How to Reduce PCB Manufacturing Costs Through Panel Optimization

Overview

Nothing impacts PCB manufacturing costs more than how many boards 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 board and array panel layouts, plus techniques to find small changes to your board dimensions that fit more boards per panel.

How to fit more boards per panel

Your fabricator builds your board on a standard production panel, commonly 18 x 24 inches. How many of your boards fit on that panel feels fixed, but it is not. It is the result of a handful of choices you still control, and any panel space your boards do not fill is area you still pay to process on every panel you build.

Five things decide how many boards fit on a panel, and you can influence all of them.

Rotation. Allowing a board to rotate 90 degrees often raises boards per panel. There is a tradeoff: PCB laminate has a grain direction, and rotated boards have a different grain orientation, which can introduce dimensional variation and potentially affect impedance on controlled impedance boards. So rotations may not be practical for all designs. Your fabricator can advise you based on their process capability.

Spacing and borders. The spacing between boards and the border areas your fabricator reserves for tooling reduce the space left for boards. Setting them to your fab's real minimums, rather than a guess, leaves the most room for boards. Ask your fabricator for their required spacing and border values and the panel sizes they run, and use those numbers rather than generic defaults; they differ between fabricators, and the best layout changes with them. If you are not sure what to request, our panelization guidelines article lists typical published values and the exact list to ask for.

The array. Smaller boards are usually grouped into an array, a sub-panel of boards with its own borders, and the array repeats across the production panel. More boards per array does not mean more boards per panel: an array with fewer boards can fill the panel with less waste and yield more boards per panel.

The panel size. The standard 18 x 24 inch panel is not always the best one for your board. Your supplier may run several panel sizes, and a different one can fit more boards with less waste. The best array changes with each panel size too.

The board size itself. Early in design you still have room to adjust the outline. Making a board a fraction smaller eventually crosses a threshold where more boards fit, which lowers your cost per board on every panel for the life of the product.

Start from the panel, not the board

The common mistake is to settle on a board size without checking how it fits the panel. The number that decides your cost is how many boards fit on the fabricator's panel after the border areas reserved for tooling are removed. Start from that available space, try the board with and without rotation, and count boards per panel against the price of that panel. That gives you a cost per board you can compare between layouts and panel sizes. The free PCB panelization calculator does that count for you: enter your board and panel dimensions and see boards per panel and panel utilization, with no account or signup.

Panel layout basics

Throughout this guide, we use standard terminology: panel (the manufacturing substrate), array (multiple PCBs arranged together), and board (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 board layout

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

Let's use a 5.1 x 8 board 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 boards, 9 per panel versus 5 and 8 for the smaller panels. However, whether rotation is allowed can change which panel is optimal.

Notice that some boards on the 16 x 18 and 21 x 24 panels are rotated. Rotation added one more board 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 boards 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 boards), 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 PCBs are placed on a sub-panel for assembly. Arrays require spacing between boards, plus border areas around the array for assembly tooling. The area of the array not occupied by PCBs is waste material and is discarded after assembly, so the ultimate measure of efficiency is still boards per panel, not arrays per panel. The examples below show a 1 x 3 array (3 PCBs) and a 2 x 6 array (12 PCBs).

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 boards per panel.

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

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

Consider a 1 x 2 board with .062 board spacing on the array, .562 array borders, .1 array spacing on the panel, and .75 panel borders. For arrays containing 4-10 boards, 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.

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

Know how board size affects boards per panel

This critical insight is often overlooked: small reductions in PCB size can significantly increase boards 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 boards, an 8.33% cost savings.

While trimming .066 from the board width may not always be feasible, knowing these thresholds early in your design process is invaluable. When you understand the cost impact, you can decide whether the size change is worth making.

Panel	Original Qty	Better Qty	Board 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, the chance to adjust the board size is gone.

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 runs this analysis in seconds. At just $27/month, it breaks even when you save just $324/year.

Related: The PCB Cost Cliff shows what these layout decisions are worth in real dollars, which PCB panel tool you actually need, and where panel optimization fits in the design flow.