JEC COMPOSITES MAGAZINE - Issue #63 - March 2011 - 102

CNC machine

Cutting and forming of honeycombs
The processing of composite materials such as honeycomb requires certain special equipment. Geiss, a company with 50 years of experience in the processing of plastics materials, has already delivered several machining centres and forming presses for composite materials.

PIERRE MOREL, CEO ANDREAS

PMA COMPANY, GEISS IN FRANCE, GSANGER, ENGINEER, CNC MACHINING CENTRE CONSTRUCTION, GEISS
OF SOLE AGENT FOR

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jec composites magazine / No63 March 2011
Geiss has used this method since 1996. The machines required for the process
Test results - Cutting and chamfering of Aramid reinforced honeycomb (Nomex)

ltrasonic cutting technology is neither new nor experimental. This process has long been used for specific applications, such as the cutting of PVC tiles. Cutting using blades vibrating at ultrasonic frequencies had already been tested in the mid-1980s at the Fraunhofer Institute for Production in Aachen, Germany. The obvious benefits of ultrasonic cutting are the absence of chips, offcuts, dust and noise.

were originally developed for cutting thin-walled thermoplastic materials. A patent was lodged in 1996 for this new method. Some of the applications for which this process has been used to date include: cutting thin-walled, thermoformed, thermoplastic parts; fullyautomated cutting of stacks of PVC tiles from a feeder or a stack of panels; cutting out ski bases, pieces of rubber, carpets, fabrics and felt; cutting out soles for sports shoes; pre-cutting for airbag compartment concealment in dashboards; etc. Since 1996, Geiss has constructed around one hundred ultrasound machines. One such example is a machine equipped with a shuttle table, two panel loaders and a second vertical axis with a milling spindle, for the chamfering of cut-out tiles.

being required. For trimming layers of material for ski bases, Geiss has designed a machine with two cutting heads and a shuttle table, providing suction by means of turbines fitted with air inlet ducts on the side, rather than a vacuum pump solution. Frequencies outside the audible limit, above approximately 20 kHz, are described as ultrasound. Frequencies in the 20-40 kHz range are used for trimming. The current technology mainly uses the piezoelectric effect and electrostriction to produce the ultrasound. The cutting force reduction during cutting using the ultrasound solution is linked to the increased cutting speed generated by the longitudinal oscillation of the blade. When cutting with a blade without oscillation, the cutting speed is equal to the feed speed (for example, 12 m/min.). For a blade vibrating at 20 kHz with an amplitude of 50 µm, the cutting speed generated by oscillation is: V= 4 * f * Xmax = 4 * 50 * 20/1000 = 4 m/s = 240 m/min The standard cutting frequency is 20 kHz.

Machines suited to various applications
For cutting out air soles for sports shoes, Geiss has designed a machine with three cutting heads and a lateral shuttle table, enabling loading to take place away from the machine while the machine is in operation. The lateral shuttle table means that the machine itself can be smaller, in the event of a two-workstation machine

JEC COMPOSITES MAGAZINE - Issue #63 - March 2011

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #63 - March 2011