[Did You Know?] Why We DON'T Cut Your Stencil Exactly 1:1 ✂️

Hey JLCHUB community! 👋

Ever received a stencil and noticed the cutouts look slightly different from the exact paste mask layer you exported from your EDA software? Don't panic—it's actually a feature, not a bug! 😉

By default, our CAM engineers apply industry-standard aperture modifications to your files before laser cutting.

For components like ICs, BGAs, and passives (0805 footprint and above), a strict 1:1 paste-to-pad ratio usually deposits way too much solder. This leads to frustrating assembly defects like solder bridging on fine-pitch chips and tombstoning on your resistors during reflow.

To protect your PCBA yield, our default standard automatically tweaks the aperture geometry (applying slight reductions, "home-plate" shapes, or U-cuts) to ensure the perfect paste volume. We do the complicated math so you don't have to!

Already designed your own custom paste mask? No problem! 🛠️
If you are an advanced user who has already calculated and shrunk your own paste layer in Altium or KiCad, you are still in full control. Simply leave a remark during checkout stating you want the apertures cut exactly as your paste layer. We will bypass our default processing and follow your files 1:1.

Curious about the exact DFM math and shapes we use behind the scenes? Check out our full Aperture Processing Standard here:
👉 JLCPCB Opening Process Standard of Stencil