Mesh Count
325
Openings per linear inch
Sifting Solutions
325 mesh corresponds to a nominal opening of 45 microns (0.045 mm). In botanical screening, this is generally treated as a ultra-fine separation step for dry sift, pollen, and powder handling lines.
Mesh Count
325
Openings per linear inch
Opening
45 microns
0.045 mm
Opening Inch
0.00177
Nominal clear opening
Open Area
33.1%
Wire diameter 0.033 mm
| Mesh count | 325 |
|---|---|
| Nominal opening (micron) | 45 microns |
| Nominal opening (millimeter) | 0.045 mm |
| Nominal opening (inch) | 0.00177 in |
| Nominal wire diameter | 0.033 mm |
| Nominal open area | 33.1% |
A 325 mesh screen is built with 325 openings per linear inch. For this reference, the clear opening is listed at 45 microns, with a nominal wire diameter of 0.033 mm and an open area near 33.1%. These values are used for engineering comparison, not as a substitute for final supplier drawings.
At 45 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
0.045 mm x 1000 = 45 microns
mm from micron
mm = micron / 1000
45 / 1000 = 0.045 mm
Inch conversion
inch = micron / 25400
45 / 25400 = 0.00177 in
Process notes are assembled directly from the selected opening value so each page stays consistent with the table above.
When a 325 mesh screen is used for pollen collection, the nominal opening is 45 microns. This range is typically reserved for selective finishing passes where very fine particulate control is required.
For dry sift separation, 325 mesh gives a nominal clear opening of 45 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, 325 mesh is roughly equivalent to 45 microns. This level is more appropriate for fine powder classification, test work, and controlled laboratory evaluation.
For botanical pre-screening, a 325 mesh cloth opens at about 45 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.
300 mesh at 48 microns will pass a coarser cut and hold higher throughput. 350 mesh at 42 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.