Machining Applications Views: 15

Cutting fluid selection and concentration: Functions - cooling, lubrication, chip removal, rust prevention. Types: 1) Emulsion (soluble oil) - milky white; good lubrication, moderate cooling, cheap; for carbon steel, alloy steel, stainless - most common; 2) Semi-synthetic - translucent; balanced cooling/lubrication, good cleanliness; for steel, alloy steel, aluminum; clean jobs; 3) Full synthetic - transparent; excellent cooling and cleanliness, moderate lubrication; for grinding, roughing, aluminum, copper; 4) Cutting oil - oil-based; best lubrication, poor cooling, some smoke; for precision work and hard materials (stainless, superalloys), high-finish jobs; 5) EP cutting fluid - extreme-pressure additives; heavy cutting, hard materials. Selection guide: 1) carbon steel, alloy steel - emulsion, 5%-8%; 2) stainless, superalloys - EP emulsion or semi-synthetic, 8%-12%; 3) aluminum, copper - semi- or full synthetic, 3%-5%, prevents discoloring; 4) precision/mirror jobs - cutting oil or high-concentration emulsion; 5) roughing/large stock - full synthetic or low-concentration emulsion for cooling. Concentration: 1) too low - poor lubrication, fast wear, poor finish; 2) too high - waste, foaming, hard cleanup, possible discoloring; 3) measure with a refractometer, top up and replace regularly; 4) slightly lower in summer, higher in winter; 5) water evaporates in use, raising concentration - add water periodically. Notes: 1) replace fluid every 1-3 months to prevent spoilage and odor; 2) keep fluid clean, remove chips and oil; 3) do not mix different fluid types (reactions); 4) wear gloves with cutting fluid (skin irritation); 5) dispose of waste fluid per environmental rules - never dump. Right cutting fluid extends tool life 20%-50% and improves finish.