Using PCBN for turning of medical implant components 07:30

The medical industry is a growing segment. People are getting older and older, and there is an increased need for replacing worn out joints and other parts, so that people can be active and live a good life even at a higher age.

The materials used for replacement parts are often made of polymer, titanium or a cobalt-chrome alloy, materials where PCBN is usually not recommended. Polymers are machined with either PCD or carbide, and titanium and cobalt-chrome are normally machined with carbide.

The components are often asymmetrical, and the majority of the applications are with round tools, with little need for turning tools. One exception is finishing of joints for hips, elbows etc. The component is a spherical ball, called a femoral head, with a diameter of between 25 and 50 mm, and with a hole on one side. After forging, the components are rough and finish turned, and then polished to final dimensions, with very tight requirements on the tolerances.

Cobalt-Chrome is an alloy with about 60% cobalt and 40% chrome. The hardness is only about 30 HRC, but the material is very abrasive. Turning has traditionally been done with carbide, but in finish turning of the sphere, tool life is very low due to the abrasiveness of the material, and the high tolerances required.

Seco UK has been successful in turning of these components, using CP500 for roughing and CBN200 for finishing. We have now used this information to implement the solution at one company in China, with large improvements in productivity and component quality. An additional benefit in finishing is the much longer tool life with PCBN, from a few components with carbide to over 100 with PCBN. We are now working with this at a second company with potential for further growth.

Three conclusions drawn from this:

• The application area for PCBN is growing, as new materials are being developed and used in the market.
• We have a very good solution to offer our medical customers.
• The importance of sharing success stories cannot be underestimated. If we have good results on a specific component, this should be spread to colleagues domestically as well as internationally, in order to avoid “inventing the wheel again”, or even “never inventing the wheel at all”.

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Author: Henrik Sandqvist Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS Shanghai CO., Ltd. Level 2, Building 8, 456 HongCao Rd., Shanghai 200233, China Office: +86 21 5426 5849 Mobile: +86 186 167 90063 e-mail: henrik.sandqvist@secotools.com

Secomax™ CBN600 – A new universal option for machining Grey Cast Iron, High Chrome Iron and High Manganese Steel 01:07

The well-known SECO grades CBN300, CBN400C and CBN500 are premium products designed for peak performance in machining of Grey Iron, High Chrome Iron and High manganese steels. Those grades have been successfully used for many years machining components like brake discs, brake drums, fly wheels, pumps, rolls and crushing cones. As a complement to those premium grades addressing machining conditions that are not optimized regarding e.g. machinery, material, cutting data etc, SECO is now introducing CBN600, a new universal option.

CBN600 is designed and positioned to be a universal, cost effective solution in applications where it’s not possible to utilize the technical benefits from our premium grades CBN300, CBN400C and CBN500.

Secomax™ CBN600 with 90 % cBN content, multi modal grain size and Al ceramic binder comes together in a product which offers great toughness high wear resistance and a wide application window machining below mentioned materials.

Secomax™ CBN600 has proved successful in the machining of the following materials.

• Grey Cast Iron
• Chilled cast irons
• High Manganese steels

With Secomax™ CBN600 SECO now has the most complete high cBN product portfolio on the market targeting cost effective, high productivity machining in all possible machining conditions.

 

 

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Product Manager: Anders Wickman Product Manager SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340254 Mobile +46703431200 e-mail:anders.wickman@secotools.com

SECOMAX™ Ceramic inserts 22:46

Did You know that Seco Tools is now offering a range of competitive SiAlON Ceramic inserts?

Seco Tools has been successfully active within the Aerospace and Power Generation segments for many years offering high performance solutions for components such as shafts, engine parts, landing gears etc. The addition of Ceramic products will now further enhance our portfolio and strengthen our position as a full line supplier.

The features of these inserts come together in a product line that offers optimized wear resistance and toughness in machining of nickel-based heat resistant superalloys.

CS100 (SiAlON)

In Sialons, the advantages of pure silicon nitride ceramics; notch wear resistance, toughness and thermal shock resistance, are maintained, while the flank wear resistance at higher cutting speeds is increased.

Grade CS100 has the following features:

• High notch wear resistance
• High toughness
• High thermal shock resistance
• Optimized flank wear resistance

Read more here: www.secotools.com/cs100

 

 

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

 

Product Manager: Anders Wickman Product Manager SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340254 Mobile +46703431200 e-mail:anders.wickman@secotools.com

Seco Crossbill™ wiper – Unique and patented design 22:45

Wiper technology is now an established method for decreasing cycle times and increasing productivity.

A drawback when machining with wipers, is that it is not possible to generate the true corner radius when machining towards a shoulder. The wiper goes all the way down the flank of the insert, so the wiper geometry will be copied into the corner.

The Seco Crossbill™ wiper has addressed this issue. The unique patented design of the wiper allows for the utilization of handed wiper technology on all cutting edges on a solid insert.

The Crossbill™ wiper can be used for axial turning with all the usual benefits of wiper technology towards a shoulder and, due to the design, also machine a perfect radius.

The Crossbill™ wiper inserts are now available as TNGX110308S-01020-L-WZ and TNGX110308S-01020-R-WZ in the new grade CBN010.

The Seco way, Crossbill™ wiper Wiper technology - Perfect radius – 6 cutting edges – New PCBN grade CBN010.

 

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

 

 



Author: Per Ola Jönander Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340818 Mobile +46703163555 e-mail:perola.jonander@secotools.com

Plunging – The patented time saver 22:43

One big break through of hard turning was patented by Seco in 2001. That was plunging, a true productivity booster. It reduces the time in cut up to 90 %, but is also improves surface quality. General turning generates a spiral pattern which is dependent on feed and corner radius, which sets the surface finish. By using plunging, the surface topography is set by the whole cutting edge and is dependent on the quality of the cutting edge.

Solid inserts or full face inserts are needed to be able to use plunging as a method since long cutting edges are needed. Conventional holders are not suitable for plunging due to clearance angles. Separate plunging holders are therefore needed.

The residual stresses after plunging are compressive both in the tangential and axial direction, which are beneficial to the fatigue properties of the component. Ground workpieces show tensile residual stresses deep below the surface before changing into compressive residual stresses at the surface.

Overall, plunging has great potential for decreasing manufacturing costs, and the surface integrity of the workpiece is superior to conventional hard turned or ground parts.

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Author: Stefan G Larsson Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340572 Mobile +46761367807 e-mail:stefan.g.larsson@secotools.com

Selecting the right PCBN grade in finish hard turning 22:42

Usually wear resistance (hardness) and toughness are used to describe the characteristics of an insert. For continuous machining, wear resistance is needed, but in interrupted machining, the wear resistance has to be balanced with a certain amount of toughness, to withstand the interruptions.

For a component with both continuous and interrupted cuts, two different inserts should be used to get the best performance. The more wear resistant grade does not have enough toughness for the interrupted cut, and the tougher grade does not have enough wear resistance for the continuous cut.

This means that it is important to select the right grade for the operation. Selecting the wrong grade will seriously affect the tool life. In continuous hard turning of a gearbox gear, a customer was using a CBN-grade for heavy interrupted turning. Tool life was low, and the customer wanted improvements.

After analysing the application and the existing machining conditions, we decided to use CBN060K, a grade developed for continuous hard turning. We did not do any changes to the cutting data.



By selecting the right grade for the application, tool life was increased by over 3 times.

Always try to understand the application, and if the right insert/grade/edge preparation is used. If a crossover table had been used in this case, we would have proposed CBN160C, a grade for interrupted machining, and this would not have given the improvement we now got.

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Author: Henrik Sandqvist Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS Shanghai CO., Ltd. Level 2, Building 8, 456 HongCao Rd., Shanghai 200233, China Office: +86 21 5426 5849 Mobile: +86 186 167 90063 e-mail: henrik.sandqvist@secotools.com

Edge preparation – The key to success 22:42

To be really successful in any metal cutting application, it is of outmost importance to control the cutting forces and the material flow. This is of course also valid for PCBN cutting tools. In turning, the rotation of the work piece generates a tangential force, Ft, on the cutting edge and the feed generates a radial force, Fr, on the cutting edge. These two forces added together, generates a resultant force which must be taken care of by the edge preparation.

If the radial or the tangential force is too big, top flaking or edge breakage will occur. By choosing inserts with a proper edge preparation, the resultant force can be taken care of and be directed into the centre of the insert. The optimized edge preparation gives a cutting edge as strong as possible, but still as sharp as possible which together with optimized cutting data generates a controlled wear pattern and long tool life.

Our long experience within the PCBN area has resulted in a wide product portfolio, suitable for many different application areas. It is of course not optimized for every unique application, but it always gives a good start. For full optimization, do not hesitate to contact the PCBN product specialists for support.

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Author: Stefan G Larsson Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340572 Mobile +46761367807 e-mail:stefan.g.larsson@secotools.com

SECOMAX™ Ceramic inserts 22:41

Seco Tools is now complementing the existing CS100 Ceramic range with a range of competitive Whisker Ceramic grooving inserts, CW100.

Seco Tools has been successfully active within the Aerospace and Power Generation segments for many years offering high performance solutions for components such as shafts, engine parts, landing gears etc. The addition of Ceramic products will now further enhance our portfolio and strengthen our position as a full line supplier.

The features of these inserts come together in a product line that offers optimized wear resistance and toughness in machining of nickel-based heat resistant superalloys.

CW100 (Whisker)

The wear resistance of the aluminium oxide, combined with the toughness of the ultra-strong whiskers, comes together in a product with increased wear resistance, fracture toughness and notch wear resistance in machining of superalloys at high speed.

Grade CW100 has the following features:

• Excellent wear and thermal shock resistance
• Superior notch wear resistance
• Outstanding fracture resistance

Grade CW100 is a whisker reinforced ceramic for grooving inserts while CS100 is a SiAlON type ceramic for ISO inserts.

 

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Product Manager: Anders Wickman Product Manager SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340254 Mobile +46703431200 e-mail:anders.wickman@secotools.com

Some basics of cutting with ceramics 22:41

There are some basics when it comes to applying ceramic cutting materials into a metal working process that needs to be considered. Our ceramics, CS100 and CW100, are designed to be used for roughing of heat resistant super alloys, HRSA, and to be successful in applying them, these basics needs to be addressed to get the maximum tool life.

For example, always use a radial path with a radius bigger than the inserts radius when machining into a shoulder to avoid breakage. The feed should also be reduced to about 50 % when machining into the corner.

Ceramics tend to get big notch wear and to maximize the tool life, two very important techniques for roughing can be used. By varying the depth of cut when several passes are needed, the notch wear can be spread out on a bigger part of the cutting edge and the tool life can be heavily increased. Start with the biggest depth of cut and decrease the depth for every pass and keep the depth of cut constant during each pass. The other technique for spreading out the notch wear is ramping. It means that the depth of cut is varied during each pass, starting the first cut with a big depth of cut and decreases it. The next cut is started with a low depth of cut and is increased during the whole cut.

 

These are just some tips and tricks when machining with ceramics to avoid some easy mistakes.

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Author: Stefan G Larsson Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340572 Mobile +46761367807 e-mail:stefan.g.larsson@secotools.com

Turning of crushing cones in austenitic manganese steel 22:40

The two main application areas for CBN are:

• machining of hardened steel
• machining of grey cast iron

There are several types of hardened steels including case hardened steels (in gears, shafts etc), through hardened steels (in bearings etc) and tool steels (in moulds, dies, rolls etc).Grey cast iron is not hardened, but highly abrasive, and can be found in automotive brake components (brake discs, brake drums etc).

Normally CBN only works when the steel component is hardened, with a hardness above 50 HRC. One exception are the so called austenitic high manganese steels. These are steels with a manganese content of 11% or more, originally invented by Sir Robert Hadfield. In its original state, the material is usually around 250 HB, but the hardness is increased significantly through deformation hardening when used, without any loss of toughness. The hardness is also very difficult to measure with high accuracy due to the high level of work hardening.

The application areas for these materials are in the mining industry, such as in components for cement mixers, rock crushers, railway switches and crossings, crawler treads for tractors, teeth for excavators and other high impact and abrasive environments.

The deformation hardening will affect the material also during machining, and this impacts the selection of materials that can be used for machining.

Cutting data when using carbide has to be very low, cutting speeds in the range of 20 to 30 m/min is normal. By instead using CBN, cutting speeds can be increase to 200 m/min, which significantly improves productivity.

One typical application where Seco Tools has a long experience and has been very successful is turning of crushing cones.

 These components are usually cast, and machining include one or more roughing cuts depending on the stock allowance, and one finishing cut. Seco Tools’ grade CBN500 has been developed to meet the challenges when machining these materials.

CBN500 is a high cBN-content grade with high wear resistance and high toughness. Other application areas for CBN500 include machining of hardened chrome irons and rough machining of hardened steel components.

Crushing cones are usually machined with round inserts or large nose radii inserts. A round insert has the advantage of multiple “edges”. At a depth of cut of 2 mm, there are six usable edges per side (twelve edges in total) on a round R...12-insert.

A typical example is shown below, where they were using carbide. The cutting speed is low, and they have to do several insert changes during the cut. The much higher cutting speed with CBN reduces significantly the machining time and the machining down time due to tool change. Due to the high wear resistance of CBN500, typical tool lives in these materials are up to 60 minutes time-in-cut.

What used to require 20 pcs of carbide inserts, can now be done with one single CBN insert. This means that not only are the components machined much faster, the insert cost per part is also lower. By using CBN, the productivity is increased, and the tooling cost is reduced.

 

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Author: Henrik Sandqvist Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS Shanghai CO., Ltd. Level 2, Building 8, 456 HongCao Rd., Shanghai 200233, China Office: +86 21 5426 5849 Mobile: +86 186 167 90063 e-mail: henrik.sandqvist@secotools.com