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Laser & Waterjet Profiling
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As the founding member of the P.P. Group of companies, St Helens-based P.P. Profiles has over 35 years’ experience in the steel plate industry specialising in the laser, bevel plasma, flame and high density plasma profiling of carbon steels. Dave Tudor reports.
The P.P. Group of companies, as far as processing sheet and plate material is concerned, has just about every base covered. Whilst P.P. Profiles’ sphere of expertise is centred around the processing of carbon steel, the other members of the group all offer related, specialised skills: P.P. Plasma, for the processing of stainless steels, nickel-based alloys; yellow metals, duplexes and aluminium using laser, waterjet, bevel waterjet and plasma technology; P.P. ProTube, offering a 3D steel tube processing service; and P.P. Processing which provides a bending and rolling service.
Offering specialised services is the foundation of the P.P. Group’s success. Whilst there’s an obvious synergy between the group members – and a natural cross-pollination of skills, resources and expertise – the operation is deliberately decentralised and each constituent company operates as a separate profit and loss centre. This is good news for customers – if you have a job that requires the processing of sheet or plate material, however complex or diverse, chances are one or more of the group companies will rise to the challenge.
A walk around P.P. Profiles’ 35,000ft² site in St Helens invokes two words – heavy engineering! The 30 employee company (which includes two apprentices) operates a double shift system and processes some 500 tonnes of material a month – both free issued and sourced – and offers a range of CNC controlled services including flame cutting, laser cutting, bevel plasma cutting and HD plasma cutting. With so much heat around, post flame cutting stress relieving of heat affected zones is often essential depending on the process, and PP Profiles offers that capability too – via a 4m x 4m x 2.5m oven with 10 tonne weight capacity and customisable heat cycles. Three large Lumsden grinders provide capacity for finish grinding operations. It’s plain to see that keeping as much of the process in house is how PP Profiles likes to do things – a policy that is also appreciated by its customers.
“When the company began, nearly all of our work involved flame cutting but it’s definitely true to say that over time, our customers’ needs have changed and they now expect more flexibility, better accuracy, better quality and better surface finishes,” explains Mark Derbyshire, managing director of P.P. Profiles and P.P. ProTube.
“We’ve evolved to meet those needs – particularly with thinner gauge material. Our flame cutting capability can handle carbon steel sheet 25m by 5m and up to 260mm thick to tolerances of ±2mm; our bevel and high definition plasma machine – which offers triple the energy density of conventional plasma machines – has a 10m by 3m profiling capability to tolerances of ±0.25mm; and on the laser side, our Trumpf TruLaser 3040 4.5kW laser is capable of profiling intricate shapes to tight tolerances, minimising the need for post-cutting machining. It can profile 4m by 2m sheet, 1mm to 20mm thick to accuracies of ±0.1mm.”
For laser cutting on the Trumpf machine – chosen incidentally for its robust construction and compact footprint – P.P. Profiles uses only S335M laser quality steel – a grade designed specifically for laser cutting purposes offering a higher quality of cut and superior surface finishes. “Although the material is more expensive than conventional carbon steel, the difference in quality and the fact that our Trumpf machine can cut it more rapidly means that it’s well worth the outlay,” Mr Derbyshire states. “The improved performance is due to the fact that the material contains less silicon and because it’s a grade specifically formulated for laser cutting, we recommend its use with all our laser profiling work.”
The Lumsden grinders play a pivotal operational role in the manufacturing process. “Grinding is often necessary for three main reasons,” Mr Derbyshire reveals. “Steel sheet and plate is supplied in a range of standard sizes but sometimes customers request non-standard thickness and grinding provides that flexibility. The second reason is simply flatness and parallelism. As supplied, it’s not unusual for material thickness to deviate by up to 7mm over a 1m length so grinding is often necessary to ensure uniform thickness. The third reason is cosmetic appearance.”
Committed to quality
Perhaps predictably – bearing in mind the kind of work P.P. Profiles is actively embroiled in – around 40% of the company’s business is with the construction sector with notable projects being providing structural support products for the construction of the Olympic Stadium in London. Other sectors include oil and gas, automotive, aerospace and energy.
“We may not be the largest company in terms of turnover, but we are committed 100% to providing excellent customer service,” Mr Derbyshire adds. “Our strengths are our knowledge, expertise and flexibility and the fact that we can react quickly to our customers’ requirements. It’s the main reason why we run a dedicated night shift – to offer a 24/7 service.
“We also own a dedicated fleet of vehicles to ensure product is delivered on time, In addition, we offer full traceability on all the material we process, including mill test certification and can provide cast stamping and individual identification of profiles.”
Representing a £350,000 investment last November, P.P. Profiles purchased the UK’s first HD plasma machine from Japanese manufacturer Koike. Purchased primarily to undertake bevel cutting duties for weld preparation, the new Koike Versagraph 4500 has the capability, through an infinite rotational head, to change profile mid-cut.
“The machine makes effective use of the latest cutting technology available to offer contour and bevel cutting up to 10m x 3m x 40m and up to 45º,” Mr Derbyshire enthuses. “In practice, this means that the machine can be cutting straight, then mid-cut be offset to cut a 45º angle and then programmed to cut straight again – all without stopping the machine. It can even produce features such as bores and countersinks.”
Not surprisingly, installation of the machine was a challenging project but once the decision was made to purchase and Mr Derbyshire had physically visited the Koike plant in Japan to see the machine close up, the whole process took only three months from start to finish. Particularly crucial was the foundation work carried out. Large holes were excavated and made waterproof to accommodate the machine’s ventilation and electrical components. Contract engineers were flown in from Italy to install the cutting bed while engineers from the Netherlands installed the rail, gantry and cutting head.
Dealing with dross
Although virtually unknown in the UK, Koike has over 90 years’ experience in the sheet and plate cutting industry. The Versagraph 4500 is designed from the ground up with rigidity, accuracy and reliability in mind, but as Mr Derbyshire affirms, the machine underwent a degree of customisation to suit P.P. Profiles’ specific needs.
“One of the biggest problems with plasma cutting machines is the removal of the dross after cutting so I asked Koike to incorporate a bespoke self-drossing system into the machine that was loosely based on the conveyor system on our Trumpf laser.
“Basically, it comprises two beds, inclined at a slight angle located underneath the machine. Then, via two motors, the beds are vibrated at rapid speed which essentially shakes all the dross into two bins at the end of the machine. It works really well. The vibratory action keeps the machine clear of dross and disposal is a relatively simple process with good access. The traditional method would be for an operator to remove dross via shovel manually or physically remove the bins from the machine. The fundamental difference with the Koike however is the fact that all this happens while the machine is still running – no machine downtime or lost productivity is necessary. All credit is due to Koike – although I planted the conceptual seed for the system, they ultimately designed and incorporated it into the machine.”
Another plus point for the Koike machine was its native, inherent compatibility with the Sigmanest nesting software used throughout the P.P. Group. “Having an all singing, all dancing machine is pointless if it falls short on the CAD side,” Mr Derbyshire observes. “The Versagraph ticked all the boxes where this was concerned and with an extensive support and service network throughout Europe, I’ve found Koike excellent to work with.”
Located in the same building as P.P. Profiles and management wise falling under Mr Derbyshire’s watchful eye is P.P. ProTube, a company specialising in the profiling of circular hollow section tubes. The tubes are either flame or plasma cut and, unlike PP Profiles, the company processes both carbon steel and stainless steel with all material being free issued by the customer.
“Our main sectors on the tube side are construction and the offshore industry,” Mr Derbyshire concludes. “We’ve been fortunate enough to be involved in a number of high profile projects such as supplying 1,000 tonnes of processed material for the Olympic Stadium infrastructure, the AccelorMittal Orbit observation tower at the Olympic Park in Stratford, The Emirates Stadium, the National Conference Centre in Dublin and the redevelopment of St Pancras Station in London.”