Continuous)

For an OEM setup, a singular BOM suffices. Suppliers' RFQs should be reviewed against prior product BOMs, examining both price deviations and justifications. Additionally, services from third-party suppliers that maintain comprehensive databases can often yield insights on component pricing. For components with matching manufacturer part numbers where affordability is verified, you can negotiate with PCBA suppliers for cost reductions by redirecting them to the cheaper component sources or facilitating discussions directly between PCBA suppliers and manufacturers.

Ensuring that you have a fully optimized BOM entails identifying issues early in the component lifecycle. Teams can collaborate with subject-matter experts (SME) for BOM optimization. These experts can compare current BOMs with previous models and alternate supplier BOMs to uncover cost reduction potential. Questions to ask might include the necessity of certain PCB features, the possibility of combining components for material savings, or finding alternatives to pricey parts. Engaging in this dialogue helps maintain high product value for the end customer while pursuing cost efficiency.

By now, you should have an effective BOM prepared, alongside potential pricing avenues. However, smaller companies with limited budgets may find purchasing components in bulk financially inaccessible. Many times, the PCBA supplier's sourcing capabilities can offer competitive pricing advantages. It's advisable to request transparency regarding purchase invoices when negotiating component sourcing responsibilities before production; this allows you to ensure smooth and timely production cycles.

To explore more about OEM PCBA Service, feel free to reach out for expert advice!