Evidently as with every new idea comes unexpected twits and challenges.

Cavity plate material

The first time I tried this process I picket the wrong material for the cavity plate.

So far I have presented the idea in the next phase of this project, the implementation phase I anticipate spending a lot of time finding the right material to use to make cavity molds.

3D printing

If I go with 3D printing I'll be limited with the materials usable with this technology. 

The  good news is that I know someone who has access to a 3D printer at work and he is keen to try this technique out too.

In the country I live the government encourages 3D printing and provides facilities free of charge. I'll be checking this service for sure.

I don't have direct experience with 3D printing yet and I am skeptical that I will be able to create rigid boundaries between cavities.

I have seen some 3D printed objects and was not impressed with the overall quality.

Electronic components dimensions have tolerances. Some parts may fit snugly in cavities others of the same package type might be too loose. In designing the cavity the right tolerance and material stiffness has to be found so that I don't end up with parts rattling inside.

Someone brought up the issue of heat and deformation or even melting of 3D printing materials. This remains to be seen. 

CNC milling

I had a Sherline 2000 + many mods before so I know what it is capable of. I'll fall back to CNC milling if 3D printing does not work out.

Contact pressure

There is a possibility that the contact pressure of the cavity plate is not sufficient to make all contacts reliable.

The mitigation plan for this is glue and or fasteners. Small screws that will squeeze it against the PCB.

I am not so keen on glue because of defeats the purpose of having easy access to the parts but it has value. See next.

Corrosion

The PCB traces may suffer from oxidation from being exposed to the elements especially if I omit the solder mask process in the PCB manufacture. That's why I am thinking it may be a good idea to glue down the cavity plate for it will seal the components in place.

Another idea is to put the whole thing in a recyclable vacuum bag and seal the whole thing. Like shrink wrapping.

Adoption

The next hurdle is getting folks to adopt this packaging method. Does the benefits outweigh the added process and cost? That remains to be seen. Imagine if all the circuits you can buy from hobbyist online stores like Sparkfun or Adafruit provided a cavity plate alternative purchasing option would you go for it? Anyhow here I am speaking about the electronics hobbyist market, there may be a reuse interest there however to maximize the impact on the planet it would be best that the technique is adopted in consumer electronics.

Imagine your run of the mill TV remote control unit being made this way. When it fails maybe you could sell it back to a shop that can open it up and resell the components. 

The PCB industry has advanced and streamlines its process and here I come along with a disruption.

What no solder mask?

What no reflow?

And now you also want our pick and place machines to pick up parts upside down and drop them inside little cavities in a plate.

I can see a lot of resistance there. Can existing tooling do this? Can glue dot placing machines drop glue dots inside small cavities? 

Scaling

Yet another hurdle is the scaling aspect. It is not far fetched to think that one a cavity plate is designed for a product it can be stepped and repeated to make a mold that will mass produce them. Its like making a mold for a mold.

These are a few of the issues that I'll be faced with next.