Metal 3D Printing: DMLS and SLM for Functional Metal Parts
Metal additive manufacturing with DMLS and SLM technologies. Print titanium, aluminum, stainless steel, and cobalt-chrome parts with complex geometries impossible via CNC. Layer height 0.02mm, tolerance ±0.05mm, HIP densification, and CNC post-finishing. Aerospace and medical grade quality. 7 to 14 day lead times.
Metal 3D Printing: DMLS and SLM for Functional Metal Parts
Metal 3D printing — also known as metal additive manufacturing — produces fully functional metal parts by selectively melting metal powder with a high-power laser, layer by layer. Technologies including DMLS (Direct Metal Laser Sintering) and SLM (Selective Laser Melting) create parts with complex internal geometry, topology-optimized lightweight structures, and integrated features that CNC machining simply cannot produce.
At FIRMFG, our metal 3D printing service covers six premium materials: Titanium Ti6Al4V for aerospace and medical implants, Aluminum AlSi10Mg for lightweight automotive, Stainless Steel 316L and 17-4PH for corrosion and strength, Cobalt-Chrome CoCrMo for medical and wear applications, and Inconel 718 for high-temperature turbine components.
Metal 3D printing excels where traditional manufacturing reaches its limits: internal cooling channels in injection molds, lightweight lattice structures for aerospace brackets, patient-specific medical implants with porous bone-ingrowth surfaces, and consolidated assemblies that replace multi-part assemblies with a single printed component. Parts achieve 95 to 99% density, with HIP (Hot Isostatic Pressing) pushing density above 99.5% for critical applications.
This guide covers metal materials, the DMLS/SLM process, design for metal additive manufacturing, post-processing, comparison with CNC machining, and cost factors. Or, skip ahead and request a quote for your metal 3D printing project.
Metal 3D Printing Quick Specs
Key capabilities and specifications for DMLS and SLM metal additive manufacturing at FIRMFG.
Layer Height
0.02 – 0.04 mm
Dimensional Tolerance
±0.05 mm (±0.002")
Maximum Part Size
250 x 250 x 300 mm
Surface Finish (As-Printed)
Ra 6 – 12 μm (requires post-machining)
Lead Time
7 – 14 business days
Available Metals
Titanium, Aluminum, Stainless Steel, Cobalt-Chrome
Metal Materials for 3D Printing
Six premium metal alloys optimized for laser powder bed fusion. Each material has specific applications, mechanical properties, and cost characteristics.
Titanium (Ti6Al4V / Grade 5)
The most widely used titanium alloy in additive manufacturing. Exceptional strength-to-weight ratio, biocompatible, and corrosion resistant. Used in aerospace, medical implants, and high-performance automotive. Tensile strength 950 MPa, density 4.43 g/cm3.
Properties: Tensile 950 MPa · Yield 880 MPa · Density 4.43 g/cm3 · Hardness 33 HRC
Applications: Aerospace brackets, medical implants, motorsport, marine
Cost: $10 – $15 / g
Aluminum (AlSi10Mg)
Cast aluminum alloy optimized for laser powder bed fusion. Excellent strength-to-weight ratio, good thermal conductivity, and weldability. Commonly used for lightweight housings, heat exchangers, and automotive components. Tensile strength 400 MPa.
Properties: Tensile 400 MPa · Yield 230 MPa · Density 2.67 g/cm3 · Hardness 120 HB
Applications: Automotive, aerospace housings, heat exchangers, brackets
Cost: $5 – $8 / g
Stainless Steel (316L)
Austenitic stainless steel with excellent corrosion resistance and biocompatibility. Used in chemical processing, medical instruments, food equipment, and marine applications. Non-magnetic, weldable, and formable. Tensile strength 540 MPa.
Properties: Tensile 540 MPa · Yield 470 MPa · Density 7.99 g/cm3 · Hardness 90 HRB
Applications: Chemical processing, medical instruments, marine, food industry
Cost: $5 – $10 / g
Stainless Steel (17-4PH)
Precipitation-hardening stainless steel combining high strength and good corrosion resistance. Can be heat-treated to achieve tensile strengths up to 1,200 MPa. Used in aerospace, defense, and industrial applications requiring both strength and corrosion resistance.
Properties: Tensile 1,200 MPa (H900) · Yield 1,100 MPa · Density 7.80 g/cm3 · Hardness 44 HRC
Applications: Aerospace, defense, industrial tooling, valve components
Cost: $6 – $10 / g
Cobalt-Chrome (CoCrMo)
Cobalt-chromium-molybdenum alloy with exceptional wear resistance, biocompatibility, and high-temperature strength. Used for medical implants (hip and knee replacements), dental prosthetics, and turbine engine components. Tensile strength 1,300 MPa.
Properties: Tensile 1,300 MPa · Yield 950 MPa · Density 8.30 g/cm3 · Hardness 40 HRC
Applications: Medical implants, dental, aerospace turbines, wear parts
Cost: $8 – $12 / g
Inconel 718 (Nickel Superalloy)
Nickel-based superalloy with exceptional high-temperature strength and oxidation resistance. Maintains mechanical properties up to 700°C. Used in gas turbine engines, rocket motor components, and high-temperature industrial applications.
Properties: Tensile 1,240 MPa · Yield 1,030 MPa · Density 8.19 g/cm3 · Service temp 700°C
Applications: Gas turbines, aerospace engines, rocket components, oil and gas
Cost: $12 – $15 / g
How Metal 3D Printing Works
The DMLS and SLM process uses a high-power laser to melt metal powder layer by layer in an inert gas atmosphere. Here is the complete six-step build process.
Step 1: CAD & Build Preparation
The 3D CAD model is imported into metal AM build preparation software. The part is oriented to minimize support material and residual stress. Support structures are generated for overhangs, heat sinks, and build plate anchoring. The model is sliced into layers of 0.02 to 0.04mm. Build parameters including laser power, scan speed, and hatch spacing are set per material.
Key detail: STL/STEP files, 0.02-0.04mm layers, support generation, thermal optimization
Step 2: Powder Bed Setup
Metal powder (15 to 45 micron particle size) is loaded into the powder feeder. The build chamber is sealed and filled with inert gas (argon or nitrogen) to reduce oxygen below 0.1%. This prevents oxidation, fires, and contamination during the laser melting process. Oxygen levels are continuously monitored.
Key detail: 15-45 micron powder, argon atmosphere, oxygen level below 0.1%
Step 3: Laser Melting (DMLS/SLM)
A high-power fiber laser (200-500W) selectively melts the metal powder layer by layer. The laser traces each cross-section, fusing powder to the layer below at temperatures exceeding 1,500°C. DMLS uses lower energy with partially sintered powder; SLM uses higher energy for full melting. The build platform descends by one layer thickness after each pass.
Key detail: 200-500W fiber laser, 1,500°C+ melt, DMLS (sinter) or SLM (full melt)
Step 4: Layer-by-Layer Build
A recoater blade or roller spreads a fresh layer of powder across the build plate after each laser pass. The process repeats for every layer until the full part is complete. A typical build runs 10 to 40 hours depending on part volume and layer height. The build chamber remains sealed under inert gas throughout.
Key detail: Recoater powder deposition, 10-40 hours typical build time, inert gas maintained
Step 5: Cooling & Removal
After the build completes, the chamber cools to room temperature slowly to prevent thermal shock and residual stress. The build plate with the attached parts is removed from the machine. Unused powder is recovered, sieved, and recycled for the next build. The entire block is moved to post-processing.
Key detail: Slow cooling, powder recycling, build plate removal
Step 6: Stress Relief & Support Removal
The build plate and parts undergo thermal stress relief (typically 600 to 800°C for 2 to 4 hours) to reduce residual stresses from rapid thermal cycling. After stress relief, supports are removed with band saw, EDM, or hand tools. The part is detached from the build plate by wire EDM or cutting.
Key detail: 600-800°C stress relief, support removal, wire EDM separation
Design for Metal Additive Manufacturing
Designing for metal 3D printing requires different rules than CNC machining or injection molding. Proper design ensures successful builds, minimal supports, and optimal mechanical properties.
| Design Feature | Recommended | Minimum | Notes |
|---|---|---|---|
| Minimum Wall Thickness | 0.5 mm | 0.4 mm | Thin walls require support and may warp |
| Minimum Feature Size | 0.5 mm | 0.4 mm | Fine pins, text, and small details |
| Minimum Hole Diameter | 0.8 mm | 0.5 mm | Vertical holes; horizontal holes need 0.6mm+ |
| Overhang Angle | 45 degrees from horizontal | 30 degrees (with supports) | Angles below 45 degrees require support material |
| Clearance for Assemblies | 0.3 mm gap | 0.15 mm gap | Post-processing tolerance for mating parts |
| Support Placement | On non-critical surfaces | Minimal contact points | Supports must be accessible for removal |
| Maximum Part Size | 240 x 240 x 290 mm | Up to 250 x 250 x 300 mm | Limited by build chamber dimensions |
| Tolerance | ±0.1 mm | ±0.05 mm (small features) | Post-machining available for tighter tolerances |
Topology Optimization
Use topology optimization software to remove material where stress is low, creating organic, lightweight structures. Typical weight reduction: 30 to 60% with no strength loss. Ideal for aerospace brackets and automotive components where weight directly impacts performance.
Lattice Structures
Replace solid volumes with internal lattice structures. Reduces weight by 40 to 70% while maintaining structural integrity. Enables bone-ingrowth surfaces for medical implants and conformal cooling channels for injection molds.
Stress Relief
Residual stresses from rapid thermal cycling can cause distortion and cracking. All parts require stress relief heat treatment (600 to 800°C). For critical applications, HIP closes internal porosity and achieves near-full density.
Support Design
Overhangs below 45 degrees require support structures. Design supports on non-critical surfaces for accessibility. Supports anchor the part to the build plate and conduct heat away from the melt pool to prevent warping.
Post-Processing for Metal 3D Printed Parts
Metal 3D printed parts require post-processing to achieve final mechanical properties, dimensional accuracy, and surface quality. Here are the options available at FIRMFG.
Stress Relief Heat Treatment
Thermal treatment at 600 to 800°C for 2 to 4 hours to reduce residual stresses from the build process. Essential for all metal 3D printed parts to prevent distortion during subsequent machining and in service. Performed before support removal and part separation.
HIP (Hot Isostatic Pressing)
Applies high temperature (1,000 to 1,200°C) and isostatic gas pressure (100 to 200 MPa) to close internal porosity. HIP achieves near 100% density (above 99.5%), improving fatigue strength and mechanical properties. Critical for aerospace and medical applications.
CNC Machining & Finishing
CNC milling and turning achieve tight tolerances (±0.01mm) on critical mating surfaces, threads, and precision features. As-printed surfaces (Ra 6 to 12 μm) are machined to Ra 0.8 to 3.2 μm. Required for functional interfaces and sealing surfaces.
Surface Treatment & Coating
Anodizing (titanium), passivation (stainless steel), bead blasting, polishing, and PVD coating. Surface treatments improve corrosion resistance, wear resistance, and aesthetics. Available per material specification and application requirements.
Wire EDM Separation
Wire EDM cuts parts from the build plate with minimal material loss and no thermal distortion. Preferred over band sawing for precision parts. EDM also removes internal supports in inaccessible areas where hand tools cannot reach.
Inspection & Certification
CT scanning detects internal porosity and defects. CMM measurement verifies dimensional accuracy. Tensile testing, hardness testing, and metallographic analysis certify mechanical properties. Full documentation for aerospace and medical certifications.
Need specialized surface finishing? Explore our surface finishing services for anodizing, passivation, polishing, and coatings.
Metal 3D Printing vs CNC Machining
When to choose metal 3D printing versus CNC machining depends on geometry complexity, volume, accuracy requirements, and budget. Here is how they compare.
| Criteria | Metal 3D Printing | CNC Machining | Advantage |
|---|---|---|---|
| Complex Geometry | Excellent — internal channels, lattices, topology-optimized | Limited — cannot produce internal features | Metal 3D |
| Accuracy | ±0.05 mm (as-printed), ±0.01 mm (with post-machining) | ±0.005 mm (as-machined) | CNC |
| Cost (1-10 parts) | $200 – $2,000+ per part | $50 – $500 per part | CNC |
| Cost (complex geometry) | Cost unchanged by complexity | Cost increases with complexity | Metal 3D |
| Speed | 7 – 14 days (plus post-processing) | 5 – 10 days | CNC |
| Material Waste | Minimal — powder is recycled | High — subtractive process | Metal 3D |
| Surface Finish | Ra 6-12 μm (requires finishing) | Ra 0.4-0.8 μm (excellent) | CNC |
| Best For | Complex, lightweight, low-volume parts | Precise, simple, high-strength parts | Depends |
Choose Metal 3D When
Geometry is complex with internal channels, lattice structures, or topology-optimized shapes. Quantities are 1 to 50 parts. Weight reduction is critical. Design changes are expected during iteration.
Choose CNC When
Tolerances tighter than ±0.05mm are required. Geometry is simple and accessible. Surface finish must be excellent (Ra 0.4 μm). Quantities are over 50 parts where per-part setup amortizes.
Choose Hybrid When
Print the complex portion by DMLS, then CNC machine critical mating surfaces, threads, and sealing interfaces. Combines design freedom with precision. Best for parts with both complex and precision features.
Metal 3D Printing Cost Factors
Metal 3D printing cost is driven by material weight, machine time, and post-processing. The small-batch advantage is significant for complex geometry where CNC setup costs are prohibitive.
Titanium (Ti6Al4V)
$10 – $15 / g
Most expensive material. High powder cost and slower build speeds. Typical part: $500 – $2,000+.
Stainless Steel (316L/17-4PH)
$5 – $10 / g
Mid-range cost. Good balance of properties and price. Typical part: $200 – $800.
Aluminum (AlSi10Mg)
$5 – $8 / g
More economical metal. Faster build speeds. Typical part: $150 – $600.
Cobalt-Chrome (CoCrMo)
$8 – $12 / g
Premium material for medical and aerospace. Typical part: $400 – $1,500.
Machine Time
$50 – $150 / hour
DMLS/SLM equipment cost is high. Build time drives total cost significantly.
Post-Processing
$100 – $500+ / part
Stress relief, HIP, CNC finishing, and surface treatment. Essential for functional parts.
Cost Example: Aerospace Titanium Bracket
A topology-optimized titanium bracket (45g) with internal lattice structure:
Material (Ti6Al4V)
$450 – $675
Machine Time
$400 – $800
Post-Processing
$200 – $400
Total
$1,050 – $1,875
The same bracket by CNC machining would cost $800 to $1,200 for a single part due to complex geometry and high material waste. Metal 3D printing becomes cost-competitive for complex parts at low volumes.
Metal 3D Printing FAQ
Answers to the most common questions about metal 3D printing (DMLS and SLM) at FIRMFG.
QWhat accuracy can metal 3D printing achieve?
DMLS and SLM achieve dimensional tolerances of ±0.05mm (±0.002") for features under 100mm, and ±0.05% for larger dimensions. Layer heights range from 0.02 to 0.04mm, producing fine detail and smooth transitions. However, as-printed surface finish is Ra 6 to 12 μm — significantly rougher than CNC machining (Ra 0.4 μm). For critical mating surfaces, threads, and sealing interfaces, we apply CNC post-machining to achieve tolerances of ±0.01mm and surface finishes of Ra 0.8 μm or better. CT scanning verifies internal integrity and dimensional accuracy for aerospace and medical parts.
QWhat materials are available for metal 3D printing?
FIRMFG offers six primary metal materials: Titanium Ti6Al4V (Grade 5) for aerospace and medical, Aluminum AlSi10Mg for lightweight automotive and aerospace, Stainless Steel 316L for corrosion-resistant applications, Stainless Steel 17-4PH for high-strength components, Cobalt-Chrome CoCrMo for medical implants and wear parts, and Inconel 718 for high-temperature turbine and rocket applications. Each material has optimized build parameters for laser power, scan speed, and layer thickness. Material certificates (CoC) and mechanical property test reports are provided with every order.
QWhat is the maximum part size for metal 3D printing?
The maximum build volume is 250 x 250 x 300mm (9.8 x 9.8 x 11.8 inches). Parts larger than this can be split into multiple segments and joined by welding or brazing, but this requires engineering review. For parts exceeding 300mm, we recommend CNC machining or a hybrid approach where metal 3D printing produces the complex portion and CNC machines the large body. The build chamber also constrains multi-part batch builds — typically 5 to 20 parts per run depending on size and nesting efficiency.
QHow strong are metal 3D printed parts compared to machined parts?
Metal 3D printed parts achieve 95 to 99% of wrought material density after HIP (Hot Isostatic Pressing). Mechanical properties are comparable to cast or forged equivalents. Titanium Ti6Al4V DMLS parts achieve tensile strength of 950 MPa — matching wrought titanium. However, metal 3D printed parts are anisotropic: strength is 10 to 15% lower in the Z-axis (build direction) due to layer bonding. Stress relief heat treatment and HIP improve isotropy and fatigue performance. For safety-critical applications, we provide certified mechanical property test reports from tensile and hardness testing.
QWhat post-processing is required for metal 3D printed parts?
All metal 3D printed parts require stress relief heat treatment (600 to 800°C) to reduce residual stresses. Supports must be removed by hand tools, band saw, or wire EDM. For aerospace and medical applications, HIP (Hot Isostatic Pressing) closes internal porosity and achieves near-full density. CNC machining is used for critical mating surfaces, threads, and sealing interfaces to achieve tight tolerances (±0.01mm) and smooth finishes (Ra 0.8 μm). Surface treatments like anodizing (titanium), passivation (stainless steel), and bead blasting are optional for corrosion and aesthetics.
QHow much does metal 3D printing cost?
Metal 3D printing costs $5 to $15 per gram of material, with titanium being the most expensive. A typical small part (20 to 50g) costs $200 to $800, while larger parts (100 to 300g) range from $500 to $3,000+. Cost is driven by material weight, machine time ($50 to $150/hour), and post-processing ($100 to $500+ per part). The small-batch advantage is significant: unlike CNC machining (which has high per-part setup cost for complex geometry), metal 3D printing costs are largely independent of geometric complexity. For 1 to 50 complex parts, metal 3D printing is often more economical than CNC machining.
Metal 3D Printing Applications
Industries and use cases where metal additive manufacturing delivers unique value.
Aerospace Engines
Turbine, bracket, and structural components
Medical Implants
Titanium and cobalt-chrome implants
Functional Parts
Complex brackets and housings
Lightweight Structures
Topology-optimized lattice designs
Tooling & Molds
Conformal cooling injection molds
Heat Exchangers
Complex internal channel geometry
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Upload your CAD files and get a free metal 3D printing quote within 24 hours. Titanium, aluminum, stainless steel, cobalt-chrome, and Inconel available. Our engineers provide DFM feedback, material recommendations, and topology optimization support at no cost.