Welding moves an assembly, and machining afterwards exists to recover what it lost. Why datums shift, what facing and boring can and cannot fix, and how to sequence both.
A formed bend flattens the tube section before it turns the axis. What that ovality costs in flow, why it ruins clamped joints, and how to place a joint so it still seals.
Three cut processes separate metal in three different ways, and each leaves the edge in a different condition. How heat, kerf and squareness decide which cut actually suits a part.
What a printed model proves about envelope, clearance, assembly order and access, what it cannot prove about heat and distortion, and how to use it honestly.
Casting and fabrication spend money at different times. Tooling, draft, wall thickness, porosity and change tolerance, and where a hybrid route makes sense.
A joint that cannot be reached cannot be welded well. Torch angle, cup clearance, purge access and the closing weld as drawing decisions rather than bench problems.
Cutting a hole is a sequence, not a void. Edge distance, ligament width, slot geometry, clearance and drilling order all decide whether the part assembles.
Reference and basic dimensions look similar and bind a supplier very differently. Where each belongs, how tolerances stack, and why duplicates cause scrap.
