How to Reduce PCB Manufacturing Costs Through Panel Optimization

Overview

Nothing impacts PCB manufacturing costs more than how many parts fit on the panel. While manufacturers excel at optimizing layouts, they can only work with the design they're given. This guide teaches you how to optimize panel utilization during the PCB design process-not after-to achieve a panel layout that can offer considerable cost savings.

We'll cover individual part and array panel layouts, plus techniques to identify hidden optimizations in your part dimensions. Whether you're a beginning PCB designer or an experienced engineer looking to maximize parts per panel, this guide will help you reduce manufacturing costs.

Panel layout basics

Throughout this guide, we use standard terminology: panel (the manufacturing substrate), array (multiple PCBs arranged together), and part (the individual PCB). All dimensions are in inches.

PCBs are manufactured on panels that contain either individual PCBs or arrays. Smaller PCBs are typically manufactured in arrays, while larger PCBs are placed individually on panels. Manufacturing panels have border areas reserved for tooling that reduce the available space for PCBs.

The individual part layout

The individual part layout is the simplest. Even for array designs, understanding this layout is essential since the array becomes the "part" on the panel.

Let's use a 5.1 x 8 part with .1 spacing and .75 borders on three common panel sizes: 16 x 18, 18 x 24, and 21 x 24. As expected, the largest panel (21 x 24) yields the most parts, 9 per panel versus 5 and 8 for the smaller panels. However, other factors can change which panel is optimal.

Notice that some parts on the 16 x 18 and 21 x 24 panels are rotated. Rotation added one more part per panel on both sizes. Allowing rotations typically increases panel utilization.

However, rotations have a tradeoff. PCB laminate has a grain direction that affects how material expands during manufacturing. Rotated parts will have varying grain orientation, which can introduce dimensional variation that impacts assembly or electrical properties like impedance.

Without rotations, the 21 x 24 panel produces the same quantity as the 18 x 24 (8 parts), but the 18 x 24 has higher utilization (75.6% vs 64.8%), meaning less waste and lower cost. In this case, the 18 x 24 panel without rotations is optimal.

The Array layout

With an Array multiple PCB's are placed on a sub panel for assembly. Arrays require spacing between the parts and border areas for assembly tooling. The area of the array that's not occupied by PCB's is waste material and is discarded after assembly, so the ultimate measure of efficiency is still parts per panel, not arrays per panel. The examples below show a 1 x 3 array (3 PCB's) and a 2 x 6 array (12 PCB's).

Array designs are often chosen arbitrarily without considering panel fit and cost implications. Ideally, evaluate array options early in your design process to select the configuration that maximizes parts per panel.

Focus on getting the most parts per panel, not arrays per panel

When designing arrays, focus on maximizing parts per panel, not arrays per panel. Counter-intuitively, an array with fewer parts can sometimes yield more total parts per panel.

Consider a 1 x 2 part with .062 part spacing on the array, .562 array borders, .1 array spacing on the panel, and .75 panel borders. For arrays containing 4-10 parts, there are 21 possible array matrix configurations (2x2, 4x2, 2x5, 4x1, 1x10, etc.). Evaluating how each configuration fits on the available panel sizes (16 x 18, 18 x 24, 21 x 24) especially with rotations becomes complex quickly.

When we analyze the options it reveals that different panel sizes favor different arrays: a 10-part (5 x 2) array is optimal for 16 x 18 and 21 x 24 panels, but a 9-part (3 x 3) array is best for 18 x 24. On the 18 x 24 panel, choosing the "wrong" 10-part array yields 90 parts versus 99 parts with the optimal 9 part array. A loss of 9 parts per panel compounds over production runs.

Know how the part size affects the part per panel yield

This critical insight is often overlooked: small reductions in PCB size can significantly increase parts per panel. The analysis below shows that reducing the PCB size of our previous example from 1 x 2 to .934 x 2 increases yield on the 18 x 24 panel from 99 to 108 parts, a 9.1% cost savings.

While trimming .066 from the part width may not always be feasible, knowing these thresholds early in your design process is invaluable. When you understand the cost impact, you can explore optimizations to achieve those savings.

Panel	Original Qty	Better Qty	Part Size	Change X	Change Y	Cost Savings
16 x 18	60	63	1 x 1.984	0	-0.016	4.76%
18 x 24	99	100	1 x 1.889	0	-0.111	1%
18 x 24	99	108	0.934 x 2	-0.066	0	8.33%
16 x 18	60	63	0.929 x 2	-0.071	0	4.76%
18 x 24	99	100	0.95 x 1.951	-0.05	-0.049	1%
21 x 24	120	126	0.912 x 2	-0.088	0	4.76%
21 x 24	120	130	1 x 1.807	0	-0.193	7.69%
21 x 24	120	126	0.934 x 1.934	-0.066	-0.066	4.76%

Summary

Evaluate PCB panelization at the start of your design process—once the design is complete, optimization opportunities disappear.

Arbitrary array designs or leaving panelization to your supplier typically results in higher manufacturing costs. By integrating panelization analysis into your design workflow, you'll consistently achieve optimal panel layouts and lower PCB prices.

KwickFit simplifies this analysis and delivers ROI on every production run. It will pay for itself many times over.