Fresh thinking for post-molding operations
By Cindy Macdonald, associate editor
As secondary, post-molding operations, assembly and decorating are prime targets for cutting system costs through optimization and automation. New technologies and equipment are moving processors ever...
As secondary, post-molding operations, assembly and decorating are prime targets for cutting system costs through optimization and automation. New technologies and equipment are moving processors ever closer to those cost-cutting goals, and also opening up new options for both assembly and printing.
Quick turnaround lets decorators be more adventurous
A new manufacturing process from API Foils is making patterned foil more accessible. Combination Printing Foil (CP Series) is manufactured using designs that are printed onto a gravure release coat. This process is easier and less expensive than traditional patterned foils, so customers will see shorter turnaround times (about three weeks, compared with six to 12 weeks, reports API) and reduced costs. Customers will be able to see a color proof without the expense of a draw down (actual foil sample). In addition, the minimum order can be as little as 10% of a minimum for traditional patterned foils.
“Combination foils offer the answer to the new market requirements of our customers,” says David Hornby, managing director of Foilco, a foil user based in the U.K. “Our customers want to change their designs more regularly to stay ahead of fashion trends and competitors. CP Series’ low origination costs and short lead time is the ideal solution. They don’t have to commit to a large volume when they produce a new design, so they can more adventurous without a large capital investment.”
For companies that use pad printing for small lots and experience frequent image changes, Tampoprint offers a solution that integrates digital printing press production and pad printing in one unit. The machine consists of a pneumatically-driven pad printing machine with hermetically sealed doctoring unit and a diode pumped Nd:YAG laser with control and optics for cliche production. The advantage is that there’s no need for separate cliche production so the conversion time for a change of image is reduced. To create a new image, the cliche printing roll is cycled forward and adjusted beneath the laser unit and the doctoring unit. A new cliche is lasered and then made available to the printing unit.
Fresh thinking solves challenges
In response to the needs of customers in the mobile telephone industry, Spirol’s Automation Division has developed a complete line of installation equipment for miniature threaded inserts. The equipment is designed for inserts with internal thread sizes from 1.6 mm to 2.5 mm, and from 3 mm to 6 mm in length.
These inserts are installed, post-molding, into thermoplastic products using either heat or ultrasonic techniques. Spirol’s inserters use the heat method, which allows the equipment to be configured for automatic feeding and placement of inserts. This eliminates the difficulty of manually placing such small parts, and decreases the installation cycle time. Precise heat and pressure controls assure unparalleled uniformity of torque-out and jack-out values.
For assembly of delicate parts that are not weldable with normal plunge welding, Branson Ultrasonics has developed a lateral actuator that uses shear motion. The shear motion permits the welding of components housing delicate and precision parts, such as electronics, contacts, crystals and ceramics. Branson states that shear welding is also an effective way to join molded components that have thinner wall sections or materials that have high melting points, such as PPS and LCP. In addition, this method can provide a hermetic seal. The lateral actuator is available in 20, 30 and 40 kHz frequencies.
On a larger scale, Avery Dennison’s Performance Films Division has introduced a new way to achieve a soft finish for automotive interior parts. Soft Touch decorative formable thermoplastic sheet offers the warm, tactile feel that was previously only available through a secondary wet paint finish. The company views Soft Touch film as an alternative to soft touch paint on ABS, thermoplastic olefins (TPO) and polycarbonate components, especially in automotive interiors.
The film is available as a thin sheet, less than 30 mil thickness, for thermoforming and injection molding applications. It can also be pressure formed and twin-sheeted with standard practices as well.
“We are seeing a strong movement towards this type of finishing process for TPO materials which do not perform well with paint,” reports Mike Kozbial, marketing manager for Soft Touch. “The quality and ease of processing are striking when compared with the use of paint.”
Also making an appearance in auto interiors are hook and loop fasteners, similar to the well-known Velcro brand. A truck manufacturer in Germany, Sachsenring, is using Duotec fastening strips to hold the cab interior of its Econic-Kommunal truck in place. The cab chassis is made of aluminum with plastic components lining the interior. Duotec strips from Binder, Kletten-Haftverschlusssysteme GmbH are covered in plastic mushroom-shaped nodules. When two strips are pressed together, they interlock to provide a secure hold. In addition, the strips have a high-quality adhesive coating on the backing to adhere to a variety of surfaces. In the truck cab application, the interlocking strips have shearing resistance of over 10 tonnes per square metre.
Quality always matters
For medical components, the weld-by-distance feature on some Dukane ultrasonic welders has proven to be important in maintaining part quality. Hycor Biomedical ultrasonically welds a polycarbonate cover to a polycarbonate slide, creating 10 pockets for lab specimens. Because the pocket volume is so critical (checked hourly in production), Hycor uses Dukane’s microprocessor with a linear encoder to weld by distance. This controls melt/cooling collapse and holds the assembly to tight tolerances.
Tight tolerances in decorating are achievable with United Silicone’s Accutrak heat transfer system. The machine achieves precise heat transfer alignment from part to part, without sacrificing speed. Heat transfer positioning is held to tight tolerances by an advanced photocell sensing system that detects the web registration mark right at the stamping head. Stepping motors control web movement in both X and Y directions to ensure accurate positioning on the decorating surface. The web mechanism is also adjustable in the R direction for even greater precision. In addition, the stamping head is adjustable in X, Y, and R directions to accommodate die-to-nesting fixture alignment. These features, together with floating nesting fixtures, assure maximum flexibility.
More assembly systems
Inexpensive: Ultrasonics for Less is offering the Zapper range of ultrasonic plastic welders, an inexpensive line of benchtop welders with a compact footprint and easy set-up. Both the PW-10 and PW-20 units are equipped with constant amplitude circuitry, force trigger and pre-trigger mechanisms, calibrated controls and standard accessories.
Easier to read: Sonics’ FM power supply has been redesigned to incorporate a back-lit LCD for easier visual monitoring of the weld cycle. The weld parameters can now be viewed from various angles and under many lighting conditions. The unit offers force triggering capability and welds in either time or constant energy mode.
Heavy-duty design: The Solution Series line of heavy-duty ultrasonic welding and insertion systems from Plastic Assembly Systems have 2000 W of available output power, variable amplitude control, and automatic frequency control that adjusts and tunes the horn to the converter prior to the weld cycle. Digital controls for weld time, delay time, hold time, pre-trigger and force trigger are all adjustable through the operator display. The latest addition to the Solution Series is the Model 2020S, 20 kHz ultrasonic welder.
Experienced: Stapla Ultrasonics is introducing an ultrasonic welding system that incorporates technology originally developed to support high-precision ultrasonic metal welding applications. The Stapla K1 system has the flexibility to control time, energy and both absolute and relative weld
depth. The system also includes an indexed exchange system for welding tools and self-calibrating force measurement.