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D2534-88 – Standard Test Method Technical Guide
🎯 Scope and Significance
This standard test method, designated D2534 – 88 (Reapproved 2017), specifies the procedure for determining the coefficient of kinetic friction for petroleum wax coatings and wax-based hot melt coatings when sliding over themselves. This property is critical for assessing the slip and handling characteristics of commercial articles, specifically butter cartons, wax-impregnated board, and hot melt coated corrugated materials.
Technical Note: The coefficient of kinetic friction measures the resistance to motion when one coated surface is already in motion over another. It differs from static friction, which measures the force required to initiate motion. This test exclusively evaluates the kinetic value.
⚙️ Apparatus and Test Setup
The test utilizes a specifically defined Sled Assembly and a Horizontal Plane Assembly. The entire apparatus is designed to ensure uniformity and precise measurement. The sled is pulled at a uniform rate, and the pulling force is measured using an electronic load cell.
| 🟦 Component | 📏 Specification | 🎯 Required Tolerance |
|---|---|---|
| Brass Block (Sled Base) | 25 mm x 13 mm x 75 mm | ± 0.5 mm (typical) |
| Microscope Slide (Sled Face) | 25 mm x 75 mm | Cemented to block |
| Sled Handle | 1.5 mm weld rod | Detachable |
| Total Sled Weight | 180 g | ± 1 g |
| Glass Plane Surface | 150 mm x 300 mm | Smooth, flat, level |
| Low-Friction Pulley | Phenolic-type material | Hardened steel cone bearings |
Critical Setup Requirements: The horizontal plane assembly must be adjusted so the glass surface is perfectly level. The pulley must be positioned so that its outer side is centered directly beneath the load cell, and the bottom side is level with the sled handle. The connection cable must be a light, flexible metal cable or polyester cord.
📊 Terminology and Calculation
Kinetic friction is defined in this standard as the force that resists motion when a surface is moving with uniform velocity. It is equal and opposite to the force required to maintain sliding of the surface.
The Coefficient of Kinetic