Prototype to production: planning your first PCB assembly run in India

By the Shara Circuits engineering team

Your prototype works. Investors, customers or your own team now want fifty units — or five hundred. This is the moment where hardware projects either scale smoothly or stall for a quarter. Here's what actually changes when you move past hand-built quantities, and how to plan for it.

1. Freeze the design — properly

Production means committing to a specific revision. Before the run: fix every "we'll patch that with a bodge wire" item from the prototype, re-run DRC, regenerate Gerbers and BOM from the final schematic, and give the revision a number that appears on the silkscreen. Chasing which of three "final" versions went to the fab is a rite of passage nobody enjoys.

2. The BOM becomes the schedule

At prototype stage, you buy whatever's in stock. At production scale, component availability drives your entire timeline:

• Check stock depth, not just availability. A part showing 200 units in stock is fine for prototypes and a trap for a 500-board run.
• Identify single-source parts now. Any component with exactly one manufacturer and no approved alternative is a schedule risk. Qualify a second source before you need it.
• Watch for EOL and NRND flags. A part marked "not recommended for new designs" will eventually force a redesign — better to swap at 50 units than at 5,000.

3. Panelisation changes your board

Assembly lines work with panels, not individual boards. Your single design gets arrayed into a panel with rails, fiducials and breakaway tabs or V-grooves. This can affect connector overhang and edge clearances, so it's worth discussing panel layout with your assembler before the fabrication order — not after boards arrive.

4. Stencils, fiducials and the things prototypes skip

Hand-soldered prototypes don't need a solder-paste stencil or fiducial marks. Machine assembly needs both. A laser-cut stainless stencil is a small one-time cost; fiducials are free if you add them before fabrication and impossible to add after.

5. Decide your test strategy per board

At 5 units you test everything by hand. At 500, define what "tested" means: powered-on checks, functional test of key interfaces, or a proper test jig. The right answer depends on your product's cost of failure — but decide it before the run, because test points, like fiducials, must be designed in.

6. Realistic lead times (India, 2026)

• Fabrication: 5–10 working days for standard multilayer production quantities; faster for prototypes.
• Component sourcing: same-week for stocked parts; 4–20+ weeks for allocation-prone parts — this, not fabrication, is usually the critical path.
• Assembly: 3–7 working days once boards and parts are in hand.

Total: a comfortable production cycle is 4–6 weeks from frozen design to tested boards — dominated almost entirely by how early you locked the BOM.