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Cutting conditions

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Cutting conditions description.
Ebaketa baldintzen deskribapena.
Descripción de las condiciones de corte.

Cutting conditions

  1. 1. Feed rate Spindle Speed Radial cutting depth Axial cutting depth … CUTTING CONDITIONS BACHELOR OF ENGINEERING MANUFACTURING TECHNOLOGIES CUTTING CONDITIONS by Endika Gandarias
  2. 2. 2by Endika Gandarias Dr. ENDIKA GANDARIAS MINTEGI Mechanical and Manufacturing department Mondragon Unibertsitatea - www.mondragon.edu (Basque Country) www.linkedin.com/in/endika-gandarias-mintegi-91174653
  3. 3. 3 CONTENTS  BIBLIOGRAPHY  CUTTING TOOLS  CUTTING PARAMETERS  CUTTING FLUIDS  SELECTION OF CUTTING CONDITIONS  GLOSSARY by Endika Gandarias
  4. 4. 4 BIBLIOGRAPHY BIBLIOGRAPHY by Endika Gandarias
  5. 5. 5 The author would like to thank all the bibliographic references and videos that have contributed to the elaboration of these presentations. For bibliographic references, please refer to: • http://www.slideshare.net/endika55/bibliography-71763364 (PDF file) • http://www.slideshare.net/endika55/bibliography-71763366 (PPT file) For videos, please refer to: • www.symbaloo.com/mix/manufacturingtechnology BIBLIOGRAPHY by Endika Gandarias
  6. 6. 6 CUTTING TOOLS CUTTING TOOLS by Endika Gandarias
  7. 7. 7 CUTTING TOOLS by Endika Gandarias (HSS) VIDEOVIDEO
  8. 8. 8 CUTTING TOOLS by Endika Gandarias
  9. 9. 9 CUTTING TOOLS by Endika Gandarias Temperature [ºC] Hardness[HRC] 1550 1400 1300 900 800 Ceramic CBN Carbide (Hard metal) Diamond HSS ºC
  10. 10. 10 Feed [mm/rev] Cuttingspeed[m/min] 50 CUTTING TOOLS by Endika Gandarias
  11. 11. 11 Solid tool Brazed insert Mechanically clamped insert TOOL GEOMETRY Turning CUTTING TOOLS by Endika Gandarias VIDEO
  12. 12. 12 CUTTING TOOLS by Endika Gandarias TOOL GEOMETRY Turning RAKE FACE Front Clearance (or end-relief) angle Major (or side) cutting edge Minor (or end) cutting edge Front or back rake angle Nose (or corner) radius MAJOR CLEARANCE (FLANK OR RELIEF) FACE Minor (or end) cutting edge angle MINOR CLEARANCE (OR FLANK) FACE Side rake angle Major (or side or lead) cutting edge angle Side clearance (or relief) angle Major cutting edge angle Minor cutting edge angle RAKE FACE CLEARANCE FACEClearance angle Rake angle Side clearance angle Side rake angle VIDEO
  13. 13. 13 CUTTING TOOLS by Endika Gandarias TOOL GEOMETRY Milling Flat End Mill Ball nose End Mill Corner radius End Mill END MILLING CUTTERS PERIPHERAL AND FACE MILLING CUTTERS Shell End Mill Side and Face cutter Single and double angle cutter
  14. 14. 14 TOOL GEOMETRY CUTTING TOOLS by Endika Gandarias Drilling Solid carbide drill Chisel edge Main cutting edge Rake face Major flank faceMargin Drill diameter Web thicknessMajor flank face Major cutting edge Rake face Point angle Minor cutting edge Helix angle Point angle 140° High Speed Steel (HSS) Point angle 118° VIDEO
  15. 15. 15 TOOL INSERT Main cutting edge design Cheap-breaker macrogeometry Geometry for small cutting depths (ap) Rake angle 20° Main facet 5° Tip cutting edge design Cheap-breaker macrogeometry Cutting edge reinforcement of 0,25 mm CUTTING TOOLS by Endika Gandarias VIDEO Insert design
  16. 16. 16 CUTTING TOOLS by Endika Gandarias TOOL INSERT Insert material types
  17. 17. 17 TOOL INSERT CUTTING TOOLS by Endika Gandarias VIDEO POSITIVE Rake angle NEGATIVE Increased tool insert resistance. Higher cutting forces. Shorter chip length. Clearance angle = 0º. Double side inserts. Lower cutting forces. Longer chip length. Clearance angle > 0º. Used for internal machining. Clearance angle Clearance angle always > 0º.
  18. 18. 18 TOOL INSERT CUTTING TOOLS by Endika Gandarias Lead angle / Entering angle Entering angle Lead angle Side Rake angle  Same advantage discussed for rake angle, applies to side rake angle.  When rake angle is positive so is side rake angle, and vice versa.
  19. 19. 19 TOOL INSERT CUTTING TOOLS by Endika Gandarias Nose radius and Nose angle Chipbreaker Each insert has an appliation area. Groove type Obstruction type Nose radius Nose angle
  20. 20. 20 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert grade VIDEO VIDEO VIDEO VIDEO
  21. 21. 21 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Raw material Crushed Spray drying Carbide powder Ready to be pressed Cobalt Tungsten carbide Titanium Tantalum Niobium Powder fabrication VIDEO
  22. 22. 22 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Pressing force 20 - 50 t Upper and lower die Die and center pin Pressing
  23. 23. 23 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Sintering Sintering duration: 8 hours Temperature between 1200 - 2200 °CInserts trays Insert contraction (18% in all directions, 50% in volume)
  24. 24. 24 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Insert grinding Higer and lower face Free profiling Profiling Beveling, negative facet Peripheral Bisel Faceta neg.
  25. 25. 25 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Insert grinding ER Treatment (Edge Roundness) W/H proportion depends on the application
  26. 26. 26 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Chemical Vapor Deposition (CVD) coating - Large coating thickness. - Mechanical wear resistance (TiCN). - Thermal & chemical resistance (Al2O3). TiCN Al2O3 Substrate Inserts trays CVD oven
  27. 27. 27 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Physical vapor deposition (PVD) coating PVD oven TiN Substrate - Thin coating thickness. - Sharp cutting edge. - Good edge toughness. - Used in all monoblock rotating tools. - Can be used with soldered tips.
  28. 28. 28 TOOL INSERT CUTTING TOOLS by Endika Gandarias Insert fabrication Visual inspection, marking, packaging Visual inspection Marking Distribution Labelling Packaging
  29. 29. 29 CUTTING PARAMETERS CUTTING PARAMETERS by Endika Gandarias
  30. 30. 30  SELECTION CRITERIA: Make the highest profit considering the technical requirements.  OPERATIONS: – ROUGHING: It aims to remove as much as possible material from the workpiece for as short as possible machining time. Quality of machining is of a minor concern. – FINISHING: The purpose is to achieve the technical requirements (i.e., dimensional, surface and geometric tolerances). Quality is of major importance. In order to make most profit the most relevant variables are: • Cutting time. • Cutting tool expenditure. Machining parameters that most affect the above variables are: • Cutting speed (Vc) • Feed (fz, fn, F) • Radial and axial depth of cuts (ap, ae) ROUGHING FINISHING Vc fn   fz   F CUTTING PARAMETERS by Endika Gandarias
  31. 31. 31 DEFINITION: Relative linear speed at the contact point between tool and the workpiece. Vc · 1000 N = π · Dm CUTTING PARAMETERS: TURNING 1. Cutting Speed (Vc) by Endika Gandarias N Vc: Cutting speed (m/min) N: Spindle speed (rpm) Dm: machined diameter (mm) VIDEO VIDEO VIDEO VIDEO
  32. 32. 32 CUTTING PARAMETERS: TURNING 1. Cutting Speed (Vc) Given the following parameters calculate the spindle speed for each diameter: Cutting speed Vc = 120 m/min Diameter D1 = Ø 50 mm Diameter D2 = Ø 80 mm VC x 1000 π x d N = N1 N2 by Endika Gandarias
  33. 33. 33 F [mm/min] DEFINITION: Relative movement between the workpiece and the tool. fn [mm/rev] IN TURNING FEED PER REVOLUTION (fn) → 2. Feed 3. Cutting depth (ap) FEED PER REVOLUTION F = fn·N CUTTING PARAMETERS: TURNING FEED RATE or FEED PER MINUTE by Endika Gandarias F ap ap ap
  34. 34. 34 MACHINE WORKPIECE MATERIAL TOOL MATERIAL OPERATION Vc (m/min) fn (mm/rev) Ap (mm) TURNING MACHINE STEEL HIGH SPEED STEEL (HSS) Turning and facing D 30 – 40 A 40 - 50 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 Parting and grooving 10 – 15 0.02 – 0.1 Threading 10 Thread pitch According to formula Drilling 18 Manual Knurling 10 Boring D 20 – 30 A 30 - 40 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 HARD METAL Turning and facing D 80 – 100 A 100 - 120 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 Parting and grooving 60 – 80 0.04 – 0.1 Threading 40 - 50 Thread pitch According to formula Drilling 30 – 40 Manual Boring D 70 – 90 A 90 - 110 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 ALUMINIUM HIGH SPEED STEEL (HSS) Turning and facing D 40 – 60 A 60 - 80 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 Parting and grooving 20 – 30 0.02 – 0.1 Threading 15 Thread pitch According to formula Drilling 30 Manual Knurling 20 Boring D 30 – 50 A 50 - 70 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 HARD METAL Turning and facing D 150 – 180 A 180 – 200 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 Parting and grooving 80– 100 0.04 – 0.1 Threading 50 – 60 Thread pitch According to formula Drilling 60 – 80 Manual Boring D 140 – 170 A 170 - 190 D 0.1– 0.25 A 0.02/ 0.1 D 0.75-2 A 0.2-0.8 by Endika Gandarias D: Roughing operation A: Finishing operation CUTTING PARAMETERS: TURNINGORIENTATIVECUTTINGTABLEFOREXERCISES
  35. 35. 35 SURFACE ROUGHNESS: Surface finish depends on: • Tool nose radius • Feed per revolution (fn) WIPER INSERTS: Advantages: Productivity ↑ CUTTING PARAMETERS: TURNING by Endika Gandarias VIDEO
  36. 36. 36 CUTTING PARAMETERS: TURNING by Endika Gandarias TOOL CENTRE HEIGHT
  37. 37. 37 CUTTING PARAMETERS: TURNING VIBRATION _ + Vibration by Endika Gandarias Round R 90º S 80º C 80º W 60º T 55º D 35º V _ + Vibration ER: Edge Rounding GC: Ground coated inserts VB: Flank wear _ + Strength
  38. 38. 38 CUTTING PARAMETERS: TURNING VIBRATION They can reduce machining vibration in turning, milling or drilling. VIDEO – Diameters starting from Ø > 10mm. – Maximum overhang value 14 × Ø. by Endika Gandarias Dampened tool Undampened tool SSV technique may reduce or eliminate chatter. VIDEO VIDEO Dampened tools Spindle Speed Variation (SSV)
  39. 39. 39 DEFINITION: Relative linear speed at the contact point between tool and the workpiece. CUTTING PARAMETERS: MILLING 1. Cutting Speed (Vc) by Endika Gandarias N N Vc · 1000 Vc: Cutting speed (m/min) N = N: Spindle speed (rpm) π · Dc Dc: Tool diameter (mm) VIDEO
  40. 40. 40 Feed per tooth (fz): It defines the chip thickness, and so, the load that the tool is subjected to. Feed per revolution (fn): It defines the tool displacement per tool revolution. Feed rate or Feed per minute (F): It defines the tool movement speed. fn = fz·z  z tooth number (flute number) F = fn·N = fz·z·N  N spindle speed DEFINITION: Relative movement between the workpiece and the tool. IN MILLING FEED PER TOOTH (fz) → 2. Feed CUTTING PARAMETERS: MILLING by Endika Gandarias fn F VIDEO
  41. 41. 41 As there are greater tooth breakage chances during tooth entry and exit, in facing operations the following tool size and positioning are recommended. ap: axial depth of cut  ae : radial depth of cut 3. Cutting depth Better size Better positioning CUTTING PARAMETERS: MILLING by Endika Gandarias VIDEO
  42. 42. 42by Endika Gandarias MACHINE WORKPIECE MATERIAL TOOL MATERIAL OPERATION Vc (m/min) fz (mm/tooth*rev) Ap (mm) Ae (mm) MILLING MACHINE STEEL HIGH SPEED STEEL (HSS) Face milling D 20 - 25 A 25 - 30 0.05 – 0.1 0.01 – 0.05 D 1-2 A 0.2-0.5 D (~2/3)Ø A (~2/3)Ø Side milling D 20 - 25 A 25 - 30 0.05 – 0.1 0.01 – 0.05 D (50%-80%)Ø A (50%-80%)Ø D (10%-25%)Ø A (5%-10%)Ø Other milling D 15 - 20 A 20 - 25 0.05 – 0.1 0.01 – 0.05 HARD METAL Face milling D 80 - 100 A 100 – 120 0.05 – 0.1 0.01 – 0.05 D 1-2 A 0.2-0.5 D (~2/3)Ø A (~2/3)Ø Side milling D 80 - 100 A 100 – 120 0.05 – 0.1 0.01 – 0.05 D (50%-80%)Ø A (50%-80%)Ø D (10%-25%)Ø A (5%-10%)Ø Other milling D 70 - 90 A 90 – 100 0.05 – 0.1 0.01 – 0.05 ALUMINIUM HIGH SPEED STEEL (HSS) Face milling D 50 - 70 A 70 - 90 0.05 – 0.1 0.01 – 0.05 D 1-2 A 0.2-0.5 D (~2/3)Ø A (~2/3)Ø Side milling D 50 - 70 A 70 - 90 0.05 – 0.1 0.01 – 0.05 D (50%-80%)Ø A (50%-80%)Ø D (10%-25%)Ø A (5%-10%)Ø Other milling D 40 - 60 A 60 - 70 0.05 – 0.1 0.01 – 0.05 HARD METAL Face milling D120 - 150 A 150 – 180 0.05 – 0.1 0.01 – 0.05 D 1-2 A 0.2-0.5 D (~2/3)Ø A (~2/3)Ø Side milling D120 - 150 A 150 – 180 0.05 – 0.1 0.01 – 0.05 D (50%-80%)Ø A (50%-80%)Ø D (10%-25%)Ø A (5%-10%)Ø Other milling D100 - 130 A 130 – 150 0.05 – 0.1 0.01 – 0.05 Other milling: slot milling, t-shape milling, dovetail milling, form milling. D: Roughing operation A: Finishing operation CUTTING PARAMETERS: MILLING ORIENTATIVECUTTINGTABLEFOREXERCISES
  43. 43. 43 DOWN MILLING or CLIMB CUTTING Same cutter rotation and feed UP MILLING or CONVENTIONAL MILLING Opposite cutter rotation and feed The insert starts cutting with a large chip thickness:  It is more suitable.  Backlash elimination is necessary. Vibration tendency ↑.  Fc tend to pull the workpiece into the cutter.  Not recommended when using ceramic inserts (fragile). The insert starts cutting at zero chip thickness:  Rubbing  Friction ↑, Fc ↑, Machine power ↑  Temperature ↑, work-hardened surface, Ra ↓  Fc tend to: lift the workpiece from the table, push the cutter and workpiece away from each other.  Tensile stresses ↑ when teeth exit, tool life ↓ Mc Ma MILLING: Discontinuous cutting process Ma Mc CUTTING PARAMETERS: MILLING MILLING DIRECTION by Endika Gandarias VIDEO VIDEOVIDEO
  44. 44. 44 CUTTING PARAMETERS: MILLING HIGH SPEED MACHINING (HSM) by Endika Gandarias HSM: Feed faster than heat propagation. Traditional milling: time for heat propagation. In comparison with traditional milling:  Spindle speed (N) ↑, feed rate (F) ↑ and axial cutting depth (ap) ↑.  Radial cutting depth (ae) ↓ and feed per tooth (fz) ↓. F F VIDEO
  45. 45. 45 CHARACTERISTICS:  More productive cutting process in small sized components.  Possible to be used with high-alloy tool steels up to 60-63 HRc (EDM process can be avoided).  Excellent surface roughness can be achieved (Ra ~ 0.2 µm).  Machining of very thin walls is also possible.  Typical applications: dies and moulds, difficult to machine materials,… CUTTING PARAMETERS: MILLING HIGH SPEED MACHINING (HSM) by Endika Gandarias Trochoidal milling (typical HSM technique) Progressive cutting (constant stock) Constant peripheral cutting speed (Vc)
  46. 46. 46 CUTTING PARAMETERS: MILLING HIGH SPEED MACHINING (HSM) by Endika Gandarias DISADVANTAGES:  Higher maintenance costs: Faster wear of guide ways, ball screws and spindle bearings.  Specific process knowledge, programming equipment and interface for fast data transfer is needed.  It can be difficult to find and recruit advanced staff.  Human mistakes, hardware or software errors give big consequences. Emergency stop is practically unnecessary.  Good work and process planning necessary.  Safety precautions are necessary:  Machines with safety enclosing (bullet proof covers).  Avoid long overhangs on tools.  Do not use “heavy” tools and adapters.  Check tools, adapters and screws regularly for fatigue cracks.  Use only tools with posted maximum spindle speed.  Do not use solid tools of HSS.
  47. 47. 47 CUTTING PARAMETERS: MILLING by Endika Gandarias MILLING STRATEGY  When using a ball nose end mill, tilting the cutter 10 to 15 degrees can improve tool life and chip formation and provide a better surface finish. VIDEO ROLL-IN TECHNIQUE
  48. 48. 48 CUTTING PARAMETERS: MILLING by Endika Gandarias MILLING STRATEGY
  49. 49. 49 CUTTING PARAMETERS: MILLING by Endika Gandarias MILLING STRATEGY THIN WALLS  ae sould be minimized (20% Dc).  ap should not exceed 100% Dc  Big entry-exit radii should be programmed.  Sharp and positive cutting edges should be used. WEAK FIXTURE
  50. 50. 50 CENTER-LINE OF THE CUTTER OUTSIDE THE WORKPIECE CENTER-LINE OF THE CUTTER IN LINE WITH THE WORKPIECE CENTER-LINE OF THE CUTTER INSIDE THE WORKPIECE CUTTING PARAMETERS: MILLING hex = fz  cutter hits, no shearing CUTTERENTRY MILLING STRATEGY by Endika Gandarias ae > 70% x Dc ae < 25% x Dc hex < fz  high productivity CVD coating inserts recommended (better thermal protection) hex < fz  F ↑ to mantain productivity PVD coating inserts recommended (sharper cutting edge) Carbide handles the compressive stresses at the impact of entering well.​ VIDEOVIDEOVIDEO
  51. 51. 51 CENTER-LINE OF THE CUTTER OUTSIDE THE WORKPIECE CENTER-LINE OF THE CUTTER IN LINE WITH THE WORKPIECE CENTER-LINE OF THE CUTTER INSIDE THE WORKPIECE Chip thickness is at its maximum CUTTING PARAMETERS: MILLING At exit, chip bends and generates tensile forces on the carbide increasing fracture possibilities. VIDEO by Endika Gandarias MILLING STRATEGY CUTTEREXIT
  52. 52. 52 CUTTING PARAMETERS: MILLING • Best for shoulder face milling & where 90° form is required. • Low axial forces  Thin walls, weak fixtured components,… • Best for face milling & plunge milling. • Excellent for ramping operations. • Lower radial forces  Lower vibration. • Chip thickness ↓  feed ↑ to keep productivity. • Best for face milling & profiling operations. • Excellent ramping capabilities. • Strongest cutting edge with multiple indexes. • The chip load and entering angle vary with the depth of cut. : Cutting edge angle affects the cutting force direction and the chip thickness.​ENTERING ANGLE (Kr) VIDEO VIDEO VIDEO VIDEO _ + Chip thickness _+ Length of contact by Endika Gandarias 90º 45º 10º VIDEO
  53. 53. 53 CUTTING PARAMETERS: MILLING  The pitch is the distance between the effective cutting edges.  Different pitches:  Differential pitch: A very effective way to minimize vibration tendencies.​ PITCH (u) _ + Productivity Machine power consumption by Endika Gandarias Vibration VIDEO
  54. 54. 54 TOOL HOLDER ALIGNMENT RECOMMENDATIONS: Finishing CUTTING PARAMETERS: MILLING by Endika Gandarias < 0.006 mm Roughing Tool overhang (A) and total length (B) should be minimized. Attention to the max. allowable torque. It depends on the tool holder type and tool diameter.
  55. 55. 55 Surface finish, i.e. Surface Roughness, is mainly determined by the distance between the contiguous toolpaths, tool radius and surface slope. How to calculate the axial (ap) and radial (ae) cutting depths to achieve a certain theoretical roughness? In this type of milling; Ra ≈ Rmax/4 ae = Radial depth of cut ap = Axial depth of cut Rmax = Rz = Max. roughness Rhta = Tool radius α = Surface slope Rmax ↓ ae ↓ ap ↓ Rhta ↑ CUTTING PARAMETERS: MILLING SURFACE ROUGHNESS: by Endika Gandarias
  56. 56. 56 In ball end mills, cutting happens at points with different diameters. Thus, as the whole tool rotates at the same spindle speed, the cutting speed varies along the ball end. Effective radius in ascending toolpaths Effective radius in descending toolpaths EFFECTIVE TOOL RADIUS CUTTING PARAMETERS: MILLING by Endika Gandarias
  57. 57. 57 CUTTING PARAMETERS: DRILLING 1. Cutting Speed (Vc) DEFINITION: Relative linear speed at the contact point between tool and the workpiece. by Endika Gandarias vc N Vc · 1000 Vc: Cutting speed (m/min) N = N: Spindle speed (rpm) π · Dc Dc: Tool diameter (mm) N VIDEOVIDEO
  58. 58. 58 2. Feed DEFINITION: Relative movement between the workpiece and the tool. IN DRILLING FEED PER REVOLUTION (fn) → 3. Cutting depth (ap) F [mm/min] FEED RATE or FEED PER MINUTE F = fn·N CUTTING PARAMETERS: DRILLING by Endika Gandarias ap VIDEO
  59. 59. 59 DRILL ALIGNMENT RECOMMENDATIONS: by Endika Gandarias CUTTING PARAMETERS: DRILLING 0.02 mm 0.02 mm Rotary drill Stationary drill B A Feed force Better B than A tool position (lower torque). Tool alignment method. VIDEOVIDEO
  60. 60. 60 fn ⅓ fn ⅓fn ⅓fn A B C D ENTRY AT NON-PLANAR SURFACES: by Endika Gandarias CUTTING PARAMETERS: DRILLING MACHINE WORKPIECE MATERIAL TOOL MATERIAL OPERATION Vc (m/min) fn (mm/rev) DRILLING MACHINE STEEL HIGH SPEED STEEL (HSS) Spot drilling 18 0.04 – 0.1 Drilling 18 0.04 – 0.1 Counterboring 9 Countersinking 9 ALUMINIUM HIGH SPEED STEEL (HSS) Spot drilling 30 – 40 0.04 – 0.1 Drilling 30 – 40 0.04 – 0.1 Counterboring 15 – 20 Countersinking 15 – 20 ORIENTATIVECUTTINGTABLE FOREXERCISES
  61. 61. 61 Excellent Acceptable​ Start chip​ ​ Chip jamming The start chip from entry into the workpiece is always long and does not create any problems. Chip jamming can cause radial movement of the drill and affect hole quality, drill life and reliability, or drill/insert breakages. A hole affected by chip jamming.​A hole with good chip evacuation. CHIP CONTROL The chip formation is acceptable when chips can be evacuated from the drill without disturbance. The best way to identify this is to listen during drilling:  A consistent sound = chip evacuation is good.  An interrupted sound indicates chip jamming. CUTTING PARAMETERS: DRILLING by Endika Gandarias VIDEO
  62. 62. 62 PECK DRILLING CUTTING PARAMETERS: DRILLING by Endika Gandarias  Peck drilling may be necessary if chip evacuation is difficult due to a deep hole or the use of external lubricant. VIDEO
  63. 63. 63 CUTTING PARAMETERS VARIABLE UNIT DESCRIPTION HOW TO CALCULATE? TURNING MILLING DRILLING Vc m/min Cutting speed TABLES N rpm or rev/min Spindle speed N=(Vc*1000)/(π*Ø) fz mm/tooth*rev Feed per tooth TABLES fn mm/rev Feed per revolution TABLES fn = fz * z F mm/min Feed rate or feed per minute F = fn * N Ap mm Axial cutting depth TABLES Tool radius Ae mm Radial cutting depth TABLES Parameter introduced into the machine. Parameter NOT introduced into the machine. by Endika Gandarias SUMMARY TABLE
  64. 64. 64 CUTTING FLUIDS CUTTING FLUIDS by Endika Gandarias
  65. 65. 65 Cutting fluid is any liquid or gas that is applied to the chip or cutting tool to improve cutting performance. Cutting fluids serve 4 principle functions: 1. To remove heat in cutting (=COOLING): The energy used in the cutting process is almost exclusively transformed into heat that goes to the workpiece, tool and chip. The effective cooling action depends on the method of application, type of fluid, fluid flow rate and pressure. 2. To lubricate the chip-tool interface (=LUBRICATION): It reduces friction forces and temperatures. 3. To wash away chips (=CHIP REMOVAL): This is only applicable to small and discontinuous chips. 4. To avoid part oxidation (=ANTI-CORROSION): The environment humidity in combination with the high temperatures (500-900ºC) obtained during machining may cause part oxidation. Thus, the cutting fluid must contain anti-corrosion additives. Use of cutting fluids contributes to:  Diminish tool wear (longer tool life).  Produce workpieces of accurate sizes (reduce thermal expansion).  Achieve proper surface quality of the workpiece.  Support chip removal.  Reduce thermal stress on machine tool. CUTTING FLUIDS by Endika Gandarias
  66. 66. 66 CUTTING FLUIDS - METHODS OF APPLICATION LUBRICATION TYPE CONTENT USED VOLUME CHARACTERISTICS Wet machining (using coolant) Manual application 10 to 100 l/min Used for manual tapping. Cutting fluids are used as lubricants. Flooding supply Lubricating system of machine tools need to be cleaned from time to time to eliminate microorganisms. Coolant-fed tooling or internal cooling Some tools (typically drills) are provided with axial holes so that cutting fluid can be pumped directly to the cutting edge. Coolant pressures up to 80 bars. Coolant-fed tool holders Special tool holders required for milling, turning or drilling operations. Coolant pressures up to 30 bars. Reduced lubrication Minimum quantity llubrication (MQL) 50 ml/h up to 1-2 l/h Cutting fluid is deposited as drops or air-oil mix. Valid for not very demanding machining operations. It can be external or internal. Without lubrication Dry machining without It shows economic and environmental benefits. Under research. Novel cooling methods are under research: high pressure cooling (> 70bar), criogenic cooling (N2, CO2),... by Endika Gandarias VIDEO VIDEO
  67. 67. 67 CUTTING FLUIDS Manual application Flooding supply Coolant-fed tooling Coolant-fed tool holder by Endika Gandarias Titanium alloys Nickel Stainless steel Hard steel ( 0.4 to 0.7 % C ) Copper Cast-iron Steel (More carbon more difficult) Aluminum Brass Bronze Zinc alloy Broaching Shaping Gear machining Drilling Reaming Sawing Milling Turning
  68. 68. 68 CUTTING FLUIDS by Endika Gandarias  Cutting oils are based on mineral or fatty oil mixtures. Commonly used for heavy cutting operations.  Soluble oils is the most common (95% of the time), cheap and effective form of cutting fluid. Oil droplets suspended in water in a typical ratio water to oil 30:1. Emulsifying agents are also added to promote stability of emulsion, as well as anticorrosive additives.  Chemical fluids (synthetic) consists of chemical diluted in water. They may have harmful effects to the skin. - TYPES OF CUTTING FLUID Lubrication Refrigeration Cutting oils Soluble oils Chemical fluids Water Dry machining Low speed applications (broaching, threading,…) ↓ High friction ↓ Maximum lubrication High speed applications (turning, milling,…) ↓ Low friction ↓ Maximum refrigeration
  69. 69. 69 SELECTION OF CUTTING CONDITIONS SELECTION OF CUTTING CONDITIONS by Endika Gandarias
  70. 70. 70 SELECTION OF CUTTING CONDITIONS Productivity is a combination of factors that really make a difference, such as: • Increased cutting conditions = more parts per hour • Predictable tool life = machining security • Fewer tool changes = less down time • Fewer rejects = higher quality – more valuable end product • Product availability = less inventory • Technical training of employees = better understanding and less scrap by Endika Gandarias Important to identify the most relevant factors that influence the FINAL COST: ≈ 31% ≈ 27% ≈ 22% ≈ 3% ≈ 17%
  71. 71. 71 Important to identify the most relevant factors that influence MACHINE-TOOL UTILIZATION TIME: SELECTION OF CUTTING CONDITIONS by Endika Gandarias
  72. 72. 72 Machining efficiency suggests that good quality parts are produced at reasonable cost and at high production rate. Most relevant cutting parameters that affect machining costs and productivity are: 1. Depth of cut 2. Feed 3. Cutting speed SELECTION OF CUTTING CONDITIONS It is predetermined by workpiece geometry and final part shape.  In Roughing operations  As large as possible (max. 6-10 mm). It depends on machine tool, cutting tool strength and other factors.  In Finishing operations  A single pass to achieve the final dimensions. Finishing pass in a turning operationRoughing passes in a turning operation 1. Depth of Cut (ap, ae) by Endika Gandarias
  73. 73. 73 SELECTION OF CUTTING CONDITIONS  In Roughing operations  As large as possible (max. 0,5mm/rev). It depends on cutting forces and setup rigidity.  In Finishing operations  Small to ensure good surface finish (~ 0,05-0,15 mm/rev). Cutting at high cutting speed involves...  Reduction of tool life  Increase of production costs as more cutting tools are needed.  Increase of productivity  less time consumption. Hence, optimal cutting speed range has to be calculated for:  Cutting speed for minimum cost per unit (Vmin).  Cutting speed for maximum production rate (Vmax). 3. Cutting Speed (Vc) 2. Feed (F, fn, fz) by Endika Gandarias
  74. 74. 74 Production cost Fixed costs Economic Vc Tooling cost Cutting speed Vc Costperpart Parts per hour Vc for max. productivity High efficiency range Machinery costs SELECTION OF CUTTING CONDITIONS by Endika Gandarias
  75. 75. 75 SELECTION OF CUTTING CONDITIONS - HOW TO CALCULATE THOSE VALUES? Several limitations need to be considered: 1. MACHINE 2. TOOL 3. GEOMETRY 4. MATERIAL 1. MACHINE: The machinery usually exists in the workshop, and it may be a limiting factor. Anyway, either an existing or a new machine is used, attention should be paid to the following machine features:  General characteristics: number of axes, machine configuration type, general dimensions and weight,…  Axes: traversing range, power, accuracy, max. workpiece weight, max. acceleration and feed.  Workholder system: Forces, vibrations,…  Spindle head: power, speed range, run-out, stiffness, clamping system, automation possibilities, internal cooling.  Toolholder system: Run-out, torque,…  Tool changer: chip to chip time, max. number of tools, tool length and diameter,…  Cooling unit system: internal or external, MQL, HPC  CNC controller: capabilities  … by Endika Gandarias
  76. 76. 76 SELECTION OF CUTTING CONDITIONS 2. TOOL: Tool wear will occur. There are five main wear mechanisms which dominate in metal cutting: 1. Abrasion. 2. Diffusion. 3. Oxidation (corrosion). 4. Fatigue (thermal). 5. Adhesion. These wear mechanisms combine to attack the cutting edge in various ways depending upon the tool material, cutting geometry, workpiece material and cutting data. Flank wear is the most common type of wear (abrasion) and the preferred wear type, as it offers predictable and stable tool life. by Endika Gandarias VIDEO
  77. 77. 77 SELECTION OF CUTTING CONDITIONS 2. TOOL by Endika Gandarias In the case of pasty materials, layers / new edges are formed. Adhesive SiC inclusions of Fe foundry materials may create cutting edge wear. Abrasive Chemical reaction between tool carbides and the machining part create wear. Chemical Temperature variations create cracks in the cutting edge. Thermal Mechanical efforts on the cutting edge create tool failures. Mechanic CauseWear descriptionSymbolLoad type FA FA = Filo de aportación
  78. 78. 78 SELECTION OF CUTTING CONDITIONS ​1. Flank wear 2. Crater wear 3. Plastic deformation 4. Notch wear 5. Thermal cracks 6. Mechanical fatigue cracks 7. Chipping on edge 8. Tool breakage 9. Built-up edge (BUE) TOOL WEAR TYPES  Inappropriate cutting conditions  Inappropriate tool features  Material properties  Too low or high cutting temperature  … by Endika Gandarias
  79. 79. 79 SELECTION OF CUTTING CONDITIONS by Endika Gandarias VIDEO
  80. 80. 80 SELECTION OF CUTTING CONDITIONS 3. GEOMETRY: Part geometry will define:  Dimensional tolerances, expected surface roughness values and geometrical tolerances to be obtained.  Process limitations such as vibration, chatter,… Tool geometry will be chosen according to the process operations to be accomplished. 4. MATERIAL: Tool-workpiece material combination is very important. According to that, tool manufacturers usually offer customers cutting condition tables for free. These tables are the result of many experiments carried out. Usually these values correspond to a tool life of 15 minutes and should be regarded as starting values. They are obtained according to Taylor’s equation. Taylor’s Tool life formula: Vc * Tn = C Expanded Taylor`s Tool life formula: Vc * Tn * fn a * ap b = C Vc : Cutting speed [m/min] fn : Feed per revolution [mm/rev] ap : Cutting depth [mm] T : Tool life [min] a, b, n, C: Constants by Endika Gandarias VIDEO
  81. 81. 81 SELECTION OF CUTTING CONDITIONS Vc fn ap Workpiece material hardness Tool material R: Roughing M: Medium machining F: Finishing by Endika Gandarias INSERT GRADE
  82. 82. 82 SELECTION OF CUTTING CONDITIONS WORKPIECE MATERIAL INSERT GRADES by Endika Gandarias
  83. 83. 83  Select geometry and grade depending on the type of the workpiece material and type of application. SELECTION OF CUTTING CONDITIONS by Endika Gandarias
  84. 84. 84 SELECTION OF CUTTING CONDITIONS CUTTING DATA ON DISPENSERS by Endika Gandarias TURNING INSERTS
  85. 85. 85 SELECTION OF CUTTING CONDITIONS by Endika Gandarias
  86. 86. 86 SELECTION OF CUTTING CONDITIONS When increasing the cutting speed (vc), feed rate (fn) should be decreased and vice versa. Cutting speed and feed data compensation for turning by Endika Gandarias
  87. 87. 87 GLOSSARY GLOSSARY by Endika Gandarias
  88. 88. 88 GLOSSARY by Endika Gandarias ENGLISH SPANISH BASQUE Alignment Alineación Alineazio Alloy Aleación Aleazio Aluminium casting Fundición de aluminio Aluminio burdinurtua Axial cutting depth Profundidad de pasada axial Sakontze sakonera Backlash Desajuste Desdoitze Ball nose end mill Fresa de punta esférica / punta de bola Boladun fresa Bend Doblar Tolestu Beveling Biselado Alakaketa Brass Latón Letoia Brazed Soldado Soldatua Breakdown Averiar Matxuratu Broaching Brochado Brotxaketa Bronze Bronce Brontzea Built-up edge Filo de aportación Aportazio ertza Carbide Metal duro Metal gogorra Carbon steel Acero al carbono Karbono altzairua Cast-iron Fundición Burdinurtu CBN (Cubic Boron Nitride) Nitruro de Boro Cúbico Boro nitruro kubikoa Cheap breaker Rompevirutas Txirbil hauslea Chip Viruta Txirbil Chip Viruta Txirbil Chipping Astillado Zati Chisel edge Filo central Erdiko sorbatz Clamp Abrazar Lotu Clearance face Cara de incidencia Eraso aurpegia Climb cutting Concordancia Konkordantzia Coarse Basto Baldar Coat Recubrimiento Estaldura
  89. 89. 89 GLOSSARY by Endika Gandarias ENGLISH SPANISH BASQUE Contiguous Contiguo Alboko Conventional milling Contraposición Kontrajartze Coolant Lubricante Lubrifikatzaile Corner radius end mill Fresa tórica Fresa torikoa Crush Machacar Birrindu Cutting edge Arista de corte Ebaketa ertz / Sorbatz Cutting speed Velocidad de corte Ebaketa abiadura Cutting tool Herramienta de corte Ebaketa erraminta Dampened tool Herramienta antivibratoria Bibrazioen aurkako erraminta Die Molde Molde Diminish Disminuir Gutxitu Dispenser Dispensador Kaxa Dovetail Cola de milano Mirubuztan Down milling Concordancia Konkordantzia Drilling Taladrado Zulaketa Drop Gota Tanta Edge rounding Redondeo de arista Ertz biribiltze EDM Electroerosión Elektro-higadura Enclosing Cerramiento Itxitura End mill Fresa plana Fresa laua Engagement Empañe Lausotua Fatty Graso Oliotsu Feed per revolution Avance por vuelta Aitzinamendua birako Feed per tooth Avance por diente Aitzinamendua hortzeko Feed rate Avance por minuto Aitzinamendua minutuko Finish Acabado Akabera Flank Flanco / Lateral Albo Flooding Inundación Gainezkatze
  90. 90. 90 GLOSSARY by Endika Gandarias ENGLISH SPANISH BASQUE Friction Fricción Marruskadura Gauge Calibrar Kalibratu Gear Engrane Engranai Grinding Rectificado Artezketa Hard metal Metal duro Metal gogorra Hardening Endurecimiento Gogortze Hardness Dureza Gogortasuna Harmful Dañino Kaltegarri Heat Calor Bero Height Altura Altuera High Speed Machining Mecanizado a alta velocidad Abiadura azkarreko mekanizazioa High Speed Steel (HSS) Acero rápido Altzairu lasterra Hit Golpear Kolpe Insert Plaquita intercambiable Plakatxo trukagarria Jamming Atasco Trabatze Labelling Etiquetado Etiketa jarri Load Carga Karga Major Mayor Nagusi Margin Faja guia Faxa gidaria Marking Marcado Markaketa Milling Fresado Fresaketa Minor Menor Txiki Nose radius Radio de punta Muturreko erradioa Notching Entallado Hozkaketa Oven Horno Labe Overhang Voladizo Hegalkin Overhead Gastos generales Gastu orokorrak Packaging Empaquetado Paketeak egin
  91. 91. 91 GLOSSARY by Endika Gandarias ENGLISH SPANISH BASQUE Pecking Picada Ziztada Pin Punzón Puntzoi Pitch Paso Neurri Plunge Penetración Barneratze Powder Polvo Hauts Power Potencia Potentzia Pressing Prensado Prentsaketa Profiling Perfilado Profilaketa Radial cutting depth Profundidad de pasada radial / ancho de pasada Iraganaldi zabalera Radii Radios Erradioak Rake Desprendimiento Jaulkitze Reaming Escariado Otxabuketa Reject Rechazo Errefus Relief face Cara de desahogo Lasaitasun aurpegia Revolution Vuelta Bira Roughing Desbaste Arbastaketa Rubbing Bruñido Txartaketa Sawing Serrado Zerraketa Scrap Residuo Hondakin Seat Asiento Eserleku Shank Mango Kirten Shape Forma Forma / Itxura Shaping Limado Karrakaketa Sharp Afilado Zorrotz Shearing Cizallamiento Ebakidura / Zizailadura Shell end mill Fresa hueca Kofadun fresa Shift Relevo Txanda / Errelebu Shim Calza Altxagarri
  92. 92. 92 GLOSSARY by Endika Gandarias ENGLISH SPANISH BASQUE Shoulder milling Escuadrado Eskuairaketa Side Lateral / Secundario Albo/Bigarren Sintering Sinterizado Sinterizazio Skin Piel Azal Slope Pendiente Malda Solid tool Herramienta enteriza Pieza bakarreko erraminta Spindle Cabezal Buru Spindle speed Velocidad de giro Biraketa abiadura Spray drying Secado por pulverización Lainoztatze bidezko lehorketa Staff Personal Langilego Stiffness Rigidez Zurruntasun Strength Resistencia Erresistentzia Stress Fatiga / Estrés Estres Substrate Sustrato Substratu Surface roughness Rugosidad superficial Gainazal zimurtasuna Tapping Roscado con macho Ardatzarekin egindako hariztaketa Thickness Espesor Lodiera Tilting Inclinación Inklinazio Tip Punta Punta Toolholder Portaherramientas Erraminta etxea Torque Par Momentu Toughness Tenacidad Zailtasun Tray Bandeja Erretilu Trochoidal Trocoidal Trokoidal Turning Torneado Torneaketa Unleaded Sin plomo Berunik gabeko Up milling Contraposición Kontrajartze Wash away Limpiar Garbitu
  93. 93. 93 GLOSSARY by Endika Gandarias ENGLISH SPANISH BASQUE Weak Debil Ahul Wear Desgaste Higadura Web Alma Arima Wedge Cuña Kuña / Falka Weight Peso Pisua Wet Humedo Busti Workpiece Pieza Pieza Workshop Taller Tailer
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Cutting conditions description. Ebaketa baldintzen deskribapena. Descripción de las condiciones de corte.

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