Technical Screening FAQs

This FAQ addresses the technical questions that operators, maintenance teams, and process engineers encounter when running vibratory screening equipment. Whether you are troubleshooting a performance issue, optimizing an existing setup, or trying to understand the science behind vibratory screening, you will find detailed answers here. For product-specific questions, see our replacement screen FAQs and vibratory screener FAQs.

What does mesh size mean?

Mesh size is the number of openings per linear inch in a woven wire screen. A 60-mesh screen has 60 openings per inch. Higher mesh numbers mean smaller openings and finer screening. The actual opening size depends on both the mesh count and the wire diameter. See our mesh size chart for complete size conversions.

How do I convert mesh size to microns?

Common conversions (U.S. Standard / ASTM E11): 10 mesh = 2,000 microns, 20 mesh = 841 microns, 40 mesh = 400 microns, 60 mesh = 250 microns, 80 mesh = 177 microns, 100 mesh = 149 microns, 200 mesh = 74 microns, 325 mesh = 44 microns, 400 mesh = 37 microns, 500 mesh = 25 microns. Visit our mesh size chart for the full table.

What is the open area percentage of a screen?

Open area is the percentage of screen surface consisting of mesh openings rather than wire. Higher open area increases throughput. Typical wire cloths have 30% to 50% open area. Open area depends on mesh count and wire diameter. Finer mesh sizes generally have lower open area.

What are counterweights and how do they affect screening?

Counterweights on the motor shaft control vibration pattern. Top weights affect horizontal throw (material spread). Bottom weights affect vertical action and material travel speed. The angle between them (lead angle) determines whether material spirals slowly (higher precision) or quickly (higher throughput). See our weight adjustment guide.

What is the lead angle on a vibratory screener?

The lead angle is the angular offset between top and bottom counterweights. Small lead angle (0-30 degrees) = longer residence time, higher precision. Large lead angle (45-90 degrees) = faster discharge, higher throughput. Typical starting point is 45-50 degrees for general applications.

How do I increase throughput on my vibratory screener?

Increase the lead angle to speed material travel. Increase motor vibration amplitude via weight settings. Use coarser mesh if specs allow. Add self-cleaning systems to prevent blinding. Ensure proper screen tension. Verify motor RPM. If still insufficient, a larger screener may be needed.

How do I improve separation accuracy?

Decrease the lead angle for longer residence time. Reduce feed rate. Verify mesh size matches your cut point. Ensure screens are properly tensioned. Check that the screener is level. Consider finer mesh with self-cleaning to maintain throughput.

Why is material not discharging properly from my screener?

Common causes: lead angle too small, insufficient vibration amplitude, blocked discharge spout, excessive feed rate overloading the screen, improper screen seating, or screener not level. Check weight settings, feed rate, and physical obstructions first.

What causes a vibratory screener to walk or move on the floor?

Screener walking results from unbalanced vibration: uneven weight settings, a damaged or missing spring, screener not level, bent motor shaft, or spring failure. Check all springs, verify level, and confirm symmetrical weight settings.

What is near-size material and why does it cause problems?

Near-size particles (75% to 125% of mesh opening) wedge in openings causing blinding, or pass through inconsistently reducing accuracy. Solutions: self-cleaning screens, ultrasonic deblinding, and reduced feed rate.

How do I determine the correct spring rate for my screener?

Springs must match the total vibrating mass. Always replace with the exact specification for your model. Mixing spring rates changes vibration characteristics and risks equipment damage. Contact ScreenerKing with your screener model for the correct spring specification.

What is the difference between screening and scalping?

Scalping is a coarse operation removing a small percentage of oversize material at high feed rates (4-20 mesh). Screening is broader, including scalping plus finer classification, grading, and check screening where accuracy matters more.

How does moisture affect screening performance?

Moisture causes particles to agglomerate and stick to the screen surface, reducing throughput and accuracy. Even 2-5% moisture dramatically affects fine screening. Solutions: dry material before screening, use self-cleaning ball trays, add ultrasonic deblinding, or switch to wet screening.

Can I screen the same material at two different cut points simultaneously?

Yes, with a multi-deck screener. A two-deck unit with coarser mesh on top and finer mesh on the bottom makes two separations in one pass, producing three fractions. ScreenerKing screeners are available with up to five decks.

What causes excessive noise from a vibratory screener?

Common sources: motor bearing wear (grinding), loose bolts (rattling), broken springs (irregular vibration), improperly seated frames (chattering), and material impact (inherent). Motor bearing noise and loose hardware are the most common abnormal noise causes.

How do I calibrate my screener for a new material?

Start with factory default weight settings. Run material at target feed rate. Collect and analyze overs and throughs samples. Decrease lead angle or reduce feed rate if too much undersize is in overs. Increase lead angle if throughput is too low. Adjust in small increments and re-sample after each change.

What is the difference between 1200 RPM and 1800 RPM operation?

1200 RPM: slower, higher-amplitude vibration for coarse, heavy, or wet materials. 1800 RPM: faster, lower-amplitude vibration for fine powders and general dry screening. RPM is fixed by motor pole count. See our motor selection guide.

How do I prevent product contamination from screen wire breakage?

Use T-430 magnetic stainless steel screens detectable by downstream metal detectors. Implement regular screen inspection schedules. Consider sandwich screens for added durability. Some facilities use dual-layer safety screening for critical applications.