Jean-Charles Wibo looked across the parking lot of the Las Vegas convention centre with pride. It was 19 March 2002, the first day of ConExpo. Among the many new telescopic boom cranes on show, three appeared particularly prominent and drew, perhaps, the most attention: Grove’s GMK 7450 and RT 9000E, and Link-Belt’s RTC-80100. His company, Vlassenroot, had supplied the boom for all of them.
This Belgian company based in Groot-Bijgaarden, on the outskirts of Brussels, has supplied telescopic booms to most of the mobile crane manufacturers around the world. It currently supplies complete booms for various models of Link-Belt, Liebherr, Marchetti, Rigo and Kato. Link-Belt, to date, only has the one model with a rounded boom, but we can expect more to follow and perhaps the Boss box boom will be phased out.
Vlassenroot also supplies complete booms to ENMTP, the Liebherr licensee in Algeria, and this month ships the first 10 booms to Avtokran of Russia. For Grove’s US and German operations, as well as for PPM and Luna, Vlassenroot supplies prepared boom sections, cut and bent, ready for welding. The chances are that if you own telescopic mobile cranes, they made one or more of your booms. If your crane was built in the USA and has a tubular boom, it definitely came from these guys.
Vlassenroot has been cutting and bending steel since 1926, under the ownership of the Vlassenroot family.
By March 1997, however, the company had declined and was in the hands of the banks. Jean-Charles Wibo, an entrepreneur with a background in banking, was persuaded that here was a company ripe for growth. He bought it and in six years has grown the turnover tenfold, from E 3m to E 30m.
Growth has been assisted by a strategically crucial acquisition. In November 1999 Vlassenroot bought Kanten Schweissen Komponenten (KSK) based in Schwerte, near Dortmund in Germany, from Thyssen Krupp. In Belgium, Vlassenroot’s capabilities were, and remain, specifically the cutting and bending of steel. KSK brought expertise in welding. Wibo says that there are two other companies with whom Vlassenroot competes for cutting and bending work, and two others with whom KSK competes for welding. But the combined organisation is the sole supplier, he claims, capable of undertaking complete boom delivery, from steel plate to finished boom, and it is this advantage which so far is proving decisive.
Wibo claims: ‘We are the only company, except for Demag, that can cut, bend, weld and finish booms. None of our competitors have all the different facilities within the same group.’
The boom is perhaps the most decisive component of a mobile crane, the key element that enables one manufacturer to distinguish its product from its competitors (since below the slew ring the major components can be bought off the shelf). Crane manufacturers have to make them as strong as possible, and as light as possible, and make the ‘least bad’ compromise between those two goals. The weight of the boom can take up a large proportion of the allowable road going vehicle weight. The seven-axle Grove GMK 7450, for example, has a gross vehicle weight of 84t, of which the boom accounts for about 30t.
Given how important booms are, it is perhaps surprising that Demag is the only leading mobile crane manufacturer still making its own booms. Although Liebherr uses a higher degree of proprietary componentry, including, notably, its own engines, its has outsourced all boom cutting, bending and welding to suppliers that include KSK.
Thus the acquisition of KSK also brought new customers. Vlassenroot was already cutting and bending booms for Grove in Germany. KSK was a Liebherr supplier. With the combined capabilities of the Vlassenroot and KSK, other contracts have come in.
Some business was also lost as a result of buying KSK. Vlassenroot used to cut and bend booms for Tadano Faun, under subcontract to the Belgian welding company Henchel. Henchel and KSK are competitors so when KSK joined Vlassenroot, Henchel went elsewhere for cutting and bending. KSK/Vlassenroot and Henchel continue to compete for work: Henchel supplies booms for Liebherr’s smaller telescopic cranes, Wibo says, while KSK supplies booms for models of 80t and larger.
At its works in Belgium, Vlassenroot has two laser cutting machines, 30m by 7m, that can cut precise bevelled weld edges. Both machines are CAD-CAM controlled with five axes and can cut steel up to 20mm thick, depending on steel quality. These machines, one installed in 2000, the other in 2001, are working 24 hours a day, seven days a week. Vlassenroot also has 12 bending machines here, with lengths up to 24m and force up to 4000t. Here it cuts and bends about 1,000 booms a year, which is in the region of 20% of the world market. For this, it bends about 10,000 profiles. In the mid 1990s, before Wibo took ownership, Vlassenroot was preparing about 200 booms a year.
From Vlassenroot, boom sections are either shipped in containers to the customer or sent to Schwerte in Germany for KSK to weld together.
Over in Schwerte, KSK also does some bending. The Liebherr booms are cut on Vlassenroot’s laser beds but are bent here, since Liebherr has always been a KSK customer. At KSK there are two robots for outside welding, which is done under powder, and two for inside welding, for which metal active gas (MAG) weld is used. The boom sections are tack welded by hand first to line them up, to prepare them for the robots. After welding, they are put through an X-ray booth for inspection.
In May 2002 Vlassenroot GmbH was established in Bochum, Germany as a third manufacturing centre. Here the the booms are finished – fitted with head plates and foot plates – and painted. Also at Bochum are four machines through which the welded booms are passed to remove the deformations that are induced by the longitudinal welding. The tolerances to which the booms are bent are remarkable. When bending a typical 12m boom section there is a +/-1.5mm tolerance on height and a +/-3mm tolerance on width, to ensure that all sides line up for welding. Then the welding induces buckling, which is clearly visible to the eye. Straightening out the boom again is an expert job.
In fact the whole process requires a high degree of expertise. Vlassenroot production manager Bart Deumens says: ‘Bending is not a strict technology. You have to have a feeling when bending.’
Bending is made more of an art the higher the strength of the steel used. Vlassenroot, as a group, buys between 9,000t and 11,000t of Weldox steel from Swedish supplier SSAB each year. Mostly it uses Weldox 960 (960N/mm2). Normal steel will spring back just one degree when it is bent. Bend it to 89° and it will spring back to 90°, Deumens says. But this is not normal steel. ‘With this stuff, we have to bend it to about 65° and it springs back to 90°. It has to be this flexible for lifting heavy loads.’
The thinnest steel Vlassenroot works with is 4mm Weldox 1100, currently the strongest steel that SSAB produces. This is used for the booms of some 100t cranes. If SSAB goes up to 1300N/mm2, says Deumens, it would be ‘great for cranes’, but difficult to bend and weld. ‘There is no welding wire on the market for such material,’ he says.
The Liebherr LTM 1500, rated capacity 500t, has the option of an 84m long main boom. The first section is 14m long and weighs 7t. If you were less than 1.6m tall, you could walk through it without stooping. Even on such a massive boom as this, in parts the steel is just 6mm thick. A section might have varying thicknesses of steel. The rounded underside of the third section, for example, which is 14.5m long, is made from three plates of bent steel, and each is a different thickness. For 4.5m the steel is 9.5mm thick, for 8m it is 8.6mm thick, and for 2m its is 10mm thick.
It takes about 30 bends to create the round profile for this crane, compared with about half as many for the 80t Liebherr. The 84m boom is comprised of about 24 pieces of steel that have to be cut, bent and welded. The 50m boom that customers can also choose for this model has four telescoping sections made up of 15 pieces of plate.
Deumens says that it is hard to say that one crane boom is more difficult than another to produce. The big 500 tonners are difficult, of course, but so is the new Luna boom, which has a small radius with comparatively thick materials. ‘Each crane has its own difficulties,’ he says.
Though Vlassenroot clearly has expertise in telescopic booms it does not get involved in design. It produces booms only according to the designs supplied by its customers. It is no use, therefore, hoping that it will supply you with Grove or Liebherr booms. Nor does it supply end users with replacement booms or sections.
Says Wibo: ‘We don’t get involved in design but we seek to get involved in the process as soon as possible to offer advice on buildability and efficiency of production.’
While telescopic boom production accounts for about 75% of the company’s business, Vlassenroot has other markets for which it bends steel plate. For the Dutch railways it produces grooved rail sections for the wheels of trains to run in, rather than on. These are particularly used on so-called ‘silent bridges’ because wheel noise is dissipated within the U-shaped steel profile. Vlassenroot is also supplying steel tubes to the European Centre for Nuclear Research (CERN) particle physics laboratory in Switzerland. These tubes have to be produced with a +/-1mm tolerance along their 16m length. The company has also bent 45mm thick aluminium for CERN.
Expansion remains on Wibo’s mind. Next year he plans to open a steel de-coiling facility in Rotterdam.
The growth of Vlassenroot has not just been due to the drive and energy of 46 year old Wibo. Most success stories have an element of fortune on their side. Vlassenroot’s acquisition of KSK, and the resulting ability to provide the complete range of services from cutting to finishing, came at a time when crane manufacturers were looking to outsource more and more, to reduce their costs.
Simultaneously, the old box shape boom that requires no bending has passed out of favour. Rounded booms are what the market wants. Several crane manufacturers have tried bending their own booms and swiftly concluded that specialist subcontractors can do it either better, or more efficiently. A crane manufacturer would need a remarkable output to justify the expense of tooling up for laser cutting, bending and welding. As a specialist supplier, Vlassenroot can keep its machines busy enough to pay for themselves.
