Thread Turning Technical Section

Transcription

1 Thread Turning Technical Section Contents: Page: Contents: Page: Carbide Grade Selection Type B inserts Recommended Cutting Speed Conversion of Cutting Speed to Rotational Speed Number of Threading Passes Selection Number of Threading Passes Selection for Single Point Inserts Thread Turning Methods Important Points about C.P.T. Threading Inserts Flank Clearance Angle Anvil Change Recommendation Thread Turning Step by Step Troubleshooting Threading Inserts Standards

2 Carbide Grade Selection Choose the C.P.T. grade specifically formulated for your application from the following list: Coated Grades HBA (H10-H25) (S10-S25) BLU (M10-M20) (K05-K20) (N10-N20) (S10-S20) BMA (P20-P40) (K20-K30) P25C (P15-P35) MXC (K10-K20) (P10-P25) BXC (P30-P50) (K25-K40) Uncoated Grades P30* (P20-P30) K20* (K10-K30) * Upon request Note: Extra-fine sub-micron grade with high toughness, for optimized performance on hardened steels and cast iron up to 62HRc, titanium alloys and super alloys (hastelloy, inconel and nickel based alloys). PVD triple layer coated sub-micron grade for stainless steels, cast iron, titanium, non ferrous metals and most of the high temperature alloys. PVD TiAlN coated sub-micrograin grade for stainless steels and exotic materials at medium to high cutting speeds. PVD TiN coated grade for treated and hard alloy steels (25 HRc & up) at medium to low cutting speeds. PVD TiN coated micrograin for free cutting untreated alloy steels (below 30 HRc), for stainless steels and cast iron. PVD TiN coated grade for low cutting speed. Works well with wide range of stainless steels. Carbide grade for carbon and cast steels, works well at medium to low cutting speeds. Carbide grade for non ferrous metals, aluminum and cast iron. Due to our unique and specialized production techniques, C.P.T. coated inserts provide superior cutting performance and exceptionally long tool life. Grade availability per inserts size! Type B - Threading Inserts A combination of ground profile, and sintered chip-breaker threading inserts. s. Unlike most other manufactures inserts, this combination ensures a consistent high quality thread, with precise shape and dimensions. Two different unique styles of chip-breaker were designed to suit the different specific requirements of Internal threads and External threads. All of C.P.T. Type B inserts are made of BMA Sub-Micrograin grade. 60

3 U U c c c c Recommended cutting speed (m/min) for thread turning inserts -. /. ' ) $ % ) + % ( ) ' * + & ), " # $ % & ' & # $ ; : 5 ( " ( 6 " 5 6 " O P QR S T I J J K L MK N I J J K L MK N V W J X I M MW Y Z [ K K M ` K J d e K N L J N U L \ [ Z [ K K M ] O P QS S T f g K h i K _ K N?? = > H? = C G D E C F D C D D E C F D? = = >? B = A = >? < = < = = ^ _ K K U ` [ [ a J b Z [ K K M I J J K L MK N ` K J d e K N f g K h i K _ K N n W o I M MW Y Z [ K K M L J N U L \ [ I J J K L MK N Z [ K K M p MK \ \ [ e L J S T L M MW Y a J b ` K J d e K N k = >? m = B = = l D E C G D A = >? H = j = > k = < = > B = K MK h K J [ \ q f g K h i K _ K N I J J K L MK N t ab e I M MW Y Z [ K K M ] U L \ [ Z [ K K M ] A = > k = j = > B = r D E s D < < > A = < = > j = m = > < = L J N g W W M Z [ K K M ` K J d e K N f g K h i K _ K N ^ K a[ ad z Z [ L a J MK \ \ Z [ K K M { L _ [ K J \ a[ ad L J N v v w x v y w k = = s D E u D j = > k = < = > B = < = > B = U L \ [ Z [ K K M { L _ [ K J \ a[ ad I ` \ [ K J a[ ad ^ K a[ ad z U L \ [ _ W J V W N ` M L _ p q K L _ M a[ ad v } w x v ~ w v w w x v w B = >?? = j = > k = K L _ M a[ ad ^ K a[ ad _ K Y U L \ [ _ W J p q v w x v ~ w v } w x v w k = >? = = j < > B < K L _ M a[ ad ^ K a[ ad { L M MK L ƒ MK U L \ [ _ W J v v w x v w v w w x v w B = >? = = j = > B < K L _ M a[ ad V W [ I M ` h a J ` h X _ W ` b e [ I M MW Y U ` _ K L ƒ MK l D D E C D D D j = = > B = = m < = > j = = y w w x w < = > < = = U ` _ K N V W [ O ˆ R T Z a U ` _ K L ƒ MK I M ` h a J ` h X U L \ [ ] } w x ~ w H = = > < < =? < = < = } w w x ~ ~ w?? = = = I M MW Y K N U ` _ K N t ab e ˆ R T Z a g K h i K _ L [ ` _ K ^ _ K K ˆ T ƒ U ` [ [ a J b U W i i K _ I M MW Y \ _ L \ \ v Š w x ~ w? < = > H < =?? = >? B = v ~ w x } ~ w k = >? < = Œ MK d [ _ W MY [ ad U W i i K _ ` _ W i M L \ [ ad \ ] ^ a ƒ K _ M L \ [ ad \ V W J { K [ L M M ad H = = = =? < = > H? = v w w x } w w?? = >? < = t L _ N Ž ` ƒ ƒ K _ I J J K L MK N ^ K ƒ L \ K N U ` _ K N t ab e g K h i Q I M MW Y \ ] Z H = > B = > j < H < > j = ` i K _ I M MW Y \ I J J K L MK N V a W _ U W ƒ L \ K N U ` _ K N U L \ [ I M i e L g a[ L J a ` h I M MW Y \ K [ L I M MW Y = > j = m = > < < > m < > m < U ` _ K N t L _ N K J K N S X S P t Ž d t L _ N K J K N Z [ K K M t L _ N K J K = > j = m = > < < > m < S ˆ X S S t Ž d t L _ N K J K N S X R t Ž d U e a M MK N U L \ [ _ W J U L \ [ H = > < = > m = H < < U L \ [ _ W J t L _ N K J K N H = > m = H = =? < > H < 61

4 Conversion of Cutting Speed to Rotational Speed Conversion of a selected cutting speed to rotational speed is calculated by the following formula: 30 mm Number of passes and depth of cut per pass for multitooth insert œ Ÿ ž œ œ œ œ œ œ 62 V=120 m/min

5 Number of threading passes selection for single point inserts ª!!!!!!!!!!! NOTES: 1. For most standard applications the middle of the range is a good starting point. 2. For most materials, the tougher the material, the higher the number of cutting passes you should select. 3. As a general rule of thumb, fewer passes are better than more speed. Thread Turning Methods 63

6 Important Points about C.P.T. Threading Inserts 1. In most thread forms internal and external threads have different depth and radii, thus tools are not interchangeable 2. The Insert relief angle of a standard C.P.T. external toolholder is 10º; for an internal toolholder it is 15º. This 5º difference is to provide additional necessary radial clearance. 4. Profiles of C.P.T. internal & external threading inserts are precision ground to ensure accurate thread geometry when used in their corresponding toolholders. Using internal inserts with an external holder will result in distortion of angle and insert geometry. 3. Our built-in relief angles ensure automatic insert flank angle clearance. 5. Insert and toolholder should always match. An IN-RH insert must be used with an IN-RH toolholder. No mismatch is allowed. Flank Clearance Angle 64

7 Anvil Change Recommendation As can be seen from the chart, some Pitch to Diameter combinations require an anvil change. If change is required, use AE anvils for EX-RH and IN-LH toolholders and AI anvils for IN-RH and EX-LH toolholders. ACME STUB ACME TRAPEZ (DIN 103) ROUND (DIN 405) As can be seen from the chart, most applications do not require an anvil change. If change is required, use AE anvils for EX-RH and IN-LH toolholders and AI anvils for IN-RH and EX-LH toolholders. PARTIAL PROFILE 60 PARTIAL PROFILE 55 ISO UN WHIT. NPT BSPT As can be seen from the chart, most applications require an anvil change. In most cases a negative anvil is required. Use AE anvils for EX-RH and IN-LH toolholders and AI anvils for IN-RH and EX-LH toolholders. AMERICAN BUTTRESS SAGENGEWINDE (DIN 513) 65

8 Thread Turning - Step by Step Step 1 : Choose Thread Turning Method from page 63 Step 2 : Choose Insert Step 3 : Choose Toolholder Step 4 : Choose Insert Grade Step 5 : Choose Thread Turning Speed Step 6 : Choose Number of Threading Passes In most cases the above mentioned 6 steps would be the steps needed to ensure a good thread. When cutting more complicated threads such as TRAPEZ, ACME, BUTTRESS or SAGE, it is advisable to check the effect of the thread HELIX ANGLE on the RESULTANT FLANK CLEARANCE. If is smaller than 2, an anvil change is required. Step 7 : Find Thread Helix Angle Step 8 : Choose Correct Anvil EXAMPLES: Example No. 1: Step 1: Step 2: Step 3: Step 4: Step 5: Step 6: Example No. 2: Step 1: Step 2: Step 3: Step 4: Step 5: Step 6: Choose Thread Turning Method from page 63, we chose EX - RH Insert & Toolholder Choose Insert from page 9: 16 ER 1.5 ISO Choose Toolholder from page 39: SER 2020 K16 Choose Insert Grade from selection on page 60 Our choice for Alloy Steel is Grade P25C Choose Thread Turning Speed from chart on page 61, we chose 100 m/min Rotational Speed calculation: Choose Number of Threading passes from table on page 63, we chose 8 passes Choose Thread Turning Method from page 63 Usually, an IN-RH Toolholder and Insert will be chosen, however, in this particular case we prefer to pull the metal chips while thread turning outward, thus we chose to work with IN-LH Insert & Toolholder Choose Insert from page 13: 16 IL 12 UN Choose Toolholder from page 41: SIL 0025 R16 Note: since we thread cut IN-RH thread outward with an IN-LH tool, do not forget to replace the standard anvil (supplied with the holder) with a negative anvil AE Choose Insert Grade from selection on page 60 Our choice for Brass is Grade K20 Choose Thread Turning Speed from chart on page 61, we chose 150 m/min Rotational Speed calculation: Choose Number of Threading passes from table on page 63, we chose 9 passes ISO 1.5 mm 30mm 66

9 Example No. 3: Step 1: Step 2: Step 3: Step 4: Step 5: Step 6: Step 7: Step 8: Choose Thread Turning Method from page 63 We chose EX-RH Insert & Toolholder. Choose Insert from page 33: 16 ER 12 ABUT Choose Toolholder from page 39: SER 2525 M16 Choose Insert Grade from selection on page 60 Our choice for Stainless Steel is Grade BMA Choose Thread Turning Speed from chart on page 61 We chose 120 m/min Rotational Speed calculation: 954 Choose Number of Threading passes from table on page 63. We chose 13 passes Find Thread Helix Angle: on page 48 for Pitch of 12 TPI and 40 Diameter Helix Angle as shown in the chart is 1º Choose correct Anvil: As can be seen from the chart on page 65, for AMERICAN BUTTRESS Thread, for 12 TPI and 40 Diameter a negative anvil AE should replace the standard anvil supplied with the toolholder Troubleshooting Chipping Crater Wear Build-up Edge 40 RPM EX-RH. AMERICAN BUTTRESS 12 TPI on 40 mm diameter. Stainless Steel 304 Replacing the standard anvil with an anvil with negative angle will eliminate side rubbing Anvil chosen: AE Use a tougher carbide grade 2. Eliminate tool overhang 3. Check if insert is correctly clamped 4. Eliminate vibration 1. Reduce cutting speed 2. Apply coolant fluid 3. Use a harder carbide grade Thermal Cracking Deformation Fracture 1. Increase cutting speed 2. Use a tougher carbide grade 1. Reduce cutting speed 2. Apply coolant fluid 3. Use a tougher carbide grade 1. Use a harder carbide grade 2. Reduce cutting speed 3. Reduce depth of cut 4. Apply coolant fluid 1. Use a tougher carbide grade 2. Reduce depth of cut 3. Index insert sooner 4. Check machine and tool stability 67

10 œ œ Ò œ Threading Inserts Standards Ä Å Æ Ç È Æ É È Ê Ë É Ì Æ È Í Î Æ Ï Ï Ð œ Ñ œ Ò œ œ «± ² ³ µ ¹ º ³» ¼ º ½ ³ ½ ¹ ³ ½ ¾ ½ ³ À ½ À ² ³ ¼ º ½ ³ Á ¹ ¾ º ² ³  ± ½ ³ À ½ À ² ³ ³ ½ ¹ ³ ½ ¾ û ½ ³ ½ ¹ ³ µ ¹ ½ ³ À ½ À ½ ¹ ³! œ œ œ Ó! Ó! Ó! Ó!!!!!!!!!!!!!!!!!!! Ô œ!!! Ó Ó! 68