Digital Transformation: Seamless Hand-off from Design to Manufacturing


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Pat_McGoff_300.jpgWithout a seam. That’s what seamless means. There is no evidence of the transition from one material to another, or in the case of processes, from one process to another. The transition happens smoothly, effortlessly.

That is the goal of everyone in the PCB ecosystem—designers, fabricators, and contract manufacturers alike. Every designer wishes they could send a data package out to their suppliers and never have to worry about whether it will be built correctly or be bothered with answering technical queries. Likewise, bare board fabricators and contract manufacturers wish all their customers would send them complete, clean, unambiguous, non-contradicting data so they can get on with their value-added work without asking for missing information or seeking clarification.

Technical queries are seams. They are evidence the transition from design to manufacturing is less than perfect. There are two reasons for technical queries:

  • Instructions are incomplete, ambiguous, or conflicting
  • Aspects of the design make it difficult or costly to build

Communication Breakdown
Contributing to the first cause for technical queries, most OEMs still send an “unintelligent” manufacturing package to their suppliers. It may be surprising that Gerber 274X is still used by roughly 70% of the industry, according to a survey published by Design007 Magazine in October.

Yet, Gerber 274 files do not contain all the information necessary to even fabricate a PCB, much less assemble one. That is why there is simply no such thing as sending only Gerber 274 files. In order to provide a fabricator and contract manufacturer everything they need to build a custom PCB, the OEM needs to include the following additional material in their manufacturing package:

  • Gerber files
  • Drill files
  • Netlist files
  • Test files
  • Centroid data
  • BOM
  • Drill drawings
  • Assembly panel drawings
  • Rout drawings
  • Stackup drawing
  • Drawing notes

That makes 11 different types of files, drawings, and instructions, most of which are created by different systems. What are the chances that each of those 11 pieces of the puzzle are based on the correct revision, and that, combined, they provide all the necessary instructions without any conflicting details? Pretty slim. This leads to the manufacturing supplier putting the job on hold while they work through the technical queries with you, the designer. And given that you likely have multiple PCB fabrication suppliers and multiple contract manufacturing partners, you can count on repeating this inefficiency with each supplier as you ramp up to your definition of volume production.

Even if the manufacturing package is complete and without conflicting instructions, designers still impose significant inefficiencies on their manufacturing partners when they compel them to wade through all the packages manually to find the details required to manufacture a PCB, such as identifying which features are actually test points and determining the finished hole size vs. drill size. And the contract manufacturers doing the PCB assembly need to know pin-1 and polarity indicators as well as the process direction going through the SMT line—because the process direction affects shadowing of adjacent components for wave solder and AOI.

Have you stopped to wonder how much time your manufacturing partners spend performing these non-value-added tasks? More importantly, have you ever thought about how much faster you could get your PCBs if your suppliers didn’t have to have CAM engineers spend so much time manually processing files?

Digitally transforming the sharing of data and files between all the players in the PCB design and manufacturing flow eliminates these inefficiencies and manual busywork, delivering significant cost and quality benefits. The promise of digital transformation is a seamless process where the digital twin model of the design passes from step to step without any rework or ambiguity, ensuring design intent is maintained and the new product introduction process is accelerated.

Siemens_Jan_Fig1_cap.jpg

ODB++Design 
From a manufacturing supplier’s perspective, this encompasses the manufacturing data formats they need to support. Today there are intelligent data formats such as ODB++ that hold all the necessary manufacturing instructions in a single, unified, validated container. There are over 80 software tool companies that support the ODB++ format, from CAD vendors to test software. You can see the full list here. It is important to have all the tool suppliers within the ecosystem support a single format to achieve a truly seamless hand-off.

Building in Extra Costs
The second cause for technical queries involves aspects of the design that make it difficult or costly to manufacture. This is where design for manufacturing (DFM) comes in. For more than 25 years, PCB manufacturers have been using DFM software to identify issues that will likely cause challenges in their manufacturing process. They flag these issues in a DFM report and send them back to the OEM before beginning production. This results in delaying the finished product.

Fabricators and contract manufacturers can build just about anything you send them. The question is, “At what cost?” For every additional process step needed there is a cost. If the projected yield is going to be lower than normal, they will build in overage to assure a sufficient quantity will be shipped in time. That overage is extra cost to the OEM.

However, it is now common practice for the OEMs to run DFM software themselves to identify potential issues before they even release the design to their supply partners. After all, wouldn’t you, as a designer, want to know about potential quality and cost issues as early as possible so that you can make the decision about how to resolve it?

Siemens_Jan_Fig2_cap.jpgBy running DFM concurrently with the design process, you can release your designs knowing they can be easily manufactured by your suppliers, at the lowest possible cost. With concurrent DFM, your designs are optimized for manufacturing during the initial release.

Closing the Seams
Whenever I am asked how to go about changing the status quo in our industry, I recommend that the OEMs approach their fabrication and assembly suppliers with one question, “What can we do together to make your job easier?” Quite often the answer is:

  1. Use an intelligent data exchange format.
  2. Perform DFM during the design process.

Anything less and your seams are showing.

This column originally appeared in the January issue of Design007 Magazine.

Check out this additional content from Siemens Digital Industries Software:  

 

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