To turn prototype into manufacturing, PCB designers have two options. The first one is to design in a vacuum, and then find a manufacuring chain that can build the design. The other choice is to learn about the
manufacturing chain and optimize the design to the fabricator’s strengths with no sacrifice to desired functionality.
Here are 4 strategies that help you reduct the unneccessary cost of time and money in design cycle and plan ahead for success.
1. Verify your layout’s manufacturability with a supplier DFM tool.
A trustworthy PCB fabricator will run your design through a design-for-manufacturability tool to check for errors above and beyond any visual inspection of the design details. A top-tier fabricator will make that
report available to you when submitting your design for quotation. Using the contents of that report, which verifies if your design will fit inside the manufacturing process, is a valuable step to getting a properly
fabricated board, and is the first measure toward developing a board optimized for production.
2. Research and select suppliers earlier in the design cycle.
The design team knows that at prototype design completion, the next logical step in the design process is to get back a working example of the prototype design for testing. Though this represents one logical
step to the design team, this process consists of multiple steps—components must be procured; the PCB has to be fabricated; and the parts need to be correctly attached to the PCB. How this manufacturing flow
ultimately occurs is up to the design team to select and manage.
According to our experience in cooperating with PCB design teams, we find a correlation. Professional teams turning lots of simpler designs with wide tolerances in the process window tend toward using a one-
stop supplier for the overall convenience. Professional teams whose designs require careful tuning and attention to manufacturing details tend toward managing each relationship throughout the build process,
handpicking each supplier for their strengths, abilities, and turn times. For the teams with limited budgets, price is a much more important factor than turn times when choosing PCB manufacturer. For other teams
under the urge of deadlines, fast delivery is the top priority. Of course, in all cases, the PCB must be manufactured to the design.
Requirements varies for different projects. But that doesn’t mean it is necessary to find a different supplier for each project. It is definitely a smart choice to talk with the your PCB manufacturing supplier’s customer
service, tech support, or sales teams. From these conversations, you can find how well they can respond with quality, turn times, pricing, and delivery across the whole range of your anticipated project styles. It will
help you a lot in making good decisions.
PCB fabrication, parts procurement, and assembly should be the three key themes in the conversation :
Fabricating the PCB that serves as the connection medium for all the components and connectors that make up your circuit design. While this may seem like just another “part” on the design team’s bill of materials
(BOM), this is a critical, custom-manufactured part. It requires adherence to your design parameters and can represent the most variable cost in the BOM.
These are the chips, connectors, and other parts that operate to make your circuit perform as intended. The components come from a parts distributor or retailer. The more one-stop services your manufacturing
chain supplies, the more likely they will offer the parts procurement services for you… at a price, of course.
Many design teams prefer to take a very hands-on approach with parts for their prototypes. This is neither the time nor place for parts substitutions to save cost; that step comes later. Direct involvement by the
design team requires careful attention to detail and time, but the team also eliminates a number of potential bugs in the prototype with this approach, saving time and cost in the long run.
The process of attaching components to the printed-circuit board. Depending on the design team, you may or may not have the expertise or equipment to perform this function yourself. As parts and designs get
smaller and denser, the need for an outside service becomes more indispensable.
In the process of communicating with your manufacturing chain, you should evaluate your contacts for their ability to consult on your design concerns. he more suggestions a manufacturing supplier can give you,
or help make your design optimization more efficient, the more value they provide to the design process, and that means free consultation to you.
You should know that costs don’t simply refer to the number of components used in a design. They also tie into PCB real estate and design complexity, flying probe test times, and opportunities for design-related
3. Develop your layout to the fabricator’s “sweet spot.”
Regardless of whom you choose, your fabricator has a sweet spot—that place where designs are well inside the middle of the manufacturing process window. From this spot, minor variations in manufacturing still
keep your design well inside manufacturing capabilities, and thus increase your yields and reliability.
4. Manage prototyping costs and hidden costs.
Prototyping creates more robust designs from the first revision with proper preparation. While it may seem like a lot of useless preparation work, consider the hidden costs of a five-person design team, spending
five person-days to complete the preparations mentioned here. Such a preparatory process might save you at least one prototype spin of—you guessed it—five calendar days. Except five calendar days for a
design team of five is a total of 25 person-days.
When the PCB design is simple, or far away from the current technological edge, these strategies have less impact on your design cycles. One school of thought is that, as you move to surface mounts to QFN/QFP
packages, or as you move to tight tolerances in circuit timing, then these strategies become more and more important. Of course, the other school of thought is that, as you start out, even though the designs may
be simpler, it’s the designer’s skimpy knowledgebase that needs more support.