Application: Manufacturing Metal Powders for 3D Printing Applications

Introduction

Additive manufacturing (AM) lives and dies on powder quality. Spherical particle shape, tight size distribution, flowability, and zero contamination are table stakes. The less glamorous—but mission-critical—work happens before printing: conditioning, coating, drying, and binder mixing under controlled atmospheres. PerMix designs inerted, ATEX/ExP-ready mixing and drying systems that deliver homogeneity, flow performance, and repeatability for metals from stainless and Ti-6Al-4V to Inconel and CoCr.

How Metal Powders for AM Are Made (and Why Mixing Matters)

1. Powder production
   Gas/plasma atomization, centrifugal, or chemical routes produce near-spherical particles. Post-atomization sieving/classification isolates fractions for SLM/LPBF, EBM, Binder Jetting, and DED.
2. Conditioning & surface modification
   Blending lots, adding flow aids, anti-caking agents, or thin functional coatings to tune spreadability and apparent density.
3. Binder mixing (don’t skip this!)
   • Binder Jetting: precise binder formulation and premix (solvent + polymer + additives) is essential for wetting, penetration, green strength, and de-powdering behavior.
   • Feedstock prep for bound metal/extrusion routes: metal powder + binder mixed to a highly filled, viscous compound with tight rheology targets to avoid voids and warpage.
   • Coated powders (select processes): sub-percent binder/agent films applied in a mixer to improve layer adhesion or reduce oxidation.
4. Drying, degassing & storage
   Residual moisture and dissolved gases kill layer quality. Vacuum drying/degassing plus inert handling preserve performance.

Processing Pain Points

• Segregation across size/density; minor stratification wrecks melt pool consistency.
• Oxidation & moisture—especially for Al, Ti, and fine fractions.
• Agglomeration of fines/nanos; needs controlled de-agglomeration energy.
• Contamination control (wear metals, oils) to keep chemistry in spec.
• Static & ignition hazards with metallic dusts; demand grounding, purge, temp monitoring, and certified electrics.

How PerMix Answers the Need

Vertical Vacuum Ribbon Mixer — PerMix PVR (Vertical)

Your most popular model earns center stage.

What it does best

• Low-shear, full-volume turnover for delicate, high-value powders.
• Vacuum drying & degassing: remove moisture and dissolved gases at reduced temperature; ideal before sieving/packing or right before printing.
• Uniform micro-additive/binder film application: the vertical ribbon’s top-to-bottom circulation avoids dead zones and over-working.

Why vertical (vs horizontal)

• Gravity assists axial circulation → better homogeneity at lower tip speeds.
• Smaller footprint with tall, jacketable shell—great in inerted glove-room or clean zones.
• Excellent condensate recovery path when paired with a condenser/receiver.

Options that matter

• Full vacuum rating, jacketed shell/cover, and N₂/Ar purge.
• Hygienic 316L/Hastelloy contact surfaces; anti-stick or conductive linings.
• ATEX/ExP electrics, shaft purges, continuous temperature and torque logging.
• Load cells for precise batching; dust-tight, sealed discharge.

Conical Screw (Nauta) Mixers

Ultra-gentle, zero-dead-zone blending for premium alloys and fragile spheres; vacuum option for light drying or oxygen removal. Perfect for lot blending and micro-additive distribution without attrition.

Plow Mixers (with Choppers)

When you need fast, uniform dispersion or de-agglomeration, the fluidized plow regime shines. Excellent for distributing flow aids, nano-scale additives, or thin binder films; purgable and ATEX-ready.

Double Cone & V-Blenders

Low-energy tumbling for small lots and validation batches where morphology must be preserved; intensifier bar optional for light de-agglomeration.

Vacuum Ribbon Mixers & Dryers (Horizontal)

For larger, drier loads that need gentle vacuum drying with very even heat transfer. Great post-wash or after aqueous surfactant steps; integrates condenser/receiver for solvent or moisture capture.

Sigma (Z-Blade) & Double Planetary (for Binder Compounding)

When binder becomes the matrix (high-solids feedstock, paste-like rheology):

• Sigma/Z-Blade: high-torque, low-rpm kneading to a target viscosity without overheating. Optional extruder discharge for sealed transfer.
• Vacuum Double Planetary: planetary action for uniform filler dispersion and vacuum deaeration. Ideal for binder development or high-solids masterbatches used in bound metal or BJ infiltration systems.

Safety & Atmosphere Control (Non-Negotiables)

• ATEX/ExP designs (Zone 21/22) with explosion-proof motors and sealed junctions.
• Inert gas purge on vessel headspace and mechanical seals.
• Grounding/antistatic paths, temperature interlocks, and torque alarms.
• Materials of construction: 316L/Hastelloy/Ti; wear-resistant yet non-sparking internals.
• Closed transfer: vacuum loading, sealed discharge to classifiers, packers, or AM feed hoppers.

Typical Line Integrations

• Lot blending → Vertical Vacuum Ribbon → vacuum dry/degass → inert pack
• Nano-additive dispersion → Plow (with choppers) → N₂ purge → classifier
• Binder masterbatch → Sigma or Double Planetary → QA rheology → storage
• Final pre-print conditioning → Conical Screw/Nauta → sieve → inert feed

Why AM Leaders Choose PerMix

1. Process-first engineering: mixers sized by rheology, heat/mass transfer, and shear budget, not brochure ratings.
2. Inert + vacuum ecosystem: pumps, condensers, receivers, and purge logic integrated under one PLC/HMI.
3. Validation package: FAT/SAT docs, lot traceability, recipe audit trails.
4. Scale path: lab → pilot → production with geometrically similar kinematics.
5. Global support with UKCA/CE, ATEX, and ExP compliance.

FAQs (ready for schema)

How do I choose between Vertical Vacuum Ribbon vs Conical Screw?
Use Vertical Vacuum Ribbon when you need vacuum drying/degassing plus uniform micro-additive or thin binder film application at scale. Choose Conical Screw for ultra-gentle lot blending where morphology preservation is paramount and drying demand is light.

Can PerMix help formulate the binder premix?
Yes. We supply Sigma/Double Planetary systems for binder chemistry development and high-solids masterbatches, plus inline polishing or vacuum steps to hit viscosity and wetting targets for Binder Jetting.

What about oxidation during mixing?
All critical vessels can be nitrogen/argon purged, with O₂ monitoring and sealed transfer to classifiers or packers.

Conclusion

Perfect prints start with perfect powder—and perfect powder starts in a mixer designed for homogeneity, inert safety, and moisture/gas control. With the Vertical Vacuum Ribbon Mixer as the workhorse and a supporting cast of conical, plow, ribbon, sigma, and double-planetary systems, PerMix delivers a complete toolkit for modern metal powder AM.