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