suring stations, crack detection equipment, embossing and plating units and, of course, a monitoring system that covers all components in the production system. In the end, what we supply is a production system that is designed to guarantee the greatest possible degree of process integrity,” said Schif- fler. EMAG also supports its equipment globally with service specialists so that both user and maintenance staffs are fully trained. “A 24/7/365-day telephone service is available, ensuring that machine downtimes are reduced to an absolute minimum,” said Schiffler. ME
For more information from EMAG, go to www.emag.com, or phone 248-447-7440.
Tooling for Aerospace Composites Holemaking
ith the dramatic increase in the use of composites in the form of carbon fiber reinforced polymers (CFRP) in the aerospace industry as well as for automotive and defense industry applications, holemaking is challenging cutting tool development and process technology. According to Sandvik Coromant (Fair Lawn, NJ), drilling the CFRP material involves different material-specific issues like delamina- tion, splintering and dust of the CFRP, and machinability issues like chip formation and evacuation that alumi- num and titanium present in CFRP/ metal stacked components. The follow- ing discussion is an edited version of a report by Sandvik Coromant on the CFRP drilling process and cutting tools required for quality holemaking. Production planning begins with the usual assessment of drilling require- ments, including the number of holes, the hole size, depth and quality, the manufacturing equipment or machine type available, stability of the setup, and the mix of CFRP and stacked metal properties. Machines are normally au- tomated, power-fed or hand-held in the form of CNC machine, robot, portable
power-feed machine or an operator’s hand tool. Machine tech- nology available and the demands of the operation and experi- ence of the operator can vary to the extent that these have to be compensated for by tool selection.
The amount of machining needed on CFRP and CFRP/ metal stacked components is typically less than that required for conventional metal components, but due to the material properties, holemaking can be more demanding to machine to critical specifications. CFRP machining involves fracturing the fiber part of the material. CFRP is a poor heat conductor and with no chips being formed, the heat generated during machining composites is a risk to the resin part of composites at elevated temperatures.
CFRP materials are abrasive when machined because of the fiber hardness. When bonded in the weaker resins, there are tendencies for fibers to be pulled out, for elastic mismatch to occur, and also for interlayer fracture to take place. This makes hole entry, exit, and walls of holes prone to damage