Like a lot of new dads, I went completely overboard the first Christmas my son was old enough to enjoy opening presents. As far as I was concerned, he couldn’t open them fast enough, and I kept pushing present after present at him trying to live vicariously through him. Finally, he had enough of my overbearing behavior and yelled at me to “STOP!” He then calmly picked up one of the boxes and played with it instead of the treasure it had contained. My wife noted with amusement the score that morning was one point for the toddler, zero points for Dad.
In hindsight, I think my son had it right, though. The box is just as important as the present inside. We see this same kind of thing in electronics, where the priority is often given to getting the PCBA completed first, while the system enclosure ends up being more of an afterthought. The problem is that most electronics depend on their enclosures for operational purposes, whether it is for electrical performance or human interaction. To truly prove the capabilities of a prototype, the PCBA should be built by your contract manufacturer along with the system enclosure. Let’s take a look at what you should expect from your CM when it comes to electronics box build assembly.
What’s Involved in Electronics Box Build Assembly from Your CM?
For those building a prototype system, using a PCBA contract manufacturer that can also provide box build assembly services is a real plus. Instead of coordinating the construction of a prototype system between two manufactures, the entire system can be built by just one. This removes a lot of the communication and scheduling problems as well as helps you keep a tighter control on the costs.
Your CM may not be able to build every conceivable system enclosure, as they will be limited by their facilities and staffing. For example, super large enclosures may require specialized equipment, like a crane, that most CMs won’t have available. However, many quality CMs can typically build most prototype systems according to the following parameters:
- Terminations: From less than 10 to over 1,000.
- Size: From smaller than your hand to the size of a side-by-side refrigerator.
- Testing: From simple five-minute tests to multiple-day tests using manual and automated testing procedures.
- Power: From less than five volts of power to more than 30,000 volts.
Your CM may be able to build the cables and harnesses that your box build will need as well. This again cuts down on the number of manufactures you must deal with, and the cables and harnesses are built specifically for the box being assembled at the same time. Along with the circuit board that the CM is producing, this truly makes the system a much cleaner build with all of the necessary components developed and assembled under the same roof.
CM Capabilities and the Data Needed to Get the Job Done
To successfully build a complete system for you, your contract manufacturer will likely need the following data and information from you:
- A detailed bill of materials.
- The system schematic.
These items are the minimal amount of data your CM would need. However, as you can probably guess, there will be a lot of back and forth discussions to get all of the other parameters of the build settled. To be fully prepared, you should also provide the following:
- Detailed assembly drawings of the system.
- Complete wire lists.
- Test specifications.
- A previously built unit to use an example if available.
Once prepared with the information, your CM will be able to start on the box build assembly. They typically will be able to build the PCBAs, cables and harnesses, sub-assemblies, labels, and text fixtures. This will comprise the bulk of the box build assembly. They may work with suppliers on items such as sheet metal and plastics, specialized cables, custom coils and transformers, and custom labels. In some cases, a CM may be able to build the box assembly without building PCBAs for you.
The Benefits of Having Your PCBA CM Build Your Box Assemblies
As we’ve noted earlier, there are several benefits to having your box build assembly developed and built by the same CM that is building your PCBAs and the associated cables and harnesses. On complex assemblies with hundreds of wires, as much as 80% of the debug time typically comes from wiring errors. Having your CM build wiring harnesses that are fully labeled and tested can save you the time and expense for all of that debug time.
In addition, working with a CM that can review a multi-level bill of materials on a box build assembly, spot potential errors, and work with you to correct them, helps save you even more time and money throughout your project.