By Patrick A. Toensmeier Awhile increasing process economy · blow molding (EBM) machines are...

s the container market addsstyles, sizes, and end-userequirements to products,manufacturers of extrusionblow molding (EBM)machines are upgradingtheir systems with arange of technologies tomeet evolving processneeds and improvecost-performance ben-efits.Key features ofrecent offerings in

shuttle, rotary, and reciprocatingscrew equipment include a growingtrend toward all-electric machines in

North America; efforts to reducemachine size; greater use of net-worked controls to improve moldingprecision, throughput, and quality;and increased reliance on proprietarydesign and engineering to fine-tunesystem performance, speed productchangeover, and, in some cases,improve container design. The result is machines that widen

the process envelope ever further toaccommodate diverse containers,resins, and molded structures, whilegiving processors more options toreduce manufacturing costs andthereby increase somewhat the razor-thin margins of the mostly commodi-ty products they produce. “There is a relentless drive toward

reducing the cost of producing anypart or container,” says RichardSmith, commercial director of Uniloy

Milacron North America, a manufac-turer of hydraulic and electric shuttleand reciprocating screw machines inTecumseh, Michigan, USA.Examples of end-use products that

are influencing machine designinclude progressively smaller single-serve containers—some down to 50ml (1.5 oz); coextruded structures forextended shelf life, chemical resist-ance, or for adding inner layers ofrecyclate to a package; and large con-tainers with special requirements,such as clear 5-gallon water bottles ofpolyethylene terephthalate moldedwith integral handles.Suppliers report growing demand

around the world in almost everymajor market EBM serves—frompersonal care, household and indus-trial chemicals, and lawn and gardento medical, pharmaceutical, food andbeverage, and automotive. Processorswho are investing in new machineryhave access to technologies and capa-bilities that will improve their com-petitiveness in all these applications.

Electrics optimize performanceChief among the technologies is elec-

20 | PLASTICS ENGINEERING | JUNE 2011 | www.4spe.org

By Patrick A. Toensmeier

Top: Extrusion blow-molded containerscome in many shapes and sizes, andcan be processed in monolayer orcoextruded structures. Photo courtesyof Dow Plastics.

Evolving technologies extendextrusion blow molding capabilitieswhile increasing process economy

A

tric machines. All-electrics have beenavailable for some time in Europeand Asia, but they only recently start-ed making inroads in North America.The main benefits they offer overconventional hydraulic EBM systemsinclude increased precision, suitabilityfor clean rooms and aseptic-fillingoperations—with no hydraulics thereis no need for hydraulic fluid andthus no potential for leaks—andlower energy costs. For many mold-ers, this last point is a significant con-sideration.“Electric-drive motors are highly

efficient,” says Jeff Newman, vicepresident of sales and marketing atWilmington Machinery, arotary-machine manufac-turer in Wilmington, NorthCarolina, USA. “Our new[SB, for Small Bottle]machines consume 20% to30% less energy than com-parably sized hydraulicmodels” (see machinedescription in last sectionof this article).Double-digit energy sav-

ings over hydraulics arecommon to all-electricmachines, manufacturersreport. Some suppliers citeenergy savings of as muchas 50% depending on theapplication. When it comesto molders in areas with

high electricity costs, such as NewEngland and states like California inthe USA, or those in WesternEurope, the energy savings ofelectrics can help build bottom-lineprofitability.Processors in the U.S. also benefit

when rebates are available from utili-ties and states for installing energy-efficient systems in place of oldermachines. Bernard Graebener, ownerof Blow Mold Solutions of Elwood,New Jersey, USA, a distributor ofMagic machines from Italy, says oneundisclosed customer inMassachusetts received a $20,000rebate from the state for buying an

all-electric machine.Graebener adds that while

hydraulic and hybrid machines runalmost as fast as electrics, their cyclesfluctuate and they are not as repeat-able. “The advantage of a faster cycle[by itself ] does not seem to be allthat significant,” he remarks. “Thereal, substantial savings and benefits[of electric machines] are in less ener-gy use, less downtime, and more pro-duction output over time.”Some companies, citing growing

demand, make nothing but electricmachines; others, while offeringhydraulics or hybrid-electric drives,are shifting to all-electrics. Magic

makes only hybrid and all-electric machines.Graebener says that electricsmake up more than 50% ofhis company’s sales, and hewants to eventually phasehybrids out in favor of anall-electric line.Hydraulics will, of

course, always have a placein EBM. Nevertheless, all-electric sales are growing inNorth America and else-where. Some manufacturersbelieve demand will increaseexponentially as more sup-pliers provide them andmolders better understandtheir benefits despite a costpremium over hydraulics.

www.4spe.org | JUNE 2011 | PLASTICS ENGINEERING | 21

MSB40-DP dual-parison rotary extrusion blow-molding machine from Wilmington Machinery is designed for high-volume production of 80-ml containers. The unit has 40 stations and 80 cavities and molds 40,000 bottles/hr. Photo courtesy ofWilmington Machinery.

ME-UE L1/D electric machine from Magic (sold in the U.S. byBlow Mold Solutions) is priced comparably with the manufac-turer’s hybrid-electric models, or about 30% less than otherelectrics made by the company. Photo courtesy of Magic.

Machine costs come downThe cost premium is problematic formany processors, but this couldchange. For one thing, electric priceswill probably come down as demandgrows and manufacturers vie for busi-ness. Bekum of Germany launchedits first electric EBM machine, E-Blow, last year at K2010. The compa-ny said it would be priced compara-bly to its hydraulic models.

Graebener says that a double-sidedMagic machine for molding 5000-mlcontainers, with a 90-mm extruder,300-point process control, 12-metric-ton clamp and inline secondary oper-ations, costs €279,000, or about$405,000. The purchase price, how-ever, does not reflect lifetime savings.The machine has a two-year warrantyon parts and service; electrical partsare generally long-lasting; and thereare no proportional valves, filters,other hydraulic parts or oil to replace.Graebener says, in fact, “Magic hasnoted a significant fall-off in its spareparts business as more of its machinesales are all-electrics.”

Bekum said on introducing the E-Blow machine that in tests the elec-tric drive required virtually no main-tenance over 8000 hr of operation. The features of an all-electric

machine have a ripple effect on pro-cessing that makes other benefits pos-sible.One is smaller footprint. As EBM

systems increase speed and accuracy,generating higher volume and greater

quality, processorscan increasinglyreplace multiplesmall machines withone high-volumesystem, whetherrotary, shuttle, orreciprocating screw.“Most of the timewhen customerscome to us they areremoving two, three,or four of their smallshuttle machines toinstall one of ourmachines,” says

Wilmington Machinery’s Newman.“Therefore, we have to design ourmachines to fit into the smallerspaces these machines occupied.”One way electrics facilitate this is

by repositioning controls. Withouthydraulic valves there is no need for acontrol cabinet to be standing next toa machine taking up floor space; itcan be placed within a machine—insome cases beneath an extruder.Manufacturers are also incorporat-

ing secondary operations such as cut-ting, trimming, and neck finishing inmachines. When this isn’t possible,the push is on to get suppliers of sec-ondary systems to downsize equip-ment, shorten finishing lines, ormake finishing an inline operation. Newman says Wilmington can fit

an electric machine sized for 800 bot-

tles/min in a space 50 x 20 ft. “Beforeadding our new technology, themachine would have needed twicethat space,” he notes. In a Brazilianplant, Wilmington replaced severalshuttle machines with one rotarymodel. As a result, the molder wasable to reassign up to nine workersthat were needed for the shuttleequipment to other operations,reducing labor costs. The machineproved so manageable and accuratethat it didn’t require a full-time oper-ator—one worker could monitor itpart-time.Reducing human intervention

through greater automation is anoth-er advantage of new machines, espe-cially all-electrics. “Electrics areextremely accurate from startuponward,” Graebener says, “owing tothe ability to dial in extremely precisesettings that don’t change.”

More network controlThere is also the potential for greaternetworking of operations and morecomputer control throughout theprocess. Gary Carr, national salesdirector of Bekum America Corp. inWilliamston, Michigan, USA, citesgrowing use of “stealth monitoring”such as vision systems to check partsfor defects as they are made, andcomputer control at various stages ofthe process that continually regulatesoperations from the extruder to theparison profile, molding cycles,demolding, and finishing.Carr says Bekum has spent a lot of

time optimizing such technologies asplastication, extrusion, and automa-tion to meet increasingly technicalspecifications for container produc-tion. One important area is shelf-sta-ble packaging for food and dairyproducts. Among the advances hecites: “We have optimized our coex-


Electric drive and tiebarless design ofE-Blow machine from Bekum contributeto precision molding, high output, anddouble-digit energy savings. Photocourtesy of Bekum.


trusion head technologyso barrier resins run at thethinnest repeatable andreliable layer thicknesses.”Fine-tuning machine

performance is nothingnew for manufacturers, ofcourse. But the advancesthey are adding to theirsystems not only optimizethe production of existingcontainers, they also pro-vide a basis for revampedspecifications that yieldsizable savings to molders.One example involves

work that UniloyMilacron did for a majorconsumer products company inMexico. The company bought twoUniloy R2000 reciprocating-screwmachines to do its own molding ofan 850-ml rectangular fabric softenerbottle of high-density polyethylene.The machines, with 90 tons of clampforce and 16-cavity molds, were thelargest reciprocating units built byUniloy. They required 10%–25% lessenergy than a shuttle or rotary sys-tem, a major saving right there.Uniloy also developed design modifi-cations that reduced bottle weight to35 grams from 39 grams, and low-ered cycle time by 33%, to 8 secfrom 12 sec. Further tweaks to thecontainer resulted in weight drop-ping another 10%, to 31 grams, anda further cycle-time reduction, to 7.2sec. The company recently bought athird R2000 machine for the process.Uniloy not only builds machines,

but like some suppliers it does itsown container and mold design forcustomers, which Richard Smithviews as part of a total system engi-neering capability. “We’re aboutguaranteeing the end article, thecycle time, and throughput,” he says.

The company applies its design andengineering expertise to developingcomponents such as extrusion screwsthat contribute to process efficiencyand cost savings for molders. “Ourproprietary screw designs let us processmore resin at less power consumptionthan any like-sized extruder on themarket—about 20% less power than ashuttle machine,” he says.Despite the energy sav-

ings, the extruders Uniloyprovides on its reciprocat-ing screw machines arealways capable of morepower than an applica-tion requires. “Wewant a cushion—wedon’t want to run anextruder at 100%power all the time,”Smith says. Thecushion is greater on

small-containermachines. “A moldercan double through-put and still havereserve energy.”Another technique

that Uniloy and othersuse to boost produc-tion is neck-to-neckmolding, where bottlesof up to 500 ml (inUniloy’s case) aremolded together at theneck and separated ina secondary operation.The company installedtwo such machines inRussia, each capable of

molding 100-ml drinkable yogurtcontainers at a rate of 20,000/hr.

New machines add featuresA sampling of new and recentlyintroduced machines shows how sup-pliers are incorporating new tech-nologies and capabilities into theirEBM systems. Uniloy Milacron, for example,

added the UR-65, -80, -90 and -100reciprocating screw machines to itsequipment line. The numbers referto extrusion screw diameter, inmillimeters. Model lengths

range from 243 inches(UR-80) to 264 inches(UR-100), widthsfrom 89 to 123 inch-es, and height for allversions is 123inches. A newscrew design yields10%–20% greaterproduction effi-ciency versus manycomparably sizedcompetitivemachines; energysavings are up to

UR-100 reciprocating screw EBM system from Uniloy Milacron has aproprietary 4-inch-diameter screw design that’s capable of process-ing 1100 lb/hr of resin. Photo courtesy of Uniloy Milacron.

Laundry detergentbottle represents aniconic size and shapein the householdchemicals market.Photo courtesy ofProcter & Gamble.

25%; and units include advancedmicroprocessor controls, online trou-bleshooting, and a clamp area that’sdesigned for easy access. Clamp sizingranges from 28 x 12 inches for a sin-gle-clamp system to 48 x 15 inchesfor a double-clamp unit.Wilmington Machinery’s SB all-

electric rotary EBM machines aredesigned for containers of 80 to 500ml and targeted at single-serve dairy,juice, food, and water markets.Models can be equipped with 18 to60 cavities and configured for coex-trusion; they can generate extrusionrates of 1200 lb/hr and produce upto 500 monolayer or coextruded

bottles/min. Energy savings fromelectric operation are 20%–30%,and inline finishing systems can beintegrated. They have a small foot-print and a low-profile design forease of access. The latest machines offered by

Magic (through Blow Mold Solutionsin the U.S.) are in the ME-UE(Ultra-Economical) all-electric range.Machine specifications are similar tothose of the ME hybrid range. Theyinclude container sizes of 100 ml to 3liters; ease of operation and mainte-nance; and claimed energy reductionof 40%–50%. The ME-UE machinesare comparably priced to Magic’s

hybrid-electric equipment, which thecompany says prices them 30% lowerthan one of its comparable ME all-electric models. Features of Bekum’s E-Blow electric

machines include tiebarless C-clampsthat reportedly achieve platen paral-lelism of less than 0.1 mm per stroke;five clamp sizes of 350–700 mm(13.7–27.5 inches); and clamp pres-sures of 10–24 metric tons. Modelscome in single-station or double-sta-tion configurations, include a range ofautomatic controls, and, like other all-electrics, are designed for double-digitreductions in power consumptionover comparably sized hydraulics.


36 THERMOFORMING QUARTERLY

September 17 – 20, 2011

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Welcome Back to Chicago!

20th Annual Thermoforming Conference

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Schaumburg, Illinois (20 minutes from O’Hare Airport)

For Reservations: 1-800-468-3571or 847-303-4100Request SPE Room Rate of $159.00

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By Patrick A. Toensmeier Awhile increasing process economy · blow molding (EBM) machines are...

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