Mesh Count
400
Openings per linear inch
Sifting Solutions
400 mesh corresponds to a nominal opening of 38 microns (0.038 mm). In botanical screening, this is generally treated as a ultra-fine separation step for dry sift, pollen, and powder handling lines.
Mesh Count
400
Openings per linear inch
Opening
38 microns
0.038 mm
Opening Inch
0.00150
Nominal clear opening
Open Area
36.0%
Wire diameter 0.025 mm
| Mesh count | 400 |
|---|---|
| Nominal opening (micron) | 38 microns |
| Nominal opening (millimeter) | 0.038 mm |
| Nominal opening (inch) | 0.00150 in |
| Nominal wire diameter | 0.025 mm |
| Nominal open area | 36.0% |
A 400 mesh screen is built with 400 openings per linear inch. For this reference, the clear opening is listed at 38 microns, with a nominal wire diameter of 0.025 mm and an open area near 36.0%. These values are used for engineering comparison, not as a substitute for final supplier drawings.
At 38 microns, this screen size tends to shift the process toward laboratory-style classification where particle size control matters more than open throughput. In production terms, it sits in the ultra-fine part of the screening range and is usually selected after operators define the target fraction, feed dryness, and deck loading rate.
These formulas explain the unit relationship shown in the table.
Micron from mm
micron = mm x 1000
0.038 mm x 1000 = 38 microns
mm from micron
mm = micron / 1000
38 / 1000 = 0.038 mm
Inch conversion
inch = micron / 25400
38 / 25400 = 0.00150 in
Process notes are assembled directly from the selected opening value so each page stays consistent with the table above.
When a 400 mesh screen is used for pollen collection, the nominal opening is 38 microns. This range is typically reserved for selective finishing passes where very fine particulate control is required.
For dry sift separation, 400 mesh gives a nominal clear opening of 38 microns. At this point the screen is acting as a fine classification layer, so feed consistency and blinding control become more important.
In powder grading work, 400 mesh is roughly equivalent to 38 microns. This level is more appropriate for fine powder classification, test work, and controlled laboratory evaluation.
For botanical pre-screening, a 400 mesh cloth opens at about 38 microns. At this fineness the screen is no longer a rough pre-screen. It becomes a precision control point inside a multi-stage grading workflow.
350 mesh at 42 microns will pass a coarser cut and hold higher throughput. 425 mesh at 34 microns will shift the cut point finer and tighten material control.
Nominal opening values were curated from commonly referenced industrial wire cloth and U.S. sieve conversion charts. Actual clear opening can vary by weave style, wire diameter, and manufacturing tolerance.
Nominal opening values may vary slightly by weave and wire diameter. For purchase approval, always confirm the actual cloth specification issued by the manufacturer.