Extruder screen pack convention is the governing standard for multi-layer filter packs. This page sets out the scope of the document, reproduces the full specification table, and lists the ISO/ASTM/DIN cross-references cited in datasheets and purchase orders.
Extruder screen pack convention — Scope
Extruder screen pack convention specifies the designation system, dimensions and tolerances of multi-layer filter packs — mesh count or nominal opening, wire diameter and the permissible aperture deviations. Alloy chemistry, mechanical testing and delivery condition are governed by separate documents in the same standards family.
Tolerance Classes
Extruder screen pack convention defines tolerance limits on the average aperture and on the maximum single aperture, tightening as the aperture gets finer. For test-sieve duty the tighter ISO 3310-1 tolerances apply instead of the general cloth tolerances — specify sieve grade explicitly if the mesh will be used for particle-size analysis.
Specifications Defined by Extruder screen pack convention
| Diameter (mm) | Mesh / micron options | Layers | Edge treatment | Reference standard |
|---|---|---|---|---|
| 20 | Coarse guard + fine + support | 3 | Spot welded | Extruder / SPM pack |
| 38 | Coarse guard + fine + support | 3-5 | Spot welded | Extruder / SPM pack |
| 50 | Coarse guard + fine + support | 3-5 | Bound rim | Extruder / SPM pack |
| 90 | Coarse guard + fine + support | 5-7 | Bound rim | Extruder / SPM pack |
| 155 | Coarse guard + fine + support | 5-7 | Bound rim | Extruder / SPM pack |
Equivalent Standards
Where direct equivalents exist (ISO ↔ ASTM ↔ DIN), they are listed on the parent Multi-Layer Filter Packs page. Confirm against the specification table on this page — nominally equivalent documents can differ in tolerance limits.
When to Specify Extruder screen pack convention
Choose Extruder screen pack convention for international procurement and OEM supply where ISO documents are the contractual reference. It is the default modern specification for multi-layer filter packs.
