September 28, 2022

Manufacturing with Zero Tolerance – Metrology and Quality News

Since its launch, ALIO Industries’ Hybrid Hexapod has revolutionized the approach to 6D motion and redefined the role of motion control in applications that require flatness and straightness of motion plus rigidity, such as for applications in machining and bonding.

Bill Hennessey, President of ALIO Industries said: “In the world of 6-degree-of-freedom (6DOF) nanotechnology applications, Hybrid Hexapod technology helps provide documented proof of performance across all 6DOFs of a moving body at the nanometer level of precision. As such it is unique, and this is the first time this has been possible. We are now seeing blue-chip OEMs working on nanoscale applications in optics, semiconductors, manufacturing, metrology, laser processing, and micromachining, achieving successes that were previously unattainable.

All hexapod motion systems operate in three-dimensional space and exhibit errors in all six degrees of freedom. However, hexapod motion systems have generally only been characterized by performance data of a single degree of freedom. This practice leaves sources of error unaccounted for in several degrees of freedom, especially in the areas of flatness and straightness, which are critical precision needs at the nanometer level. Thus, to say that a legacy hexapod will exhibit a loss of accuracy on the order of tens of microns per axis when measuring flatness and straightness of travel. The Hexapod hybrid® completely overcomes these problems.

Hennessey continues, “Because hexapods have six independently controlled links joined together to move a common platform, the error in motion of the platform will be a function of the errors of ALL links and joints. Hexapods are known to have precision and best repeatability when performing Z-axis movements because all links perform the same movement at the same relative link angle, however when another X, Y, pitch, yaw or roll movement is controlled, the accuracy and geometric trajectory performance of the hexapod degrades significantly because all the joints perform different movements.In the case of legacy hexapods built with non-precision joints and motion controllers that are not capable of direct and inverse kinematic equations, the source of error is even more pronounced.

The hybrid hexapod was developed by ALIO to address the critical weaknesses of conventional legacy hexapod designs, as well as the weaknesses of stacked series stages, and to achieve high integrity accuracy, repeatability, and flatness and straightness. during the movement. It uses a tripod parallel kinematic structure to provide Z-plane and tilt/tilt motion, integrated with a monolithic series kinematic structure for XY motion. A rotating stage built into the top of the tripod (or below depending on application needs) allows for 360 degree continuous rotation. In this hybrid design, individual axes can be customized to provide travel ranges from millimeters to over a meter, while maintaining nanoscale levels of precision.

Hennessey concludes, “Let’s look at the 4K lens manufacturer. Typical 4K lenses require very high-tech material technologies, precision assembly practices, and very sophisticated manufacturing processes and techniques. The tolerances are practically zero in all directions. The manufacturing processes used to create the lenses can often lead to inaccuracies, which is why they require constant active alignment. The sensor and the lens are aligned while several targets are projected along the lens, towards the sensor, and then the image is taken. The modulation transfer function (MTF) is always continuously monitored by the active aligner to keep each MTF value within predetermined limits. When the limits are met, an adhesive is partially cured using ultraviolet light and then full thermal curing will be done later. This ensures pinpoint accuracy when aligning the lens and sensor planes. The Hybrid Hexapod proves perfect for this application, as its absolute repeatability and accuracy produce accurate results time and time again.

“Engineers working at the cutting edge of what’s possible must be challenged to demand more because they see that this technology does things others can’t, has the potential to drive innovation, and can maximize efficiency. and manufacturing cost-effectiveness.The Hybrid Hexapod is orders of magnitude more accurate than traditional hexapods, being 100 times stiffer, 30 times faster, and with 10 times the usable work envelope of industry standard options .

For more information: