This trophy can be obtained on Quartu during the Clank-only puzzle portion of the level. If you miss it during your initial trip to the planet, you can go back to the planet any time before the final level and grab it. On to the solution:
About halfway through the level, right after you use an electric gadgebot to open a crusher so you can pass, you'll come to a circular conveyor belt that you'll need to figure out how to use in order to proceed in the level.
Before you worry about that, though, take the gadgebot near the conveyor belt, turn it into the bridge, and cross it to grab the second gadgebot on the other side. Bring it back with you to the conveyor belt area. You now have the two gadgebots you need for this trophy. Grab the bridge gadgebot, and turn it into an electric gadgebot. Then it's just a matter of doing the following five times:
1) On the long side of the circular conveyor belt, there are five electric pylons that are uncharged. Drop the electric gadgebot next to the first one (but don't drop it ON the conveyor belt). It should electrify the pylon and raise a crusher immediately on the other side of the wall. You'll notice a second conveyor belt running underneath the crusher.
2) Toss the second gadgebot on that conveyor under the crusher.
3) Retrieve your electric gadgebot so that it no longer supplies power to the crusher.
4) Second gadgebot SMASHED!
The second gadgebot will respawn next to the circular conveyor belt, and you just have to do this four more times to get the trophy. Good luck!