A printed metal part is a process rather than a purchase, and the invoice reflects that: the build is often less than half of it. Buying one well means specifying the post processing and the acceptance criteria as carefully as the geometry, because two suppliers can print the same file and deliver parts with genuinely different properties.
What arrives from the machine and what happens next
A part welded to a build plate on supports, stressed, rough surfaced and possibly holding loose powder. Then depowdering, stress relief on the plate, plate removal by wire cutting or bandsaw, support removal by hand or machine, optional hot isostatic pressing, heat treatment, machining of critical features, and surface finishing. Each of those is a line on the quote.
What to put in the specification
The alloy and the heat treatment condition. Whether hot isostatic pressing is required. Which surfaces are machined and to what tolerance and finish. What inspection is required, including whether witness coupons are tested. Whether powder lot traceability is needed. And the build orientation, if the part's properties depend on it, which they usually do.
How to design so you can 3D print metal parts
Overhangs below the self supporting angle need supports, and supports inside a closed channel may be unreachable. Horizontal holes deform and are usually made teardrop shaped. Large flat downward faces are trouble. Add machining stock to every feature that has to be accurate. And put a flat face somewhere the part can be fixtured for machining afterwards.
Judging a supplier
Ask what they do in house and what they subcontract, because a supplier who prints and then sends the part away for everything else is coordinating rather than controlling. Ask how they qualify a build. Ask about powder handling and reuse. And ask for a sample part with its inspection record rather than a photograph.
Questions people ask about 3d printed metal parts
Why does 3D printing metal parts cost so much?
Because the build is often the smaller half. Stress relief, support removal, heat treatment, machining and inspection routinely cost more than the printing itself.
Do printed metal parts need machining?
Any surface that has to be accurate, yes. Fits, sealing faces and threads are printed with stock and machined conventionally afterwards.
Does build orientation matter?
Considerably. It affects properties, accuracy, surface finish and how much support is needed, so specify it whenever the part depends on any of those.
What should I ask a supplier for?
The alloy and heat treatment condition, what is machined, what inspection is included, whether hot isostatic pressing applies, and powder traceability if the application requires it.