Handling and Manipulation of Microcomponents: Work-Cell Design and Preliminary Experiments

Abstract

Abstract. The paper introduces an experimental setup for the automatic manipulation of microcomponents, based on a 4 dof robot with Shoenflies motion and a two-camera vision system. The general architecture of the workcell is presented. The work-cell functionality was tested via repeatability experiments using a set of vacuum grippers. Due to their intrinsic simplicity, vacuum grippers are very cheap and appear a promising solution for micromanipulation. An innovative nozzle for a vacuum gripper was designed, fabricated and tested, comparing its performance with traditional needles. The design was conceived to reduce the frequency of occlusions of the gripper and handle a wide range of particles. The performed tests evaluate the success and precision of the part release. Indeed, this is a crucial aspect of micromanipulation because microparts tend to stick to the gripper preventing the successful performance of manipulation tasks. The results confirm that adhesive effects prevent the release of components. For this reason different strategies were adopted in order to improve the efficiency in the release of stuck components. This solution increases the percentage of release and, setting appropriately the intensity of the pressure, it does not affect negatively the accuracy nor the repeatability of the positioning.

Precision Handling of Electronic Components for PCB Rework

“…With the same approach adopted in [6], the performance indices we calculated for each test cycle were the repeatability and accuracy, according to the definition given by the international standard ISO 9283. Moreover, the gripping and release percentages, representing the success of the correspondent operations, were calculated.…”

“…However, in [6], it has been shown that the release is greatly affected by the presence of the adhesion forces and that the simple switch off of the vacuum is often not sufficient. Therefore, suitable expedients need to be found.…”

“…Moreover, the microcomponent could be guided to hit a sharp edge or rolled on the release plane. The inertial force of the component, generated by moving the gripper brusquely upwards for a short stroke, can also be exploit to ease the release, although results can be inaccurate [6]. Finally, the application of positive pressure, that is of a soft blow for some milliseconds, allows the achievement of a high release percentage and does not affect negatively the final precision of positioning.…”

A review of micro-devices assembly techniques and technology

“…In [46], Ruggeri discussed the results of micromanipulation experiments using two standard vacuum micro-grippers and an innovative multi-lumen nozzle microgripper. Based on simple pick-and-place operations involving spheres with varying diameters, it was noted that the nozzle had more flexibility while the needle's performance was more efficient.…”

A Laser Calibration Device for Mini Robots

“…The research, conducted in the framework of the project PRIN2009 MM&A, funded by MIUR, has been carried out exploiting the instrumentation available in a workcell designed for the manipulation and assembly of micro-scale sized components [12,13].…”