Tips for Electronic Engineers when Designing Enclosures
Last time we talked about the elements that should be taken in consideration when designing an enclosure for prototyping, even if they are not 100% necessary, but make a huge difference when planning a mass production run. Now, let’s talk about the next natural step: designing and prototyping the enclosure so months are not wasted waiting for tooling.
Here are some tips when designing PCBs that will make the designer’s life easier and by extension, yours.
Uniformity in communication is crucial for product development. This is not trivial, there are many aspects of product planning that need to be consistent and accounted for during the whole process to prevent mistakes or inaccuracies. I would recommend to define as early as possible things such as:
- PCB design software and its import/export properties
The more file export properties a PCB design software has, the better. In general, 3D design suites work very well with DXF files for 2D design and STP for 3D. SVG might require a few workarounds, but it might be doable. Most 3D design software cannot handle Gerber files.
- Enclosure design software and its import/export properties
The more export capabilities, the better. If an enclosure shape has to be shared, DXF, SVG’s or PDF’s (vector, not raster) can also be useful. If you want to make an electronic engineer’s life difficult, send them a bitmap drawing.
- Units (mm/in) and potential country of manufacturing
I cannot overstate how important this is with precision components. Everything can be affected, from screw types (threads per inch anyone?) to shrinkage formulas and predefined allowances.
- Breakdown of components with special requirements / properties / dimensions
Sharing the PCB design with the design team as early as possible goes a long way in terms of allowing a broad understanding of the inherent challenges of the project. Even if there are changes later, it is much easier for the design team to adapt based on what has already been processed. Uncomfortable but necessary questions have to be asked, such as: Are we positive “x” chip will be available by the time we go for production? What is Plan B?
- Buttons and other feedback devices placement
Simple things such as choosing a button’s travel and placement can be the difference between having to make an additional mold or not, meaning thousands of dollars.It is important to know where and how buttons are to be placed, and if from an ergonomics point of view, they all can be placed on the same PCB plane. Do we need water resistant enclosures?
- Some of the constructive elements we discussed in the last article
Bosses and assembly pins, display windows, etc.
- BOM ownership
With the risk of getting too managerial here, the electronics and manufacturing BOM’s should be fairly synced. Sometimes mechanical parts are sourced with a specific component in mind, and if that component stops being available, problems are ensued. Having a person responsible of keeping BoM’s current for everyone in the team pays off in efficiencies.
Nowadays, some Product Design suites such as Fusion 360 or SolidWorks have project pages with a wiki, discussion forums and even calendars. This is a truly great way of sharing project information with the team, provided that everyone has an online account and are willing to use the interface. Another great alternative for keeping everyone in the loop is sharing a cloud-based document and files repositories.
In the next entry we will talk about SLA 3D printing for enclosures and whether or not it is a good alternative for our projects.
