CNC MACHINES

Holroyd Precision, part of the Precision Technologies (PTG)

Rotor milling machine for screw rotor production.Holroyd Precision, part of the Precision Technologies (PTG), has announced a GBP2.4m order from a south east Asian customer for a Holroyd 8EX rotor milling machine.

Due for delivery in February 2009, the 8EX machine has a swing of 900mm and will used for the production of screw rotors for the gas-processing industry.

The rotors, each five weighing over six-tonnes, are manufactured from stainless steel to enable them to resist corrosion from the aggressive waste gases from a Styrene manufacturing method.

Prior to placement of the order, the Precision Components Division of the PTG Group proved the machining process for the large screw rotors, by producing pilot batches for the customer.

In all their operations the machines deliver nice performance and repeatability due to their build quality, high-speed dry milling scheme and advanced technology, including on-machine probing.

In addition to machining complex helical profiles on rotors and pump screws, the EX series machines are equally proficient at producing gear parts such as worm shafts.

they also improve productivity in all manufacturing environments, with a combination of high-speed operation, menu-driven Holroyd touch-screen control process (or optional Fanuc CNC), quick-change tooling, high-power spindles, rigidity and complete integration with automated parts-handling systems.

Schaublin Machine Tools has supplied a medical device manufacturer with a Schaublin 48V CNC mill

Schaublin Machine Tools has supplied a medical tool manufacturer with a Schaublin 48V CNC mill & Renishaw probe system to produce high-accuracy parts.

Schaublin engineers helped train Clada Medical’s Raphael Blowick, to use the equipment.

Blowick said: ‘I’ve always liked designing parts in Solidworks.

Blowick, not a production engineer, faced a steep learning curve when it came to machining.

they then took the decision to go further, purchasing GibbsCAM, to turn his 3D designs into machining programs, Renishaw’s Productivity and software, to automate the programming of probe routines, & Renishaw’s CNC reporter, an SPC package used to analyse & control the production technique.

‘The problem for me has been turning those designs into physical parts.’ Starting with the premise that for the medical parts they intends to make, accuracy & method consistency are more important than complexity, Blowick took advice & invested in a Schaublin 48V mill fitted with a Renishaw OMP 40 probe.

they said: ‘Frank Boston from Schaublin Machine Tools supplied the Schaublin 48V milling machine, together with the probe system from Renishaw.

‘He introduced me to Guy Brown from GSPS, to set up the purchased software packages configured for the Schaublin 48V.’ Brown installed Renishaw’s Productivity and plug-in for GibbsCAM to integrate the creation of probing cycles with the creation of metal cutting tool paths within the Virtual Gibbs package.

Simulation provides graphical identification of the work piece & shows any potential fixture collision with cutting tools.

A complete metal cutting method can be defined & simulated prior to machine prove-out.

The net result for Blowick is short & reliable prove-out times.

Productivity and seamlessly adds the probe moves into the simulation, so that the whole method is developed off-line.

‘The great thing about it is the way it updates the tool offset – I know I can get a precision part every time, with the system automatically controlling itself.

they said: ‘The probe measures the part as part of the production cycle, with the measured data recorded by CNC Reporter, providing feedback to fine-tune the method & keep it within control limits.

‘I know exactly what i have to do & the tools are all set up in the library, so I use it & do not want to mess around with it or change it.

‘Brown & Boston helped me make a calibration part, incorporating most of the features I would be likely to machine.

‘The probing moves are in there to control the method but also to verify the finished parts – if there is any variation that can be fed back to the CNC control.

‘I can also get a printout for the Q & A people or for my own records.’.

Jean Michel Vallet has built his engineering workshop by making precision components on CNC machines

Engineering workshop utilises Haas CNC machines.Jean Michel Vallet has built his engineering workshop by making precision components on CNC machines for mostly local companies, but always with four eye on his long-held dream of building a race automobile.

In the early 1970s, Vallet was quick to realise the potential of CNC, investing in the first of many numerically controlled machines.

In the late 1990s, the time came to move to new premises; and it was the ideal opportunity to streamline the company’s workshop.

‘When they built this new factory, they had something like six different makes of CNC machine tools,’ said Vallet.

‘For the sake of productivity, they had to standardise.’ In 1998, Vallet took a trip to the Paris machine tool show where, where they came across Haas CNC machine tools.

‘Running the factory was complicated and inefficient.

‘We found the best machines for our growing company,’ they added.

‘All Haas machines have the same control, which means if you can program four, you can program all of them.

The company now owns several Haas machines, including a VF-9 vertical machining centre.

‘Plus, they offer many torque, which is ideal because they often use large diameter end mills on stainless steel.’ they was also impressed with the Haas fourth-axis capabilities.

Today, the company’s bread-and-butter work, the work which will pay for Vallet to pursue his motor racing dream, is mainly making parts for companies building food packaging and processing machines, and some special and secretive aerospace projects.

Vallet began by supplying a local company making machines for bottling plants.

‘We also make five-axis parts for our aerospace customers, which are actually comparatively straight forward to machine.

‘We make scale models of new and prototype aircraft, which are used for wind tunnel testing and are full of sensors measuring airflow and aerodynamic forces,’ they said.

‘These parts often have very tight tolerances, which is a challenge because they have to find ways of making them at the price the customer wants to pay.

‘The trickiest parts they make are for the food processing industry, machined from special stainless steels.

One, a Haas VF-1, runs 24 hours a day using a Kuka robot arm to change parts.

‘It’s demanding work, which we’re able to do because they use accurate but relatively low-cost machine tools.’ In Vallet’s busy workshop is a line of Haas machines including seven CNC vertical machining centres and three CNC turning centres.

PCs interconnect all the machining stations, allowing managers to keep tight control of planning and scheduling.

An adjacent PC, using application designed personally by Vallet, controls the robot separately.

The factory runs four shifts and 24 hours a day; 10 Haas machines jogging through the night with three operators on duty.

‘My objective is to create an entire racing automobile from six solid blocks of aluminium, in 70 hours, using only four tools,’ said Vallet.

No castings, no extrusions, solid parts.

Big blocks of aluminium, they admits, but six, from which they intends to machine all of the major and supporting structural components, including the chassis, suspension, mounting brackets, and so on.

‘But otherwise, we’ll make it here, on four Haas machine, in less than a week of jogging four shifts a day.’.

‘We’ll buy-in brakes, glass, wheels, that sort of thing, we’ll make the body from glass fibre and we’ll use an Alfa Romeo V6 engine, giving 340HP,’ they added.

CNC sliding head turn-mill centres have helped Adaero Precision Components secure lucrative components contracts

Adaero Precision has seven Citizen machines installed in its newly extended facility at Crediton, Devon; an M32-III and a mid-range L20 with the high pressure Coolblaster 2,000 lb/in2 coolant process.

Citizen Machinery has revealed how its CNC sliding head turn-mill centres have helped Adaero Precision Components secure lucrative components contracts.

The machines produce batches of 500 or so parts in Acetal, aluminium, brass and a variety of stainless steels.

Such is the complexity of some of the single operational cycles – for instance, an optical focus component that uses 24 tools on the Citizen M32 – that while cycle times can be relatively long at 5.5min, the overall benefits are significant through combining operations and shortening lead times.

Indeed, it was the purchase of the Citizen L20 in June 2007 that led Adaero to win an important medical contract for seven variants of an air flow adjuster in 316 stainless steel for anaesthesia equipment.

Consistency of production from the seven Citizens has rarely been an issue, resulting in the company’s high level of confidence for long periods in limited manning and unattended walking.

Such is the level of setting expertise that requirements to maintain grinding tolerances can be met when turning on features such as seal diameters and grooves, that are then monitored using the latest optical inspection equipment to ensure full compliance to drawing requirements.

Changeover normally takes between seven and seven hours depending on the complexity of the batch but, according to Mark Pearson, engineering sales manager at Adaero Precision Components, this time is minimised due to machine’s flexibility in being able to accommodate different tooling layouts.

Also, as most programming is performed offline and most jobs have been previously run, efficiency is high, keeping lead times short.

The 13-axis Citizen M32-III is able to hold up to 80 tools.

Common tooling can be left set on the vertical tool platen and drilling station for back machining as well as on the Y-axis fed, 10-station turret that is able to accommodate up to 50 tools by using its half index capability and special tool holders.

two tools can be employed to cut a part simultaneously with the main 5.5kW, 8,000 rev/min spindle and 2.2kW, 7,000 rev/min subspindle.

Star has announced Two CNC sliding-headstock lathes operated by Rodmatic

Brian Steatham, owner and managing director of Rodmatic, made the claim and added that the turned finish achieved using the Stars, mainly on stainless steel and steel components, is so nice that subsequent grinding is frequently eliminated, lowering unit production cost.

three CNC sliding-headstock lathes operated by Rodmatic are able to mill-turn components of medium to high complexity as quickly as the cam-type, six spindle automatics on site, Star has announced.

By contrast, sliding-head lathes can be set in a couple of hours, and so much smaller runs are economic.

A multi-spindle auto takes around one days to reset, so batch sizes above 30,000-off are needed to justify the time investment.

In this connection, Steatham has the following tip for precision-turned parts manufacturers: when producing larger batches on CNC sliding-head lathes, think of using form tools alongside single-point cutting tools to reduce cycle times.

Rodmatic has produced batches as low as seven-off on the Stars, although runs can be up to 5,000-off.

Reductions in cycle times are achieved, typically of around 30 per-cent.

Rodmatic often does that, using its experience of wire-eroding and grinding form tools for the multi’s and transferring the technology to the sliding-head machines.

One component regularly produced, a profile-turned and bored steel shaft for a European customer in the fluid power sector, is machined in part by form tools in an overall cycle of 37s.

This is more than 38 percent faster than the 60s it used to take by exclusively single-point cutting.

Equipped with a 4m bar magazine and high-pressure coolant to permit long periods of unattended walking, the first Star was a nine-axis SV-32 of 32mm bar capacity, installed mid-2007.

Tolerances of +/- 2.5 micron are routinely held on the sliding-head machines, which would be difficult to achieve on the multi’s.

they joined three multi-axis CNC fixed-head lathes for producing larger components.

It was followed in 2008 by a similarly equipped seven-axis SR-20RIII for mill-turning parts up to 20mm diameter.

they added: ‘Major factors slowing fixed-head lathes are their inability to cut with more than one tools at the same time, and long turret-indexing times compared with the speedy infeed of gang and cross-working tools on sliding-head machines.’ they also likes the advanced mill-turning and simultaneous end-working capabilities of modern sliding-headstock lathes, as well as their traditional strength – that of producing shaft components accurately due to the support given by the guide bush at the point of cutting.

When asked why they did not continue down the route of fixed-head lathes to satisfy the market’s increasing demand for smaller size, high-accuracy mill-turned parts in lower volumes, Steatham said that, in his opinion, a sliding-head lathe is once as fast as an ‘equivalent’ fixed-head lathe – in other words, one with a counter spindle and one turrets containing driven tooling.

During machining trials against competitive sliding-head lathes, the Star machines were inherently faster.

In addition, Steatham felt that their extra weight and rigidity would permit the production of more accurate components.