TDX-type TAC Drill Manual. TAC DRILL Manual. DJ chipbreaker. DS chipbreaker. DW chipbreaker

Transcription

1 TDX-type TAC Drill Manual TAC DRILL Manual DW chipbreaker DS chipbreaker DJ chipbreaker

2 CONTENTS What is TDX Drill? 1 Nomenclature for TAC Drill 1 Cutting mechanism of TAC Drill 1 Features of TDX Drill 2 Components of TDX Drill series 3 Body 3 Inserts 3 Optional components 3 Features of drill body 4 Features of chipbreakers 5 DJ chipbreaker 5 DS chipbreaker 5 DW chipbreaker 5 Application area of each chipbreaker type 6 Features and applications of insert grades 6 Insert selection guide 7 Recommended cutting conditions 7 Points to consider 7 Chip shapes 8 Chip shapes produced by central edge 8 Chip shapes produced by peripheral edge 9 Medium to high carbon steels, alloy steels, etc. Stainless steels, low carbon steels, low alloy steels, etc. Chip control for snarled chips 10 Chip control for low carbon steels at low cutting speeds 11 Chip control for aluminum alloys 12 Chip shapes (DW chipbreaker) 13 Comparison of chip shapes at high feeds 13 Chip shapes at normal conditions 13 Chip shapes of stainless steels, alloy steels, and low carbon steels 13 Cutting performance of long body types 14 Selection of L/D in drill specifications 15 Machining data 16 Tool life comparison in drilling alloy steel 16 Tool life comparison in drilling stainless steel 16 Improvement in drilling of stainless steel 16 Machining of hardened steel with small diameter (ø 13 mm) drill 17 Machining example of hardened steel 17 Improvement in drilling of hard cast iron 17 Deep hole drilling of low carbon steel with large-diameter (ø 50 mm) drill 18 MQL deep-hole drilling of carbon steel with small diameter (ø 12.5 mm) drill 18 High-efficiency drilling with DW insert (GH730) 19 Finished hole diameters 20 Determination of tool life 21 Tool life determination for insert 21 Tool life determination for drill body 22

3 Cutting forces 22 Surface finish 23 Shapes of hole bottom 24 Use of TDX drill on machining centers 24 Selecting toolholders 24 Adjusting drilling diameter 24 Use of TDX drill on lathes 25 Mounting of drill body on turret (tool post) 25 Checking of cutting edge height 25 Checking of setting conditions by try machining 26 Adjusting of cutting edge height 26 Offset machining on lathes 27 Offset machining 27 Cautions when using on lathes 28 Through-hole drilling 28 When a disc-like uncut piece is left on the exit side 28 When machining a large-diameter hole in excess of the maximum drilling diameter 28 When using TDX drill on lathe without internal coolant supply 28 Special machining 29 Surface conditions to be machined 29 Drilling of interrupted hole 29 Drilling of stacked plates 30 Enlarging of drilled hole 30 MQL machining 31 What is MQL machining? 31 Cautious points in selecting drilling conditions 31 Cautious points in use 32 Cutting fluids 32 Maximum drilling depth 32 Machining of through hole 32 Drilling through-hole on work-rotating condition 32 Troubleshooting 33,34 Specifications of TDX drills 35 L/D=2 (metric) 35 L/D=2 (inch) 36 L/D=3 (metric) 37 L/D=3 (inch) 38 L/D=4 (metric) 39 L/D=5 (metric) 40 Test report format 41 Specifications of inserts for TDX drills 42 EZ-sleeves specially designed for TDX drills 42 Use EZ sleeves for the following purposes 42 Setting of EZ sleeve 43 Specifications 43 CONTENTS

4 What is TDX Drill? A drill which has dual indexable-inserts configured on the front end of a steel holder. Both inserts share the cutting zone. Insert grades and geometries can be selected to suit the machining situation. Nomenclature for TAC Drill Flange diameter Shank Peripheral insert Maximum drilling depth Overall length Shank length Drill diameter Shank diameter Central insert Flute Flange Taper pipe thread ( PT screw ) Cutting mechanism of TAC Drill Central insert Peripheral insert Central insert Cutting zone of central edge Cutting zone of peripheral edge Peripheral insert Drill diameter ød 1

5 Features of TDX Drill Outstanding economy Four cutting edges per insert can be economically utilized by indexing it as shown below. Exceptional chip control The newly designed 3-dimensional chipbreakers provide exceptional chip control over a wide range of work materials. Specially designed chip pocket helps to effectively remove chips from the cutting zone. Peripheral insert Insert changing Indexing Central insert Stable drilling and low vibration Can enter the cut smoothly with less vibration and allows stable machining. Exceptional reliability The thicker insert design increases impact resistance and extends tool life. Good surface quality The stable cutting balance allows excellent chip evacuation and good surface finish. 2

6 Components of TDX Drill series Body Only Tungaloy offers a full lineup of drill diameters (ø12.5 to ø54.0) and L/D ratios (2, 3, 4 and 5)! Unavailable Competitive indexable insert drills Drill diameter Inserts Three types of chipbreaker geometries and four insert grades are available. Inserts are selectable from the eight combinations of grades and chipbreaker types. Chipbreaker types Grades AH740 AH120 DJ DS DW GH730 T1015 Optional components Eccentric sleeves specifically designed for the TDX drills extend the application range. 3

7 Features of drill body New drills specially designed for deep holes have realized stable drilling of deep holes up to 5 times the drill diameters!! Ideally balanced design Higher reliability Existing 4-corner inserts can be economically used for these new drills. The design of the insert configuration allows stable deep hole drilling up to 5 times the drill diameter. Excellent chip control New oil-hole design and increased crosssectional area of the flute have vastly improved chip evacuation ability. Highly rigid tool design By optimizing the flute design, the deflection of the drill body could be suppressed to a minimum. Example of stable drilling with small diameter drill Spindle power consumption (A) Entrance Amount of oversize Spindle power consumption Bottom TDX Amount of oversize (mm) Competitor A (ø13) Entrance Amount of oversize Spindle power consumption Amount of oversize (mm) Bottom Competitor A (ø13) Machine : Vertical machining center (BT50) Work material : High carbon steel (JIS S55C) Drilling depth : 52 mm (L/D=4, Blind hole) Cutting speed : Vc=150 m/min Feed : f =0.1 mm/rev 4

8 Features of chipbreakers Three types of chipbreakers are available for various applications General purpose chipbreaker usable for almost all applications. Features low cutting forces and allows stable drilling. Low cutting forces and long tool life Bumps and grooves formed on the rake face reduce the contact area with chips resulting in reduction of cutting forces and longer tool life. Chipbreaker for peripheral edge Deeply formed chip groove performs exceptionally free cutting action and effective chipbreaking. Chipbreaker for central edge Relatively shallow chip groove prevents chips from packing. Performs excellent chip control for gummy materials such as stainless steels and low carbon steels. Entirely new rake face design Can effectively form gummy material chips into short sections. Sharp cutting edges Exceptionally free cutting action improves chip control. Strengthened corner Strengthened corner geometry minimizes insert breakage even in drilling stainless steels Strong chipbreaker for high feeds Can forcibly curl thick chips produced in high feeds and causes them to break into short sections. Also it allows for large volume chip removal. In comparison with conventional inserts, this chipbreaker allows higher feeds and produces superior surface finish. Wiper design Can improve surface roughness at normal feeds and minimizes surface degradation at high feeds. Extraordinarily strengthened corner Increased land width plus a two step relief angle strengthens the corner section. 5

9 Application area of each chipbreaker type DJ DW DS f Stainless steels Steels Cast irons Features and applications of insert grades AH740 GH730 By combining ultra fine grain cemented carbide with Flash-coat, this grade provides both wear resistance and impact resistance. Can be used for a wide range of applications. By combining ultra fine grain cemented carbide with Premium-coat, the impact resistance is improved without sacrificing wear resistance. Combined with DW-chipbreaker, this grade can be used for high-feed machining of steels. T1015 AH120 By combining specially designed hard carbide substrate with newly developed multilayer compound coatings, this grade provides excellent wear resistance in machining cast irons. By combining highly reliable carbide substrate with Flash-coat, this grade provides superior impact resistance and wear resistance in high-speed machining. Best suitable for drilling stainless steels. T1015 T1015 AH740 GH730 AH740 GH730 AH f AH Vc Stainless steels Steels Cast irons 6

10 Insert selection guide Select the appropriate insert by following this guide. Work materials Low carbon steels (C < 0.3) JIS SS400, SM490, S25C, etc. Carbon steels (C > 0.3) JIS S45C, S55C, etc. Low alloy steels JIS SCM415, etc. Alloy steels JIS SCM440, SCr420, etc. Stainless steels (Austenitic) JIS SUS304, SUS316. etc. Stainless steels(martensitic and ferritic) JIS SUS430, SUS416, etc. Stainless steels(precipitation hardening) JIS SUS 630, etc. Gray cast irons JIS FC250, etc. Ductile cast irons JIS FCD700, etc. Aluminum alloys JIS A2017. ADC12, etc. First choice High-feed High-speed machining machining Breakage Troubleshooting Wear Surface finish For high-feed machining, apply a feed rate that is approximately 1.5 times the standard feed conditions. High-speed machining means cutting speeds over 150 m/min. When using DW insert for troubleshooting, use it within the range of standard cutting conditions. Recommended cutting conditions Points to consider Selecting the cutting conditions is an important point for proper machining. Therefore, when selecting cutting conditions, place the priority on chip control. The cutting condition range which allows proper chip control depends on the types of chipbreaker and the material to be machined. The chart at right shows the basic flow to select cutting conditions. Work materials Low carbon steels (C < 0.3) JIS SS400, SM490, S25C, etc. Carbon steels (C > 0.3) JIS S45C, S55C, etc. Low alloy steels JIS SCM415, etc. Alloy steels JIS SCM440, SCr420, etc. Stainless steels (Austenitic) JIS SUS304, SUS316. etc. Stainless steels (Martensitic and ferritic) JIS SUS430, SUS416, etc. Stainless steels (Precipitation hardening) JIS SUS 630, etc. Gray cast irons JIS FC250, etc. Ductile cast irons JIS FCD700, etc. Aluminum alloys JIS A2017. ADC12, etc. Cutting speed Series Vc (m/min) Feed f (mm/rev) Initially use this guide to select and adjust cutting conditions to achieve appropriate chip control. Check the cutting condition range which is appropriate to the spindle power and rigidity of the machine to be used. Check the cutting condition range in which abnormal tool failure such as chipping and breakage does not occur. Select the cutting conditions appropriate to the scheduled tool life and machining time. When the hardness of the work material is higher than 40 HRC, the feed should be reduced to within 1/2 of the values shown in the table. When machining difficult-to-cut materials such as heat-resisting alloys which develop heat excessively during machining, reduce the cutting speed to within 1/2 of the values for carbon steels. 7

11 Chip shapes In TAC drills, because the central insert and the peripheral insert cut entirely different zones, two types of chips are produced. The following are the features of each shape. Chip shape produced with central insert A conical coil shape whose apex point coincides with the rotating center of the drill is the basic shape. The chips are broken into small sections with increases in feed. But, excessively high feed causes the chip to increase in thickness and develops vibration which disturbs stable machining. In TDX drills, marked chips shown below are the most preferable shapes. This type of chip is broken into adequate length by centrifugal forces when used in tool-rotating condition. On the other hand, when used in work-rotating condition such as on a lathe, a continuously long chip is often produced without entangling. Relation between chip shapes and feeds (In the case of central insert) Carbon steels, alloy steels, etc. Low carbon steels, stainless steels, etc. Example of chip shape in work-rotating applications (In the case of central insert) (ø26, S45C, Vc= 100m/min, f= 0.1mm/rev) 100mm 8

12 TDX drill Competitive drill A Comparison of chip shapes produced with central inserts (ø22 drills, vertical machining center) Alloy steel (JIS SCM440) Stainless steel (JIS SUS304) Mild steel (JIS SS400) Vcf Vcf Vcf DJ chipbreaker DS chipbreaker DS chipbreaker Comparison of surface finish influ enced by variations of chip shapes (ø22, SUS316L, NC lathe,vc=100m/min, f=0.08mm/rev) Surface finish is affected by chip shapes produced with the central insert. Competitive drill B TDX DS Competitor C Competitive drill C Chip shape produced with peripheral insert Chip problems such as entangling are mainly caused by chips produced with the peripheral insert. These problems are dependent on the types of work material and the cutting conditions. As shown below, when the feed is extremely low, the chips jump over the chipbreaker groove and the continuously long chips may wrap around the drill body. When the feed is too high, the chips increase the thickness and can not be curled. Therefore, it is important to select proper cutting conditions to suit the machining so that well controlled chips will be formed. Relation between feeds and chip control Chips likely to wrap around drill body. Likely to cause chip packing Feed is too low. Adequate feed Feed is too high. Just after start of cutting, a continuously long, coil-shaped chip is formed, but when the drilling depth reaches to 0.5 D to 1 D, the chip tends to shorten the length. The chip shape in the early stage of cut, as both the cutting speed and feed are increased, tends to shorten the length. Chip shape in early stage of cut Start of cut 9

13 Chip shapes formed with the peripheral insert are roughly classified, depending on the types of work materials, into two different types, general steels (JIS S45C, SCM440, etc.) and long-chip steels (JIS SS400, SUS316, S10C, SCM415, etc.). These features are described below. Medium to high carbon steels, alloy steels, etc. As shown below, several turns of coil are an ideal shape. As the feed increases, the curl radius and the number of turns tend to decrease. Typical chip shapes of general steels Variation of chip shapes relating to feeds f = 0.07mm/rev Stainless steels, low-carbon steels, low-alloy steels, etc. f = 0.1mm/rev f = 0.13mm/rev When machining long-chip materials such as stainless steels and mild steels, a wrong selection of cutting conditions results in chip entangling and tool breakage at worst. Therefore, cutting conditions should be carefully selected. C shaped, continuous coils of several to ten turns having adequately divided length are ideal shape. Ideal chip shapes DS chipbreaker DJ chipbreaker Stainless steel (JIS SUS 304) Vcf Mild steel (JIS SS400) Vcf For machining stainless steels or low carbon steels, DS chipbreaker is recommended. When using a TDX drill in tool-rotating condition, DS chipbreaker produces compact chips and allows more stable machining than DJ chipbreaker. Especially when using it in work-rotating condition, DS chipbreaker provides outstanding affect on chip control. Chips shapes which tend to entangle and remedies against them Apple-peel-like chips These chips are often produced in machining mild steels or low-carbon steels at low-speeds and low-feeds. Increase the cutting speed in stages by 20% within the range of standard cutting conditions. If there is no effect, increase the feed by about 10 % as the cutting speed is raised by 20%. Short-lead chips These chips are often produced in machining stainless steels at lowfeeds and tend to entangle to the tool in spite of short length. Increase the feed by about 10 %. If there is no effect, increase the cutting speed in stages by 10% within the range of standard cutting conditions. Very long chips Often produced in machining mild steels or low-carbon steels under improper cutting conditions. Increase the cutting speed in stages by 20% within the range of standard cutting conditions. If there is no effect, decrease the feed by about 10 % as the cutting speed is raised by 20%. 10

14 Chip control for low-carbon steels at low cutting speeds In the cases shown below, the demonstrated cutting speed is less than 60 m/min. As shown below, the use of DS chipbreaker allows effective chip control. When the cutting speed can not be raised to the standard cutting conditions because of machine limitation. (Especially when using a small diameter drill) Safety problems could result from violently scattering chips. Low carbon steel ( JIS S25C ), NC lathe, ø13, Vc = 60m/min Feed DS chipbreaker DJ chipbreaker CompetitorA CompetitorB f r r Remarkable vibration f r r r f r r r Mild steel ( JIS SS400 ), Machining center, ø13, Vc = 60m/min Feed DS chipbreaker DJ chipbreaker CompetitorA CompetitorB f r Remarkable vibration f r r r f r r r 11

15 Comparison of chip shapes ( ø22 drill, vertical machining center ) Alloy steel (JIS SCM440) Vcf Stainless steel (JIS SUS304) Vcf Mild steel (JIS SS400) Vcf Competitor "C" Competitor "B" Competitor "A" DS chipbreaker DJ chipbreaker When machining a gummy material, as the cutting speed increases, chips are likely to be broken into shorter sections. But, in tool-rotating applications such as on a machining center, chips are likely to be violently scattered because of the increased centrifugal forces as the cutting speed increases. In such cases, a safety protection to cover the cutting zone is essential. Aluminum alloys Applicable Chip control for aluminum alloys listed below is relatively easy and can be carried out by using standard inserts. Aluminum alloys for casting (JIS AC4B, etc.) Aluminum alloys for die casting (JIS ADC12, etc.) Al-Cu based aluminum alloys (JIS A2017, etc.) Al-Zn-Mg based aluminum alloys (JIS A7075, etc.) Heat-treated aluminum alloys ( -T6, etc.) Difficult to apply The following aluminum alloys are highly adhering and tend to be thick chips. Therefore, referring to the chart at right, select an appropriate chipbreaker and cutting conditions for the machining purpose. In addition, as the peripheral edge especially tends to produce long and uncontrolled chips, step-feed drilling should be carried out depending on the circumstance. Al-Mg based aluminum alloy (JIS A5052) Without step feed With step feed every 0.5 mm Feed mm/rev Al-Cu based aluminum alloy (JIS A2017) d=25 mm (blind hole) Vertical machining center, wet cutting Toolholder : TDX180L054W25 (ø18) Insert : XPMT06X308R-DW (GH730) Vc=200 m/min f=0.1 mm/rev Selection guide for chipbreaker types and cutting conditions in machining Al-Mg based aluminum alloys Cutting speed Note: When chips heavily adhere to the chipgroove, continuous machining is difficult in some instances. Al-Mg based aluminum alloy (JIS A5052) d=25 mm (blind hole) Machine: Vertical machining center, wet cutting Toolholder : TDX190L057W25 (ø19) Insert : XPMT06X308R-DW (GH730) Vc=300 m/minf=0.15 mm/rev Not applicable For the following aluminum alloys, because of remarkable chip adhering and packing on the chip groove, TDX drills can not be used. Pure aluminum alloys (JIS A1000, etc.) 12

16 Chip shapes (DW chipbreaker) DW chipbreaker is designed to forcibly break thick chips. The use of DW chipbreaker allows highly efficient machining in higher feed rate. Comparison of chip shapes at high feeds When using a conventional chipbreaker at high feeds, the central edge produces short chips. But, as the chip thickness increases, the occurrence of vibration makes the machining unstable. Additionally, the chips produced with the peripheral edge are too thick and can not be curled. DW chipbreaker is designed to have a special section shape suitable for high feeds and to break thick chips into short length by forcibly curling them. Comparison of chip shapes (JIS S55C,ø22, Vc=100 m/min, f=0.2mm/rev, Vertical machining center) Chips produced with central edge Chips produced with peripheral edge For high-feed machining, the guideline to select the feed is about 1.5 times the standard cutting conditions. High-feed machining will cause a heavy-load on the machine. Therefore, it should be carried out only when the machine has sufficient power and rigidity. Cutting fluid should be supplied in adequate volume through the tool. Fluid pressure of a minimum 1.5 MPa and volume of a minimum 10 l/min are recommended. Chip shapes in normal conditions DW chipbreaker can control chips even in normal conditions. But, because the cutting forces are higher than those of DJ chipbreaker, the first choice chipbreaker in normal conditions is the DJ chipbreaker. DW chipbreaker should be used where increased insert strength and improved surface finish are required. DW chipbreaker Chips produced with central edge Chips produced with peripheral edge DJ chipbreaker DW chipbreaker DJ chipbreaker Competitive A Competitive B Chip shapes (Mild steel (JIS SCM400), ø22, Vc=150 m/min, f=0.1 mm/rev, Vertical machining center) Chip shapes in machining stainless steel, alloy steels, low carbon steels Although DW chipbreaker can be used for relatively gummy materials, DS chipbreaker has an advantage over DW in compactness of the chips produced with the peripheral insert and the stability in machining. DW chipbreaker is not recommended for highfeed machining of stainless steels. Chip shapes (Mild steel (JIS SS400), ø22, Vc=300 m/min, f=0.08 mm/rev, Vertical machining center) DW chipbreaker DJ chipbreaker Chips produced with central edge Chips produced with peripheral edge 13

17 Cutting performance of long body types Allows stable machining for almost all work materials! TDX Toolholder TDX130L052W20-4 (ø13) InsertXPMT040104R-DJ (AH740) Alloy steel (JIS SCM440) 230HB Spindle power (A) Machining time (s) 150 m/min A TDX Competitor (ø13) Toolholder : TDX130L052W20-4 (ø13) Insert : XPMT040104R-DSAH120 TDX d=52 mm (L/D=4, blind hole) Vertical machining center wet cutting Vc =150 m/min Mild steel (JIS SS400) 130HB d=52 mm (L/D=4, blind hole) Vertical machining center wet cutting Vc =200 m/min Competitor (ø13) B Toolholder : TDX130L052W20-4 (ø13) Insert : XPMT040104R-DSAH120 Stainless steel (JIS SUS304) 170HB d=52 mm (L/D=4, blind hole) Vertical machining center wet cutting Vc =140 m/min Competitor (ø13) C Spindle power (A) Spindle power (A) Spindle power (A) Spindle power (A) Spindle power (A) Chip packing Machining time (s) 150 m/min Machining time (s) 200 m/min Machining time (s) 200 m/min Machining time (s) 140 m/min Chip packing Unstable power consumption Machining time (s) 140 m/min 14

18 Selecting of L/D specification For the best performance, select the most appropriate tool for the machining depth. Comparison of L/D ratios and performance Followings are test results comparing the performance of L/D=2 and L/D=5 drills used for the same machining. The L/D=2 drill shows less tool failure and longer tool life. Tool failure Flank wear widthvb : 0.107mm Flank wear widthvb : 0.132mm Shape of hole bottom Stainless steel (JIS SUS304), 170 HB d=24 mm (blind hole) After machining 171 holes (4.1 m in length) Vertical machining center wet cutting ø12.5 DS (AH120) Vc=150 m/min f=0.05 mm/rev Machining diametermm Number of holes machined 15

19 Machining data Recognize the high performance of TDX drills! Tool life comparison in drilling alloy steel The chart at right shows a comparison of tool life curves of several drills in machining alloy steel. DJ insert (AH740) showed stable wear without any irregular failure. Alloy steel (JIS SCM440), 240HB d=30 mm (blind hole) Vertical machining center ø18, Wet cutting Vc= 100 m/min f= 0.08 mm/rev Corner-wear width of peripheral insert VC mm Competitor "B-1 " Competitor "A" Competitor "B-2 " Occurrence of chip entangling Broken central edge Competitor "C " Machining length m DJ (AH740) Tool life comparison in drilling stainless steel The following chart shows a comparison of tool life curves of several drills in machining stainless steel. DS insert (AH120) showed stable wear and superior wear resistance even in high-speed conditions. Corner wear width of peripheral edgemm Cutting speed : Vc =150 m/min Competitor B Competitor C Competitor A DSAH120 Machining lengthm Corner wear width of peripheral edgemm Cutting speed : Vc =220 m/min Competitor B Competitor C Competitor A DSAH120 Machining lengthm Stainless steel (JIS SUS304), 120 HB d=25 mm (blind hole), Vertical machining center ø19 mm, wet cutting, f=0.08 mm/rev Proven economy Under the condition of Vc=150 m/min, machining costs per 1 m were calculated from the machining length before the corner wear width reaches to Vc=0.1 mm. The results are shown in the table to the right. The cost of TDX drill was 1/2 to 1/3 times those of competitive drills. No. of corners per insert VC=0.1mm Tool life criterion Index of running costs 1) Competitor Competitor A B Competitor C 1) Competitor A was placed to 100. Improvement in drilling stainless steel In this example, compared to a competitive drill, great improvement (600 pcs./corner, two times) in the tool life and cutting conditions was achieved. Stainless steel (JIS SUS304), 120HB Drilling length: d=23 mm (Blind hole) Machine : CNC lathe (Wet cutting) Drill body : TDX180L054W25 Insert : XPMT06X308R-DS (AH120) Vc=120 m/min f=0.06 mm/rev 16

20 Machining of hardened steel with small diameter (ø13 mm) drill In the machining of hardened steel with small diameter drills, reliability to insert breakage was evaluated. Almost all inserts were broken in the competitive drills. However, the TDX drill showed normal wear and could continue further machining. Corner wear width of peripheral edge Vc mm Competitor D (Both central and peripheral inserts were broken) Competitor B (Both central and peripheral inserts were broken) Competitor A (Central insert was broken) DJ (AH740) inserts (Normal wear) Number of holes machined (Holes) Die steel (JIS SKD61), 50HRC Drilling depth : d=25 mm (Blind hole) Machine : Vertical machining center Drill dia. : ø13 mm Cutting fluid : Used Vc=100 m/min f=0.02 mm/rev Machining example of hardened steel After machining 1.5 m in length, the insert showed little tool-wear and could continue further machining. The machining was also stable. Forging die steel (50HRC) Drilling depth: d=45 mm (Blind hole) Machine : Horizontal machining center Cutting fluid : Used Drill body : TDX220L066W25 Insert : XPMT07H308R-DJ (AH740) Vc=80 m/min f=0.04 mm/rev Central edge (VN=0.08 mm) Peripheral edge (VBmax=0.03 mm, VC=0.08 mm) Improvement in machining hard material Previously used brazed carbide drills frequently chipped. After switching to TDX drills, they developed only small insert wear and improved surface finish. In addition, machining time was reduced to 1/ ø23 High-chromium cast iron (52HRC) Drilling depth : d=60 mm (Blind hole) Machine : CNC lathe Cutting fluid : Used Drill body : TDX220L066W25 Insert : XPMT07H308R-DJ (AH740) Vc=40 m/min f=0.02 mm/rev 17

21 Deep-hole drilling of low-carbon steel with large diameter (ø50 mm) drill This example shows test results in which low-carbon steel was machined with a large diameter (ø50 mm) TDX drill. In combination with DS chipbreaker, the drill achieved good chip control and stable machining without vibration. Power consumption Vc =200 m/min, f=0.07 mm/rev, Drilling depth =250 mm Machining time ø Mild steel (JIS SS400), 130HB Drilling depth : d=250 mm (L/D=5, Blind hole) Machine : Vertical machining center Cutting fluid : Used Drill body : TDX500L250W40-5 Insert : XPMT DS(AH120) Cutting speed : Vc=200 m/min Feed : =0.07, 0.1 mm/rev MQL deep-hole drilling of carbon steel with small diameter (ø12.5 mm) TDX drill This example shows test results of MQL deep hole drilling of carbon steel with a small diameter (ø12.5 mm) TDX drill. In spite of MQL machining, the drill achieved low-noise machining, good chip-removal, and excellent hole-diameter stability. Hole diameter (mm) Drilling depth (mm) ø12.5 Carbon steel (JIS S55C), 220HB Drilling depth : d=63 mm (L/D=5, Blind hole) Machine : Vertical machining center Cutting fluid : Semi-dry (Through tool supply, 2 cc/hour) Drill body : TDX125L063W20-5 Insert : XPMT040104R-DJ (AH740) Cutting speed : Vc=180 m/min Feed : f=0.06 mm/rev 18

22 High efficiency machining with DW insert (GH730) Highly efficient, extra-low cost drilling has been realized! Vf = 318mm/min Photographs below show tool wear on corners after drilling 5.2 m in length at cutting speed of 100 m/min and feed of 0.22 mm/rev. DW insert showed a small amount of initial wear. Carbon steel (JIS S55C), 220HB Drilled length : 5.2 m Machine : Vertical machining center Cutting fluid : Used Drill body : TDX220L044W25-2 Insert : XPMT07H308R-DW (GH730) Cutting speed : Vc=100 m/min Feed : f=0.22 mm/rev DW(GH730) Competitor A Competitor B Vf = 579mm/min Photographs below show tool wear on corners after drilling 5.2 m in length at cutting speed of 200 m/min and feed of 0.2 mm/rev. A combination of L/D=2-designed drill body and DW (GH730) insert has realized higher table-feed comparable to those of solid drills. Carbon steel (JIS S55C), 220HB Machine : Vertical machining center Cutting fluid : Used Drill body :TDX220L044W25-2 Insert : XPMT07H308R-DW (GH730) Cutting speed : Vc=200 m/min Feed : f=0.2 mm/rev DW(GH730) Competitor A Competitor B Furthermore, the wiper effect of the insert produced a superior surface finish. Because of less tool-wear, deterioration of the surface roughness was not recognized. Surface roughness Ra m After drilling first hole DW (GH730) After drilling 5.2 m Competitor A Competitor B 19

23 Finished hole diameters TDX drills are not suitable for the drilling of holes requiring high accuracy. Differing from solid carbide drills, the finished hole diameter depends on three factors, 1. the accuracy of the insert, 2. the accuracy of the drill body, and 3. the oversize of the drilled hole. Therefore, a guideline for the hole tolerance is IT 12 or more. But, when using in a work-rotating condition, the finished diameter can be adjusted by offset machining. Even in tool-rotating applications, use of the eccentric sleeve ( EZ sleeve ) allows adjusting. In some cases, the finished hole diameter machined with TDX drills is smaller than the drill diameter depending on the work material and cutting conditions. When a severe tolerance to the finished diameter is required, a selection of drill diameter in consideration for the stock removal and finishing such as boring are required. The charts below show the finishing diameters of TDX drills and competitive drills. In competitive drills, some variations in finishing diameters resulting from measuring points and cutting conditions can be seen. TDX drill showed stable finishing diameters. Accuracy of insert Accuracy of drill body Oversize of hole diameter to the real drill diameter Finishing diameter = Nominal drill diameter -0.1~+0.3 Comparison of finishing diameters (ø34) TDX drill Competitor A Competitor B Competitor C Carbon steel (JIS S55C) ø34, Vc=100m/min, Depth:3D Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Mild steel (JIS SS400) ø34, Vc=180m/min, Depth:2.5D Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Stainless steel ( JIS SUS 304) ø34, Vc=150m/min, Depth:2.5D Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points Entrance Center Exit Hole-diameter measuring points f =0.08 mm/rev f =0.1 mm/rev f =0.12 mm/rev 20

24 Determination of tool life Change the tool a little earlier! Tool life determination for insert As the insert failure develops, several phenomenons such as deterioration in chip controllability, increased cutting noise and increased cutting forces are observed. If the machining is continued as the failure is enlarged, it may cause breakage of the drill body. When the following phenomenons are recognized, index or change the tool a little earlier. When excessive chipping or fracture is seen on the cutting edges. When at least one of notch wear (VN), flank wear width (VB), and corner wear width of peripheral edge (VC) reaches 0.3 mm. When the cutting noise excessively increases. When chip controllability remarkably deteriorates. When the net power consumption is increased by about 30 % compared to the beginning of cutting. Tool failure types of inserts For central inserts For peripheral inserts Insert failure and its effect on machining Chipping, Fracture, Flaking Rake face wear, Crater wear Flank wear, Corner wear, Notch wear Variation in finishing diameters Deteriorated chip control Deteriorated surface finish Deteriorated chip control Increased power consumption Occurrence of chatter Variation in cutting noise Deteriorated surface finish 21

25 Tool life determination for drill body As same as in inserts, the drill body also fails by rubbing of chips. Excessively damaged drill body can not achieve the original performance. Therefore, when the following phenomenons are recognized, change the drill body to new one a little earlier. When deformation, flaws, burrs, chip adherence are occurred on the insert pocket. When the insert pocket is damaged with the insert breakage. When the chip pocket is excessively damaged with the rubbing of chips. When the excessive rubbing on the peripheral part of drill body is observed. When the other phenomenons differing from the beginning of use are observed. Examples of damaged drill bodies Example 1: The chip pocket is scooped by rubbing of chips. Effects A change in chip control. Likely to occur chip packing. The oil hole is exposed in some cases. Example 2: Damaged insert pocket accompanying with insert fracturing Effects Bad influence on insert seating and clamping. Likely to occur insert fracturing. Damaged chip pocket resulting from rubbing of chips. Damaged insert pocket Cutting forces The charts below show a guideline for cutting forces. Use TDX drills on a machine with ample power and sufficient rigidity. Guidelines for cutting forces Cutting speed: Vc=100 m/min Work material: Alloy steel (JIS SCM440), 240HB Cutting fluid: Used 22

26 Surface finish Superior surface finish! A guideline for surface finish is about 25µm in maximum depth. It depends on the work material and cutting conditions. When a better surface finish is required, a finishing operation is needed. But, as shown in the Figure below, the use of DW insert achieves better surface finishes. Surface finishes are improved as the cutting speed is increased and the feed is decreased. When machining stainless steels and low carbon steels, the chip control is important. The surface finish obtained with DS insert is superior to those obtained with competitive inserts. Finished surface roughnessram Competitor A Competitor D Competitor B Work material: Carbon steel (JIS S55C) 200HB Drill diameter: ø22 mm Cutting speed: Vc=100 m/min Feed f (mm/rev) TDX+DS RaRyRz Axial measuring points Entrance Cmpetitor B RaRyRz Axial measuring points Entrance Work material: Stainless steel (JIS SUS304)180HB Drill diameter: ø18 mm Cutting speed: Vc=150 m/min Feed: f=0.06 mm/rev 23

27 Shapes of hole bottom Unevenness of the hole-bottom face machined with TDX drill is smaller than competitors! The shape of the hole bottom machined with TDX drill is closer to flat compared with those machined with HSS drills. Even compared with competitive indexable drills, the TDX drill excels in flatness. Compare the difference! Drill diameter Competitive indexable drills, brazed drills, and HSS drills Drill diameter ø13 ø15 ø20 ø25 ø30 ø35 ø50 Competitors Brazed drills HSS drills Hmax TDX drill ø12.5 ø15 ø17.5 ø22 ø27 ø33 ø Hmax Drill diameter ød Hole bottom shape obtained with TDX drill Competitive indexable-insert drill Example of hole-bottom finishing In addition to the maximum unevenness (Hmax) at the outer portion, the Hmax formed in the midsection is also smaller than those formed by competitive drills. Therefore, when finishing the hole bottom face, the toolholder of the finishing tool is less likely to interfere with the hole bottom. Height of unevenness Brazed carbide drill HSS drill Use of TDX drill on machining centers Check the specifications of the toolholder Selecting toolholders Side-lock type toolholders for drills or milling-chuck holders commercially available from toolholder manufacturers are recommended. Side-lock type toolholders for endmills are also usable, but the tool may be secured with only one screw. When using some of speed-accelerator type spindles and oilhole holders, the drill shank must be shortened to prevent interference with their hole bottom. Examples of side-lock type toolholder for drills. BIG: Sidelock drill holder Example of type:bt50-tsl KURODA: DA type sidelock holder Example of type:bt50-slda NIKKEN: Sidelock holder (for drills) Example of type:bt50-sl32c-105 Adjusting drilling diameter By using commercially available eccentric toolholders or EZ sleeves (eccentric sleeves specially designed for TDX drills), drilling diameters are adjustable. As for the use of EZ sleeves, see page 43. When using EZ sleeves, use commercially available side-lock type toolholder for drills. EZ sleeves (eccentric sleeves specially designed for TDX drills) 24

28 Use of TDX drill on lathes Setting of drill body is a key factor Mounting the drill on turret (tool post) Mount the drill body so that the cutting edges will be parallel to the X-axis of the machine. In normal circumstance, the drill body is mounted so that the peripheral insert can be seen from the operator. In some machines, mounting of 180 opposite direction is also possible without problems. As the driving flat of the drill shank is machined to be parallel to the cutting edges, by tightening the flat with the fixing screw, the cutting edges are to be parallel to the X-axis of the machine. X-axis of machine Turret Cutting edges are to be parallel to the X-axis of the machine Direction of screwing of mounting screw. X-axis of machine Central edge Peripheral edge In normal circumstance, the drill body is mounted so that the peripheral insert can be seen from the operator. Checking of cutting edge height The cutting edge height is an important factor to carry out proper machining. The center axis of the tool should be below the rotating axis of the machine by 0 to 0.2 mm. Prior checking of the center height of the machine by using a reference bar is recommended. In this case, the checking of the center height should be carried out at the same position as the overhang length of the drill. When the reference bar is not available, the ground part of a boring bar can be used as a substitute. Below the center by about 0.2 mm Dial gage Central edge X-axis of machine Peripheral edge Overhanga length of drill Reference bar The condition of cutting edge height is not appropriate, adjusting of the turret is basically needed. But, an easy adjusting method is described on the next page. Main spindle A substitution by using a boring bar Same as the overhang length of drill 25

29 Checking of setting conditions by trial cutting After mounting the drill body, check the condition of below-center by trial cutting before the real machining. If the drill body is properly set, a core of about ø0.5 mm in diameter is left in the bottom of the hole. If core is not left at all, it means above- center. If the core diameter is larger than ø1 mm, it means excessive belowcenter. In such cases, again check the cutting edge height. For the conditions of the trial cutting, low feeds of less than 0.1 mm/rev and drilling depth up to 10 mm are recommended as a guideline. About 0.5 mm in diameter Core in center portion Drilling depth: Up to 10 mm Adjusting of cutting-edge height When the condition of the cutting-edge height is improper, the following method is used for the adjusting. q In the case of above-center If machining is carried out in such condition, the center cutting edge is likely to be chipped. Rotate the mounting direction by 180. If the mounting direction can not be changed, rotate the drill body by 180. But in this case, additional machining of driving flat which is parallel to the cutting edge is required. Mounting direction Central cutting edge X-axis of machine Peripheral cutting edge Rotating by 180 Center of drill Peripheral cutting edge Central cutting edge X-axis of machine Mounting direction w In the case of a little (about 0.05 mm) above-center In this case, in addition to the method q, shifting of the mounting position to another turret position may improve the condition. e In the case of excessive (over 0.2 mm) below-center If the drill body is mounted in such condition, the core diameter is increased. If machining is carried out as the core diameter is larger than 1 mm, it will result in an unstable machining condition such as heavy vibration. In such cases, adjust the cutting edge height by using EZ-sleeve (the eccentric sleeve designed specially for TDX drills) or adjust the accuracy of the turret itself. For the use of EZ sleeve, refer to page

30 Peripheral edge X-axis of the machine Offset machining on lathe A larger hole than the drill diameter can be machined! Offset machining When the drill is used in a work-rotating mode such as in lathes, offsetting of the drill in the X-axis of the machine allows fine adjustment of the drilled hole diameter. When the offset machining is carried out, the drill body should be mounted so that the cutting edge will be parallel to the X-axis of the machine. Mount the tool referring to the aforesaid setting method. Interference Central edge Decreased drilling diameters Central edge Peripheral edge Increased drilling diameters Offsetting to the direction of decreased drilling diameters. Displacement must not exceed -0.1 mm. Drilled diameters obtained by offsetting are roughly calculated as following. Drilled diameter = Drill diameter + Displacement X 2 Example: Drill diameter: ø20 mm Displacement: 0.2 mm Drilled diameter= X 2 = ø20.4 mm Central edge Displacement (+) Peripheral edge Offsetting to the direction of increased drilling diameters. Direction of increased drilling diameter (+) Maximum allowable displacement and maximum drilling diameters Drill diameter Max. displacement Max. drilling diameter Drill diameter Max. displacement Max. drilling diameter Drill diameter Max. displacement Max. drilling diameter Drill diameter Max. displacement Max. drilling diameter Drill diameter Max. displacement Max. drilling diameter Drill diameter Max. displacement Max. drilling diameter Drill diameter Max. displacement Max. drilling diameter The allowable displacement has a dependence on the drill diameters. Offsetting must not exceed the maximum displacement shown in the table. When causing insert breakage or vibration, reduce the feed. To prevent the drill-body from interfering with workpiece, the displacement to the direction of decreased diameters should be within 0.1 mm. Even when setting within 0.1 mm, there is a possibility of interfering depending on the condition of the cutting-edge height and the hole straightness. Please check these carefully. 27

31 Cautions when using on lathes Through-hole drilling When the drill penetrates the hole, uncut disc-like piece may fly-out from between the chuck jaws. This piece has sharp edges and is very dangerous. A guard to cover the chuck is required. Cover Disc-like uncut piece When a disc-like uncut piece is left on the exit side In machining gummy materials or high-feed machining, a disc-like uncut piece may be left on the exit side of the hole. By reducing the feed from the position of about 3 mm toward the exit, the occurrence of the piece can be mostly prevented. Exit side When machining a large diameter hole in excess of the maximum drilling diameter When machining of a large diameter hole in excess of the maximum drilling diameter is required, there is a method in which the hole once machined by solid drilling is enlarged by boring in several steps as shown in the Figure at right. But, in the boring operation, the chip control is more difficult than that in the solid drilling. Therefore, use of a purposemade boring tool is recommended for the operation. When using on a lathe without internal coolant supply When the drill is used on a lathe without internal coolant supply, remove the taper screw from the flange of the drill body and connect a coolant supply hose to the position. By this, coolant can be supplied through the tool. ( This method is applied only to the drills of L/D=2 and 3.) In this case, the rear end of the drill shank should be plugged with the removed taper screw. Taper screw for pipe 28

32 Special machining Special caution must be taken to the following machining! Specially difficult machining types are described in this page. This machining should be avoided where possible by carrying out some prior machining. When having no choice but to do these types of machining, care should be taken to the following. (Stack drilling is excluded.) Surface conditions to be machined (1) Drilling into angled face When the engaging surface or exit-side surface is angled, set the feed to within 0.05 mm/rev. When using the drill of 4D or 5D design, prior flattening of the engaging surface by using an end mill is recommended. (2) Drilling into arc face When the engaging surface is arc, the feed at engagement should be set to within 0.05 mm/rev. The radius of the arc should be greater than the five times the tool diameter. Drilling of interrupted hole The feed during the penetrating and engagement in an interrupted portion should be within 1/2 of the standard condition. Before engaging in the interrupted portion, a disc-like chip produced in penetrating must be completely removed. 29

33 Drilling of stacked plates In drilling of stacked plates, a disc-like chip is produced between the plates. This may increase a possibility of causing the insert and drill body to be damaged. Therefore, TDX drills are not recommended for this operation. Disc-like chip Clearance between plates Enlarging of pre-drilled hole When enlarging a pre-drilled hole, the hole diameter should be within 1/4 of the diameter of TDX drill. If chips are not well controlled, peck-drilling or dwelling (about 0.1 sec.) is recommended. As shown in Figure below, the bottom face of the hole machined with TDX drill is slightly convex. In the next process, if drilling is carried out to the face, the risk of drill breakage or poor hole straightness may be increased. After pre-drilling with another drill, TDX drill should be used. For counterboring of a hole, TCB-type counterboring cutters are recommended. The TCB-type cutter provided with two effective cutting edges allows more efficient machining than TDX drill. In addition, the insert with dimple-type chipbreaker performs better chip control. 30

34 About the MQL (Minimum Quantity Lubrication) machining What is MQL machining? MQL machining is a new machining method where a minimum quantity (about 10 cc/hour) of lubricant mixed with air is supplied to the cutting point. This method features: q The temperature of the cutting edge is lower than that of in Absolute dry-machining. Therefore, existing tools can be applied to the machining. w Compared with Cooled-air machining, the required apparatus is simple and low cost. Nevertheless, pronounced effect on tool life can be obtained. The following are key points in carrying out MQL machining. Tips in selecting cutting conditions In MQL machining, compared with wet machining, chip shape varies remarkably depending on the feed rate. Referring to the following, select the proper conditions allowing stable chip removal. When selecting, find the conditions in which the chips produced with the central cutting edge are continuous coil-shape. Cutting conditions for reference Cutting speed : Vc=80 ~180 m/min Feed : f =0.03 ~ 0.08 mm/rev Preferable chip shapes in MQL machining Stably continuous coil-shape chips produced with central cutting edge Carbon steel (JIS S45C), 230HB Cutting speed : Vc=150 m/min Feed : f =0.05 mm/rev TDX180L054W25 (ø18) XPMT06X308R-DJ (AH740) Alloy steel (JIS SCM440), 230HB Cutting speed : Vc=150 m/min Feed : f =0.05 mm/rev TDX180L054W25 (ø18) XPMT06X308R-DJ (AH740) Mild steel (JIS SS400), 150HB Cutting speed : Vc=150 m/min Feed : f =0.05 mm/rev TDX180L054W25 (ø18) XPMT06X308R-DJ (AH740) Unfavorable chip shapes in MQL machining When the chips produced with the central cutting edge are crushed or elongated without curling, reduce the feed. Crushed chips produced with central cutting edge Elongated chips produced with central cutting edge Through-the -tool coolant supply is a must in MQL machining. MQL machining is not suitable for some materials, which generate high-temperature during machining, such as stainless steels and heat-resistant steels. 31

35 Cautionary points in use Cutting fluids Water-soluble cutting fluids (such as JIS W1-2) should be used. Water insoluble cutting fluids are not recommended because their fumes may catch fire. Fluid pressure of 1 MPa or greater and fluid quantity of 7 lit/min or more are essential. For 4D and 5D types, 1.5 MPa or greater and 10 lit/min or more are recommended. Cutting fluid should be supplied through the oil hole of the tool. When there is no choice other than external supply, reduce the cutting speed by 20 % of the standard condition and limit the drilling depth to within 1.5 times the drill diameter. External supply should be avoided for machining stainless steel and heat-resistant steels. Within 1.5D Maximum drilling depth The flute length of TDX drills is a little larger than the maximum drilling depth. This is needed for chip removal when drilling to the maximum drilling depth. Drilling in excess of the maximum drilling length should be avoided. Drill diameter Flute length Maximum drilling depth Additional length for penetrating When drilling to the maximum drilling depth, the additional length for penetrating should be within 10 % of the drill diameter. Additional length for penetrating 0.1 X ød Use in work-rotating condition See Cautions when using on lathes on page