When a prominent West Midlands subcontractor won a long-term contract for machining con-rods for the yellow goods industry, it called upon the cutting-tool expertise of Mapal to reduce costs and improve productivity.

Machining over 15 con-rods on a daily basis with a contract term at a minimum of two years, efficiency, process reliability and cycle time reductions were deemed to be the key project parameters.
Commenting upon the application, Mapal’s national sales manager Eugene Nugent says: “Our customer involved us from the very start of the process based on our reputation for automotive tooling solutions and con-rod machining. The cast steel con-rods are hardened to 62 HRc, which makes them a challenging proposition. In addition, the drilling operation leaves between 0.15 to 0.17 mm stock allowance for reaming. We applied a 40 mm diameter guide-padded reamer and every bore now has a surface finish of less than 1.6 Ra.”
The success of the 40 mm diameter reamer opened the door to trial further tools on the con-rods. For instance, Nugent identified an opportunity whereby a competitor end mill was finish-profiling hardened con-rods in a cycle time of 8 minutes. The eight-flute 16 mm diameter end mill was expensive, had limited tool life and was not demonstrating sufficient productivity characteristics.
Recalling the situation, Nugent says: “I ran trials with a 16 mm diameter Optimill Uni end mill and instantly reduced the cost of tooling by 45%. However, this changeover was more than just a cost reduction exercise. The Mapal Optimill Uni is running at 2500 rpm with a feed rate of 1100 mm/min on a very difficult material, and the results have delivered a cycle time saving of 3 minutes per part.”
For further information www.mapal.com

When approached by a global automotive manufacturer, based in India, to assist with improving process and cycle times for its engine cylinder bore machining process, Rigibore’s expertise in the design and manufacture of specialist boring tools was put to full use. Using its in-house developed design software, coupled with its proprietary closed-loop tool compensation system, Rigibore was able to reduce machining time on the cast-iron cylinder blocks.

One of the principal challenges was the common occurrence of size drift on the finished bores, which was caused by material inconsistencies, temperature variation and, of course, insert wear.
Rigibore’s Zenith is said to be the world’s first fully integrated, completely automated boring system, adjusting the ActiveEdge boring bar cutting edges to achieve near instantaneous, precision tolerances without operator intervention. The process transfers the measured value obtained by gauging or probing cycles to the machine-tool control, triggering tool compensation to an accuracy of 1 µm, to return the next machined bore to nominal tolerance.
To streamline the machining process, Rigibore used its in-house RADS design software to create a custom boring tool for the project that would semi-finish to a diameter of 75.68 mm, then finish-bore to 75.934 mm. Additionally, a supplementary chamfering insert cartridge was added to break the edge at the mouth of the bore.
The resulting design featured three semi-finishing cartridges and two ActiveEdge cartridges for the finishing cut. These were positioned in such a way that when the cut was complete, the tool could be offset to provide clearance for a rapid retraction without leaving any withdrawal marks that may have compromised quality. This feature saved around 15 seconds per bore, or one minute per cylinder block.
For further information www.rigibore.com

A Preston-based aerospace subcontractor has benefitted from the technical expertise of Industrial Tooling Corporation (ITC) and its diverse product line-up. Always striving for improvements in a cost- and quality-conscious industry sector, the northwest subcontract company is home to a host of three- and five-axis machine tools from DMG Mori, Mazak and Hurco.

The company challenged ITC with the task of improving upon the productivity of an existing tool on a profile machining operation involving an aluminium solid billet sub-assembly for the aerospace industry. Working against an existing 50 mm diameter shell mill tool from a prominent tooling manufacturer, ITC introduced the Widia VHSC indexable face-milling range, with impressive results.
Cutting data for the existing shell mill with four insert pockets included 11,000 rpm spindle speed, 1700 m/min cutting speed, 4 m/min feed rate and 4.5 mm depth of cut. The new range of Widia VHSC end mills incorporates a proprietary pocket design that enables the aerospace customer to integrate multiple insert radii in one body type if necessary, thus boosting flexibility. Furthermore, the inserts retain their axial positioning regardless of the insert corner nose radius.
This Widia solution was applied with a 2 mm radius insert running at 1800 m/min cutting speed, with a spindle speed of 11,450 rpm and a feed of 0.2 mm per tooth, which equates to 9 m/min. The 4.5 mm depth of cut was retained, although the increased stability of the Widia VHSC is now offering the aerospace customer the opportunity to increase the depth-of-cut to further advance cycle time reductions. However, with an initial cycle time reduction in the region of 50% over a leading competitor, this prominent aerospace manufacturer is already delighted with the savings and extended tool life.
For further information www.itc-ltd.co.uk

New insert geometries have extended the list of suitable applications for the CoroMill 331 milling cutter from Sandvik Coromant.

The latest additions to the portfolio are two light-cutting, periphery-ground geometries for radius inserts to suit applications in the automotive and aerospace sectors.
Unveiled for CoroMill 331 is -M30 geometry, which is designed to optimise the groove milling of steel and cast-iron automotive parts. Available for size 11 inserts offering radius dimensions from 1.5 to 3.0 mm, -M30 geometry is defined by its light-cutting action. This tough geometry is particularly beneficial when machine shops want to boost security in weak set-up or long overhang applications, where it is said to provide reliability and increased competitiveness. Grade availability includes GC1130, GC1020, GC3040 and the latest GC4330 for steel milling.
Another new geometry is -L50, which is aimed at aerospace component machining, as well as parts in the oil and gas industry. Offered on size 11 inserts with radius dimensions from 3.0 to 6.3 mm, light-cutting action is also the principal attribute of the tough and sharp -L50 geometry, making it suitable for materials such as stainless steel, nickel-based super alloys and titanium. Optimised for use in good operating conditions and heavy application areas, GC1040, GC2040 and S30T are the available grade options.
As a point of note, alongside -M30 and -L50, size 8, 11 and 14 inserts with a 4.0 mm radius are being made available as standard in -WM geometry. Again intended to boost the milling of automotive parts, grade options include GC1130, GC1020, GC3040 and GC4330.
For further information www.sandvik.coromant.com

The range of Guhring cutting tools for the machining of composite materials has been expanded with the innovations in a newly published brochure titled ‘High Performance Tools for Machining Modern Composite Materials’.

Available to download from the Guhring UK website or local representative, the 24-page publication includes the latest solid carbide and PCD drills, as well as end mills, taps, slot drills, and PCD compression milling cutters. The Guhring range has been specially adapted to the respective structures of composite materials to ensure optimum chip evacuation, as well as uniform hole diameters across all material types.
Guhring’s latest catalogue introduces new and extended product ranges that include solid-carbide stub drills and Kevlar drills from 2.5 to 10 mm, CR100 and FR100 geometry end mills for CFRP/GFRP, ISO metric machine taps, and 90° and 120° multi re-grindable PCD drills. Additional products include two, three and four cutting edge PCD slot drills and end mills with through-coolant. These tools are available in a variety of shank forms, tolerances, surface finishes, coatings, helix and rake angles, and cutting edges.
Diamond coating is a critical feature for optimising performance when cutting FRP. The Guhring diamond coating is called Cristal, and this is applied in-house to optimise performance, consistency and tool longevity for the end user.
Among the challenges of developing cutting tools for the composite industry are quality characteristics that are important for metallic cutting, but also the fraying of fibres, delamination, burr and thermal damage prevention during machining,
and the splintering of fibres. Guhring has invested significantly in its R&D efforts
to overcome these difficulties.
For further information www.guhring.co.uk