Fifty yearsofPullmaxNot so much a case of life begins at forty, more a case of carrying on thestandards set during fifty years of trading.

Pullmax, a company whose name hasbecome synonymous with state ofthe art technology in sheetmetal andplateworking machinery, this year

celebrates its fiftieth anniversary.The Pullmax story starts in 1936 when a

Swedish company, ESAB, moved frompremises in Marienholm to a new site inHerkulesgatan, leaving behind a weldingand fabrication shop which had previouslymanufactured test rigs and other equipmentas part of its customer service.

In 1938 the shop was incorporated as anautonomous company, AB Elektrosvets,and quickly made a name for itself throughparticipation in the construction of the GotaAlv Bridge. Soon, it was also turning outrefrigerators, boats and forklift trucks.

The construction business involved com-petition with ESAB's own customers, so in1942 Elektrosvets was sold to a companycalled Haldex (owned by SkandinaviskaBanken, later the Savean Group) andrenamed AB Svetsmekano. Haldex ownedthe patent for a method of cutting steel plate,and Svetsmekano were delegated to developthis—under the trade name ofPullmax.

After the Second World War, the Pullmaxplate cutting machine quickly became worldfamous, more than 50 000 being manufac-tured by the company in Sweden andHolland and under licence in England,Japan and Spain. Sales subsidiaries wereestablished in France, Germany, England,the USA, Canada, Austria and Belgium.

Conscious of the expiry of the patent in1954, the company developed a new tech-nique, nibbling, to produce the Pullmaxuniversal shearing and nibbling machine.The 1957 acquisition of patent rights for aquick stroke machine further consolidatedthe company's position at the forefront ofplateworking technology and in 1959 thiswas reflected by another name change—toPullmax AB. The new logo commemoratedthe plate shears of the company's first steelcutting patent.

In 1964, Pullmax was bought by Granges,integrated into the Granges Hedlund Groupand then sold again in 1971 to S Lindmarkand H Karinen. Pullmax's thin sheet special-ism was complemented by the medium and

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Pullmax's new P209 punching and nibbling machine carries a price tag of £25 000

thick plate expertise of other companies inthe group and an effective joint marketingorganisation was developed.

Statsforetag purchased the late machineryinterests from Lindmark and Karinen in1974 to establish the largest machine toolcompany in Scandinavia, SMT-Pullmax AB,with over 1000 employees. However, thesophistication and diversity of modern, hightechnology machine tools is such that thegroup was sub-divided by product range.

Since 1986, the Pullmax organisation hasco-owned, with the Beyeler Group, thepressbrake and shear manufacturing opera-tions of Ursvikens Mekaniska Verkstad ABand the plate rounding and ring bendingmachine activities of Kumla BendingMachines AB, together with HassleholmsMekaniska Verkstad AB.

Twenty years ago Pullmax was one of thefirst companies in the world to produce anumerically controlled machine tool—thePullmatic 193 co-ordinated punchingmachine, with a 72-tool magazine. In 1972,

there followed the P31 NC nibbling machineand in 1974 the company's first computernumerically controlled product, the 18SM.Ten years ago the first Pullmatic portalframed punching and nibbling machine,with automatic tool changing and therevolutionary eight axis SMT 300 computer,was introduced.

Today, Pullmax's own product range hasthree strands: The X93 welding bevellermachine prepares plate edges, without dis-tortion, for welding. The P200 family ofthirteen universal punching and nibblingmachines caters for material up to 4mmthick. Among four CNC models is the P209,said to be the world's least expensive CNCpunching and nibbling machine. The Pull-matic range of portal framed machinescovers material thicknesses up to 15mm andvery high speed output at lesser thicknesses.Modular optional facilities such as plasmacutting, milling and the Optitool indexablepunch head system can be retrofitted to thebasic machines. The Pullmatic 6LH FMS is

Production Engineer — October 1988

claimed to be the world's most advancedmanufacturing plant.

The company also supplies and providesspares and service for the products of theassociated companies mentioned above,including: Kumla/Roundo section rolls,plate rolls and flanging-and-punchingmachines. Ursviken pressbrakes, guillotinesand shears and are also agents for theItalian-made Ficep range of heavy beam, flatplate and angle fabrication lines.

Pullmax has supplied machines to, ormanufactured machines in, the UK for overforty years. Since 1981 Pullmax UK has beenbased in Leeds, centrally located to offer afast response service to its clients, with anextensive technical centre which houses thesales department, customer liaison depart-ment, training school, spares stock andshowroom.

Each member of the product supportgroup is a specialist in a particular sector of

a sophisticated back-up organisation and weat the Leeds Technical Centre aim to providea comprehensive service for all the com-pany's products, from the simplest to themost complex. Judging by the level ofcustomer satisfaction, we think we're gettingit about right."

And get it right it did for Brown DesignEngineering (BDE) who developed and nowmanufacture Caterpillar's new RTC60rough terrain telescopic forklift truck underan exclusive design and build contract. BDEhas installed four Pullmax plateworkingmachines in its new, £7M purpose-builtfactory at Stockton-on-Tees.

The plant is also involved in subcontract'work for Artix, makers of an extensive rangeof articulated dump trucks marketedthrough Caterpillar; and in the developmentand production of Multidrive's new all-wheel-drive, rear-wheel-steer articulatedtruck.

the Pullmax and associated ranges withEnglish speaking advisers in the Swedishfactories only a phone call away if needed.

A comprehensive stock of spares, exclus-ively dedicated to the Pullmax and associ-ated ranges, provides customers with areliable, single source service. A computeralso provides a statistical analysis facilitybased on actual service records to producereliable performance forecasts and pay-backpredictions.

The Centre also provides training coursesto ensure that customers' staff get the bestpossible results from their Pullmaxmachines.

In the words of managing director PaulRhodes: "Sophisticated equipment deserves

Looking along the 7.3metre bed length ofBDE's Pullmax EKP 640tonne press brake

BDE, Artix and Multidrive are all parts ofthe privately owned David J B Brown groupof companies which also includes AWD,formerly Bedford Trucks.

The Pullmax equipment supplied to thenew factory comprises a Pullmatic 3015/12CNC punching and nibbling machine, aGSB 650 5m x 23mm CNC guillotine shear,an EKP CNC press brake of 640 ton x 7.3metre bed capacity and an X93 bevellingmachine.

The Pullmatic unit is the third to bebought by the group: earlier machines werethe basic punching model and a unit with anauxiliary plasma cutting head and automaticplate handling. The latest version, which canpunch plate up to 12.5mm thick, incor-

porates Pullmax's new Optitool indexablepunch head system, enabling any of thetools, in fifteen workstations, to be rotated toany angle and applied with the full 40 tonnespunching force anywhere on a 1550mm x3000mm workpiece with an accuracy of+ / - 0.1mm per metre. Automatic platerepositioning increases the overall plate sizewhich can be conveniently worked.

Accurately sheared blanks with perpen-dicular edges come straight off the GSB 650guillotine, thanks to a patented electro-hydraulic blade gap adjustment systemwhich rotates the upper blade forwards orbackwards to alter the blade gap and bladeangle simultaneously. This results in the topblade hitting the sheet precisely above thebottom blade, but going on to pass it with thecorrect clearance. Sheets up to 5m wide and23mm thick can be cut by the GSB and as theonly shear in the BDE shop, it handleseverything from 3mm to 23mm material.

Accuracy was also a consideration in thepurchase of the EKP servo-hydraulic pressbrake. Despite its 640 tonne pressing forceand 7.3m bed length, it offers tolerances astight as those of much smaller machines andBDE use it for all sheet materials from 3mmto 15mm thick. It is equipped to minimisedowntime between jobs, with a motorisedtool magazine and hydraulic tool clamping.A servo-driven arrangement enables thelower vee tooling to be changed across arange of sizes from 18mm to 250mmopening, without the need to rotate the tooland with automatic tool centring. The unit isequipped with nine axis multi-processorCNC sequence control and a CRT displayfor interactive programming.

Perhaps the most interesting feature ofthis machine is the revolutionary six axisbackgauge which allows either of the back-gauge fingers to position itself in any threedimensional position within its overall travellimitations independently from the other.

Clean, distortion-free edges are a pre-requisite for effective single or double weldjoints and BDE chose a Pullmax X93beveller for the preparation of X, V, Y or Kform joints. The workpiece is automaticallyfed through the machine, to produce bevelsup to 25mm wide, at any angle between 25°and 55°, without the use of heat ofchemicals.

BDE's production engineer Ian Baxteremphasised the importance of quality andaccuracy: "As a major Caterpillar supplier,our quality assurance must be of the highestpossible standard. By producing even thesmallest components within the vehicle to ahigh level of accuracy and consistency,quality is introduced at this base level andmaintained throughout the manufacture ofthe first vehicle. For ourselves, we know firsthand that since producing componentsin-house on the Pullmax machines that werepreviously contracted out the quality andaccuracy have improved dramatically andproduction costs have dropped. TheOptitool system alone significantly reducesthe number of tool changes required, andthus increases overall productivity. It alsoreduces the number of tools used in themachine, and those which must be kept instock." •For more information on Pullmax circle PE133

Production Engineer—October 1988 31

Coordinated cuttingJust introduced to the UK by Hancock CuttingMachines Ltd, of Andover, the Combirex co-ordinate cutting machine is ideal for the produc-tion of blanks in small and medium batches. Twoversions are available, the type CXA and thehigh-speed type CXB.

Although designed primarily for oxy/fuel gascutting of sheet and plate materials in thicknessesfrom 3 to 300mm, the Combirex machines can befitted with plasma cutting torches. Control isnormally by means of a photo-electric tracing unit,but a numerical control system and Hancock'sexciting new Teach-Trace facility can be addedeither initially or at a later date.

Both the CXA and CXB can be supplied in threesizes giving cutting widths using one single torch of1500, 2000 and 2500mm. When fitted with twosingle torches the parallel cutting widths are 2 x1000, 2 x 1250 and 2 x 1500mm respectively.Whilst four single torches are the normal comp-lement it is possible to add two more on the fourwider machines.

Basic length of the track is 3000 or 4000mm butthis can be extended in steps of 1500 or 2000mm.

Drawing patterns - lines or the edges ofsilhouettes - are traced using the ASE 2001photo-electric tracing system and transferred 1:1to the torch control. By using microprocessors inthis circuit the control characteristics are particu-larly good and movements can be very fast.

When fitted with Hancock's NCE 500 numeri-cal control systems programs can be entered bypunched tape or manually. As the ASE 2001photo-electric tracing system can be linked to theNCE 500 it is possible to digitise drawings by the

Teach-Trace method; the simplest way to enterprograms for complex profiles.For more information circle PE134

Combirex cutting power in action

Vacuum clampdownVacuum clamping systems are widely usedthroughout industry thanks to their simplicity ofdesign, ease of operation and high level ofreliability. The Vacuuspan system fromOxytechnik moves away from the customarymethods based on individual vacuum elements.Instead, the vacuum is applied to the completesurface area of the sheet type workpieces arrangedon the clamping bed. This all-over clampingtechnique serves to smooth out irregularities in thesheet material effectively, whilst providingexcellent grip characteristics.

The Vacuspann system is suitable for a widerange of potential applications. Regardless of thetype of material involved, sheet workpieces ofvarious sizes can be clamped flat in readiness forall kinds of machining and other processingoperations, such as joining, planing, polishing etc.

When clamped, the full surface area of theworkpieces is freely accessible, thus creating idealconditions for the various processing duties. TheVacuspann system can be used to great advantage

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for welding sheet panels. In this instance,Vacuspann has a further important advantageover electromagnetic clamping methods in that thewelding process cannot be affected by the presenceof magnetic fields.

The Vacuspann system consists of a machinebed in which two clamping tables are integrated. Aseparate vacuum pump is assigned to each of theclamping tables. The two pumps can be operatedindependently of each other. Recessed sealing lipsare arranged longitudinally to the table edges.When the clamping system is operated, these lipsmeet up with the sealing strips that run transver-sely to the table edges to guarantee a perfect sealover the rectangular vacuum space.

Depending on the edge length of the sheets thatare to be processed, the tranverse sealing strips canbe easily adjusted accordingly. The clampingtables incorporate lifting rollers which, when intheir uppermost position, allow the sheets to bemanipulated with ease for positioning purposes.

If the Vacuspann system is used for welding

duties, a backing is arranged between the clampingtables in order to secure the weld pool. (Thisbacking can take the form of a cushion of flux,glass fibre tape, or a ceramic, stainless steel orcopper rail). End-stops are provided in theclamping tables for aligning the first individualsheet of material.

After positioning and clamping the first sheet,the second sheet is aligned along the longitudinaledge of the first, and then also clamped. Theclamping force is of the order of 40 kN per runningmetre of workpiece length with a clamping time ofapproximately 3 to 4 seconds. When the weldingoperation is completed, the sheets are released,raised on the lifting rollers and then discharged.For thicker plates, both clamping tables can beinclined (for a pre-bending effect) in order tocompensate for any distortion due to the weldingprocess. In addition, a grinding unit can bemounted on the welding gantry for grinding offexcessive weld reinforcement.For more information circle PE135

Production Engineer—October 1988

Storage solutionsIn recent years, CNC plate/sheet workingmachines have taken enormous steps in technicalknow-how. Machines such as CNC punching, andnibbling machines with automatic tool change,laser and plasma cutting machines, have realisedthe way to flexible manufacturing.

Increased production from these machines hasmeant that the necessary associated handlingequipment and supply of material must be moreefficient, in order to keep the downtimes of themachines to an absolute minimum.

Kasto, who are represented in the UK by RiversMachinery, realise this problem and using over 40years experience in the machine tool industry andnearly 20 years in handling and storage equip-ment, are in a position to offer three solutions tostorage and handling problems.

Magazine for sheet metal with individual sheetretrieval

A universal magazine, which supplies individualsheets to a sheet/plate processing machine—thefirst step towards a flexible automated manufac-turing cell.

The magazine can, in its standard execution,

hold up to 10 various sheet metal stacks. Byinputting the material specification and requirednumber of sheets, the picker crane will automa-tically collect the selected material and deliver it toone of two positions. These two positions couldrepresent two machines.

During the machine's cycle the Kasto sheetmetal magazine can be restocked with freshmaterial. Integrated separating magnets ensurethat a single sheet has been selected. For furthersecurity a double sheet detector is fitted.

Compact sheet store (Tower System)An alternative cost effective system is the Tower

System. It consists of a single shelf block with apicker crane. Material would be stored on palletsand these would be retrieved and stored using apicker crane with telescopic forks.

The system is designed so that when the sheetprocessing machine is working the system can berestocked with fresh material. In its standardexecution, it would have between eight and20 compartments, with each pallet supporting3.0 tonnes of material.

The main objective of the Tower System is to act

as a buffer for the sheet processing machines.Hence keeping the material changeover times toan absolute minimum.

High shelf sheet storage system with picker craneThe third system would be the complete system,

where any number of machines can be fed. Thesystem consists of a shelf block with a picker crane,which is guided on rails and runs down the lengthof the block. The system is built-up on a modularbasis. The picker crane drives in two-axis andservices either one block (single row block) orbetween two blocks (double row block). In orderto remove pallets from the system, the crane isequipped with telescopic forks.

The picker crane is designed to accept load cells, sothat each time a pallet is restored it is weighed and thestock level for that material specification is updated.Hence it offers complete control over inventory.

The system can be fully integrated to anynumber of sheet/plate processing machines toform a complete manufacturing cell. The systemcan be extended at a later date both mechanicallyand electrically.For more information circle PE136

Automatic storage and retrieval of sheet metal

Production Engineer—October 1988 33