IMS ENGINEERING COLLEGE
PRESENTATION ON CUTTING FLUID TOOL MATERIAL TOOL WEAR TOOL LIFE PRESENTED BY ADITYA KUMAR ME-1 3rd YEAR IMS ENGINEERING COLLEGE SUBMITTED TO Mr. DEEPAK SHARMA OBJECTIVE To make you aware about the cutting fluids , toolmaterial , tool wear and tool life in simple and easierway. OVERVIEW Cutting Fluid Types of cutting fluid Cutting Fluid Effects
Cutting Fluid Selection Criteria Tool Material Tool Wear Tool Life Cutting Fluids Cutting fluids are used in metal machining for a varietyof reasons such as improving tool life, reducing workpiece thermal deformation, improving surface finishand flushing away chips from the cutting zone.Practically all cutting fluids presently in use fall intoone of four categories: 1.Straight oils 2.Soluble oils 3.Semi synthetic fluids 4.Synthetic fluids Straight oils are non emulsifiable and are used in machiningoperations in an undiluted form. They are composed of a basemineral or petroleum oil and often contains polar lubricants suchas fats, vegetable oils and esters as well as extreme pressureadditives such as Chlorine, Sulphur and Phosphorus. Straight oilsprovide the best lubrication and the poorest cooling characteristicsamong cutting fluids. Synthetic Fluids contain no petroleum or mineral oil base andinstead are formulated from alkaline inorganic and organiccompounds along with additives for corrosion inhibition. They aregenerally used in a diluted form (usual concentration = 3 to 10%).Synthetic fluids often provide the best cooling performance amongall cutting fluids. Soluble Oil Fluids form an emulsion when mixed with water. Theconcentrate consists of a base mineral oil and emulsifiers to helpproduce a stable emulsion. They are used in a diluted form (usualconcentration = 3 to 10%) and provide good lubrication and heattransfer performance. They are widely used in industry and are theleast expensive among all cutting fluids. Semi-synthetic fluids are essentially combination of syntheticand soluble oil fluids and have characteristics common to bothtypes. The cost and heat transfer performance of semi-syntheticfluids lie between those of synthetic and soluble oil fluids. Cutting fluid effects The primary functions of cutting fluids in machining are : Lubricating the cutting process primarily at low cuttingspeeds Cooling the work piece primarily at high cutting speeds Flushing chips away from the cutting zone Corrosion protection of the machined surface Enabling part handling by cooling the hot surface Longer Tool Life Reduced Thermal Deformation of Work piece Better Surface Finish (in some applications) Ease of Chip handling Cutting Fluid Selection
Criteria Process performance : Heat transfer performance Lubrication performance Chip flushing Fluid carry-off in chips Corrosion inhibition Fluid stability (for emulsions) Cost Performance Environmental Performance Health Hazard Performance Material Milling Drilling Tapping Turning Aluminium Soluble oil (96% water) or mineral oil Soluble oil (70-90% water) 25% sulfur-based oil mixed with mineral oil Mineral oil with 10% fat (or) soluble oil Brass Soluble oil (96% water) Soluble oil 10-20% lard oil with mineral oil Mineral oil with 10% fat Bronze 30% lard with mineral oil Alloy Steels 10% lard oil with 90% mineral oil 30% lard oil with 70% mineral oil 25% sulfur base oil with 75% mineral oil Cast Iron Dry Dry or 25% lard oil with 80% mineral oil Malleable Iron Copper Low Carbon and Tool Steels 25-40% lard oil with mineral oil 25% lard oil with 75% mineral oil TOOL MATERIAL Tool failure modes identify the important properties that a tool material should possess: Toughness to avoid fracture failure Hot hardness ability to retain hardness at high temperatures Wear resistance hardness is the most important property to resist abrasive wear Plain carbon steel shows a rapid loss of hardnessas temperature increases.
High speed steel is substantially better, whilecemented carbides and ceramics are significantlyharder at elevated temperatures. HIGH SPEED STEEL Highly alloyed tool steel capable of maintaininghardness at elevated temperatures better than highcarbon and low alloy steels One of the most important cutting tool materials Especially suited to applications involvingcomplicated tool geometries, such as drills, taps,milling cutters, and broaches Two basic types (AISI) Tungsten type, designated T grades Molybdenum type, designated M grades HIGH SPEED STEEL COMPOSITION
Typical alloying ingredients: Tungsten and/or Molybdenum Chromium and Vanadium Carbon, of course Cobalt in some grades Typical composition: Grade T1: 18% W, 4% Cr, 1% V, and 0.9% C CERAMICS Primarily finegrained Al2O3, pressed and sintered athigh pressures and temperatures into insert formwith no binder. Applications: high speed turning of cast iron andsteel Not recommended for heavy interrupted cuts (e.g.rough milling) due to low toughness Al2O3 also widely used as an abrasive in grinding . SYNTHETIC DIAMOND Sintered polycrystalline diamond (SPD) - fabricated by sintering very finegrained diamond crystals under high temperatures and pressures into desired shape with little or no binder Usually applied as coating (0.5 mm thick) on WC-Co insert Applications: high speed machining of nonferrous metals and abrasive nonmetals such as fiberglass, graphite, and wood Not for steel cutting CUBIC BORON NITRIDE Next to diamond, cubic boron nitride (cBN) ishardest material known Fabrication into cutting tool inserts same as SPD:coatings on WCCo inserts Even at high temp. C.B.N is chemically inert toferrous metals and resist oxidation. Applications: machining steel and nickelbasedalloys SPD and cBN tools are expensive TOOL WEAR Abrasion - dominant cause of flank wear
Adhesion high pressure localized fusion and rupturing Diffusion Loss of hardening atoms at tool-chip boundary (contributes to crater wear) Plastic deformation contributes to flank wear CRATER WEAR FLANK WEAR Taylor Tool Life Equation
This relationship is credited to F. W. Taylor (~1900) where v = cutting speed; T = tool life; and n and C are parameters that depend on feed, depth of cut, work material, tooling material, and the tool life criterion used n is the slope of the plot C is the intercept on the speed axis A more general form of the equation is THANK YOU