Everyone knows that the W. Artifact used to do the lava crystal is looted from the forward commander in the droid army instance. Almost every one thinks that it will be hard to loot it since to defeat the droid army you must be almost a full group, and since the lottery is on it is just luck, moreover the artifact does not drop 100% of the time. The droid army in its whole cannot be soloed (or it will take you a very long time), we are talking about hundreds of NPCs.
In fact you are not going to solo the droid army but just the commander. All the droids are in fact bugged: they will automaticaly freeze in front of the first base. Just wait till the message "the commader has taken the field" to spawn (The best place to wait is high in the hill near the base you will not take any agro). then look carefully at the comander, because he will freeze too, then just hit him once and wait till he is out of the mass of droid (so you will not fire accidentaly on them). He is easily soloable for anyone who is lv 90, once you have killed him you just have to loot. The commander take around 30 min to pop. you can do an AFK forum while doing it, or just chat with you guild mate arguing you are doing the droid army alone, that you are the best and so on .......
By the way i said that the artifact was not a 100% drop so if you dont have the chance to loot it the first time, just go to the foreman koyoset and tell him you want to go out. You only have a 3 hours lockout when you just kill the forward commander so it can be done really often.