§ 01 / WHEN

When DMLS is the right answer

DMLS is an expensive technology — parts are 5–20× more expensive per kilogram than CNC machined equivalents. But for specific geometries and materials, it's the only answer.

Geometric freedom. Internal cooling channels in turbine blades. Lattice structures for weight reduction. Consolidated assemblies that replace 20 brackets and fasteners with one printed part. Shapes that cannot be machined at any cost.

Material. DMLS is currently the only practical way to produce small quantities (1-100) of parts in exotic alloys like Inconel 718, Ti-6Al-4V, or cobalt-chromium without forging or casting infrastructure.

Volume. For 1-50 parts in these alloys, DMLS beats CNC on speed and often on cost (no tooling, no wrought stock procurement). Above 100 parts, investment casting or forging typically wins.

Certification. Aerospace-grade (AS9100D) and medical-grade (ISO 13485) DMLS is mature technology. Parts are flight-rated, FDA-cleared for implants, and qualified for mission-critical applications.

§ 02 / METAL

Metal alloys we stock

Alloy	UTS (MPa)	Density (g/cm³)	Applications	Lead
Ti-6Al-4V (Grade 23)	1,070 (HIP)	4.43	Aerospace, medical implants, high-stress parts	10–14 d
AlSi10Mg	460 (T6)	2.68	Aerospace brackets, heat exchangers, lightweight structures	7–10 d
Inconel 718	1,375 (aged)	8.22	Turbine blades, combustion parts, high-temp 650 °C+	10–14 d
Inconel 625	930	8.44	Oil & gas, marine, corrosive environments	10–14 d
Stainless 316L	640	8.00	Medical, food-contact, marine, general corrosion	7–10 d
Stainless 17-4 PH	1,310 (H900)	7.80	Precipitation-hardened, high-strength brackets	10–12 d
Maraging Steel (MS1)	2,050 (aged)	8.10	Tooling, injection mold inserts with conformal cooling	10–14 d
CoCrMo	1,150	8.50	Medical implants, dental, hot-end parts	12–14 d
Copper (pure / CuCrZr)	400	8.96	Heat sinks, electrical contacts, induction coils	10–14 d

All alloys printed to >99.5% density. HIP (hot isostatic pressing) post-processing available for aerospace applications where closing residual porosity matters — adds 3 days and ~20% cost.

§ 03 / POST-PROCESSING

Post-processing always required

DMLS parts come off the build plate in an unusable state. Post-processing is not optional:

Stress relief

Parts go through a heat-treat cycle on the build plate to relieve thermal stresses from the printing process. Without this, removing the part from the plate can cause it to warp or crack. Adds 1 day.

Build plate removal

Parts are cut off the build plate via wire EDM or bandsaw. The removed surface is rough and may need machining if it's a functional surface. Tell us which surface is "down" so we can plan this.

Support removal

Overhangs below ~45° need supports. These are removed mechanically or via machining. Support contact surfaces are always rougher than the bulk surface.

HIP (optional, for aerospace)

Hot isostatic pressing closes any residual micro-porosity. Required for fatigue-critical aerospace parts. Adds 2–3 days and typically 20% cost.

Heat treatment (alloy-specific)

Ti64: solution + age. AlSi10Mg: T6. Inconel 718: solution + age. 17-4 PH: H900 / H1025. Heat treatment is where the part actually develops its rated mechanical properties.

Finish machining

Critical mating surfaces (bearings, seals, bolt holes) are almost always machined post-print to ±0.02 mm tolerance. DMLS as-built tolerance is ±0.1 mm which is insufficient for most functional interfaces.

§ 04 / DMLS

DMLS design guidelines

Self-supporting angles: ≥45°

Overhangs below 45° from vertical need supports. Design to be self-supporting wherever possible — saves cost, time, and post-processing scars.

Minimum wall thickness: 0.5 mm

Below 0.5 mm, walls are prone to warping and incomplete fusion. For structural walls, 1.0 mm minimum.

Holes: ≥0.5 mm, machine post-print for precision

As-printed holes are rough and undersize. For critical holes, print 0.3 mm undersize, then drill/ream.

Internal channels need exit holes

Conformal cooling channels must have powder-evacuation holes at every low point in the channel path. Trapped powder is a contamination source.

Topology optimization pays

DMLS rewards weight reduction — every gram saved reduces build time and material cost. A topology-optimized bracket at 60% original mass is 40% cheaper to print.

Lattices reduce cost 30-50%

Infill with a 2-4 mm unit cell lattice drops mass substantially. Lattice density optimized per loading direction is now routine design practice for printed aerospace brackets.

§ 05 / CERTIFICATIONS

Certifications & documentation

For aerospace, medical, and defense DMLS work, fobproto provides:

AS9100D-compliant build records — every build, every part traceable to powder lot, orientation, build plate position, and operator.
Powder lot traceability — COA from powder supplier, particle size distribution, chemistry verification.
Density samples — one density coupon per build plate, Archimedes method verification, certificate attached to shipment.
Heat-treat furnace charts — continuous temperature traces for stress relief, HIP, and aging cycles.
Tensile witness coupons — optional for critical parts; adds 3 days and a small fee.
CT scan inspection — available for flight-critical parts; resolves defects down to 50 μm.
First Article Inspection (FAI) — AS9102-compliant reports, with full dimensional verification.

ITAR / EAR

For parts subject to ITAR or EAR restrictions, contact us before uploading files. We have workflows to handle controlled drawings and can provide NDA-protected quotation. We do not print parts that violate export controls.

§ 06 / FAQ

FAQ

Why is DMLS so expensive compared to CNC?

Metal powder costs $150-800/kg depending on alloy. Machines cost $500K-1M. Build times are 24-60 hours. Post-processing (HIP, heat treat, machine, inspect) is labor-intensive. All of this amortizes into per-part cost that's 5-20× higher than CNC from bar stock. DMLS only makes economic sense when geometry or material justifies the premium.

Are DMLS parts as strong as machined parts from the same alloy?

After proper heat treatment (and HIP for fatigue-critical), yes — typically 95-100% of wrought equivalents in static strength. In fatigue, HIP-processed parts approach wrought behavior; non-HIP parts are lower due to residual porosity. For critical applications, always HIP.

Can I combine DMLS + machining on one part?

Yes — this is the common workflow for precision parts. We print the complex body, then set up the part on a CNC to machine bearing bores, bolt patterns, sealing surfaces, threads. Final tolerances then match CNC machining (±0.02 mm) rather than DMLS as-built (±0.1 mm).

What's the smallest part that makes economic sense?

For parts smaller than ~20×20×20 mm, we batch multiple customers' parts on one build plate to amortize build cost. Single tiny parts run $100-300 each (minimum charge). For batches of 10+ we can quote per-part rates.

Can you print copper? It's notoriously hard.

Yes, but only on green-laser systems (not the more common infrared systems). Pure copper and CuCrZr parts ship in 10-14 days, 3-week lead on rarer copper alloys. Typical applications: induction coils, high-performance heat sinks, rocket nozzle liners.

DMLS metal 3D printing — aerospace-grade titanium, aluminum, Inconel.