D-J Engineering replaces welded-metal aerospace tooling with Thermwood large-scale 3D printing, cutting lead times from months to weeks

D-J Engineering, an aerospace and defense manufacturer with three decades in production tooling, has adopted Thermwood large scale additive manufacturing (LSAM) to build stretch form blocks and mill fixtures, replacing welded-metal and machined-composite methods. The company says the change cuts tooling lead times from months to weeks. A traditional welded stretch form block required four to a dozen individually planned, programmed, machined, fabricated, welded and match-machined components. Mill fixtures were previously built by gluing up sheets of MDF or compressed plywood and milling the stack. D-J Engineering evaluated metal additive systems before settling on Thermwood's LSAM platform.

The move underscores that tooling, not the forming or machining step itself, has long been the real production constraint in aerospace manufacturing. Because tooling sits outside the flight-part certification path, it can absorb large-format polymer and composite AM's build tolerances without the qualification grind that keeps metal AM adoption slow elsewhere in the sector. That distinction is why large-format tooling has become one of the more durable near-term applications for AM in aerospace, even as structural metal parts remain gated by program-length qualification cycles. D-J Engineering's decades of legacy welded-tooling experience give its lead-time comparison practical weight rather than vendor marketing.