leton, SC), a developer of microstructures for commercially available extruded products. Hoowaki focuses on transform- ing surface structures of parts via engineered microstructures. “For example, we are enabling nylon and HDPE [high-density polyethylene] products to outperform PTFE [polytetrafluo- roethylene],” Cannon noted. “Another trend is enhancing the performance of the current product via surface microstructure engineering. Sometimes we can enhance the performance while reducing manufacturing cost.” Hoowaki has developed proprietary processes to impart
engineered microstructures onto the surfaces of curved and flat tools, Cannon said. “Our application development and modeling efforts have produced a database of hundreds of micro designs validated and tested for specific product perfor- mance. We utilize existing designs where we can and adapt the designs as needed.” With its technology, Hoowaki has created 400-nm structures
over a 30-cm-long half cylinder mold insert, he added. “Tis is very different than high tolerances and oſten means creating the right microstructures to get the desired performance regardless of microstructure geometry consistency,” Cannon said. “Some of the major process difficulties in micro manufacturing are main- taining micro-size structures over macro areas at a reasonable cost. Hoowaki provides tools to its customers so that they can
product line manager, Vertical Machines. Te iQ300 Precision Micromachining Center offers the latest in Makino’s machine and spindle design. Te VMC features a 45,000-rpm HSK-E32 spindle equipped with the company’s patented core cooling, under-race and jacket spindle temperature control system, which virtually eliminates thermal growth, deflection or vibra- tion during high-speed machining. Te iQ300’s design also includes a cast-iron Meeha-
nite construction base for rigidity, linear motors instead of ballscrew design, precision roller ways and a 10-nm, 0.005-µm scale feedback, Howard said. “Te reason for the linear motors is that you can remove all of the lost motion and backlash for much smoother motion,” Howard said. “All of those elements are working together to allow us to get down to positioning accuracy of ±1 micron, and repeatability of a half a micron.” Along with advanced temperature control, the machine’s
rigidity helps maintain precision for micro-machining appli- cations, he added. “Everything we build is a cast-iron Meeha- nite type casting. Part of the reason for the massiveness of the casting is that it serves as a heat sink providing a thermal con- stant, if you will. It takes a long time for that mass to change temperature. Now, realistically, anybody who’s considering an iQ 300 machine is already looking at putting that into a controlled environment.”
“The constant and sometimes relentless drive to miniaturization is pushing conventional micro-machining processes forward.”
leverage low-cost, high-volume molding and extrusion processes in creating the products with enhanced surface properties.” Te medical industry, for example, is leveraging Hoowaki’s
microstructured extrusion technology to reduce sliding fric- tion in catheters. “Te medical industry is also reducing the stickiness of low-durometer materials with Hoowaki technol- ogy,” Cannon said, “and the wire and cable industry is using our technology to make wire installation easier. “We have a customer who is reducing the friction of their
current catheter by 80% by using a die and mandrel that Hoowaki micro machined. Tey sent us their extrusion die and mandrel, we micro machined the die and mandrel with a design that creates low friction surfaces on extruded products, and they extruded their catheters with the micro-machined die and mandrel,” Cannon added. “We delivered 100% of what our customer needed to extrude their next-generation catheter.”
Conventional Micro Machining More conventional micro machining systems like the iQ300 VMC from Makino Inc. (Mason, OH) are target- ing precision micro machining, noted Bill Howard, Makino
44 Medical Manufacturing 2013 Te system also features temperature control through an
Oilmatic unit that regulates the temperature of the spindle and the machine’s linear motors, Howard added, to maintain the system’s high precision machining. Temperature is controlled to about ±1.8ºF [±-17ºC] with the Oilmatic, a commercially avail- able chiller. “We actually put a thermocouple in the bed of the machine so that we can monitor the temperature of the bed, and then we have this Oilmatic unit cycle on and off to maintain the lubrication that we send through the spindle and to maintain the temperature of the spindle and the linear motors so that everything is the same temperature—the castings, the chilling of the linear motors, and the temperature of the spindle. In es- sence, we’re creating an ambient manufacturing zone among all the major machine tool elements. “Tis is such a new area of technology, people are ap-
proaching it from two different ways,” Howard said. “We’re approaching it from the traditional machine tool builder in that we’re removing metal to get to a tolerance. Other people are adding chemical deposition layers and literally building a part from nothing to get to those tolerances. Tey’re literally building the tolerance by an atom or a layer at a time.”