Achieving Fast Turnaround for Prototype PCB Assembly

By Prototype PCB Assembly · Updated August 10, 2023

Introduction

For companies developing new electronic products, long delays in getting prototype printed circuit boards (PCBs) assembled can hamper progress and time-to-market. Fast turnaround PCB assembly enables testing design concepts and functionality early, informs engineering decisions, and accelerates product development timelines. This article explores strategies for rapid prototyping using quick-turn PCB assembly services.

Why Fast Turnaround Matters for Prototyping

Getting functional prototype boards back quickly from assembly shops allows engineers to:

• Test ideas and validate designs faster through rapid iterations
• Identify issues earlier that could impact schedules down the line
• Refine requirements by actually using and evaluating boards
• Stay on schedule for key milestones like demos and design freezes
• Be more responsive to changing customer needs
• Get a product advantage by reaching the market faster

Slow assembly turnaround can delay development, so utilizing quick-turn services offers big advantages.

Capabilities to Look for in Quick-Turn Assembly Services

To ensure fast prototyping, partner with an assembly provider that offers:

• Short assembly lead times – From a few days to 1-2 weeks for build and shipment.
• Fast PCB fabrication – In-house PCB fab with 3-5 day turnaround or partnered fabrication shops.
• Small order quantities – Willing to assemble small batches needed for prototyping.
• Design for Manufacturability (DFM) – Reviews to avoid assembly problems before ordering boards.
• Flexible component selection – Allows submitting Bill of Materials or utilizing their component inventory.
• Multiple assembly options – Offers quick prototyping methods like hand assembly, low-volume SMT line setups.
• Testing services – Functional testing or ICT fixture options to validate assembled boards.
• Logistics assistance – Handling of customs, shipping so boards arrive quickly.
• Engineering support – Help with diagnosing issues and fast design revisions.

Comparing Quick-Turn vs Standard Assembly

Here is a comparison of quick-turn versus standard turnaround assembly:

Evaluating the above trade-offs helps determine if quick-turn services are worth premium costs over standard turn assembly.

Enabling Rapid Assembly Turnaround

Here are some tips for optimizing prototype boards for fast assembly:

• Use larger component sizes (0805, 1206, SOIC vs smaller sizes)
• Avoid challenging BGAs, QFNs and ultra-fine pitch ICs where possible
• Design with easy-to-assemble connectors (board-to-board, wire-to-board)
• Include wiring test points for troubleshooting
• Provide reference designators on both sides of board
• Allow extra tolerances for hand soldering
• Minimize dense routing with SMT escape patterns
• Eliminate gold edge fingers which can’t be hand soldered
• Use assembly-friendly design software output formats like ODB++

Simplify designs early on for quick-turn assembly capability and optimize later for production.

Streamlining Supply Chain Logistics

The time for shipping PCBs, stencils, and components impacts total turnaround time. Here are some logistics tips:

• Use local PCB fabrication shops to avoid shipping delay
• Have stencils/frames made in parallel with PCB fabrication
• Pre-ship components to arrive just in time for assembly
• Consolidate all materials needed to a single shipment
• Pay for premium shipping methods (air, expedited) with tracking
• Use customs brokers for international shipping to avoid hang ups
• Have sales tax exemption and import paperwork ready for customs
• Provide detailed shipping paperwork (commercial invoices, BOL)

Optimizing logistics in coordination with your assembler prevents delays that erode the benefits of quick-turn.

Conclusion

Fast turnaround on prototype PCB assembly enables testing and validation that would otherwise slow development. By partnering with assemblers focused on quick-turn services, optimizing designs and logistics for speed, and applying project planning best practices, companies can slash prototyping lead times to beat development schedules. The result is higher quality product introductions with reduced risks.

Frequently Asked Questions

What is the cost premium for quick-turn vs standard assembly?

Typical premiums are 50-100% for expedited turnaround. But cost may be less relevant compared to development advantages.

What are typical lead times for quick-turn assembly?

3-7 days for simple designs and small quantities. 7-14 days for complex boards, larger orders, or offshore assembly.

Should every assembly lot include all components on the BOM?

No, consider incremental assembly and test of the core design before all peripherals.

How can designers avoid assembly problems?

Thorough DFM analysis of the design, controlled component selection, and clear assembly drawings avoid many issues.

What are signs that a prototype is nearly ready for higher volume?

It has passed all major functional tests and meets requirements. All major technical issues from prototyping are resolved. Test coverage, yields and quality match production expectations.