Precision Bending of a fibre optic array so as to not induce any stress cracks,

 

The fibre optic array needed to be formed to different off-sets according to their final position in the devices whilst keeping the input and output accurately aligned. The bending had to be permanent to prevent spring back and allow accurate post bend positioning but must not damage the fibre by causing stress cracks, fat spots or any defect that would allow light to spill out or the transmission to be compromised.

 

GBI developed a unique programmable bending system using heated bars over which the parts were formed by carefully controlled servo motions. As the product was formed into a shallow Z the ends were kept parallel whilst the spacing of the clamps was adjusted to compensate for the material being wrapped around the heating elements. The complex motion required for each being computed and controlled by the high performance closed loop servo systems

 

The system had to accept identical moulded parts loaded by robot and present the bent parts in a way that the robot could remove and place them into the next operation or buffer them in cooling racks. The slightest defect would cause reduced transmission properties that would make the final and by this stage expensive assembled array a reject.

 

Precision Heat control.

The fibre optic array had to be bent along a line uniformly over a 300mm width of 200 fibres. To achieve this critical control of the heating had to be maintained. GBI developed a special small section heater bar to fit within the tight space constraints. By careful analysis the optimal radial form for the contact part of the bar was determined and the critical heating distribution achieved with the aid of heat pipes and closed loop control of the heating system.