This would be too long to leave as a simple comment, so I decided to post it here.

First, the assembly concept is great, but the assemblies themselves may need some rebalancing/swapping around. None of the level 3 assemblies seem worth sinking two skill points into the Assembler trait to get.

In fact, the only assemblies that seem worth the skill point investment and resources to make are the CRI Blaster and Duramesh Armor. The rest are either straight downgrades (like the Toxin Rifle, Bio Rifle, and Large Combat Pack assemblies) or only useful in the early game, like if you find an early Magrail and want to keep using it as an anti-bot weapon.

Level 2 assemblies requiring a relic is problematic, because the player cannot carry more than one relic. Thus, to make a level 2 assembly, you'll possibly need to sacrifice a useful relic you have equipped, with no guarantee that you'll find a decent replacement. And for what? To reload or repair some early game limited use exotics, or to produce some of the less desirable exotics in the game.

Level 3 assemblies may simply be inaccessible to a player if Europa Ruins doesn't spawn on the given seed. And they are 100% inaccessible in Angel of Purity and Hubris game modes as well as Endless trials, because you won't encounter Europa Ruins in any of those modes, so no Frozen Heart.

If you're still working on this, I'd suggest removing the Toxin Rifle/Bio Launcher assemblies (no reason to ever make those exotics) and maybe move some of the reload/repair assemblies to Tier 1, and put the CRI Blaster and Duramesh Armour in Tier 2. Maybe add in a chainsaw assembly in Tier 2. Likewise, adding in assemblies for exotics which aren't rubbish and which complement various builds like how the CRI Blaster is great for pistol-using builds.