Roller Head/EWK-Systeme Roller Head

Roller Head-SystemKDi 300 x 850 WBK 150/700Roller Head SystemKDi 300 x 850 WBK 150/700Roller Head SystemsA Roller Head unit is a combinationof an extruder with a preform headand a two-roll calender (can also bea 3- or 4-roll calender). Roller Headtechnology offers two decisive advantages:one is the high uniformityof the material thickness over theentire sheet width, which ensuresthat there will be no air inclusions,even at higher thicknesses.Another is the outstanding homogenityof the material produced.Both production characteristics areoptimal pre-requisites for highqualityrubber products such astire components, V-belts, conveyorbelts, tank linings, cover sheets,blank sheets and roofing sheets,among many other things.This great product variety ispossible because the Roller Headunit (in comparison to the classiccalender line, which can onlyproduce sheets of up to 3 mm thickwith a single path in order toprevent air inclusions) can producesheets of up to approx. 20 mmthick.The rubber compound is plasticizedin the extruder and then fed into thepreform head. It enters the calenderdirectly in the roll gap, and is distributedover the entire working widthof the calender. This direct feedingprevents the build-up in front ofthe nip, that would otherwise beexpected as well as air inclusions,so that the sheet pre-formed in thepreform head can have a thicknessof 10 mm to 30 mm, which thecalender then calibrates to thedesired end thickness. If thicknessmeasuringequipment is downstreamfrom the calender, itsmeasured value can be used tocontrol the roll adjustment. Thisautomatically guarantees continuousthickness regulation for thecalendered product.In order to compensate for theelastic deflection of the rolls, whichwould lead to a thicker product inthe middle of the sheet, there arethree options that can be usedalone or in combination with oneanother: roll crowning, roll crossingor roll bending. The result is aproduct with an even thicknessacross its entire width.The preform head consists of twoparts with special hard-chromeplated flow channels in the materialfeeding area. They distribute thematerial evenly over the entireworking width. Both head partshave exchangeable plate dies,which make sure that the headopening is adjusted precisely for thedesired sheet thickness. Inserts canbe used to decrease the extrusionwidth to avoid excessive edgetrimming with smaller workingwidths.The temperature of the headhousing parts is controlled withheating/cooling chambers withtemperature sensors. The rolltemperature is controlled by meansof peripheral bores along the rollsurface. The bores are distributedin several groups and channel thetemperature-control medium inmeandering form – this makes forhighly precise temperature controlas well as fast heating and reactionto temperature changes over theentire roll width.The extruder is mounted on ahydraulically moveable baseplate.This makes it possible to move theextruder, including the head, awayfrom the fixed calender, for examplefor head cleaning at the end ofproduction or to exchange the platedies and insert parts when changingsizes.Roller Head Systemsat a Glance:■ high production capacity■ very thick sheets can beproduced in wide widths■ excellent product precision■ profiles can be changedwithin 5 minutes bychanging the roll sleeve■ material swelling canbe influenced by calibratingwithin the roll gapThe calender can have a profile rollfor production of profiled strips orsheets. This consists of a temperature-controlledroll core and aprofiled sleeve that slides onto it.The sleeve can be changed within5 minutes with a hydraulicchanging device.Standard equipment for the RollerHead unit includes a compoundpressure/ speed regulator. If thepressure falls out of the allowablerange but within safety parameters,the speed of the extruder and/orthe calender is corrected. When themaximum pressure is reached, or ifthere is no connection between thecompound pressure indicator andmeasuring amplifier, the extruderis automatically shut off.In addition, the Roller Head unithas many safety devices thatcorrespond to the latest accidentpreventionregulations. An emergencystop cable runs along thewidth of the roll, which causes thecalender to shut down immediately.The adjusting motors automaticallyopen the calender gap and anauditory signal sounds to report theshut-down. The calendercan then be set to runat slow speed injog mode.