JLCPCB Blog

Design Tools & Best Practices

How to Design Your Own Keyboard PCB: From Layout to Firmware

Designing a custom keyboard PCB is one of the most rewarding entry points into practical electronics. You not only get a really useful product on your desk, but also you learn schematic capture, matrix scanning, footprint selection, USB, and firmware. Most of the hardware engineers use the same skills that show up on professional boards. This guide walks the entire build from choosing switches, wiring the diode matrix, adding the microcontroller and USB-C, laying out the board, and flashing QMK or VIA......

Aug 03, 2026

Stencil Technology

Stencil Aperture Design: Geometry, Area Ratio & Tips

Key Takeaways Stencil aperture design controls paste volume, deposit shape, and print registration — it's the key controllable variable in SMT print quality. IPC-7525B rules are non-negotiable: stencil area ratio ≥ 0.66 and stencil aspect ratio ≥ 1.5. Aperture geometry is component-dependent: 1:1 with pad for BGA, window-pane splits for QFN/BGA thermal pads, home-plate shapes for 0201/01005 chips, and modest reductions for fine-pitch QFP. Aperture reductions intentionally decrease the opening relative......

Aug 03, 2026

Stencil Technology

Solder Paste Stencil Defects: Causes and Fixes for Higher SMT Yield

Usually, the circuit board stencil is responsible for roughly 60% to 70% of all SMT defects. That number surprises people. It shouldn't. The stencil controls paste volume, deposit geometry, and positional accuracy all at once. When it gets wrong, everything downstream pays for it. The shift in thinking that separates good engineers from great ones is simple: stop seeing the PCB stencil as a metal sheet with holes in it. It is a precision fluid delivery system. Every aperture wall, every micron of foil......

Aug 03, 2026

Stencil Design

Pin-in-Paste: Through-Hole Reflow With a Stencil

Key Takeaways One Reflow Process: Pin-in-paste combines SMT and through-hole soldering into a single reflow pass, eliminating the need for separate wave, selective, or hand-soldering steps when the board has only a few through-hole components. Paste Volume Is Critical: Solder paste is roughly 50% flux by volume, so you need to print about twice the solder volume the finished joint requires. Stencil design—overprint apertures and step-up zones—makes or breaks the process. Target 75% Barrel Fill: Per IP......

Aug 03, 2026

Stencil Design

Solder Paste Layer: How to Create and Optimize It

While designing a PCB, you've probably noticed two layers in your EDA tool that look almost identical: the solder paste layer and the solder mask. Both sit alongside the copper layers and use pad-shaped outlines, making it easy to assume they serve the same purpose. They don't, and knowing the difference matters for how your board gets assembled. This guide breaks down the solder paste layer (a.k.a. cream layer) — what it is, how it differs from the solder mask, how to generate it, and how to optimize......

Aug 03, 2026

Stencil Technology

SMD Glue & Red Glue: A PCB Assembly Application Guide 2026

The reality of modern PCB assembly is that "mixed-technology" is still very much the norm. When a board hits the wave soldering machine, bottom-side SMD components face a high-velocity river of molten metal. Without a solid mechanical bond, they’ll simply wash away into the solder pot. That’s where the precision application of SMD glue becomes the difference between a successful run and a bin full of scrap. Quick Answer: How to Apply SMD Glue in SMT If you need to configure your SMT stencil for adhesi......

Jul 31, 2026