Profile extrusions are finding their place in a variety of new markets, but the challenges of outputâincluding productivity, efficiency, and qualityâ remain the same.
Tooling developments, such as Technoplasts TC One, help extruders raise their output of quality profile.
Battenfelds techBEX is billed as a new low-cost machine option for profiles.
A variety of profiles, decking, and fencing panels rely on accurate haul-off following extrusion and calibration.
Special cleats (top) for custom profiles (below) provide accuracy and insurance against slippage.
As profile extrusion lines increase in speed, equipment makers like Canadas CDS have had to respond with longer downstream equipment, such as the CHH120-10Q cleat puller with its 10-ft (3m) contact length.
Greiner Extrusions StartLine features the Smart.COM haul-off with forces of 24 kN at 6 m/min to handle profile extrusion speeds from 0.2-9 m/min.
This cleat puller from CDS is suited for wide and rigid profiles.
Short setup time of Greiner Extrusions Start.COM haul-off results from quick-change pads.
Cleats, in a width of 235 mm, numbering 104 each on both top and bottom caterpillars provide steady pulling power.
Conairs servo-driven MedLine puller/cutter is said to be priced 20% lower than competitive units.
Theres a lot that goes into creating the perfect profile, with tooling and cooling playing a major role in the all-important output rate. Traditionally, its always been the cooling capacity, because the limitation for output is cooling the profile and still controlling the dimensional tolerances requiredâand most are very tight tolerances, says Paul Godwin, sales director for American Maplan Corporation (McPherson, KS).
To address these issues, Godwin says the trend is toward more sophisticated tooling. From the extruder standpoint, weve always had the ability to do high output rates, and our emphasis is on the screws to get a high-quality melt exiting the extruder, so the processor is provided a homogenous blend at the lowest possible melt temperature to reduce cooling time, Godwin says. Its a game of âenergy in has to be energy out, and tooling manufacturers have made great strides in tooling with improved cooling efficiency.
Tooling manufacturers have also developed âtwo up or âfour upâdual- or quad-strand outputâto increase productivity and efficiency. Line speeds have to be slow enough to facilitate the necessary cooling but fast enough to enhance productivity. Any time you increase line speed, issues of wear come into play, and the tooling guys have developed the technology to support increased line speeds, says Godwin. Recent tooling developments include the Micro-Mini II introduced last year by Guill Tool & Engineering (West Warwick, RI). This tooling allows extrusion of product with an outer diameter of 0.005-0.100 inch (0.127-2.54 mm), significantly smaller tubing than its established predecessor. Target users include processors of medical tubing, wire and cable, electronics and specialty applications.
The Micro-Mini IIs die/crosshead includes what Guill calls a FeatherTouch adjustment in the die holder, which does not require the loosening of retaining screws to make adjustments.
Also introduced last year was the TC (Technoplast Calibration) One by profile tooling manufacturer Technoplast (Micheldorf, Austria). The manufacturer bills these tools as the first enabling profile extrusion at low energy-use rates, with speeds for a main profile of 3-5 m/min. According to Technoplast, energy savings can approach 50%.
B&C and beyond for growth markets
Profile extrusion machinery manufacturers report an increase of sales into the building and construction industry. Bob Beaudry, senior sales engineer for profile/pipe/tubing systems at Davis-Standard, said that building and construction remains the companys top market. Were seeing a lot of replacement of wood with plastic and wood-plastic composites. He notes that many processors have cut back on engineering personnel, and seek out suppliers offering a turnkey extruder package including downstream equipment and tools.
Beyond B&C, there remain plenty of new opportunities for processors prepared to fulfill demanding requirements. Profile Plastics Inc. (Hartville, OH), for instance, added acrylic optical fiber to the list of components that can be encapsulated in its extrusions. This was first done for a customer whose tubing required a tight bend radius, so using glass fiber optics was not an option.
The fiber is extruded inside a material with processing temperatures 100ÂºF in excess of the melting temperature of the fiber, and 200ÂºF above the maximum service temperature of the fiber, while still preserving the fibers optical properties. The ability to extrude the part pleased the customers pocketbook, as hed considered overmolding the fibers via injection molding.
Bryan Knowles, president of Profile Plastics, says firms such as his cant compete on price alone.
We tell potential customers if you come to us just looking for low prices, were not that type of company, he says. We try to push the processing envelope and offer more value. The more value we can deliver beyond just pushing plastic through a die, the better we all areâus and the customer.
Secondary processing ever more important
Knowles says its important to do many of the secondary operations inline, citing CNC routing as an example. Some customers considered handling routing in-house, but Knowles showed how Profile could do this operation in the extrusion line. Weve already got a person manning the line, so its a lot more efficient for us to run the router as well. Theres no double handling or double labor, so we can add a lot of value to the process, he says.
Maplans Godwin says cut-length accuracy is one of the technologies that customers are demanding today. His firm sources cutting equipment from sister firm Battenfeld Extrusionstechnik (Bad Oeynhausen, Germany). In the extrusion business, if you dont have precision cutting equipment, you measure once and cut twice, which is not what we want, he points out.
Battenfeld Extrusionstechnik recently extended its universal compact profile extrusion linesâwhich to now included miniBEX (for small technical profiles) and winBEX (for window main profiles)âto include the techBEX standard line, manufactured and assembled in China for global distribution. The techBEX costs about 30% less than conventional lines, says Battenfeld, and is available with outputs of 40 kg/hr or 60 kg/hr. The downstream package includes a calibrating table, a belt haul-off, a flying knife cutter, a servo saw and a tip table.
Consistent pulling has high effect on profile end-quality
by Robert Colvin
As profile extrusion lines speed up , the downstream equipment has had to expand in length to better cool and handle the output.
Rudolf Wessely, sales-marketing director at equipment maker Technoplast Kunststofftechnik (Micheldorf, Austria) says it is not unusual today to deliver calibration tables up to 21m long.
Pullers or caterpillar equipment to facilitate haul-off have grown with the rest of the machinery. Canadian machinery manufacturer Custom Downstream Systems (CDS, Lachine, QC) says it recently delivered a 3m-long cleat puller to accommodate a longer calibrating unit belonging to one of its customers.
Bob Bessemer, senior product engineer-downstream extrusion at equipment maker Conair (Pittsburgh, PA), says higher pulling forces are required, therefore pullers are becoming longer, to haul-off the increased output. Longer pullers enable higher pulling forces without the potential to distort the profile with higher contact area, Bessemer says. Yet at the same time processors and tooling suppliers are using lower vacuum levels in the calibration unit to do the same job. Lower vacuum levels generally require lower pulling forces and less tooling wear. He points to several projects his company, along with extrusion equipment maker American Maplan (McPherson, KS), have worked on to replace dry calibration tables with modified spray tanks to do the same job as dry tables, but with less than half the horsepower and lower tooling costs.
Torsten Sahrhage, sales manager-profile extrusion at Battenfeld Extrusionstechnik (BEX, Bad Oeynhausen, Germany), says his company has provided window profile extrusion lines where the cooling baths with their calibrating discs were extended, but the number of dry calibrators could be reduced from seven to between one and four. This leads to a reduction of pulling force needed to below 30 kN for a haul-off speed up to 7.5 m/min, above the usual 6.5 m/min at which most BEX profile processors run their equipment.
Bessemer says there is a trend for both belt pullers, generally designed for small-to-medium-sized flexible or semi-rigid technical profiles, and cleat pullers for pulling forces up to 20,000 lb, to be equipped with independent drives, either vector or servomotors, on the upper and lower booms.
Especially with servo drives, the use of servo-rated gear reducers to accommodate higher input rpm and produce lower backlash (a problem of end-product quality) are considerations profile processors look at very closely, he says.
Yet Walter Roidinger, senior product manager, Greiner Extrusionstechnik (NuÃbach, Austria), says the kind of motor is not as important as the equal allocation of the force between the upper and lower caterpillar. His lines are designed to check the drive systems at a test haul-off to enable a simulation of different haul-off forces in all speed variations. The upper and lower caterpillar are mounted freely and are equipped with load cells to measure the real haul-off force.
Alan Benlolo, marketing coordinator at CDS, a supplier to extruder builders such as Deltaplast Machinery (Concord, ON), Davis-Standard (Pawcatuck, CT), and Milacron (Batavia, OH), says many processors opt for cleat pullers for any size application if their applications end quality cannot tolerate slippage of any kind. Cleats tend to be made of natural rubber (40-90 durometer), but his company is offering as an option caterpillars made of ethylene-propylene diene monomer (EPDM) that vary in height (1-4.5 in/2.54-11.5 cm) and durometer ratings.
Bondabelt (Warminster, PA) a supplier of haul-off blocks, says processors are sometimes faced with a working surface on rubber cleats that becomes shiny and dried out, therefore reducing the coefficient of friction needed to grip the profile. Bondabelts solution is a specialty cleat manufactured from a wear-resistant polyurethane that doesnt crush the profile but provides adequate grip.
Quick-change cleats represent a significant value to processors who execute multiple product changeovers, says CDS Benlolo. They facilitate a decrease in downtime while making puller maintenance (greasing the underlying chain, fixing the locking pins, or replacing a damaged cleat) easier.
BEXs Sahrhage says that as processors have tried to cut production costs, coextrusion of single-strand profiles to use more of their post-production scrap has become standard. Yet Benlolo says some processors fear coextrusion could result in distortion as the profile is being pulled by the downstream unit. If the puller runs too fast, the profile could be stretched and if it is too slow, the profile will be compressed. In such cases CDS suggests that each conveyor of the cleat puller be directly driven with its own gearbox and motor, thereby eliminating the use of wear-sensitive chains and sprockets found in some standard models.
Two other developments CDS offers are self-centering conveyors for the simultaneous movement of the top and bottom conveyor to eliminate profile shearing, as well as a pneumatically driven conveyor (generally for the top conveyor of a belt puller), which adjusts automatically like a reactive spring to the height variations in the post-extruded product. BEX has developed special haul-offs with a belt on the top and pads on the bottom or belt on the top and rollers on the bottom for especially sensitive profiles, Sahrhage says.
Equipment manufacturer G.F. Goodmann & Sons (Ivyland, PA) has developed the Synchro-Pull caterpillar puller with double-sided timing belt drive or drive shaft with bevel gearbox that it says helps reduce maintenance costs and minimizes drive-train backlash, as well as facilitates rapid acceleration and deceleration at consistent running speeds. These can be retrofitted on most existing units.