A simpler, smarter way to get stackups right the first time.

For years, we talked about “handing off” design data to manufacturing partners. Many still do. The handoff model is simple: design sends “build intent” in one direction, usually through a mix of emails, spreadsheets, PowerPoints and Word documents.

Almost every handoff – 99.99% – contains conflicting or incomplete data. This forces the fabricator to come back with questions, clarifications and technical queries. There’s no true back-and-forth, no structured loop and no clean way to exchange data that is consumable by the electronic design or CAM tools.

This month, we will focus on a key piece of the puzzle: electronic stackup data exchange. Next month, we’ll dive into electronic DfM and technical queries (TQs).

PCB stackups were previously driven mainly by routing density, thermal concerns and mechanical needs. Life was simple.

But today? High-speed content is everywhere.

• USB went from 1.0 to USB4, hitting 40Gbps
• PCIe 6.0 jumps from 32 to 64Gbps using PAM4
• Thunderbolt 5 pushes 80-120Gbps.

With speeds like these, stackup design has become a science of balancing signal and power integrity, impedance control, return paths, loss budgets, thermal performance, manufacturability and cost.

Picking the right materials – especially low-loss materials – can make or break signal performance. But those choices directly affect cost.

So naturally, designers work more closely with their fabrication partners early in the design cycle. That’s good. What’s not good is how this exchange happens today.

A Painful Workflow

Here’s the typical designer-fabricator loop:

1. Designer sends SI/PI requirements in a spreadsheet or slide deck.
2. Fabricator builds a proposed stackup in its spreadsheet or slide deck.
3. PCB designer manually enters that stackup into their PCB tool.
4. Fingers crossed nothing gets entered incorrectly.

Figure 1. Legacy stackup coordination still relies on spreadsheets, emails, and manual reentry between designers and fabricators; creating delays, errors and late-stage surprises.

This manual process is slow, error-prone and risky. Mistakes often surface late in the design cycle, leading to delays in NPI, expensive prototype spins, performance issues that force compromises and rework that can easily hit six-figure costs.

And all of this happens in an era where AI is reshaping workflows everywhere. Yet we’re still copying numbers from Excel into CAD tools? Hard to believe.

Direct Bidirectional Exchange

IPC-2581 already supports stackup-only bidirectional exchange. It’s simple. It’s accurate. It’s free. And it eliminates all the manual steps we just described.

Here’s what it enables:

• PCB designers export their proposed stackup (only) in IPC-2581 format.
• Fabricators import it directly into their CAM tools.
• They adjust materials, thicknesses, etc., based on what they can actually build.
• They export the updated stackup back to the designer in IPC-2581 format.
• Designer imports it directly into their PCB tool – no hand entry, no typos, no slowdowns.

This is true bidirectional design data exchange, not a one-way handoff.

And again: You do not need to send the full design in IPC-2581 format to use the stackup-only exchange. This is a standalone capability, supported by most PCB design tools today.

How Stackup Sharing Works

To begin the PCB design process, build the initial stackup within your PCB design tool. This involves specifying layer counts, dielectric requirements, thicknesses and material properties needed for the design. Once these parameters are established, export the stackup data in IPC-2581 format.

Next, share this file along with the SI/PI goals with your fabricator. They will import the data and make any necessary adjustments to ensure manufacturability within their own CAM environment. After they have validated the stackup, they will export an updated version again in IPC-2581 format.

Finally, import this updated stackup back into the design tool, allowing zero retyping.

That’s it. Simple. Everything that is needed to define your stackup accurately is included in the IPC-2581 stackup only exchange.

Figure 2. Bidirectional IPC-2581 exchange lets designers and fabricators share stackup data digitally.

Advantages of IPC-2581 Integration

Choosing IPC-2581 for stackup exchange is an obvious decision for several reasons. First, its accuracy significantly reduces the likelihood of errors that often arise from using spreadsheets or PowerPoint presentations. IPC-2581 offers speed by eliminating the time-consuming process of retyping stackup data. Moreover, the standard promotes consistency by providing a digital record that captures what both parties have agreed upon.

Another key advantage is that IPC-2581 integration is already supported by every major PCB design tool, making it accessible without incurring additional costs. Finally, the standard fosters collaboration within the industry by transitioning the approach from mere “handoff” to a more interactive “exchange.”

This capability was one of the first steps that transformed IPC-2581 from a simple output format into a full design data exchange standard. A single, open, neutral file becomes the foundation for clean collaboration – before design starts, during design and at manufacturing handoff.

When designers and fabricators share stackup data digitally and accurately, everyone wins: better performance, fewer surprises, faster NPIs and fewer painful late-cycle discoveries. Ask your fabrication partner to exchange stackup-only data using IPC-2581 today.

Hemant Shah is chairman of the IPC-2581 Consortium (ipc2581.com). Shah led the effort to create an industry-wide consortium of design and supply chain companies to get IPC-2581 – the standard for transferring PCB design data to manufacturing – adopted.

He spent 20 years at Cadence as product manager for various PCB design products. Shah also led the industry adoption of the IBIS-AMI algorithmic modeling standard. Prior to joining Cadence, Shah worked at Xynetix and Intergraph. He is passionate about developing and marketing leading-edge software products for PCB design.