News in FRP equipment.

Innovations in machines, molds, controls and auxiliaries for SMC and GMT compression molding, RTM, spray-up and filament winding were presented at the recent SPI Composites Institute annual show and conference in Cincinnati. Last month (p. 35), we rounded up news in materials, reinforcements and additives. Below, we examine the more significant new hardware developments.

WHAT'S NEW FOR SMC & GMT

A group of suppliers represented in FRP markets by RP/C Corp., Brighton, Mich., exhibited together in Cincinnati and several presented new developments. One newcomer to the SPI show was [EMC.sup.2] of Sterling Heights, Mich. This company specializes in automated dispensing of reactive fluid systems, including adhesive bonding and high-speed RTM systems (see PT, March '93, p. 11) . In addition, [EMC.sup.2] is building for an RP/C customer an SMC sheet impregnating line that distributes the resin paste with an extruder and slot die rather than with doctor blades. RP/C has sold two such systems in the past, which are said to be more expensive than conventional ones, but provide greater sheet-weight uniformity. (CIRCLE 10)

Another new face was Orchid Automation Group Inc., Cambridge, Ont. (U.S. office in Brentwood, Tenn.). Orchid specializes in systems for quick mold changing and automated die storage and retrieval. It has worked mainly in metal forming, where one customer, for example, changes dies 15-20 times a day on a single press. Orchid is now seeking applications in FRP compression molding and injection molding. It offers half a dozen styles of quick mold-clamping mechanisms, as well as transfer mechanisms ranging from mobile die carts to rotary and slide tables. It offers preheat stations and a die opener that opens, tilts and lowers the mold halves for cleaning and inspection. Mold-change times can be 15-30 min. (CIRCLE 11)

Also new to FRP molding is Perceptron, Inc., Farmington Hills, Mich. It supplies noncontacting laser inspection devices that can check part dimensions much faster than a coordinate measuring machine (CMM) . Using one or more fixed or scanning lasers connected to a computer, the systems can acquire and process an image, report dimensional deviation, and make a pass/fail quality decision in half a second. This permits 100% inspection of molded parts. Perceptron systems use the same sort of data as are used to program a CMM, are CAD-compatible, and can even be used for "reverse engineering" (acquiring dimensions from a part or mold and feeding them to a CAD system in order to create a computer model. They also generate SPC reports. A typical P-2000 system that might be used by an SMC molder would include two to four laser sensors and computer system and starts at around $35,000. (CIRCLE 12)

For compression molding or "stamping" glassmat/thermoplastic (GMT) sheet, RP/C represents Blasdel Enterprises, Inc., Greensburg, Ind., which makes conveyorized infrared preheating ovens. A new version reduces overall length by as much as 10 ft or 30%. (CIRCLE 13)

Press maker John T. Hepburn, Ltd., Mississauga, Ont., has come up with a new solution for molding GMT. For maximum economy and productivity, molders are looking to mount multiple molds on a press, said v.p. of engineering Ron Ballantyne in a paper at the conference. Use of more than two molds simultaneously has been limited by the thickness variation of the GMT sheet, which is commonly +5-7%. Variations in charge thickness limit a standard press's ability to apply uniform pressure to all molds, causing variations in part density and surface finish.

Hepburn has applied for a patent on its Paradyne Multimold system, which divides the press bed into four quadrants. Each quadrant's bolster is independently mounted on four "pancake" pushback cylinders, each one of which has a force equal to one-sixteenth the press tonnage. All the cylinders are automatically pressure-balanced by being connected to a common accumulator. When at rest, the four bolsters are forced upwards against restraining bolts that limit upward travel. When the press closes, any excess loading on a quadrant causes it to sink relative to the others, so that each quadrant seeks a level that provides equal pressure on all four molds. (CIRCLE 14)

A complementary solution to this problem is provided by a special mold design from Hi-Tech Mold & Engineering, Inc., Rochester Hills, Mich. (also represented by RP/C) . This mold design incorporates melt reservoirs into which excess material can bleed off. This is said to accomplish what the Hepburn system alone can't: ensuring equal part thickness in addition to density and finish. (CIRCLE 15)

J. Dieffenbacher GmbH & Co. of Germany (represented by Girard Associates, Inc., Middleburg Heights, Ohio) has added some sophisticated new capabilities to its hydraulic press control software. These capabilities are already in use on about a dozen GMT forming lines at a couple of German auto-parts manufacturers. One new feature is good/bad cycle discrimination based on monitoring such parameters as ram velocity, pressures at different stages of the cycle, pressure build-up time, position of the leveling cylinders, mold temperature, and sheet surface temperature when it leaves the oven. The same data are used for SPC reporting. Also relatively new is "intelligent fault compensation," which diagnoses the source of a problem and suggests a solution. (CIRCLE 16)

HIGH-TECH RTM PREFORMING

After six years in development, Owens-Corning Fiberglas Corp., Toledo, Ohio, says its Programmable Powdered Preform Process, or "P4," is rapidly approaching full commercialization in the U.S. and Europe. This directed-fiber process, in which a jointed-arm robot sprays chopped fibers and powdered binder resin onto a shaped metal screen, was developed at Owens-Corning's lab in Battice, Belgium (see PT, March '92, p. 42). It reportedly can produce a glass-fiber preform to net shape, with only 25% waste, in 40-60 sec. Owens-Corning is considering licensing the technology, and two automotive companies in France and Germany reportedly have ordered equipment. Owens-Corning says it is working with about a dozen automotive and other manufacturers in Europe and with Detroit's Big Three under the auspices of the Automotive Composites Consortium, based in Troy, Mich.

Besides automotive, Owens-Corning foresees applications in RTM or SRIM bathtubs, furniture, marine, aerospace, and appliance parts. Because the cost of a robot and conveyor would be in the range of $500,000, P4 would be suitable for part runs from 10,000 to 200,000/yr. Although Owens-Corning is still developing some aspects of the process--a higher-capacity glass chopper and robot programming software, for example--the company expects P4 to see commercial use in Europe in 1994 and in the U.S. in 1995. Actually, one commercial part, a propane tank, is already being manufactured in Scandinavia by a firm that independently developed the process based on an early Owens-Corning prototype. (CIRCLE 17)

OTHER RTM NEWS

A simple, "entry-level" RTM system was introduced by Hi-Tech Engineering, Inc., Grand Rapids, Mich. The Silencer 20 is air-driven, with a nominal output rate of 20 lb/min (or up to 30 gal/min with modifications). Material is delivered from two 7.5-gal pressurized tanks to two gear pumps. A mechanical drive train links the two pumps to maintain ratio, which is infinitely variable from 1:1 to 3:1 (or up to 10:1 by using two different-sized gear pumps) . The gun uses disposable static mixers. The system includes heated tanks and hoses and an air- and solvent-purge system. The cart-mounted system starts at $6985. (CIRCLE 18)

Venus-Gusmer of Kent, Wash., showed two new developments for RTM. One is a remotely controlled valve that attaches to the mold in place of a gun. Designed for high-production operations, it can be turned on and off by remote control. Air/solvent purge is also actuated remotely. Also new is the Pro Series Hydrajector system for RTM, based on a new, larger 8:1 Pro Series pneumatic resin pump designed to deliver 2-8 lb/min (twice as much as the Pro Series gel-coat pump) . It's said to provide smooth, pulsation-free delivery at lower pressure than Venus-Gusmer's older 11:1 H.I.S. pump. (CIRCLE 19)

Nemeth Engineering of Crestwood, Ky., another of the companies represented by RP/C Corp., is working with the Automotive Composites Consortium to develop radio-frequency curing for RTM (PT, May '92, p. 63) . The approach uses residual moisture in the resin to generate heat for curing within 30 sec after filling. At present, the mold must be placed in a special chamber with two RF electrode plates. (CIRCLE 20)

As reported previously, John T. Hepburn Ltd. has developed large-bed, low-tonnage presses specifically for RTM (PT, May '92, p. 63). The latest word is that these presses have double booking platens to facilitate mold cleaning and release application. (CIRCLE 21)

The new firm of Merva-Systems Corp., Bridgeport, Conn., showed off its first U.S. built low-pressure presses for RTM and urethane foam molding. Merva-Systems is a joint venture of Stauch GmbH of Germany, which developed these presses two years ago, and Airshield Corp. of Bridgeport.

These unusual presses use no hydraulics and operate solely by vacuum. Vacuum cylinders raise the upper platen, and a gasketed vacuum seal around the platens provides clamping pressure. Presses with beds up to 19.5 x 6.5 ft have been built, with stroke of up to 50 in., generating 27.7 tons of closing force and 14.5 tons of opening force--by vacuum alone. Max. mold weight on such a press would be 9.9 tons on each platen. Because vacuum is drawn on the entire platen area, the smaller the mold area in relation to the platen, the greater the pressure-intensifying effect. Thus, these vacuum presses reportedly can generate up to 10 atmospheres, or 145 psi, of mold clamping pressure. What's more, the vacuum presses are said to be very quiet and extremely miserly in energy consumption, and they cost less than half as much as a conventional hydraulic press. Molding under vacuum helps degas the resin, and styrene monomer and other contaminants evacuated from the mold are filtered out rather than being drawn through the vacuum pump or discharged into the workplace. Features such as mold heating control and a lightbeam safety curtain are available. The company is presently building a sliding-table shuttle-press version to carry two molds for a truck hood. It will have a bed size of 12.8 x 11.5 ft and stroke of 5.25 ft. (CIRCLE 22)

NEW FOR SPRAY-UP

Venus-Gusmer has a new syntactic-foam spray system with a 22:1 pump to provide more power to spray these heavy systems. A double-acting piston transfer pump on the drum feeds the spray pump. Larger hose and wider orifices are provided along with a double slave arm for the catalyst and optional blowing agent (used in Alpha Resins, Alcel system).

Glas-Craft Inc., Indianapolis, has a new machine for spraying granite-effect gel coats. Owing to the larger filler particles, this material is inherently harder to spray, and larger equipment orifices are required, says Glas-Craft. (CIRCLE 23) Another granite-effect spray system was recently introduced by Poly-Craft Systems, div. of Binks Manufacturing Co., Burbank, Calif. (PT, April '93, p. 95).

Glas-Craft also introduced an airless resin "sprinkler" nozzle adaptable to either internal or external mixing, to be used in place of a normal spray gun. With internal mixing, it can be used for RTM or connected to a resin roller. With external mix and air assist, it can be used with a chopper or just for wetting out mat (air assist holds the lines of droplets closer together). It costs about the same as a spray gun, but reportedly offers better transfer efficiency and less overspray. A spray gun can be converted to the sprinkler system in 30 sec with a change of fluid tip. (CIRCLE 24)

HIGH-PRODUCTION FILAMENT WINDING

Engineering Technology Inc., Salt Lake City, has recently built several newly designed multi-spindle, automated high-production winding systems. Several 10-spindle golf-shaft machines were built in the last year, capable of making 700 shafts in 8 hr. They include automatic tie-on and cutoff and easy-release pneumatic-tensioned mandrel chucks. Base price is around $160,000. EnTec also has built five machines recently that wind four compressed-natural-gas bottles at once. These versatile three-axis machines can wind four parts up to 33 in. diam. x 2 meters long or one part up to 50 in. diam. and 6 meters long. Both the center stock and tail stock are movable; so a very long part could be made by backing off the tail stock and using the center stock as the tail stock. Up to six spindles can be accommodated.

At this month's SAMPE meeting in Anaheim, Calif., EnTec is introducing new software that uses a friction-coefficient model to program the machine for difficult tasks such as maintaining a constant wind angle on a tapered part. This software reportedly minimizes turnaround waste and reduces the time necessary to develop a satisfactory winding pattern from 1 day down to 5 minutes. EnTec's new software also tells the real-time thickness of a part at different locations while it's being wound, and provides a materials cost analysis--e.g., how much resin and fiber will be required to wind a part. (CIRCLE 25)