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Monument Tools, a UK manufacturer of plumbing hand tools, has used turn-mill technology from Miyano and Citizen to redesign the Tulip cutters.

The Tulip cutter device, which is shaped similar to the head of a spring flower, has been patented by a German company and can be used for clearing blocked drainpipes measuring between 1.75in (4.45cm) and 6in in diameter.

Now, by using turn-mill technology, Monument Tools has been able to secure a licence for its manufacture and distribution.

According to Jon Norton, the company’s works manager, by taking the initial concept of the tool that was originally produced in Eastern Europe and redesigning the range of tool heads for production around the capability of Miyano and Citizen turn-mill centres, Monument’s engineers were not only able to reduce manufacturing costs by half against the Eastern European supplier but also create a better-performing product.

Through the capability and flexibility provided by the machines and input by tooling specialist Sandvik Coromant, excessive weight was engineered out of the device, making it easier to use, handle and transport.

The Tulip cutter is a multi-functional tool that ranges in size from 22mm to 110mm in diameter and is used for handheld drain clearing.

As a result of its shape, involving a series of scallops (petals) that provide cutting edges and a number of options of cutting inserts screwed into the nose of the tool, it is able to remove the likes of uric scales and hardened fatty deposits from the inside of pipes.

By changing the design, Monument improved its weight-to-size ratio and rotational speed, which mechanically pilots the cutter head to work in the centre of the pipe.

Owing to the short, effective length of the Tulip head, it has high levels of manoeuvrability within the pipe and is able to cut at the front, the edges and rear of the tool as it is worked forwards and backwards in the pipe.

‘The whole project has an enormous potential for our business but winning the contract and being able to take so much cost out of the design was only possible because of our installation of a Miyano BNE-51 SY5 turning centre and the two Citizen M32 CNC sliding-head lathes,’ said Norton.

The Tulip head, which can accept a range of 12 different cutters screwed into the nose of the tool, is shaped to act as a milling head in the pipe to be cleared.

It is attached to a flexible cable via a rear connector, which is fed into the blocked pipe to contact the obstruction.

The cable is rotated to build up tension and the torque developed enables the cutter head to mill away and break up the material causing the blockage.

Tulip bodies up to 32mm in diameter and all the individual cutting inserts screwed into the body are produced in one operation from bar on the Citizen machines.

For tool bodies between 32mm and 50mm in diameter, these are machined on the Miyano in a single automatic cycle from bar.

However, as a ramp-up production process, bodies from 50mm to 110mm in diameter are machined from sawn billets on the Miyano in semi-automatic mode, requiring the operator to load and unload the main spindle and sub-spindle.

According to Norton, the reason for operator involvement is that Monument Tools is still in the embryo stages of building up supply and making full use of existing machines.

The Miyano BNE-51 SY5 was installed in 2008 and has a 15kW main spindle and a 7.5kW sub-spindle, giving 50 to 5,000rev/min serviced by a 12-station, all-driven tool upper turret with +40mm Y-axis cross feed and a lower 12-station, all-driven turret.

It has served Monument by producing a range of plumbing devices and equipment from bar up to its 51mm capacity.

Since its installation, 60 components have been programmed for production and more than 50 development prototypes and pre-production parts have been turn-milled.

The Miyano complements the two Citizen machines, which, in turn, had replaced fixed-head lathes, milling machines and manual drill spindles in 2004 and 2005 respectively.

As the Tulip project develops – there are already 27 variants of the head – Monument plans to increase its turn-mill capacity with a larger-capacity Miyano.

‘This means we can use automation to produce all the Tulip bodies in a single cycle,’ said Norton.

The Tulip cutter head product range will be sold across Japan, the Middle East, the US, South Africa, Australia, Canada and Europe, with the exception of central Europe, which will be covered by the distribution network of the German patent holder with parts supplied from Monument’s Hackbridge facility in Surrey, UK.

According to Norton, the Miyano can be used with a variety of tooling positions.

It has the ability to allow the setter to juggle cutting tools between the two turrets, which allowed them and the tooling engineer from Sandvik Coromant to create such an effective process.

On the largest Tulip head, swarf would normally be an issue as the original billet weighs some 10kg and when finished it is reduced to just 0.9kg, but the working area and swarf evacuation of the Miyano means this process is trouble free.

Currently, the cycle time is less than 35 minutes, but with tooling developments being carried out with Sandvik, Monument believes that it will be significantly reduced.

This has already been achieved on a mid-range 60mm Tulip, which starts out as a 1.6kg billet, and, following machining, creates some 1.4kg of swarf.

Following tooling development, the cycle time has just been reduced from 12 minutes to seven minutes and 25 seconds.

To produce the largest 110mm-diameter version, a 100mm-long billet is loaded in a three-jaw chuck in spindle one and a central bore drilled through.

In order to hog out material for the 12 main slots to create the petals of the Tulip in the outside profile, 24 holes are cross-drilled and the outer spherical profile rough and finish turned.

A further 12 slots are then progressively milled in the periphery.

The front is rough and finish-bored to accept an M55 thread, which is then counterbored and screw cut.

Angular slots are milled in the periphery of the components.

While the machining cycle is being run in spindle one, spindle two is overlapped with a rough and finish turn and a hole is drilled and tapped in the front face.

Using a slot drill, the 24 holes previously drilled in the periphery are then interpolated to create 12 radius-formed slots between the petals.

Transposing the part from spindle one to spindle two is performed by the operator.

He or she loads a lock-up mandrel to the bore of the partially turned component in the three-jaw chuck and the cycle is started.

Spindle two, which is fitted with a collet, feeds across to locate and orientate the mandrel before feeding back to the machining position to enable the second part of the cycle to be completed.

A further billet is then loaded to spindle one.

By utilising this method, Monument can ensure that the relative geometric positions of the slots are maintained and that operator involvement is kept to a minimum.

Norton said that, with the initial method proven and cost effective, the company has a clear view of how to move the project on with a larger-capacity machine and take further advantage of a fully automated process.

He added: ‘We use many canned cycles and sub-programs to keep the various tasks as simple as possible.

‘Due to the flexibility of the machine’s turret configuration, we can overlap cycles using spindle one, turret two with spindle two and turret one and combine simultaneous working with turret one and two with spindle one,’ said Norton.

He believes that the key to minimising cycle times and improving tool life is to balance the cutting cycles between the spindles.

To achieve this, Monument has worked with David Higgins, sales engineer of Sandvik Coroment, to balance metal removal rates and include the latest tooling developments such as the Coromill 316 exchangeable-head milling system.

To simplify changeover, Norton said that, with the Miyano, there are more than enough tool positions to hold common tooling on the machine to accommodate the different components within the Tulip range.

‘We also have the added advantage that multiple tool holders can be used to further increase the on-machine capacity if required,’ he added.

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