A laser material processing system comprises: a housing defining an engraving chamber, an xy laser beam steering system, and a non-telescoping sliding focus mechanism. The housing includes a removable bottom panel that allows processing of workpieces that exceed dimensions of the engraving chamber and allows stacking of the system on modular attachments for specialized functions. The focus mechanism includes a carriage mirror subassembly attached to the x-axis carriage, a sliding member moveably attached to the carriage mirror subassembly, and a focusing lens subassembly attached perpendicularly to the lower end of the sliding member. The carriage mirror subassembly and the focusing lens subassembly are configured to receive and focus a laser beam to a focal point. The focusing lens subassembly is adjusted along a z-axis by disengaging the locking component and vertically sliding the sliding member and is locked into a position by engaging the locking component with the sliding member.