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Plastics Distributor® & Fabricator

Volume 27, Number 2Reprinted From March/April 2006

THE ROTARY

ADVANTAGE

Thermoforming2 6/15/06 8:00 AM Page 1

he Rotary Thermo-forming Machinehas seen constant

improvements and contin-ues to be the fastest stan-dard sheet fed thermo-forming machine manufac-tured in the country. As itcontinues to gain popular-ity, it is persistently beingadapted to gain more andmore advantages overother types of sheet fedthermoforming machines.The rotary is mainly uti-lized for mid to high vol-ume production of parts,which is its single largestadvantage. The latest rota-ries offer many additionaladvantages that allowusers to gain a competitive advantage, not only by havinghigh production capabilities but much more. The additionalbenefits can be overlooked by companies not aware of them,whether they are utilizing a rotary or competing with one. Theimproved designs and technology implemented in the rotaryhave made it a much more versatile machine.

More Parts Per Hour / Energy Savings

Rotaries guarantee more capacity and faster cycle timeswhile utilizing less electrical consumption per part whencompared to a single station or shuttle type machine. This isdue to the fact that a rotary machine continuously has asheet in the oven, as all stations are being utilized simulta-neously. In a three station rotary, after unloading a finishedpart from station 1, the next sheet is loaded back into thestation, meanwhile station 2 is being heated and station 3 isbeing formed. This allows the rotary machines to be capableof producing product with 1/3rd the amount of oven energythat a single station would require. While utilizing a rotary,the cycle time is either dictated by the heating time or cool-ing time, whichever is longer. The constant is 2.8 to 3 timesthe parts per hour output with oven electrical consumptionequal to a single station. This makes the rotary machinemore energy efficient. With faster cycles, less machine timeis needed, allowing companies to spend fewer hours, useless energy per part and less labor while at the same time,

gain machine time andcapacity.

More Consistent and

Repeatable

The Rotary machine canensure high daily outputsregardless of the operator’sinfluence. The machine’scycle time is not dictatedby the time it takes theoperator to load and aligna sheet and unload a fin-ished product like it is on asingle station. The operatorrunning a rotary is requiredto load and unload withinthe products cycle time,therefore allowing thermo-formers to be more con-

stant with higher productions as well as more consistent withfinished products.

Since a rotary cycles constantly, based on a pre-set cycletime, the atmosphere within the oven also remains very con-sistent. This oven consistency makes the rotary a favorablemachine with some of the new applications and materialsthat require tight and repeatable temperatures, such as paintfilms. Since materials are becoming much more advanced,the oven consistency provides a more reliable oven, thereforemaking it much easier to hold tighter tolerances.

The finished part consistency of the rotary is beginning toforce some of the lower volume applications to be utilizedexclusively in this type of machine.

Although most thermoformers utilize water-cooled alu-minum molds when running a rotary machine, shorter runswith ceramic, resin, fiberglass or non water-cooled molds arestill possible with a rotary. The limiting factor when using anon temperature controlled mold is overheating it. Themachine can be slowed down to accommodate this type ofsituation, but cooling the tool will be the deciding factor onthe cycle time.

Furthermore, the new rotaries are programmed to allowformers to use a skip frame technique, which will form a partevery other cycle, allowing the mold additional time to cool.By not loading a sheet into station one; the machine willremember not to perform any function when that station

THE ROTARY

ADVANTAGE— by Michael P. Alongi —

T

Thermoforming2 6/15/06 8:00 AM Page 2

reaches the forming area. Although this may not be an idealprocedure, formers with high and low volumes can still adaptto their marketplace and utilize the consistency of a rotary.You can also simply slow down the rotary, or just apply theright amount of cooling to your tool, depending on your spe-cific applications.

With the higher demand of lower volume rotary applica-tions, machine manufacturers have quickly implementedfeatures that allow machine changeover times to be dras-tically reduced. Three station rotaries can be changedover in less than 35 minutes with the use of adjustableclamp frames, mold centering and securing devises andthe latest in machine controls. Preheated tooling is alsobecoming more common for even faster part to partchangeover times.

Several advantages of recent model rotary machines areapparent with machines that have a high sheet line and lifttable system for semi-automatic bottom loading and unload-ing of parts. Older rotary designs that have low sheet-linesand are top loaded manually do not provide as many advan-tages, nor do traditional single stations or shuttles that aretoploaded.

Safety

Safety is a primary benefit of the overhead design of ahigh sheet line machine with a semi-automatic loadingdevise or lift table. This feature removes the possibility ofplacing hands into the clamp frame when loading andaligning sheets of plastic. It also reduces the risk of touch-ing hot clamp frames and machine components that cyclethrough the oven. This design also greatly reduces the riskof personnel walking into the rotating carousel. As mostthermoformers running single stations and top loadmachines know, burns, pinched fingers or any type of injurycan get expensive.

The “no pit design” also eliminates the need for personnelto enter a pit for maintenance purposes, which helps toreduce the risk of an accident occurring. The “no pit design”allows for a quick and easy installation and gives the flexibil-ity of moving the machine around your facility instead ofbeing forced with a permanent machine location due to aplaten pit requirement. The “no pit design” also tends toimprove housekeeping of your facility.

Floor Space

Floor space is a valuable item in today’s thermoformingfacilities. Another reason the high sheet design is pre-ferred, is it creates additional floor space for loading,unloading and trimming. With room for a skid of material(usually on the right side of the load/unload station), load-ing and unloading can be accomplished within the perime-ter of the machine. The high sheet line design allows you toincorporate the vacuum reserve tank within the machine’sparameter, therefore eliminating the need for any addi-tional floor space.

Easier on the Operator

The ergonomic high sheet line design, coupled with the lifttable, eliminates the need for an operator to bend over toload and unload material. With a stack of material to theright or left of the lift table, an operator can ergonomically

slide sheets onto the lift table instead of carrying or liftingsheets. Since the lift table also retrieves the formed partwhen the cycle is complete, the operator can also select whatheight he wishes to unload the part, once again making iteasier on the operator.

A larger selection of machine operators can also beconsidered to operate these machines as they no longerneed to have the 3-foot arm span that is typically need-ed to reach over the clamp frames to load any top loadstyle of machine. Since lifting is kept to a minimum, theoperator can also be less physically fit and still keep upwith production.

Since the operator has less physical stress and can loadmuch quicker, additional free time becomes available. Thiscan allow operators to do better secondary operations oradditional operations such as: quality assurance, trimmingor even tweaking the machines parameters for more effi-ciency.

Smaller Sheet Sizes and Lower Scrap Rates

Loading sheet is more precise by the use of a lift table andsheet guide system. Sheet material is easily positioned ontothe lift table; adjustable stops are provided for repeatablepositioning of sheet into the clamp frame. Sheets can beloaded much more accurately and repeatably, which nearlyeliminates sheet “pullouts” or clamping of unaligned sheets,which are two major causes of increased scrap rates. On lowsheet line, top load machines the operator is responsible forthe continual alignment of loading sheets accurately, there-fore allowing for more error or more scrap.

The precision lift table in conjunction with good clampframes requires only the minimum blank size of material.By loading sheets more accurately and repeatably you canreduce the material blank size by 6% to 12%. With lowsheet line, top load machines most formers oversize thestarting dimensions of their sheet to accommodate theoperator on loading and aligning of the sheet. They havefound the larger sheet size reduces operator error and low-ers scrap, but the bottom line is it still adds cost to use alarger sheet size.

The thermoforming manufacturing world is now beingforced to use the most efficient procedures and equipment inorder to maintain its competitive edge in today’s market-place. Lower labor costs, lower material costs, lower energycosts, shortest changeover times and improved part-to-part

Thermoforming2 6/15/06 8:00 AM Page 3

consistency are all the main reasons our marketplace is mak-ing changes and why the latest rotary technology is being fur-ther implemented and utilized.

Written by Michael P. Alongi, Sales Director for MAACMachinery Corp., manufacturers of a wide range of cut-sheetthermoforming machinery.

For additional information, contact MAAC MachineryCorp., 590 Tower Blvd., Carol Stream, IL 60188, 630-665-1700, Fax: 630-665-7799, E-mail: sales@ maacmachin-ery.com, Web:www.maacmachinery.com

Copyright 2006. Plastics Distributor® & Fabricator mag-azine is published six times per year and is available free of charge to qualified U.S. and Canadian distributors, fab-ricators and manufacturers of plastic rod, sheet, tube,film, pipe and fittings and others allied to the field. For afree subscription see the “Visitor's Center” on our websiteat www.plasticsmag.com or call 708-588-1845 for moreinformation.

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