90% of product delays can be traced back to poor manufacturing decisions, and pcb assembly for startups is often where things start to spiral. Unlike software, where bugs can be patched in minutes, a faulty board layout, a misaligned BOM, or a lack of test coverage can cost weeks, if not months, of lost time and investor confidence.
At Karkhana.io, we’ve worked with over 100 hardware startups, and the patterns are unmistakable. Some mistakes we see again and again are avoidable with the right approach and partner.
So if you’re in the early stages of building a hardware product, here are the five most common and costly mistakes startups make in circuit board assembly for startups, and exactly how to avoid them.
1. Designing for Prototype, Not for Production
Startups often celebrate a working prototype, a success after months of design effort. But what’s good enough for a handful of boards often falls apart in a production environment. Prototypes tend to prioritize function over manufacturability.
Why It’s a Problem
Unoptimized footprints: Components may have footprints that are slightly off-standard, causing placement issues on automated lines.
Tight tolerances: Design rules for spacing and solder mask may not meet manufacturing standards, causing defects like solder bridges or opens.
Complex assembly: Overly dense layouts or mixed SMT and through-hole parts increase assembly difficulty and cost.
How to Avoid It
Early DFM collaboration: Work with your contract manufacturer early in the design phase. Our engineers provide feedback on footprint accuracy, panelization, and layout optimizations to improve yield.
Standardize components: Use industry-standard packages and avoid exotic or obsolete parts. This reduces sourcing risks and assembly errors.
Panelization strategy: Design your boards with proper panelization for automated pick-and-place and reflow processes to maximize throughput.
2. Skipping Pilot Production Runs
Excited by initial success, startups often jump straight from prototype to full production without a controlled pilot run.
Why It’s a Problem
Undetected process issues: Problems like inconsistent solder joints, component misplacement, or thermal stress during reflow can remain hidden.
High scrap rates: Without pilot testing, a large batch may fail QC, causing expensive rework or scrapping.
Inadequate testing coverage: Functional and in-circuit test setups may be immature, leading to field failures.
How to Avoid It
Plan a pilot run: Produce a small batch (50–100 units) under production conditions. Use this run to fine-tune assembly parameters and validate test procedures.
Use pilot data: Collect yield statistics, defect types, and rework rates. Collaborate with your EMS partner to identify process bottlenecks.
Iterate designs and processes: Apply learnings from pilot runs to update PCB design, BOM, and assembly instructions.
3. Underestimating Procurement Complexity
Startups rely on online distributors or small-batch suppliers to source components, assuming this will scale.
Why It’s a Problem
Supply chain disruptions: Popular parts can quickly become unavailable or have long lead times, especially in a volatile global market.
Cost fluctuations: Prices for key components can spike, affecting project budgets.
Lack of alternates: Without pre-approved substitutes, production grinds to a halt if parts run out.
How to Avoid It
Integrate procurement with manufacturing: Work closely with your EMS to secure components in advance. Karkhana.io’s extensive supplier network helps lock in prices and availability.
Define alternates: Identify and qualify alternate parts early to mitigate risks.
Forecast accurately: Share demand forecasts with your EMS and suppliers to enable better inventory planning.
4. Inadequate Testing and Quality Control
Many startups underestimate the importance of comprehensive testing, relying only on visual inspections or simple power-on tests.
Why It’s a Problem
Field failures: Without proper functional testing, defects remain hidden until the product reaches customers.
Expensive recalls: Fixing faulty products post-sale damages brand reputation and incurs high costs.
Compliance risk: Regulatory certifications often require documented testing and traceability.
How to Avoid It
Develop robust test plans: Include in-circuit testing (ICT), boundary scan, functional testing, and environmental stress screening.
Design for testability: Incorporate test points, accessible connectors, and diagnostics in PCB layout.
Use automated inspection: High-end AOI (Automated Optical Inspection) and X-ray help detect defects before they leave the line.
Enforce quality documentation: Maintain test logs, failure analysis reports, and traceability for every unit.
5. Ignoring Traceability and Documentation
Startups don’t prioritize serial numbers, lot tracking, or process documentation, treating manufacturing as a “black box.”
Why It’s a Problem
Troubleshooting becomes impossible: If a batch fails, you can’t isolate the root cause without trace data.
Compliance challenges: Industries like automotive, medical, or aerospace require stringent traceability.
Scaling headaches: As volumes increase, a lack of documentation leads to inconsistent quality and supply chain confusion.
How to Avoid It
Implement serial number tracking: Track each PCB from assembly to final integration.
Request process documentation: Get detailed build records, material certifications, and inspection results.
Use real-time SPC: Statistical Process Control dashboards help monitor yield trends and catch anomalies early.
Building Manufacturing Confidence Early
Manufacturing is not an afterthought—it’s a critical part of your product’s success story. PCB assembly mistakes not only cost time and money but can stall your entire go-to-market strategy.
Partnering with an experienced, flexible EMS provider like Karkhana.io can help you sidestep these pitfalls. From early design reviews, procurement planning, pilot runs, to rigorous testing and full traceability, we specialize in supporting startups as they scale from prototypes to thousands of units.