In the rapidly growing field of metal additive manufacturing (3D printing), metal injection molding (MIM), and powder metallurgy, stainless steel powder remains one of the most widely used materials. However, achieving the optimal particle size distribution is critical for final part quality, flowability, packing density, and printability. Many stainless steel powder producers and users face the same challenge: how to efficiently remove both ultrafine particles (typically <10–15 μm) and oversized coarse particles while preserving the valuable middle fraction (most commonly 15–63 μm or 20–45 μm, depending on the application). At Epic Powder, our HTS series high-efficiency turbo air classifiers have proven to be an exceptionally effective solution for this exact requirement of producing stainless steel powder.
Case Study: Transforming Stainless Steel Powder <69 μm into High-Quality Narrow-Cut Product
One of our customers, a leading manufacturer of stainless steel powders for laser powder bed fusion (LPBF) and directed energy deposition (DED), supplied us with the following raw material characteristics:
- Feed material: Gas-atomized stainless steel powder
- Maximum particle size: <69 μm
- Fines content: 37% <15 μm
- Target specification after classification:
- >97% >10 μm (i.e. extremely low content of particles <10 μm)
- Removal of coarse particles above a defined upper cut size (commonly 45 μm, 53 μm or 63 μm depending on final application)
The customer’s goal was to produce a narrow PSD powder with excellent flowability and minimal satellite particles or dust.
Challenge Faced by the Customer
Initial attempts using conventional air classifiers resulted in:
- Significant loss of valuable 10–45 μm material when trying to cut at 10 μm
- Poor sharpness of cut when removing coarse particles
- Low processing capacity
- Frequent filter clogging due to high fines content (37% <15 μm)
Solution: Multi-Stage Classification Using Epic Powder HTS Air Classifier
The customer ultimately adopted a two-stage classification process using the HTS series:
- First stage – Fine powder removal
HTS classifier configured to cut at ~10–12 μm
→ Removed ~35–38% of ultrafine particles
→ Achieved >97% >10 μm in the coarse product - Second stage – Coarse fraction removal
HTS classifier reconfigured with different rotor speed and secondary air settings to cut at 45 μm, 53 μm or 63 μm (depending on final product specification)
→ Obtained narrow PSD stainless steel powder with D10 >12 μm, D50 ≈ 28–35 μm, D90 <50 μm (example values)
Key Results Achieved
| Parameter | Feed Material | After 1st Stage (fine removal) | Final Narrow-Cut Product |
|---|---|---|---|
| <10 μm content | ~25–30% | <3% | <3% |
| <15 μm content | 37% | ~8–10% | ~8–10% |
| >63 μm content | ~5–10% | ~5–10% | <1% (if cut at 63 μm) |
| Yield of middle fraction | – | – | 65–75% (typical) |
| Classification sharpness (slope) | – | – | Very sharp |
The customer reported:
- Significantly improved powder flowability
- Reduced satellite formation in final parts
- Higher build density and better surface finish
- Reduced argon consumption during printing due to lower outgassing from fines
Why HTS Series Air Classifiers Excel for Stainless Steel Powders
| Feature | Benefit for Stainless Steel Powder Processing |
|---|---|
| High-efficiency turbo rotor design | Sharp cuts even at high throughput (1–6 t/h depending on model) |
| Adjustable cut size down to 2–3 μm | Capable of removing sub-10 μm fines effectively |
| Ceramic-lined wear parts | Minimal iron contamination – crucial for stainless & nickel alloys |
| Easy-to-clean design | Fast product changeover between different stainless steel grades (304L, 316L, 17-4PH, etc.) |
| Precise secondary air control | Allows very sharp upper and lower cuts in multi-stage setup |
| Low energy consumption | Lower operating cost compared to competing technologies |
Epic Powder
Whether you are a powder producer looking to upgrade your classification process or a 3D printing company seeking to improve in-house powder quality, the Epic Powder HTS series air classifier offers a reliable, high-performance solution for producing narrow PSD stainless steel powders with minimal yield loss.
If you are currently struggling with:
- High content of ultrafine particles (<10 μm or <15 μm)
- Excessive coarse particles affecting flow and packing
- Low yield of valuable middle fraction
- Contamination concerns
…then a multi-stage HTS classification process may be the most efficient path forward.
Contact Epic Powder today to discuss your specific stainless steel powder classification requirements. Our team can perform lab-scale trials with your material and propose the optimal HTS configuration for your production goals. We look forward to helping you achieve superior powder quality and production efficiency.
“Thanks for reading. I hope my article helps. Please leave a comment down below. You may also contact EPIC Powder online customer representative for any further inquiries.”
— Emily Chen, Senior Engineer
