Incomplete customer documentation can force delays in the production of PCBAs because the manufacturer must go back and precisely confirm requirements. Delays like this can cost customers time and money, and outright errors can result in poor board builds. Here are some ideas on how to best create and manage your PCB manufacturing documentation to guard against this and test your project through production as quickly and smoothly as possible.
| Types of PCB Manufacturing Documentation | |
|---|---|
| Fabrication artwork | A view of the fabrication layers, including callouts and directions for the manufacturer. |
| Assembly artwork | A view of the complete PCBA, including callouts and directions for the manufacturer. |
| Drill chart | Indicates the location, size, and plating status of all drilled holes of the board. |
| XY-data | Includes the location (from some user-defined origin) and rotation of all the design components. |
| Gerber files | The layer-by-layer copper information that’s necessary for fabrication. |
Don’t Let Documentation Be an Afterthought
Creating PCB manufacturing documentation is often treated as an afterthought instead of getting the attention it deserves. PCB designers speed through creating documentation to move on to the next project. Placing components and routing nets is much more interesting than specifying dimensions and verifying the bill of materials (BOM). Fortunately, PCB design tools can quickly create accurate manufacturing data files. Preparing all the data necessary before making the documentation is still essential. Consider the following to ensure accuracy and streamline the documentation process:
- Templates – Drawing and reporting templates in design software can save time when creating documentation by eliminating the need to reinvent the wheel for each design job.
- Copying data – Mistakes can occur in PCBA documentation when creating new documentation from old copies, such as users forgetting to edit or delete incorrect data.
- Design review – Ensure a system for all key personnel to review and sign off on the design. Some documentation corrections occur because someone’s input of missing departmental oversight during manufacturing.
- Revision check – Documentation created before finalizing the design or without checks for changes may have nonconcurrent data.
To sum it up, take the time to do the best job possible when creating documentation. It’s all too easy for the wrong layer stackup to get used on a drawing or for a component to be updated inaccurately on a BOM simply because someone rushed through their work or was unprepared for the task in the first place.
PCB Manufacturing Documentation Best Practices
Once your design is complete and ready to be manufactured, it’s time to create or update your documentation for production. Here are some recommendations that can help you ensure that your CM has the information they need to manufacture your product accurately and on time:
- Update part numbers – When updating components, such as converting old leaded parts to lead-free RoHS-compliant parts, always assign new numbers to parts to avoid confusion with revision history.
- Procurement approvals– Components on the approved parts list will change after adding or removing new equivalents for incompatibility reasons. However, suppose component obsolescence or manufacturer buyout leads to a replacement. In that case, it can create confusion about the status of functional parts that have been allowed and previously used. Collaborating with a CM when making changes to your approved parts list is essential to avoid this pratfall.
- Separate BOM and drawings – BOM lists on drawings are often poorly maintained and not updated with new drawings, and they lack the filtering/search capabilities of a functional database. Instead of bundling the two, include a separately controlled and independent BOM document with any artwork.
- Manage final documentation– Collect all feedback from PCB fabrication and initial prototype validation processes and include these with the final documentation package. If fabrication changes were necessary for the Gerber files, update the design database. This way, all the updates are in the database, so users won’t need to resurrect a previously solved problem in any future builds or redesigns.
Following steps like these can help avoid confusion and delays caused by erroneous part numbers during manufacturing. It can also help prevent potential database integrity problems hindering future redesigns.
How Your CM Can Help with PCB Manufacturing Documentation
In addition to following these recommended best practices when creating your documentation, a CM can also ease the documentation process. The right CM will work with designers on any changes or corrections to your PCB manufacturing documentation. These alterations could mean making requested changes by redlining your existing documents or creating new documentation for your approval and implementation with the rest of your design database. A CM with engineering expertise can also suggest part alternatives that include exact details about the component’s level of interchangeability. Considering these tips and best practices and working with a CM who will partner with you to maintain accurate PCB manufacturing documentation will help ensure your board is produced correctly and on time.
