JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012 - 43

design combines strongly reinforced output bearings with pinions integral to the output shaft (case hardened and ground, and the same diameter as the shaft). The pinion pitch diameter is optimized to ensure the best ratio between the torque transmitted and rigidity as seen from the rack point of view. The bearing arrangement itself consists of two tapered roller bearings, preloaded and generously oversized. This bearing arrangement is designed to support the pinion as close as possible to the applied force, with only the thickness of the locknut separating the pinion from the output bearing. This particular design provides a considerable reduction in radial deflection, which is the cause of 60% of overall deflection but is rarely dealt with satisfactorily by other systems.

sion rate. This is important because once the part is made, the whole assembly is placed into an autoclave and baked to be sure the impregnated carbon fibre will cure into its final state. After that, the tool is removed and the remaining part is completely made of carbon fibre. The X axis is equipped with four KRP planetary reducers, size 6 (the largest size available in the Redex Andantex range), to ensure accurate rotation. They mesh with two 35-m-long racks. The Y axis is equipped with two SRP planetary reducers in a TwinDRIVE configuration, which are mounted on 5.5 m of rack. For secondary encoder feedback on the X and Y axes, Electroimpact also uses Andantex’s PDP or “split pinion” to drive the encoder directly from the rack with zero backlash. This cost-effective solution is the first generation of “preloaded double pinion” for highprecision rack and pinion applications. The PDP is made of two ground WMH pinions, each one-half the width of the rack, connected together through a patented preload system to eliminate the rack and pinion mesh backlash. The PDP innovative

concept provides encoder feedback directly from the rack, ensuring high positioning accuracy and repeatability with a very competitive budget. Finally, Andantex provided Electroimpact modules 10 and 5 helical, hardened and ground racks for the X and Y axes, along with polyurethane foam lubrication pinions to automatically relubricate the racks. The racks are provided in one- or two-metre sections and designed to be linked end to end to create the required length for the axis. This means that Andantex can provide all of the mechanical components in between the servo-motor and the axis. At the end, the placement precision is equal to the cutting precision (+/0.125 mm) at maximum speed. The axis driven by the Redex Andantex reducers must be even more precise than this value, since they are all working together to form a complex shape. The X-, Y- and Z-axis precision can be estimated to be 1/10 of the placement precision or +/- 0.0125 mm. n
More information: www.redex-andantex.com

Linear and rotary axes, racks & pinions
Andantex equipment is installed on all axes, creating a unique responsibility in the global mechanical machine behaviour. The barrel rotation axis drives the tool on which the carbon fibre is being placed. This tool is typically made of Invar, which is a type of steel with a very low thermal expan-

No71 March 2012

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http://www.redex-andantex.com http://www.elgcarbonfibre.com

JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012