IMPORTANT STEPS IN TOOL COATING SELECTION
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Use the HANNIBAL Tool Coating Selector Guide to select the recommended coating for the machining operation being performed on your specific material.
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Review the selected coating's detailed description to confirm that it meets your specific conditions & requirements
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Without a trial production run, you cannot be certain that a specific coating will be the very best for your particular application.
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Do not order a large quantity of coated standard tools but rather order several with different coatings & review the trial production run results. Then order the full quantity with the most effective coating.
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When ordering coated special tools, request several tools with different coatings & review the trial production run results before selecting the most effective coating for the balance of the special tool order.
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The many variables involved in selecting the very best coating for your specific application can only be resolved by trial production run & analysis. Improved coated tool performance will offset your initial time & effort.
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PRE-CONDITIONS FOR SUCCESSFUL USE OF COATED TOOLS
- Good operator/manufacturing engineering skills to maximize coating benefits
- Adequate horsepower and rigidity for maximum feeds and speeds
- Resharpening policy to only resharpen a tool's cutting edges, thereby preserving the flute face coating
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RESHARPENING METHODS FOR PRESERVING THE FLUTE FACE COATING
- Drills: Grind lips only
- Reamers: Grind relief on chamfers only
- Counterbores: Grind relief on cutting edges only
- End Mills: Grind relief on OD and/or end teeth only
- Milling Cutters: Grind relief on OD and/or side teeth only
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PHYSICAL VAPOR DEPOSITION (PVD)
- HANNIBAL utilizes the Physical Vapor Deposition (PVD) process exclusively. PVD has a much lower process temperature than Chemical Vapor Deposition (CVD), thus preserving the strength and hardness of the alloy steel body and allowing for more aggressive machining without tool failure. The fine finish of PVD also results in a smoother, sharper cutting edge which stabilizes the cutting process, reduces edge build up, and improves surface finish on the workpiece.
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WHY COATED TOOLS IMPROVE PRODUCTIVITY
- Thermal Insulation - Heat at the cutting edge is a primary reason why tools break down. Coatings bond a thermally insulating barrier to the tool to reject heat from the tool surface back into the chip, thus protecting the tool substrate and making it last longer. Some coatings, such as TiAlN and AlTiN under certain conditions, actually produce a hard layer of aluminum oxide (an excellent insulator) during the cut.
- Mechanical Strength - Abrasion from the chip flow combined with microscopic roughness of the tool surface tends to wear the substrate and dull the cutting edge during normal operations. The high hardness, lower friction coefficient, and reduced surface roughness of coatings allow the chip to flow off the surface of the tool. This reduces built up edge and wear so tool life is increased.
- Chemical resistance - Heat, pressure, coolant, and workpiece material all add to the chemically reactive forces present at the cutting edge. When reactive elements are brought together under these conditions, the uncoated tool will degrade. Coatings protect the tool substrate from exposure to these reactive forces thus stabilizing the cutting edge even under the harshest conditions.
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COATING COMPARISONS |
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TiN |
TiCN |
ZrN |
AlTiN |
Hardness (Vickers) |
2300 (81 Rc)
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3000 (87 Rc)
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2500 (85 Rc)
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4500 (90 Rc)
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Relative Toughness (1=Toughest) |
3
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1
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2
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4
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Oxidation Temperature |
550ºC (1050ºF)
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400ºC (750ºF)
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600ºC (1110ºF)
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800ºC (1450ºF)
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Friction Coefficient |
.65
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.45
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.50
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.45
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Thickness |
2-4 microns
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2-4 microns
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2-4 microns
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2-4 microns
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Surface Roughness (Ramm) |
.20
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.17
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.20
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.15
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SPECIALLY SELECTED COATING COMPANIES
- PVD Coating Service companies have significant equipment & processing differences that can dramatically influence the coating's effectiveness for different types of tools - drills, reamers, cutters, etc.
- HANNIBAL has selected three technically focused coating companies that collectively can meet our customers' exacting needs for all coatings & tool types.
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