Engineering Prototyping Workflow Management For PCB Design
Let’s face it: work can be pretty stressful. For a long time I let the stress build-up into a frustration and lethargy after my day was over. Then I started cooking more vigorously when I got home and found a much healthier way of relieving stress. After a minimal time spent learning flavor combinations, mixing spices and dicing vegetables has proven to be a fun exercise in creativity. No matter how I mess up the recipe, the food is usually still edible.
I like to chop and prepare my vegetables in the time it takes to cook them — seasoning along the way. The better I get, the more neat my cubing is and the more tidy my meals end up looking. You’ll need to have a systematic plan in cooking, too: ingredients need to be prepped, the heat needs to be right, and you’ll need to cook in the exact order. Fortunately, I learned a lot about preparatory work while working toward engineering prototyping workflow management.
What Is Engineering Prototyping Workflow Management?
Designing a PCB prototype is more than connecting various electronic components. In any industry (automotive, aerospace, consumer electronics and beyond), time and cost are major factors in PCB design. Having proper prototyping workflow management in place is crucial to ensure your PCB gets off the ground and into production with adequate integrity.
Engineering prototyping workflow management enables you to follow a systematic process before laying out the first component. You’ll be able to minimize time wastage by identifying potential problems early on using a structured approach.
Walking into your prototyping round with a set of clear expectations around audience, device behavior and potential, clear distinctions between rounds of testing, and a strong organizational system in place for collaboration will make any process seamless.
Potential Issues When You Neglect Engineering Prototyping Workflow Management
It’s understandable that PCB designers are excited by toying around with the latest components available or trying to prove the virtue of their idea in a design. But if PCB prototyping is approached with only technicalities, there are bound to be problems that demand costly revision.
The fastest processor isn’t necessarily the best choice.
For instance, you may have overlooked cost and availability as you’re excited on the speed that the latest ARM Cortex processor. Or you didn’t realize that you’ve neglected to ask important questions on the application requirements of the final product.
These are not hypothetical assumptions, but real life mistakes that I’ve seen committed by fellow designers. The outcome is often ugly, with hours of redesigning, scrapped prototypes and unhappy managers breathing down their necks.
In both cases, I found workarounds by trusting my colleagues and peers to be able to catch the mistakes that I wasn’t catching. In a new design environment, tasked to make the circuit work, it can be easy to overlook potential PCB vulnerabilities or secondary demands from the product (looking at you, form factor).
How to Get Engineering Prototyping Workflow Management Right
As much as I’m tempted to turn on my PCB design software the moment I receive a new project, I like to take a moment to gather myself. I launch a checklist that allows me to manage the entire engineering prototyping workflow and start right from the top.
1. Establishing Design Specification
It all started with a meeting where the client or your manager will provide you a list of functional requirements for the new PCB design. In some cases, you’ll have to seek further clarification as the details may be vague.
Fundamental specifications like the power requirements, memory capacity, processing speed, peripherals, connectivities, and mechanical aspects of the design must be established before you proceed further. This can mean having a few more discussions or email to get the matter clarified.
2. Components Selection
You may be drawn to the most powerful MCU or the speediest transceiver chip. But you’ll want to consider other aspects when making components selection. Factors like availability and cost may affect the feasibility of the product.
At times, you’ll want to be pragmatic and settle with components that are good enough to do the job rather than going for high-end parts all the way. Furthermore, it is important to recognize the capacity for cost reduction in testing versus trusting verified modeling for actual device output and production.
3. Schematic Design
Once you’ve decided on the major components and have a clear idea on the technical specifications, you’ll want to start on the schematic design. I suggest separating your schematic into sub-circuits especially when you’re working on a complicated design.
Using sub-circuits increases manageability, both for you and other designers who will be collaborating on the project. Ensure that you’re using the right components with the appropriate footprints. You’ll save precious time if you’re using a PCB design software with a good library management system.
4. PCB Layout
Assuming that you’ve done all the above accordingly, you can fully concentrate on the technicalities of PCB layout. Instead of having doubts on the choice of components, you can focus on dealing with signal integrity, power delivery efficiency, heat dissipation and of course, getting the PCB design error free.
Once you’re done with the design, you’ll want to generate a BOM list to prepare for PCB fabrication and prototyping. Prototypes are usually produced in low volume, and this is why it’s important to find out the availability of samples or low-volume purchase during the components selection process.
You wouldn’t want to be worrying about design specifications when routing traces.
5. Prototype Assembly
Once the PCBs are fabricated and components prepared, you’ll need to start assembling the prototype. Some PCB designers outsourced the process to assemblers, but I prefer to build the initial prototype on my own manually. Doing so gives me an insight on potential manufacturability issues that PCB assemblers may face with the design.
6. Functionality Test & Revision
One of my greatest fears is to power on the PCB prototype and see smoke puffing from the microcontroller. But if you’ve been meticulous in your design, chances for that happening is slim.
Either way, you’ll need to get the prototype tested. If it involves a microcontroller, you’ll need a firmware engineer to assist in the testing. Chances are, there will be slight issues in the initial prototype, and you’ll need to improvise in the next revision. You’ll want to ensure that the problems and rectifications are documented clearly to ensure traceability.
Yes, as much as you may hate it, documentation is incredibly valuable — studies demonstrate that the simple action of writing something down does in fact help you to remember it in the future.
Managing engineering prototyping workflow will be less complicated if you’re using a PCB design software that integrates the critical processes. For instance, the library data management of Cadence allows you to minimize cost by streamlining electronics components within an organization. Furthermore, with Allegro you can utilize the versatile IPC-2581 format to automatically import stack-up and manufacturer considerations.
If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.