Cogsdill ZX 300 facing/contouring head

Year 2012 saw the arrival in National Oilwell Varco’s (NOV) Jebil Ali plant, a Doosan DBC 130L horizontal boring machine equipped with Cogsdill ZX 300 facing/contouring head, and a modular tooling package to enable a range of boring operations to be completed. The DBC 130L along with two Puma 700 LM horizontal turning centres form part of a full turnkey package supplied by Passtech Machine Tools ME Ltd.

NOV Dubai has established itself as a centre of excellence within the National Oilwell Varco family and has become the blueprint for other NOV plants worldwide due to the modern methods or manufacture deployed along with prudent engineering management which culminate in output of the highest quality while achieving major cost savings throughout the manufacturing process. Passtech Machine Tools ME Ltd have assisted NOV in achieving this impressive end result through knowledge share and support in conjunction with the product knowledge and experience of NOV’s experienced engineering management team.

Utilisation of the Cogsdill facing head equipment along with visionary programming of the HBM machine has allowed NOV to slash previous production times and eliminate scrap through a robust and sustainable production process. The Doosan DBC range of CNC horizontal boring machines have already established themselves throughout the GCC states major CNC machine shops and this machines flexibility is being enhanced further by Cogsdill products throughout the regions.

Contouring head basics

NOV utilises the Cogsdill ZX contouring head to the maximum. Contouring heads transform a horizontal boring mill’s W-axis quill motion into radial cutting edge motion, David Grundy, General Manager of NOV explains.

“Inside each tool is an actuator shaft with an inclined key that precisely mates with a slot in a tool slide. Quill extension pushes the actuator shaft and causes the tool slide to move outward, increasing the diameter of the rotating cutting edge. Quill retraction decreases the cutting diameter.”

Combining a machine’s quill motion with its table feed allows a single head to perform many operations. Facing can be performed by moving the quill (and thus, the cutting edge) while the machine’s table remains stationary. Keeping the quill stationary and moving the table enables boring and turning operations. Combined quill and table movements can generate features such as radii, chamfers, tapers and complex ID or OD contours.

Programming a contouring head is simply a matter of coordinating the machine’s W and Z axes to guide the cutting edge. Depending on the contouring head model, though, the ratio of quill stroke to radial cutting edge stroke might not be 1:1, this must considered when creating part programs. For example, some ZX heads have a 2:1 ratio of quill stroke to cutting edge stroke.

Machine-specific bonnets allow a single head to be used across a variety of boring mill brands. The bonnet bolts to a mill’s outer spindle (the outer spindle provides the rotation for the cutter). The contouring head quickly installs into the bonnet and is secured via locking cam pins. Other ZX heads, including modular boring tools and valve seat tools, can also be installed on a mill’s bonnet.