Lincoln-based Destec Engineering Ltd is saving time and money by using Titex XD deep-hole drills from Bromsgrove- based Walter GB Ltd (
www.walter-tools.com) to produce a series of holes (autoclave ports).
These range in diameter from 5 to 20mm and are drilled to depths up to 250mm in a range of materials that include carbon steels and super alloys. In one case these solid-carbide drills produced a series 5mm-diameter x 240mm deep holes, reducing the cycle time by seven hours while at the same time improving hole quality.
The Titex drills were first used by the company — a specialist manufacturer and supplier of high-pressure containment equipment, portable machine tools and on-site machining services to the world-wide oil and gas sector — two years ago.
Since then, the drills have not only cut hole production times from 30min per hole to just 5min, but also eliminated the problems formerly encountered — frequent tool breakage and tool wander, as well as insufficient swarf clearance.
Destec’s machining supervisor, John Mullenger, said: “Ports are machined to high accuracy for metal-to-metal sealing applications and are integral features of the autoclave ‘hubs’ that are used to join pipes with drilling heads.
“We produce a wide range of hubs up to 3ft in diameter, and in the past would machine the holes — usually two to five holes per hub — on a vertical machining centre using a pecking sequence with HSS drills of increasing length.
“However, these drills did not have through coolant and were constantly letting us down through wander and breakages. Our tooling distributor subsequently introduced us to Walter GB, and it was immediately apparent that use
of the XD drills, in combination with Walter’s deep-hole machining strategies, would be of benefit.”
Using Walter Titex XD drills, Destec now successfully and consistently generates the holes by first producing a pilot hole, followed by a 12 x diameter hole depth then a 50 x diameter hole depth.
Titex XD drills are available in the diameter range of 3-12mm and feature four lands for optimum hole quality, especially in workpieces with inclined hole exits and cross holes. They also feature a tip coating of TTP, which has been designed specifically for deep hole applications; this offers excellent hot hardness, low levels of friction and a high level of resistance to oxidation.
The Titex range extends to producing holes with length to diameter ratios of up to 70; and compared to conventional gun drills, Titex drills can be applied at much higher feed rates while achieving longer tool life.
In one instance, using a 7mm-diameter drill to produce a series of 450mm-deep holes in steel piston rods, the XD drill was applied at a feed rate of 478mm/min rather than 95mm/min — and it drilled 50 piston rods compared to 12 for the gun drill.
Mr Mullenger said: “Every hub is a very expensive product; and by the time it reaches the stage at which the ports are drilled, any errors would be very costly. We, simply cannot afford to make mistakes!”
The success of the drills has led to the introduction of other Walter tooling at Destec, including B4035 boring bars.
“It’s fair to say that all boring bars are technically very similar, but the major difference with the Walter B4035 is that it is digital, which means we don’t have to worry about compensating for backlash — the tool does this itself.”