Sandvik Coromant releases products in two stages throughout the year. Andrew Allcock reviews some of the highlights from the Coropak 2 unveiling last year. Composites machining, medical, wind power plus specific product developments are covered. (This is an extended version of a feature first published in Machinery magazine, February 2010).
Sandvik Coromant held an event at its Halesowen, West Midlands, headquarters last year to highlight latest products and trends, following the launch of its CoroPak 2 package, within which there were 1,100 products.
Of particular note were products that cater to the composites market, the medical market, while specific solutions within milling, parting, grooving and threading were also spot lit.
Kicking off with composites, it was trends in the civil aerospace sector (190 seats-plus) that were tackled first, with the swing towards the use of lighter materials, in the form of carbon fibre reinforced plastic (CFRP) the prime trend. Previous generation aircraft had airframes that were 70 per cent aluminium, graphite and steel 7 per cent, titanium 6 per cent, fibreglass 3 per cent and other 7 per cent. With current latest generation aircraft – A380 (in service), Boeing 787 (in service 2010) and Airbus A350 XWB (in service 2013) – now seeing something like 43 per cent CFRP, aluminium 20 per cent and titanium 14 per cent in their designs.
Carbon fibre is stronger than steel, lighter than aluminium, but as stiff as titanium. Lighter aircraft offer more economy, reduced emissions and an increased passenger or freight payload.
But carbon fibre is not just used alone, but in stacks, often with titanium and aluminium, requiring what Sandvik Coromant's Paul Smith, aerospace application centre manager, says are "demanding machining, product and application solutions", and who went on to give a brief overview of specific challenges and solutions in brief.
It is not enough to offer a tooling solution alone, it was said; it must take in a complete solution for material, tool and machine. For example, the production solution might be manual, semi-automatic, robotic or full CNC, with the material carbon fibre or a stack additionally involving aluminium and titanium.
In the case of wings, which are likely to comprise carbon fibre, aluminium and titanium, the challenges are: holemaking in carbon fibre alone and in a sandwich of aluminium and titanium; surface machining; trimming; and edging.
In the case of holemaking, tooling answers to these challenges take in uncoated and diamond-coated carbide drills, plus polycrystalline diamond (PCD) tools of pin, vein or brazed design. Included are its Tailor-Made range, particularly CoroDrill 854, plus engineered solutions that incorporate both drilling and countersinking in a single PCD drill and which also offer a variety of drill tip designs, such as double-angle (titanium-carbon fibre stack), 100° (aluminium-carbon fibre stack) and E-edge, the latter having a raised portion at full diameter that delivers a trepanning operation, particularly useful for epoxy resins that break up easily.
Trimming is an operation undertaken on wing edges that must be bonded to the wing box, for example. Here it is key that there is a clean edge and one of the demands is reduction of delamination (CFRP is made up of multiple layers of cloth) and splintering. In such cases, the Coromill 329 face cutter is suggested, with Corocut carbide or PCD inserts.
Moving on to surface machining, this is a requirement where other parts have to be bonded to CFRP parts. In this case, Coromill 350 and 390 are available, the former with PCD inserts and the latter with either carbide or PCD inserts.
Image: Surface machining
The company is, Mr Smith highlights, actively engaged in R&D in the UK, via the Research Technology Centre at Sheffield University, which is, in fact, opposite the Advanced Manufacturing Research Centre with Boeing (AMRC) where Sandvik Coromant is a Tier 1 partner. This allows the company to take customer challenges and develop tooling and machining solutions, it was underlined.
The tooling challenges were further amplified by the statistic that there are up to 75,000 holes in a wing section, including wing box and horizontal fins and tails. These can be from 3 to 31.5 mm in diameter and, typically, they take longer to drill than in a non-composite material. The issues in composite machining are delamination as the drill breaks through – the result of an aircraft taking to flight with such issues could be the peeling off of layers of carbon fibre, Mr Smith offers. Splintering on break-out can also lead to delamination in flight. Dimensional accuracy and surface finish are also key attributes for these holes - rubbing between fastener and hole could lead to material breakdown.
Image: Drilling problems composites
In all of this, the problem is that the material is very abrasive, rather like machining graphite, so tool wear is an issue. That, and the fact, as Mr Smith explains, that there is no ISO standard for CFRP materials. "Everybody loads their own composite. What works on one composite doesn't necessarily work on an apparently similar composite material from another company. So companies send out material coupons for us to demonstrate that tools work on that material."
Sandvik Coromant explains its composite machining solutions in its 'Solutions for composite applications' download (http://tinyurl.com/y9ego6r).
In addition to aerospace, both civil and military, the energy sector, specifically wind turbines, is an area for composite use – blades and cowling. Developing markets are marine - boats and submarines; the automotive and truck markets; and high speed trains.
But metal machining is also an element in the wind energy sector. Wind energy is a growing area, according to Paul Williams, product manager, with installed capacity growing at 20 per cent per annum. "It's not a new business, of course, and, basically, its really a helicopter, except the energy is going the other way – a propeller , a gear train, driving down into an energy area. It's not new, in terms of the materials it uses, so we have plenty of knowledge."
Now, while the major OEMs are based outside of the UK, Sandvik Coromant has identified that there are over 100 companies in the UK that state they operate within the wind energy sector. "We are looking at the business to see where the manufacturing is," Mr Williams adds.
Parts within wind turbines for which Sandvik Coromant has machining solutions include the connecting ring; hub; rotor blade; nacelles; mainshafts; bearing housings; and gearboxes. An example given was the machining of a main shaft for a 2 MW generator. A forged blank of 34CrNiMo6 or 42CrNiMo6 weighing 22 tons is reduced to one weighing 14 tons, with machining taking between 30 and 40 hours. The largest diameter is 1,800 mm, the smallest 400 mm, with overall length 3,500 mm. Heavy rough turning, through to finished turning and short and deep hole drilling, are the operations.
Image: Wind power hub solutions
Image: Wind power main frame
Image: Wind power planetary solutions
There are specific tooling solutions for hubs, main frames and planetary carriers, with these available in a downloadable PDF brochure (http://tinyurl.com/y8lvhg3).
Image: Wind turbine
Moving to the medical area, within which Sandvik Coromant has been active for some time, and is increasingly so through acquisitions*, and this is another area of strong growth. Unlike the wind energy market, the UK is strong here. More than 90 per cent of the European market for hip and knee joints is manufactured in this country. In the developed world overall, in 2008, there were around 1 million hip operations and 1.2 million knee operations. Trends in manufacturing in hip joints include: increased use of metal on metal - cobalt chrome, +15 per cent; increased use of titanium in stem, +10 per cent; increased use of ceramic for cup and head; decreasing use of stainless in same amount; decreasing use of plastics in the long term.
Image: Hip joint
Sandvik Coromant is helping manufacturers to boost productivity by bringing down cycle times, with a number of tooling innovations. For the manufacture of the cobalt chrome cup form, rough turning with a 35° diamond type insert is replaced by the use of a round insert, with dramatic results in terms of both cutting data and tool life.
Image: Turning of hip joints
For the turning of the ball form, previously undertaken using 60° triangle insert and a grooving insert, Sandvik has drawn on its aerospace expertise and introduced a square insert. The result was a reduction in cycle time from over 14 minutes to under 8.5 minutes, with this translating into a cost saving of almost £3/4 million for the manufacture of 100,000/annum. Once again, there is a downloadable brochure (http://tinyurl.com/y8q5bmo).
Image: Turning of ball joint
Specific product highlights in Coropak 2 were highlighted by Sandvik Coromant's Allan Cawtheray, senior specialist, milling products. These were: the CoroMILL 345, 45° degree face mill; CoroMILL 490, 4-edge solution end and face mill; CoroMILL 316, exchangeable head end mill system: and the CoroMILL 329 slotting cutter.
The CoroMILL 345 has seen diameters of 40 and 50 mm introduced, in L and M pitch style, but the insert grades are a particular highlight, Mr Cawtheray offered. This has seen a new geometry in the P line – PH in grades GC4220/4230/4240. More significant, he suggests, though, are the ground insert introductions - M grade range, E-PL, grades GC2030/2040 – for stainless steel and heat resistant alloys, with this the first in a range of inserts in this K area.
For cast iron, K grade, a full range of inserts in M-KH, M-KM and M-KL geometries, with inserts GC3040/3220, K20W, for KH and KM, and GC1020/3040/3220 and K20W.
For CoroMILL 490, two large diameters were introduced – 100 and 125 mm, so that the range now goes from 20 to 125 mm. In addition, L pitches in the 50-80 mm range had been added. Insert grade extensions have been made, with ISO P GC4220 in PL, PM and PH geometries added. In addition, cermet grade CT530, geometry PL (high speed, high feed, finishing), is added, while within the ISO M range there's a full range of inserts, including direct pressed and ground inserts, in grades GC1030/2030/2040. Radii are from 0.4 to 1.6 mm in all geometries, with a minimum feed of 0.1 mm and 2 or 3 mm depth of cut recommended for finishing.
ESTABLISHED RANGE EXPANDED
The CoroMILL 300 has been around for 8-9 years but has been extended. It is now available with a 20 mm button insert for use in cutters up to 200 mm in diameter. It features a new location/indexing system for these inserts. There are eight effective edges when the positive insert is used as directed at low depth of cut and running at high feed. Reduced vibration and greater insert strength allows for higher cutting performance, as was the case in one example where a slot was milled in the diameter of a large shaft of steel CMC 03.2 (300 Hb). The comparison was between a CoroMILL 200-20 and a CoroMILL 300-20. The former used GC4030, the latter GC1030. The CoroMILL 300 cutter was a R300-100Q32-20M with insert: R300-2060E-PM 1030. Results were, CM200/CM300: Vc (m/min), 160/210; Fz (mm/tooth), 0.16/0.38 z (no of inserts), 6/6; Vf (mm/min), 489/1,523; ap (mm), 3/3; and Q (cm3/min), 117/366. Tool life, in number of passes, was 1 and 4.
All grades and geometries have been released in a single Coropak for this development. Grades offered are: P, GC1030/4240/4230/4220; K, GC1020/3040; M, GC2040/2030; S, GC1030/2040/2030; H, GC1010.
CoroMILL 316 now has an additional coupling head size of 25 mm, in all the designs – corner radius end mill; high feed end mill; roughing end mill (Kordell); finishing end mill; ball nose end mill; chamfer radius end mill. Previous sizes were 10, 12, 16 and 20 mm diameter.
In addition, there's a head optimised for aluminium machining - 10-25 mm diameter - in corner radius end mill style, 0-4 mm. It is a 3-flute, 45° helix angle, h10 diameter tolerance design in grade H10F.
A chamfer radius end mill is yet another introduction. This has 4 flutes, 0° flute angle, h10 diameter tolerance, is available in diameters 10-25 mm, with radii of 1.5 to 8 mm, and the grade is GC1020.
Also in the exchangeable head 316 range, Tailor Made cylindrical and Weldon shanks are available, while Coromant Capto is a special request.
An example of an application of CoroMILL 316 was given, titanium aerofoil blade milling. Mr Cawtheray underlined that the competitor solution was well established and the customer was far from convinced that a better solution existed. The upshot was that the Sandvik Coromant solution delivered a saving of 183 hours, worth £8,649/year.
CoroMILL 429, the slotting solution, is suitable for all applications with grooves under 18 mm depth. It replaces the T-Max Q-cut , and the use of CoroCut inserts from the parting and grooving programme gives the customer modern grades, two cutting edges and access to a complete Tailor Made programme. Cutter diameter is 100-160 mm, with insert widths of 2.5 to 4 mm, but Tailot Made inserts are offered. With greater stability and strength given by the insert design and location, cutting data can be "inflated".
Product specialist, turning products Andrew Boffin took up the Coropak 2 story with respect to turning, threading and grooving. For turning, CoroThread 266x16, Corocut inserts, and grade GC1145 were the areas of enlightenment. GC1145 is a new thin (3 microns) PVD parting and grooving grade, and is the toughest in the new PVD range of inserts. The grade is the "first choice" for tough parting applications; offers better wear and deformation resistance than GC2145; offers better security than GC2145 and GC235; is the first choice for parting stainless steel; and it is good in slot milling.
It is available for CoroCut and Q-Cut Inserts, in widths from 1.5 - 11 mm, is available as Tailor Made and in special products. Tests in materials such as 316L, Jethete, 304L and X2CrNiMo all demonstrated better insert wear performance.
PARTING AND GROOVING
In the parting and grooving area, M and R seat inserts of widths 9-11 mm and 15 mm, respectively have been introduced. With the CoroCut rail clamping feature, market-leading stability is the claim, as is excellent chip control in deep grooves. All the latest grades are released with this product extension.
CoroThread 266 with a 16 mm insert size is new in Corpak 2, 2009. Sizes 22 and27 mm were already available, but this size covers some 80 per cent of the company's threading business, so is a major release. CoroThread features the iLock system, which employs three points of location, offering high security and reducing insert movement at beginning and end of cut, so reducing toolholder-to-insert wear and offering highest thread precision.
Almost all thread profiles are part of the release, while Tailor Made is also offered, plus there's a new grade, GC1125, a brand new grade for the threading range. Featuring new PVD TiAIN coating, it offers higher cutting data. Once again, numerous examples were offered, demonstrating that the system delivered far more parts per insert and did so at higher surface speeds and with fewer passes, indeed, in one case, the surface speed was limited by the machine, not the insert.
The toolholder programme with this release includes Coromant Capto C3-C6, both internal and external; 10 by 10 and 32 by 25 mm shanks; boring bars from 20 to 50 mm diameter; and SL cutting heads, 25-40 mm, both internal and external.
* Sandvik Medical Solutions (part of Sandvik Medtec), previously part of Doncasters Medical Technologies, was acquired in July, 2007. It is involved precision forging and casting of cobalt chrome,titanium and stainless steel; semi-finished orthopaedic implants; metal-on-metal orthopaedic implants; surgical instruments; trauma components; cutting tools – reamers and rasps.