Laser welding heats up
Laser welding is gaining interest, partly for its ability to join dissimilar materials but also for its good cosmetic qualities and ability to tightly control welding energy. Only the weld area is subjected to heating. The usual approach is to pass laser radiation through one plastic component that is transparent to that energy. An absorbent filler in the second plastic component absorbs energy at the interface, heating and melting the two mating surfaces. Controlled clamping helps to join the interfaces.
NPE saw the debut of a new infrared laser welding technique from Branson Ultrasonics Corp., Danbury, Conn. Called IRAM (Infrared Assembly Method), it illuminates the entire weld surface at once, rather than just a small spot of the welding area at a time. Typical cycle time is 3-5 sec.
Leister Process Technologies of Sarnen, Switzerland, introduced its new Modulas laser welders to the U.S. Its Modulas S version also illuminates the entire weld area at one time. The Modulas C version welds different areas in sequence, making possible three-dimensional welds. Modulas M accomplishes “micro” spot welds down to 100 micron size by focusing the laser through a mask.
Bielomatik Inc., Plymouth, Mich., announced three advances in laser-welding technology. One is a laser-transparent pigmentation system that for the first time permits black-on-black welding. Initial applications are in automotive parts. A. Schulman, Inc., Akron, Ohio, is Bielomatik’s partner in this technology and will custom compound black materials for laser-welding applications.
A second innovation is a mirror-controlled welding technique that allows the laser to slow down, speed up, and even retrace certain portions of the welding path. Thus, the laser could move more slowly where it must pass through thicker material or where a stronger weld is needed. A shutter device also allows the laser to stop and jump to a new position before continuing the weld. Welding paths thus do not have to be continuous.
The third new development is the ability to import a 3-D CAD model of a part. After the user designates the welding path, the laser is ready to weld without further “teaching.”
News in ultrasonics
Stapla Ultrasonics, Wilmington, Mass., a supplier of metal-welding systems, introduced its first ultrasonic device for plastics. Model K1 is a 20-kHz, 3000-W welder designed for general-purpose precision welding. It has a proprietary servo/pneumatic stroke mechanism that’s said to combine the speed of pneumatic head movement with the accurate positioning of a servo motor.
Other features include simple turn-and-push knob controls and a self-diagnostic feature, whereby the unit inspects calibration, frequency, incoming energy, air pressure, and stroke at start-up. A 35-kHz, 3500-W model is in the works.
Luehr Inc., West Bloomfield, Mich., developed a combined edge-folding and ultrasonic welding machine that is said to be suited to hard-to-weld PVC and PP materials. The system has been used in auto interior applications.
Other difficult welding applications, such as mating low-viscosity resins like nylon or acetal, reportedly can be performed with the new MC10 ultrasonic welder from Branson. Closed-loop control and a servo-driven actuator regulates melt flow, which leads to stronger welds, less flash, and less particulate, the company says.
Control and adjustment of welding force is offered on the new 2000f/aef ultrasonic system, also from Branson, which allows users to optimize welding results for applications requiring a high level of weld quality and control. The 2000 series is offered with 20 kHz and power supplies of 1100, 2200, and 3300 W; 30 kHz with 1500 W; and 40 kHz with 400 or 800 W.
Branson will also present its new Series 40 rotary ultrasonic system, a self-contained, semi-automatic system with an indexing turntable. It is designed for welding, staking, inserting, or swaging and incorporates a 900 or a 2000 Series ultrasonic welder, indexer, controls, and loading station.
The newest Ultra Series ultrasonic welder from Dukane Ultrasonics, St. Charles, Ill., provides low frequency (15 kHz) and high power (4000-W) for joining larger parts or softer materials—applications where other processes such as vibration welding have been preferred over ultrasonic joining.
Dukane has also expanded its Millennium Dynamic Process Controller (DPC) line to include four levels of control. The simplest Level I controller provides standard features like linear-ramp soft start and Dukane’s Auto-Trac tuning. At the high-end is the Level IV controller, a 32-bit RISC unit featuring more memory, faster processing, and networking capability for centralized set-up and monitoring through a single user interface.
Model PEM2010 is a new electric-driven ultrasonic welding press designed for high-precision welding of fiber-optic, medical, or electronic devices. It comes from Ultra Sonic Seal Co., Aston, Pa. The 20-kHz, 1000-W unit uses a stepper motor to control the stroke movement of the welding head. Microprocessor control reportedly keeps stroke movement accurate to 0.3 in. A 40-kHz, 700-W model is on the drawing board.
Meanwhile, Sonitek Corp., Milford, Conn., introduced two new ultrasonic welders with integrated power supplies. They are designed for easy set-up and operation, space savings, and economy. The new S840 and S870, offered in 900-W and 1500-W versions, come with a fully adjustable converter, booster, horn assembly, and controls. Prices start at $7995 for a 900-W S840. These welders can be purchased on the Web at www.sonitek.com.
Sonics & Materials Inc., Danbury, Conn., presented a new sound enclosure for its 15-kHz ultrasonic system, along with upgraded ultrasonic hand welders (20 and 40 kHz) with new autotuning controls, line-voltage regulation, programmable timers, and amplitude control.
Sonobond Ultrasonics, West Chester, Pa., introduced a low-cost integrated ultrasonic welder, offered in 1000 and 1500 W.
Ultra Sonic Seal introduced an electric-driven ultrasonic welding press, but no details were available at press time.
Vibration units advance
A new mid-range model in the high-powered M-Series linear vibration welder line was introduced by Branson. Called the M624H, it has two-phase digital drive technology that provides higher welding power and frequency.
Dukane also presented a new high-capacity vibration welder suited to large or irregularly shaped parts. Tooling up to 45 x 22 in. can handle large parts or multiple small parts at one time. A menu-driven touchscreen user interface eases set-up.
Sonics & Materials upgraded two of its vibration welders. A new Windows-based touchpad control has been added to the Sonics Vibration Welder for easier use. The firm also updated the precision and repeatability of its Sonics ElectroPress. The unit, made to weld tight-tolerance parts, is available in 20 and 40 kHz.
Other welding & staking
Dual servo drives control the spin and actuator downstroke of the new Model SWServo2 spin welder from Branson. The servomotors provide the accuracy to weld circular parts and parts with wires or other attachments that cannot rotate freely. A free-standing operator interface lets you adjust rpm, revolutions per cycle, and hold time. The controller monitors these functions and also motor torque for QC reporting.
Another new spin welder at the show was a small model from Ultra Sonic Seal.
An upgraded spin welder was also presented by Sonics & Materials.
Sonitek introduced a new high-tonnage heat-staking system at the show. The new TS series HT model has a heavy-duty “H” frame with gross head-height adjustment and force capacity up to 5026 lb. The company also showed its new Thermasoft-TCS software for heat-staking equipment. It enables the user to remotely monitor and control process parameters and status.
MS Plastic Welders, Inc., Farmington Hills, Mich. Brought out a new hot-air/cold-staking machine for assembling dissimilar materials.
Branson added servo-driven holding fixtures to its new HV-15S hot-plate welder for greater control than is provided by mechanical stops. The unit is suitable for assembling parts up to 12 x 15 in. Automatic part pick-up, multi-zone temperature control, and quick-change tooling help increase productivity.
Wegener North America Inc., Burr Ridge, Ill., showed its new Exweld Alpha hand-held extrusion welder for PVC, PE, PP, and PVDF.
Leister presented its new Weldmax hand-held extrusion welder with thermoplastic rod feed and hot-air blower.
Adhesives get a grip
A new line of adhesives that cure under uv or visible light is new from Dymax Corp., Torrington, Conn. They can be used in high-speed bonding, sealing, and laminating. The products have USP Class VI and ISO 10993 biocompatibility certification.
Adhesive Systems Technology (AST) Corp., Minneapolis, rolled out its new two-component adhesive/ sealant dispenser. The Dynamic Mixing system (DMS) is designed for urethane and silicone foams.
Gaska Tape Inc., Elkhart, Ind., introduced its Polymeric Series foam adhesive tapes (single- and double-faced) for gasketing.
Tesa 4987 is a new reinforced transfer tape from Tesa Tape, Inc., Charlotte, N.C., for laminating and bonding. It’s said to provide higher strength and less oozing.
New mechanical fasteners
Dodge Products Group of Emhart Industrial, Shelton, Conn., has developed an Automated Installation System for setting threaded inserts into plastics. The system eliminates the need for vibratory feeder bowls or hand feeding.
3M Co., St. Paul, Minn., unveiled its new Dual Lock low-profile, reclosable fastener. It has a multitude of “mushroom” heads that interlock with one another, creating a mechanical bond that’s said to be stronger than hook-and-loop fasteners.