The Techmarine is called to fight on the battlefield, to shepard his machines in the fight. Afterwards many of those machines, weapons and pieces of power armour will need to be repaired by serf’s and techmarines in the chapters workshops.
This is my battle damaged workshop.
The first, a Razorback transport tank that has suffered damage to it’s hatches, side doors and and severe hull damage just above the driver section. The tracks also took catastrophic damage and must be entirely replaced.
The whole front section of this Razorback has been replaced but still gaps remain, the chapter serfs will spend many hours smoothing out any imperfections and we must enact the correct rituals to placate the machine spirit.