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40 The PCB Magazine • September 2014 and economical and uses the same technology as the mass production to follow. Circuitry on Metal Parts With two versions of an LDS-capable powder coating, three-dimensional metal parts can be turned into circuit carriers. New product layout possibilities enable any spatial arrangement of LEDs and offer good thermal properties, open- ing up opportunities for fields such as produc- tion of LED lights with the LDS powder coating. With LPKF LDS PowderCoating, a metal base substrate, not an LDS plastic, is coated. Powder coating is ideal for metal surfaces such as steel or aluminum, but also works on electri- cally conductive plastics. The powder is applied in an electrostatic process, which guarantees a homogeneous coating of precisely controllable thickness. The metal substrates assume mechanical functions, aid in heat dissipation, and serve as contacts for the electronic parts applied to them. The coated metal parts can be laser-struc- tured and metallized in the same way that plas- tic parts are. Powder Coatings: Two Versions Two versions of LPFK LDS PowderCoat- ing—PES 200 and PU 100—are available. The satin PES surface has been optimized for high mechanical stability, whereas the glossy PU 100 features more robust chemical and thermal properties. At the minimum coating thickness- es of approximately 80 µm and 60 µm, the two powders offer good dielectric strengths when tested using AC voltages greater than 4 kV. To ensure mechanical stability and adhesion there should be a minimum corner radius of 2 mm when PU 100 is used. The adhesion strength of the electronic components on the traces is 90– 120 N, similar to the values found in FR-4 and other conventional circuit boards. PU 100 is approved for soldering for a dura- tion of five seconds at 270°C, whereas PES 200 is limited to 240°C for the same period. Accord- ing to the results of preliminary tests, PU 100 is suitable for V-0 (UL-94) certification. Applica- tions for certification have been submitted for both materials. Both powder coatings are available in 2 kg (test sample) and 20 kg (series production) con- tainers. LDS PowderCoating is neither a danger- ous good nor a hazardous material and can be processed like a conventional powder coating product. PCB References 1. Design rules are available for free down- load at www.lpkf.com. malte borges is the press officer of product communication at lpKf. 3D LDS COMPONENTS continues a team of researchers at louisiana tech university has developed an innovative method for using afford- able, consumer-grade 3d printers and materials to fabricate custom medical implants that can contain antibacterial and chemotherapeutic compounds for targeted drug delivery. the team from louisiana tech's biomedical engi- neering and nanosystems engineering programs col- laborated to create filament extruders that can make medical-quality 3d printing filaments. Creating these filaments is a new concept that can result in smart drug delivering medical implants or catheters. "after identifying the usefulness of the 3d print- ers, we realized there was an opportunity for rapid prototyping using this fabrication method," said Jef- fery weisman, a doctoral student in louisiana tech's biomedical engineering program. "through the addi- tion of nanoparticles and/or other additives, this tech- nology becomes much more viable using a common 3d printing material that is already biocompatible. the material can be loaded with antibiotics or other medicinal compounds, and the implant can be natu- rally broken down by the body over time." 3D Printers Create Custom Medical Implants