Using Microgripper in Development of Automatic Adhesive Glue Transferring and Binding Microassembly System

A system using microgripper for gluing and adhesive bonding in automatic microassembly was designed, implemented, and tested. The development of system is guided by axiomatic design principle. With a compliant PU microgripper, regional-edge-statistics (RES) algorithm, and PD controller, a visual-servoing system was implemented for gripping micro object, gluing adhesive, and operating adhesive bonding. The RES algorithm estimated and tracked a gripper’s centroid to implement a visual-servoing control in the microassembly operation. The main specifications of the system are: gripping range of 60~80μm, working space of 7mm×5.74mm×15mm, system bandwidth of 15Hz. In the performance test, a copper rod with diameter 60μm was automatically gripped and transported for transferring glue and bonding. The 60μm copper rod was dipped into a glue container and moved, pressed and bonding to a copper rod of 380μm. The amount of binding glue was estimated about 5.7nl.

Optical screw-wrench for microassembly

For future micro-and nanotechnologies,the manufacturing of miniaturized,functionalized,and integrated devices is indispensable.In this paper,an assembly technique based on a bottom-up strategy that enables the manufacturing of complex microsystems using only optical methods is presented.A screw connection is transferred to the micrometer range and used to assemble screwand nut-shaped microcomponents.Micro-stereolithography is performed by means of two-photon polymerization,and microstructures are fabricated and subsequently trapped,moved,and screwed together using optical forces in a holographic optical tweezer set-up.The design and construction of interlocking microcomponents and the verification of a stable and releasable joint form the main focus of this paper.The assembly technique is also applied to a microfluidic system to enable the pumping or intermixing of fluids on a microfluidic chip.This strategy not only enables the assembly of microcomponents but also the combination of different materials and features to form complex hybrid microsystems.

Realization of an Automated Microassembly Task Involving Micro Adhesive Bonding

An automated approach is proposed for a microassembly task, which is to insert a 10 μm diameter glass tube into a 12 μm diameter hole in a silicon substrate, and bond them together with ultraviolet （UV） curable adhesive. Two three-degree-of-freedom micromanipulators axe used to move the glass tube and the dispensing needle, respectively. Visual feedback is provided by an optical microscope. The angle of the microscope axis is precisely calibrated using an autofocus strategy. Robust image segmentation method and feature extraction algorithm are developed to obtain the features of the hole, the glass tube and the dispensing needle. Visual servo control is employed to achieve accurate aligning for the tube and the hole. Automated adhesive dispensing is used to bond the glass tube and the silicon substrate together after the insertion. On-line monitoring ensures that the diameter of the adhesive spot is within a desired range. Experimental results demonstrate the effectiveness of the proposed strategy.

MODELING OF MICROMANIPULATION ROBOT IN VIRTUAL ENVIRONMENT

Micromanipulation has been recognized to be very difficult due to the inefficiency oftraditional micromanipulation methods. The paper present a general framework formicromanipulation robot based on virtual reality technology. The significance of in-troducing virtual reality into micromanipulation is analyzed, and the current researchin this field is reviewed. Based on this, we propose a micromanipulation system thatintegrates virtual environment with vision feedback and force feedback. The systemrealizes vision close-loop control and force close-loop control to enhance the perfor-mance of micromanipulation device. A graphics modelling method is proposed for amicroassembly task. Hardware and software implementation is described and discus-sion about the research is presented.

BONDING OF MINIATURE PARTS WITH ADHESIVES AND VISION BASED PROCEDURE INSPECTION

Bonding with adhesives is an important technique for building up hybridmicrosystems. Some adhesives are tested with capillary dispensing system for microassembly, andvolume of droplets less than 10 nl with good repeatability can be acquired. 1-part UV curingadhesive hardens rapidly and is suitable for bonding of transparent microparts. Light-activatedadhesive starts the curing process in an adjustable short period of time after the radiation ofvisible light, and thus suits bonding of non-transparent microparts. A method is proposed forbonding the guides of a miniature linear motor being developed by collaborate research center 516(SFB516) in Germany. With the method high assembly accuracy in the vertical direction can beguaranteed. By making small grooves on the stator for containing adhesive, the deterioration of theaccuracy due to the thickness of adhesive layer can be avoided. The criteria on deciding the size ofthe groove are given and analyzed. Vision based inspection method is introduced for automaticassembly of the guides. The dispensing volume and position of dispensed adhesive droplets can bedetected for ensuring the bonding quality.

Controllable assembling of highly-doped linked carbon bubbles on graphene microfolds

Carbon-based microassemblies(CMs) have attracted significant attention in numerous applications due to their unique hierarchical structures and delicate building blocks,especially when hollow carbon spheres(HCSs) are reasonably introduced into the construction.Herein,a new design for novel HCSscombined CMs is proposed.Remarkably,the HCSs are linear carbon bubbles linked one-by-one, arranging into necklaces decorating on the graphene microfolds.Detailed thermal analysis confirm that high temperatures straighten the linked carbon bubbles into bamboo-like carbon nanofibers,evidently due to the attenuation of doping degree.Benefiting from the abundant active sites of carbon bubbles,the obtained CMs exhibit satisfactory electrocatalytic activity for oxygen reduction reactions.This work establishes a bridge to precisely control the synthesis of carbon-based hierarchical architectures.