Metal powders are typically screened at 20 to 500 mesh (841 to 25 microns) depending on the application. Coarse metal powders for sintering and welding use 20 to 100 mesh, while fine powders for additive manufacturing, metal injection molding, and thermal spray require 100 to 500 mesh classification with tight particle size distribution control.
Metal powder screening requires careful attention to abrasion, combustibility, and particle shape. Unlike organic powders, metal powders wear screens rapidly, may be combustible or explosive in fine sizes, and often have irregular particle shapes that affect screening efficiency. ScreenerKing provides replacement screens engineered for the demands of metal powder processing, available in all standard sizes with fast delivery from Houston, Texas.
Recommended Mesh Sizes by Application
| Material / Application | Mesh Size | Micron Size | Purpose |
|---|---|---|---|
| Iron / steel powder — sintering (PM parts) | 60–100 mesh | 250–150 µm | Classification for press-and-sinter compacts |
| Aluminum powder — pyrotechnics / paint | 100–325 mesh | 150–45 µm | Fine grading for reactivity and coating quality |
| Copper powder — sintering / friction | 80–200 mesh | 180–75 µm | Classification for powder metallurgy |
| Titanium powder — additive manufacturing | 100–500 mesh | 150–25 µm | Tight PSD control for 3D printing |
| Stainless steel powder — MIM / AM | 170–325 mesh | 90–45 µm | Fine fraction for metal injection molding and AM |
| Tungsten carbide powder | 200–400 mesh | 75–37 µm | Fine classification for cemented carbide production |
| Thermal spray powders | 80–325 mesh | 180–45 µm | Grading for consistent spray deposition |
| Welding rod flux / filler powder | 20–60 mesh | 841–250 µm | Remove oversize and fines for consistent weld quality |
| Recycled AM powder (reuse screening) | 170–400 mesh | 90–37 µm | Remove spatter and satellites from used powder |
Factors That Affect Mesh Selection for Metal Powders
- Particle shape: Gas-atomized powders are spherical and screen efficiently. Water-atomized and mechanically milled powders have irregular shapes that can bridge across mesh openings, requiring coarser mesh or ultrasonic deblinding to maintain throughput.
- Abrasiveness: Hard metals (tungsten carbide, tool steel, stainless steel) wear screens rapidly. Expect to replace screens more frequently than with soft metal powders. Keep spare screens on hand to minimize downtime.
- Combustibility: Fine metal powders (especially aluminum, titanium, magnesium, and zirconium) are combustible or explosive. Screening must follow NFPA 484 and ATEX guidelines. Inert atmosphere, explosion-proof motors, and proper grounding are essential.
- Particle size distribution (PSD) requirements: Additive manufacturing and MIM applications demand tight PSD control, often with both upper and lower cut points. This requires multi-deck screening with different mesh sizes on each deck.
- Throughput vs. precision: Metal powders are dense (iron powder is approximately 160 lb/ft3). Even modest throughput requirements produce heavy screen loading. Balance throughput against separation accuracy by selecting the appropriate screener diameter.
Screen Material Recommendations
316 stainless steel is recommended for most metal powder screening due to its superior corrosion resistance and compatibility with the cleaning solvents and inert atmospheres used in metal powder processing.
304 stainless steel is suitable for screening non-corrosive metal powders such as iron, copper, and bronze in dry environments where corrosive cleaning agents are not used.
T-430 stainless steel is used in metal powder facilities that require magnetically detectable screens for contamination control, though this is less common in metal powder processing where the product itself is metallic.
Equipment Recommendations
- Additive manufacturing and lab (under 500 lb/hr): ScreenerKing SiftPro 18" or 24" — ideal for AM powder reclamation and small-batch classification.
- Powder metallurgy production (500–5,000 lb/hr): ScreenerKing SiftPro 30" — standard for PM part production and thermal spray powder grading.
- High-volume atomization (5,000–15,000 lb/hr): ScreenerKing SiftPro 48 (48") — handles heavy metal powder throughput after atomization.
- Large-scale production (15,000+ lb/hr): ScreenerKing SiftPro 60 — maximum capacity for iron and steel powder classification.
Frequently Asked Questions
What mesh size is used for additive manufacturing metal powders?
Additive manufacturing metal powders typically require 100 to 325 mesh (150 to 45 microns) screening. Powder bed fusion processes commonly use 15 to 45 micron powder, while directed energy deposition uses 45 to 150 micron powder. Used powder is re-screened to remove spatter and satellites before reuse.
Can I screen reactive metal powders on a vibratory screener?
Yes, but with critical safety precautions. Reactive metal powders are combustible or explosive in fine sizes. Screening must use inert atmosphere, explosion-proof motors, proper grounding, and spark-free materials. Consult your safety engineer and equipment supplier before screening reactive metals.
Why do my metal powder screens wear out quickly?
Metal powders are highly abrasive, especially hard metals like tungsten carbide and tool steel. Screen life depends on powder hardness, particle size, throughput, and wire diameter. Use heavier wire mesh where possible, reduce feed rate, ensure proper tensioning, and keep ScreenerKing replacement screens on hand for fast changeover.
