This paper presents the design and testing of a novel flexure-based compliant parallel gripper with compound constant-force mechanism. One uniqueness of the microgripper lies in that it achieves two-degree-of-freedom (2-DOF) independent constant-force parallel grasping operations. In each direction, the grasping is executed along with active and passive constant-force properties. The passive constant-force property eliminates the use of force control while the active constant-force enlarges the grasping range by reducing the required driving force. Besides, the passive constant-force property can protect the grasped object from overloading. The parallel-kinematic flexure mechanism design enables nearly decoupled operations in 2-DOF manipulation. Analytical modeling of the microgripper mechanism is carried out based on pseudo-rigid-body method and elliptic integral approach, which is verified by conducting simulation study with nonlinear finite-element analysis (FEA). Parametric study is conducted to investigate the influence of dominant design variable on the microgripper performance. To demonstrate the performance of the gripper, a prototype is fabricated by 3D printer. Experimental results reveal that the devised microgripper owns a good decoupling performance and constant-force property in parallel grasping operation.

Design and Testing of a Novel 2-DOF Compound Constant-Force Parallel Gripper

https://research.chalmers.se/publication/521473/file/521473_Fulltext.pdf

The influence of single-channel liquid CO2 and MQL delivery on surface integrity in machining of Inconel 718

Micro-coordinate measuring machines (micro-CMMs) for measuring microcomponents require a probe system with a probe tip diameter of several tens to several hundreds of micrometers. Scale effects work for such a small probe tip, i.e., the probe tip tends to stick on the measurement surface via surface adhesion forces. These surface adhesion forces significantly deteriorate probing resolution or repeatability. Therefore, to realize micro-CMMs, many researchers have proposed microprobe systems that use various surface-sensing principles compared with conventional CMM probes. In this review, the surface-sensing principles of microprobe systems were the focus, and the characteristics were reviewed. First, the proposed microprobe systems were summarized, and the probe performance trends were identified. Then, the individual microprobe system with different sensing principles was described to clarify the performance of each sensing principle. By comprehensively summarizing multiple types of probe systems and discussing their characteristics, this study contributed to identifying the performance limitations of the proposed micro-probe system. Accordingly, the future development of micro-CMMs probes is discussed.

/pdf/surface-sensing-principle-of-microprobe-system-for-micro-2s3wnhz9.pdf

Surface-Sensing Principle of Microprobe System for Micro-Scale Coordinate Metrology: A Review

Carbon dioxide (CO2) snow cleaning is a straightforward surface cleaning process in which a stream of small dry ice particles impact and clean a surface via physical (momentum transfer) and solvent interactions. These interactions have been shown to remove particles of all sizes, from visible to nanometer scale, and to remove organic residues as well as reagent grade solvents. The combination of particle removal over a wide range and organic removal makes the CO2 snow cleaning technique unique in its potential. Furthermore, CO2 snow cleaning systems satisfy the increasingly stringent industrial, research, and environmental demands. Carbon dioxide cleaning is fast, gentle, and environmentally safe. Following a short background, the chapter focuses on some of the diverse cleaning applications, including cleaning vacuum systems and components; atomic force microcopy; nanoprobes; substrates for basic surface science related to polymer adhesion and self-assembled monolayers; telescope mirrors; thin film substrates; semiconductors; small parts; and substrates for biological research.

Carbon Dioxide Snow Cleaning Applications

Influence of module on measurement uncertainty of gear tooth profile deviation on gear measuring center

This paper describes the experimental verification of the novel IMT-PTB microprobe combined with a uniquely designed microenvironment. The microprobe consists of three silicon-based parallelograms stacked orthogonally, which leads to high isotropy. The probe tip deflections are detected in 3D with the help of piezoresistors placed in the parallelograms. The microenvironment facilitates and improves the measurement of workpieces with submillimeter features. The new microprobe and the microenvironment were integrated into a commercial coordinate measuring machine (CMM). To evaluate the microprobe performance, PTB produced and calibrated three reference objects: a cube, a sphere, and a microgear measurement standard. The differences between the calibration values and the measurement results obtained by the microprobe were in the sub-micrometer range. Furthermore, the microprobe was compared with the standard probing system of the gear measuring machine by measuring the reference objects with identical parameters. The results show the excellent performance of the micro probing system, thereby extending the capability of the CMM for high-precision measurements of complex workpieces at the microscale.

Integration of an isotropic microprobe and a microenvironment into a conventional CMM

Novel measurement standard for internal involute microgears with modules down to 0.1 mm

The surface cleaning of components with sub-millimeter features poses a challenge in many applications. Challenges may be strong particle adhesion at the microscale, the difficult handling of the samples, the small size of the adhering particles, and unfavorable geometry. However, components often need cleaning before processing, assembly, packaging, applications, and measurement can proceed. Previous evaluations of CO2 snow cleaning almost exclusively refer to the cleaning of smooth, flat or convex surfaces; typically examined samples were wafers and optical components. In this paper, we studied the CO2 snow cleaning of complex surface shapes as found on microgears. The performance of CO2 snow cleaning is compared with ultrasonic cleaning and a high-speed air jet. The evaluation of the 72 cleaning experiments is based on the optical microscope images of the four investigated samples before and after cleaning. Results show that CO2 snow cleaning removed more than 95 % of the micrometer-sized contamination from our test samples. Ultrasonic cleaning removed 88 % of the particles and the high-speed air jet removed 74 % of the particles.

CO 2 snow cleaning of miniaturized parts

Involute gear calibration using tactile CMMs in scanning mode

This paper gives an overview of the field of clamping and gripping principles from the viewpoint of sample fixturing for dimensional metrology for microobjects. The requirements for clamping microcomponents that allow dimensional measurements are therefore explained before principles and solutions of microclamps as found in literature are reviewed and evaluated on basis of these requirements. Results show that there is no single superior clamping principle or method of implementation but rather several effective solutions for specific applications. The core value of this paper is the link between requirements for sample fixturing in dimensional micrometrology and the many approaches already investigated in the field of microclamping. A radar chart and a decision tree summarize and visualize the major aspects of this review. Finally, directions of future key research areas are suggested.

Stephan Jantzen

Papers

Integration of an isotropic microprobe and a microenvironment into a conventional CMM

Novel measurement standard for internal involute microgears with modules down to 0.1 mm

CO 2 snow cleaning of miniaturized parts

Involute gear calibration using tactile CMMs in scanning mode

Microclamping principles from the perspective of micrometrology – A review