APPLICATION GUIDE Application guide – Silent Tools Head office: AB Sandvik Coromant SE-811 81 Sandviken, Sweden www.sandvik.coromant.com E-mail: info.coromant@sandvik.com C-1020:17 ENG/01 © AB Sandvik Coromant 2012.
More information Useful information and application techniques can be found in our catalogues, handbooks, application guides and on the Sandvik Coromant website. Visit our website for the latest news! www.sandvik.coromant.
Content 1 Introduction 2 Introduction, Silent tools, guide info Review of fundamentals Working area specification Typical components/segment Economics, ROI calculator 2 4 6 9 11 2 Milling 12 Main considerations Vibration influence factors Programming guidelines Product overview Application examples Tips and hints, summary 12 15 18 21 27 31 3 Turning 33 Main considerations Vibration influence factors Application examples Product overview Tips and hints, summary 33 41 50 54 60 4 Boring 67 Main c
1. Introduction 1. Introduction Silent Tools has long been the trademark for tool holders, designed to minimize vibration with a dampening system inside the tool body. The majority of Silent Tools customers use them for long overhangs and poor accessibility. However, great productivity increases and surface quality improvements are to be gained, even for shorter overhangs. It is not possible to avoid vibration entirely in metal cutting operations, but there are various ways of reducing it.
1. Introduction Review of fundamentals Inside a dampened tool is a pre-tuned dampening system that consists of a heavy mass, supported by rubber spring elements. Oil is added to increase the dampening. The graph shows the difference in vibration dampening between an undampened and a dampened solution. For long tool overhang and flanges, two-face contact between the spindle and the tool holder is recommended.
1. Introduction It is important to respect the limits marked on the product (load, temperature, rotation, min/ max overhang and pressure): • Temperature is highlighted to save the rubber elements in the dampening system • Maximum temperature limit depends on type of product and is marked on the tool, eg. 75-120°C (167-248 F) The dampening system consists of a heavy mass, supported on rubber spring elements.
1. Introduction Choose the right tool Choosing the correct tool is important to achieve best possible productivity and results. There is always an optimized solution for each length/diameter overhang and the dampening system is tuned to run optimally in specified conditions. Each dampened tool has a defined range of reach (bandwith) for optimum tool function and it is important that the right range for each tool is applied. Using a short tool with an extension will not deliver desired results.
1. Introduction Reduce the cutting forces Start out by choosing the best available cutting solution. Then, choose the largest possible diameter and shortest possible overhang to minimize deflection. The next thing to have in mind is that the dampening system should be as close to the cutting edge as possible, and that the weight in front of the damper should be as light as possible. Reduced weight on the cutting tool will minimize the kinetic energy in a potential vibration.
1. Introduction In summary: 1. Reduce cutting forces by choosing the right cutting tool and insert 2. Minimize deflection by increasing the static stiffness through largest possible shank diameter and minumum length 3. Reduced weight on cutting units will minimize the kinetic energy in a potential vibration 4. When extending modular tools, build large diameters 5.
1. Introduction Typical components There is a big potential for increased productivity using Silent Tools in all type of industrial segments. For components requiring long tools (~6-14 x BD) Silent Tools is the only choice for vibration-free machining. General Engineering Typical components: Shafts, brackets, hydraulic components (cylinders, sleeves), pumps and valve housings etc. Power Generation Typical components: Gas turbines, gas turbine discs etc.
1. Introduction Oil & Gas Typical components: Pump houses, threading components, body spools etc. Automotive Typical components: Cylinder blocks, stamping die components, engine components etc.
1. Introduction Economics, ROI calculator A Silent Tool investment almost always has a short pay-back time, thanks to increased productivity and less scrap. There are three Sandvik Coromant calculators available that cover the areas of boring, milling and turning, helping you calculate return on investment (ROI) of your Silent Tools. With limited input, you will instantly see the outcome and payback time for a Silent Tool investment, compared to undampened tools. Find the calculators on the website: www.
2. Milling 2.
2. Milling Reduce vibration Workpiece set up and machine stability are two important things to consider carefully to minimize vibration.
2. Milling All Silent Tools dampened adaptors are designed for different overhangs, and with differently tuned dampers. The best performance will be achieved by using the optimized length instead of adding extension adaptors. If there is a need for more than 7–8 x BD, ask for an engineered adaptor.
2. Milling Factors that influence vibration There are four basic factors that have a major influence on vibration: • Entering/lead angle and cutting forces • Cutter diameter relative to radial depth of cut • Insert geometry • Cutter pitch Entering angle The entering angle is important as it determines the direction of the cutting forces. The larger the kappa angle (KAPR), the larger the radial cutting forces. Choose cutter concept according to process and application.
2. Milling Cutter diameter relative to radial depth of cut A smaller tool diameter will reduce the power and torque requirements as well as the deflective cutting forces. The ratio of the milling cutter diameter in relation to the radial engagement needs to be kept smaller than any maximum value. Insert geometry The cutting tool geometry should be light or medium. Silent tools limits High temperatures can change the function of the dampening system. Use air or through coolant when possible.
2. Milling Cutter pitch When multiple inserts are in contact with the material, the risk of vibration increases. As long as you are working with cutting depths under the critical depth for vibration, an increased number of inserts is more productive however. Work with both radial engagement and the pitch of the cutter to find the best performance. In most cases a coarse pitch is the best choice for productive machining with dampened tools.
2. Milling Programming guidelines A general rule for face milling is to keep the milling cutter constantly in cut, instead of running several length way passes. This minimizes the number of entries and exits and keeps the inserts from disadvantageous loads that could lead to vibration. Nya bilder från Borgs! Roll into cut Keep the cutter constantly engaged Roll into cut Roll into the cut clockwise to get thin chips, approaching zero at the exit.
2. Milling Milling direction Down-milling is the first choice for most milling operations. In some cases, when the machine has insufficient power or the workpiece is very pliable, up-milling is preferred. Remember however that the cutting force tends to lift the workpiece when up-milling. This must be carefully counteracted when clamping the workpiece.
2. Milling Position and diameter In general face milling, the cutter diameter should be 20-50% larger than the cutting width and the cutter should be positioned slightly off-centre. Do not position the cutter exactly in the centre. When the cutter diameter is smaller than the workpiece, it is recommended that maximum width of cut is 60-70% of the cutter diameter. In full slot milling, it is very important to reduce the number of engaged inserts to avoid vibration.
2. Milling Product overview There is a wide range of Silent Tools milling adaptors available off the shelf, with HSK or modular Coromant Capto couplings. If none of our standard adapters are suitable, inquire for an engineered solution. Adaptors for slitting cutters, built-in dampeners in large side mills and long-edge cutters are also available as engineered solutions.
2. Milling • Dampened solutions from 20–40 mm (0.787-1.575 inch) with integrated CoroMill 390 milling cutters are available in the standard assortment • From 40 mm (1.575 inch) and above, there are dampened adaptors with Coromant Capto sizes C4–C8, with coolant through arbor mounting available as standard.
2. Milling CoroMill® 390D – application area CoroMill 390D is a real productivity booster for long and slender tools and works well in both vertical and horizontal machines. The cutters are designed for reach and at the same time efficient when machining close to chucks in multi-task machines.
2. Milling The program consists of Coromant Capto sizes C6, C5 and cylindrical shanks in diameter 20, 25, 32 and 40 mm (0.787, 0.984, 1.260 and 1.575 inch) with a reach of 3–5 times the cutting diameter, DC. • Coromant Capto® C5 – High stability – Large programme of basic holders – First choice for closed reach • Coromant Capto® C6 – – – – High stability Large programme of basic holders Integrated multi-task spindles First choice for open reach • Cylindrical shanks – H ydraulic Chucks, e.g.
2. Milling Short and long basic holders With a combination of arbor mounting on the adaptors and basic holders with different lengths, solutions for most applications up to 8 x BD are available. For overhangs above 8 x BD, or when you have other specific requirements, engineered solutions are the best alternative.
2. Milling Dampened adaptors for face mills and square shoulder face mills • Cx-391.05CD • 392.
2. Milling Application examples Case one: Valve house Operation Shoulder milling – circular interpolation Workpiece material CMC 09.1, K3.2.C.UT, Nodular cast iron Machine cost 195 EUR/hour Machined volume 179 (10.92)/pc cm3 (inch3) ZEFF 5 Assembly length 280 mm (11.024 inch) Reference Silent Tools Adaptor C6-391.05 CD-22 200 Cutting head R390-066 Q22-18M Cutting data n (r/min) 700 1352 vc (m/min (ft/min)) 176 (577) 280 (918) fz (mm (inch)) 0.31 (0.012) 0.27 (0.
2. Milling Case two: Valve house Operation Workpiece material Machine cost Machined volume ZEFF Assembly length Circular interpolation CMC 09.1 Euro 195 Q=182 cm3/min (11.11 inch3/min) 6 480 mm (18.9 inch) Recommended cutting data ae, mm (inch) n (r/min) vc (m/min (ft/min)) fz (mm (inch)) vfa (mm/min (inch/min)) AP (mm (inch)) Total cycle time, min Tool life (no of comp.) 17.56 (0.691) 900 238 (780) 0.32 (0.013) 24 (0.945) 6.0 (0.236) 27.
2. Milling Step machining from one side Reference Recommended Step 1 Rough boring to diameter 135 mm (5.31 inch) Circular interpolation to diameter 139.8 mm (5.50 inch) Step 2 Rough boring to diameter 139.8 mm (5.50 inch) Finishing boring to diameter 140 mm (5.51 inch) H7 Step 3 Flushing Step 4 Finishing boring to diameter 140 mm (5.51 inch) H7 The valve housing has a total length of 850 mm (33.46 inch) and a production volume of 300 units per year.
2. Milling Operation Deep pocket milling Component Hollow chamber Workpiece material CMC 01.2 Machine cost Euro 90 Machined volume 132 cm3/min (8.06 inch3/min) ZEFF 4 Assembly length 360 mm (14.17 inch) Cutting data Competitor Silent Tools n (r/min) 1100 1550 vc (m/min (ft/min)) 176 (578) 249 (817.3) fz (mm (inch)) 0.46 (0.018) 0.41 (0.016) vf (mm/min (inch/min)) 2030 (80) 2540 (100) AP (mm (inch)) 0.50 (0.02) 1.02 (0.04) ae (mm (inch)) 51 (2.00) 51 (2.00) Tot.
2. Milling Tips and hints, summary Insert grades and geometries Choose a small edge rounding (ER). Go from thick coating to a thin one. If necessary, use uncoated inserts. Use sharp and positive inserts with chip forming capacity. Entering angle The smaller the entering angle, the thinner the chip, and the further away it will spread along the cutting edge. This allows for higher feed per tooth.
2. Milling Achieve maximum Q Choose ae between 60%–80% as a starting value if possible. Reduce the number of inserts to maximize Q. This is particularly important when using full slot engagement. Chip evacuation Use compressed air to prevent re-cutting of the chips. This is especially important in deep-cavity milling. Notice that a coarse pitch cutter will have more space to evacuate the chips. Entry and exit Avoid situations where the centre line or the cutter is in line with the workpiece edge.
3. Turning 3. Turning Main considerations Clamping stability and correct centre height are two important factors in order to achieve the right dimension tolerances and surface finish of your component. Clamp the cylindrical boring bar in a split sleeve holder, to achieve maximum contact area. With EasyFix sleeves you will achieve the most stable clamping and exact centre height positioning. The centre height affects both the rake angle and cutting force on the tool.
3. Turning Boring bars – general • Surface finish of ~1 µm is required to ensure sufficient clamping contact • Recommended clamping length is 4 × BD. If possible, we recommend using a clamping length of 6 × BD for boring bars over 200 mm (7.87 inch) • Cylindrical boring bars in split sleeves.
3. Turning Clamping of Silent Tools bars Due to the design of the turret in a CNC lathe or the flexibility of a multi-task machine, the rigidity is usually reduced. Small turret widths reduce the ratio between the clamping length and the bar diameter on larger cylindrical boring bars and consequently reduce the set-up stability. The Coromant Capto coupling can also be a solution on a turret lathe machine.
3. Turning Flat bed lathes Compared to turret lathes, a flat-bed lathe with a tool post is often more rigid and stable and can hold larger and longer boring bars. The limitation of the machine in this case can be the tool post, the size of the machine and the rigidity in the design. The stability of the machine slides and gibs are important factors in order to achieve good results when holding Silent Tools boring bars with long overhangs.
3. Turning For best performance of the boring bar, the contact, design, and dimensional tolerance between tool and tool holder are important factors. The best stability is obtained with a holder that completely encases the bar. V-type bar holder and cylindrical holder with screws are not recommended. Split holder for 300 mm (11.81 inch) bar diameter. The distance between the cross slides is 1,200 mm (47.24 inch) (4 x BD).
3. Turning Centre height setting tool For all cylindrical CoroTurn SL bars, there is a quick and simple method to accurately ensure correct centre height setting of the cutting edge: 1. Attach the setting tool to the serrated edge of the cylindrical boring bar 2. Twist the boring bar to the right position 3. The bar is parallel when the bubble is in the centre position Even though the bar will deflect slightly below centre during the machining operation, the correct mounting of the bar is on centre line.
3. Turning Pressure and direction For best tool life and process security, use coolant directed to the cutting zone. For tools equipped with SL quick change heads, adjustment of the coolant nozzles needs to be done manually, to ensure that the coolant hits the cutting zone. For best results, use tools with integrated coolant and several nozzles. This is equally important for internal turning with long overhangs. To turn on and off the coolant flow, use a hexagon key.
3. Turning Advanced cooling technology The Sandvik Coromant advanced cooling technology is a unique concept that optimizes the use of coolant in all wet machining. By directing the coolant with precision to the cutting zone, the generated heat is efficiently removed from the cutting zone, giving excellent chip breaking, also in difficult materials, regardless of what pressure you use.
3. Turning Factors that influence vibration To minimize vibration tendencies: • Use a large entering angle and positive rake angle • Use big nose radii and point angle • Use a positive macro geometry • Control the wear pattern and ER-treatment on the micro geometry • Depth of cut should be larger than the nose radius. Lower radial force gives less radial deflection and fewer problems with vibration.
3. Turning Be aware that re-directing forces can reduce deflection: • Entering angle as close to 90° as possible (lead angle 0°) will maximize the portion of feed force coming back from the workpiece in the axial direction. A force in the axial direction will give less tool deflection than equal forces in the radial direction. • For internal turning the entering angle should never be less than 75° (lead angle 15°).
3.
3. Turning Insert point angle Select an insert shape relative to the entering angle and accessibility requirements of the tool. One rule of thumb is to always choose the smallest possible nose radius to reduce vibration tendencies.
3. Turning Positive geometries Positive geometries and positive rake angles generate less cutting forces and less deflection of the tool. Therefore, choose the most positive geometry you can, with a chip-breaker suitable for your cutting data. This may decrease the wear resistance and edge strength somewhat, as well as the chip-control, so vibration control is always a balance.
3. Turning Edge rounding A small edge rounding (ER) gives lower cutting forces in all directions. This means easier cutting action and less deflection of the tool. Ground inserts have smaller edge rounding than direct pressed inserts, which is true also for uncoated or thin-coated inserts.
3. Turning Cutting data Excessive insert wear, such as flank wear must be avoided, as it changes the clearance between the tool and the component wall, which can cause vibration problems. Cutting speed, vc Correct cutting speed will avoid built-up edge, which influences surface finish, cutting forces and tool life.
3. Turning Depth of cut, AP, and feed, fn The combination of AP and fn is important to achieve the best possible chip areas. Two rules of thumb: • Program AP larger than the nose radius • Program for an fn that is a minimum of 25% of the nose radius, depending on what surface finish is required One of the first things to consider if you experience vibration when machining with long overhangs is to increase the feed and a second remedy, change the cutting speed.
3. Turning Case one: Turning mud screws An oil & gas company machining mud screws invited Sandvik Coromant to the workshop to test Silent Tools as the existing solution was not stable enough. By utilizing the stability of the Silent Tools bar and the possibilities of using higher cutting data, the machining time was reduced by nine minutes per component. Operation Component Workpiece material Machine cost Turning Mud screws CMC 20.
3. Turning Application examples Case two: Turning internal hole Internal turning is sensitive to vibration. Tool choice is restricted by the component’s hole diameter and length, as the depth of the hole determines the overhang. Minimize the tool overhang and select the largest possible bar diameter in order to obtain optimum stability and accuracy. For internal turning, a dampened Silent Tools boring bar is the first choice.
3. Turning Operation General internal machining, light roughing Component Process flange Workpiece material CMC 01.1, P1.1.Z.AN, Low alloy steel Machine cost EUR/hour: € 75 Working hour/week 80 44% Dampened adaptors usage Machined volume/pc cm (inch ) 54 (3.295) Assembly length mm (inch) 406 (15.984) 3 3 Reference Silent tools Adaptor C6-570-3C 40 368 Cutting head 570-DCLNL-40-12-L Cutting data n, r/min: 424 955 Dm mm (inch): 60 (2.360) 60 (2.
3. Turning Case three: Bearing case, flanged The customer struggled with vibration and asked Sandvik Coromant for a productive solution. By implementing an A570-3C D32 27-40 boring bar, one of the two boring operations was removed and the productivity could be increased substantially. One comment from the customer: "Not only did the bar silence my boring operation. It also silenced all the people in the workshop who told me that the Sandvik Coromant tool would not work." Material CMC 02.
3. Turning Case four: Spindle The spindle production involves mainly internal processing and the existing process included two operations – turning from both sides. The customer experienced two issues: vibration and a need for a simplified process. By implementing a Silent Tools boring bar of 5.3xBD, the turning could be performed from one side, saving time for the customer.
3. Turning Product overview Selection of boring bar has a big impact on production economy. The Sandvik Coromant tool program is comprehensive and covers solutions from diameter 10 to 100 millimeter (0.394 to 3.94 inch) as standard off-the-shelf tools that will be delivered within 24 hours. Outside that range, engineered tools up to diameter 600 millimeter (23.6 inch) are available. Overhangs 3–14 x BD bars are available while for Coromant Capto, you will find sizes from diameter 16 to 100 millimeter (0.
3. Turning Boring bar diameter, BD (mm) %' Engineered products %' %' %' %' CoroTurn® SL – QC %' CoroTurn® SL – QC %' %' %' CoroTurn® SL %' %' CoroTurn® SL %' %' %' %' %' Integrated Max. overhang [ %' Steel dampened boring bars [ %' Carbide reinforced dampened boring bars If you work with a combination of cutting heads and Silent Tools dampened boring bars, you can easily change only the head if there is damage on the tip seat.
3. Turning A combination of cutting heads and Silent Tools dampened boring bars gives great flexibility, with cutting heads for different applications. Large cylindrical boring bars come in several different couplings, such as Coromant Capto and Quick Change coupling units.
3.
3. Turning Bar types Internal turning is very sensitive to vibration. Minimize the tool overhang and select the largest possible tool size in order to obtain the best possible stability and accuracy. For internal turning with steel dampened boring bars, the first choice is bars of type 570-3C. For grooving and rough threading operations where the radial forces are higher than in turning, the recommended bar type is 570-4C. The table below shows the maximum recommended overhang for different bar types.
3. Turning Select boring bar material to suit the appropriate length to diameter ratio. A carbide bar has a higher static stiffness than a steel bar, which is why a larger overhang can be allowed. As seen in the figure, the following boring bar materials can be selected to suit the appropriate length to diameter ratio. Threading and grooving give more radial cutting forces than turning, which limits the recommended maximum overhang.
3. Turning Tips and hints, summary Reduce the risk of vibration by choosing the largest possible bar diameter with the smallest possible overhang. Use recommended clamping length, minimum 4 x BD. Cut off of the CR boring bars above 10 x BD is not allowed. For 570-4C bars, clamping over the dampening mechanism is allowed, while it is not allowed for 3C bars. When a 570-3C short design bar is cut-off to minimum length, the clamping length must not exceed 3 x BD to avoid clamping over the dampening mechanism.
3. Turning Modification of standard bars Bar diameter L, min length after cut off Short design Long design 4–7 × BD 7–10 × BD mm mm mm 16 100 155 20 125 200 25 155 255 32 190 320 40 240 410 50 305 520 60 380 630 80 630 630 100 770 770 BD We recommend a min. clamping length of 4 × BD Bar diameter L, min length after cut off BD Short design 4–7 × BD Long design 7–10 × BD inch inch inch 0.625 4 7 0.750 5 8 1.000 7 11 1.250 8 13 1.500 10 17 1.750 10.
3. Turning Chip evacuation For best chip evacuation, use a tool holder with integrated coolant and an insert geometry that gives short and spiral formed chips. If you experience poor chip evacuation; try to increase the coolant flow, change the insert geometry or increase the cutting speed to get shorter chips. Another alternative is to consider an alternative tool path. Up-sidedown cutting units actually permit improved chip evacuation. Ensure that there is enough room for the chips between bar and hole.
3. Turning Internal threading To reduce the risk of vibration, use the following tips: • Use modified flank feed • Infeed per pass should not exceed 0.2 mm (0.008 inch) and never be less than 0.06 mm (0.002 inch) • Final pass, always with reduced infeed rate • Use a sharp geometry for lowest cutting forces For best chip evacuation: • Use modified flank feed to lead the spiral chips towards the opening of the hole • Use inside-out feed direction in stable conditions.
3. Turning Internal grooving and profiling Reduce the risk of vibration by applying the following tips: • Set-up should have the shortest possible overhang with the lightest cutting geometry possible • Use a smaller insert and make several cuts instead of one • Start from the outside and make overlapping cuts inwards for best chip evacuation • A finishing operation can be a side turning motion.
3. Turning Treatment For best performance, clean all parts and lubricate with oil at least once a year. Lubricant should also be applied to the screws when needed. Replace worn or exhausted screws and washers. Dampened bars can become deformed due to the thin wall thickness. When assembling, ensure that the bars are held correctly. Always check the clamping when working with Silent Tools products. Use a torque wrench for correct screw-tightening.
3.
4. Boring 4. Boring Main considerations The Silent Tools boring tools reach a maximum of six times the bore diameter into your workpiece. If you need to go deeper, ask for an engineered solution. Our recommendation is to always use Silent Tools for long overhangs, over 4 x BD. Tool overhang and diameter of tool BD • Choose largest Coromant Capto size possible • Choose shortest possible basic holder • If possible, use a heavy duty basic holder • For overhangs over 4 x BD, use dedicated tools, e.
4. Boring Insert shape and entering angle/lead angle Use entering angle 90° (0°) for roughing and 92°(-2°) for finishing. Less force in the radial direction gives less radial deflection and vibration. Triangular-shaped inserts (T-style) are first choice for boring operations. CoroTurn® 107 inserts meet these requirements and are first choice. Nose radius The nose radius, RE, on the insert is a key factor in turning operations.
4. Boring Nose radius in relation to depth of cut The radial forces that push the insert away from the cutting surface become more axial as the depth of cut increases. The nose radius also affects the chip formation. Generally, chip breaking improves with a smaller radius. As a general rule of thumb, the depth of cut should be greater than or equal to 2/3 of the nose radius or half the nose radius in the feed direction. Feed starting values depending on nose radius Nose radius size (mm) 0.4 0.8 1.
4. Boring Rough boring Choose a roughing geometry unless a small depth of cut is needed. For smaller cutting depths, use a medium geometry. Recommended nose radius: 0.8 mm (0.031 inch) and if you experience problems, try 0.4 mm (0.016 inch). For severe problems, try to use only one insert.
4. Boring Productive boring Involves two cutting edges and is employed for roughing operations of holes, with tolerance IT9 or larger, where metal removal rate is the first priority. Feed rate is obtained by multiplying the feed by the number of inserts. (fn=fz x ZEFF) Step boring When adding a shim under one of the slides, the insert will only take the inner half of the desired radial cut, and the result is a stepboring tool.
4. Boring Finish boring The finish boring tools are single-edge tools with radial micrometer adjustment on the cutting unit head. Finishing is used when close hole tolerances and excellent surface finish are needed. Choose a light cutting insert with a positive cutting geometry. First choice is knife-edge inserts (TCGT L-K). Use a small nose radius of 0.2 mm (0.008 inch), maximum 0.4 mm (0.016 inch).
4. Boring Vibration influence factors To reduce vibrations, choose a light cutting insert with a positive cutting geometry and small nose radius. T-style inserts are first choice for boring operations. High vibration tendency – Heavy feeds – Large depth of cut – Strong edge security Less vibration tendency – Ideal for small depth of cut – Reduces vibration Information about other vibration influence factors such as the following can be found in the application guide on page 41-47.
4. Boring Product overview Sandvik Coromant offers dampened boring tools for rough and finish boring. The adapters are designed with Coromant Capto backend couplings for best possible clamping and flexibility. This gives you unique flexibility and modularity to build desired tool assemblies. Coromant Capto basic holders are available in all common machine interfaces. Silent Tools finish and rough boring tools give increased productivity and close tolerances from lengths of 3–10 x BD.
4. Boring Rough boring Fine boring Boring range mm (inch) Ø25-150 (0.98–5.9) Boring range mm (inch) Ø23-167 (0.90–6.6) Dampened DuoBore™ Boring range mm (inch) Ø150-315 (5.9–12.4) Dampened CoroBore®825/826 Coromant Capto® back-end coupling Coolant through DuoBore™ 821 rough boring tools Dampened DuoBore adapters for roughing are designed with two inserts for high productivity in boring applications against shoulders and through holes.
4. Boring CoroBore® 825/826 – finish boring tools Dampened CoroBore 825 and CoroBore 826 are designed for finishing operations with excellent surface finish and close tolerances even in long overhangs, with possibilities to double the depth of cut and still obtain the same excellent surface finish. Boring range 23-315 mm (.906-12.402 inch) Boring depth 6 x BD Hole tolerance IT6 Cutting fluid Internal Diameter adjustment: 0.002 mm (0.
4. Boring How to use CoroBore® 825 Example of setting: In this example the blue line on the scale disc is a reference since it is aligned to a line on the vernier in the starting position. Start position Adjusted position Scale disc turned clockwise until the line of scale (red) lines up with the second line (green) of the vernier. Diameter increased by 0.002 mm (0.00008") Scale disc turned clockwise until the line of scale (red) lines up with the third line (green) of the vernier.
4. Boring Application examples Case one: Lug holes, landing gear Machining of an aerospace part, with a length of 2.1 m (7 ft) and width of 0.91 m (3 ft) was an accessibility challenge. The component has two lug holes in line on the outside and the process consisted of semi-roughing both lugs from one side. Then followed a finish pass and a ream pass of one lug hole from one side, followed by a set-up of the part to the opposite side, dialing it in to centre, completing with a new finish- and ream pass.
4. Boring Operation Finishing Workpiece material 300M, high alloy steel Machine cost EUR/hour € 75 Dampened adaptors usage 6% Machined volume/pc cm3 (inch3) 0.07 (0.004) ZEFF 1 Assembly length mm (inch) 332 (13.071) Reference Silent tools C5-R825B-FAD315A Adaptor Cutting data: n, r/min 203.7 vc m/min (ft/min) 30.5 (100) 254.6 38.1 (125) Dm mm (inch) 47.6 (1.874) 47.6 (1.874) fn mm/r (inch/r): 0.005 (0.0002) 0.038 (.0015) AP mm (inch) 0.05 (0.002) 0.05 (0.002) Tot.
4. Boring Case two: Boom bracket A customer producing boom brackets used a tailored boring bar with positive inserts for his application. He experienced vibration, poor surface finish and short insert tool life, even with low cutting data. The component was positioned horizontally and the operation included interrupted cuts. By changing to a CoroBore 825 finish tool, the cutting data could be increased as well as the component quality.
4. Boring Tips and hints, summary • Choose the largest possible tool diameter with the shortest possible basic holder • The entering angle should be close to 90 degrees to give more axial cutting forces and less radial/tangential forces • A small nose radius is ideal for small depths of cut and decreases the risk of vibrations. Large nose radii have strong edge security and allow for heavy feeds and large depths of cut. The risk of vibration gets higher the larger nose radius you use.
4. Boring Tool assembly and maintenance When using dampened tools in assemblies, care should be taken to hold the tool bodies correctly to make sure that the adaptors are not damaged. These are easily deformed due to the thin wall thickness.
5. Engineered Solutions 5. Engineered solutions Offer The standard off-the-shelf boring bar offer represents a good platform for optimized solutions and high productivity. When a tailor made solution is needed, engineered versions of dampened boring bars are available for order. The engineered dampened boring bars are often tapered, elliptical and/or curved, with the mounting adapted to the machine. Bars with overhangs of up to 14 x BD are available.
5. Engineered Solutions Silent Tools – engineered solutions Turning-, milling- and boring adapters can be engineered with most of the common back- and front-end couplings. Back-ends: • Coromant Capto • HSK • MAS BT • VDI • VTL • DIN 2080 • ISO 7388/1 • Cylindrical Front-ends: • CoroTurn SL • CoroTurn SL quick change • DuoBore • CoroBore 825 • Arbor Engineered adapters come with diameters ranging from 10–600 mm (0.394–23.62 inch).
5. Engineered Solutions Special solutions for multi-task machine tools As multi-task machines are equipped with all the necessary tooling when performing a complete machining in one set-up, they have to store both short and long tool holders in the tool magazine, plus all the cutting units needed for performing the complete operations.
5. Engineered Solutions Application example Operation Face milling Component Upper body steering unit Workpiece material CMC 09.1, K3.2.C.UT, Nodular cast iron Machine cost 125 EUR/hour Machined volume 122 (7.45)/pc cm3 (inch3) ZEFF 6 Assembly length 300 mm (11.81 inch) Reference Silent Tools Adaptor S-391.06-22 260//ISO50 Cutting head R390-063Q22-18H Cutting data n (r/min) 760 1197 vc (m/min (ft/min)) 150 (492) 237 (778) fz (mm (inch)) 0.32 (.013) 0.18 (.
6. Formulas and Definitions 6.
88 Inch Working engagement ae AP Cutting depth DCap Cutting diameter at cutting depth AP Dm Machined diameter (component diameter) Feed per tooth fz Feed per revolution fn Spindle speed n Cutting speed vc Table feed vf ZEFF Number of effective teeth hex Maximum chip thickness hm Average chip thickness Specific cutting force kc Net power Pc Mc Torque Metal removal rate Q KAPR Entering angle PSIR Lead angle BD Body diameter DC Cutting diameter LU Usable length Metric Designation/ defination Symbol 6.
6.
Symbol Designation/ defination Metric Inch 6.
6. Formulas and Definitions Turning – METRIC Tangential force, Ft ( ( Ft = kc 0,4 x 0,4 mc x fn x AP fn x sin KAPR kc 0,4: Specific cutting force at feed 0,4 mm/r mc Constant, depending on the material. Use 0,29 as general value. When the entering angle. KAPR, is 75 degrees or longer, sin KAPR ~1. Use the simplified formula: Tangential force, Ft ( 0,4 fn ( Ft = kc 0,4 x 0,29 x fn x AP Rule of thumb: Ft should not exceed 90% of maximum load stated for the bar used.
6. Formulas and Definitions 3-pass method Method for achieving high accuracy in internal turning with slender boring bars where the deflection of the bar affects the obtained diameter. 1. Enter the desired finished diameter: 40.000 2. Measure the diameter before the first pass: 37.000 3. Run the first pass. The programmed diameter is: 37.000 + (40.000 – 37.000)/3=38.000 4. Measure the diameter before second pass: 37.670 5. Run the second pass. The programmed diameter is: 38.000+(40.000-37.670)/2=39.165 6.
6.
Notes 94
95
96
APPLICATION GUIDE Application guide – Silent Tools Head office: AB Sandvik Coromant SE-811 81 Sandviken, Sweden www.sandvik.coromant.com E-mail: info.coromant@sandvik.com C-1020:17 ENG/01 © AB Sandvik Coromant 2012.
