Microconveyor platforms

Planar micromanipulation on microconveyor platforms recent developments... 

Key words planar micromanipulation microconveyor platforms programmable force fields MEMS. 

In contact-free platforms, various force fields, such as electrostatic, magnetic or pneumatic, are used to create a cushion on which the part levitates. The forces of these fields need to be directionally dependent in order to drive the part s manipulation on the workplane (e.g. the directed air streams for a pneumatic system). The main advantage of the contact-free microconveyor platforms is low friction, while the drawback is their high sensitivity to the cushion thickness (load-dependent), which can be quite difficult to control. 

This section presents indicative implementations of actuator microconveyor platforms or actuators that could potentially be used for planar micromanipulation, separated into categories according to the classification made in the introduction thermomechanical, electrostatic, electromechanical and fluidic-mechanical. For each implementation, a brief description of the actuators, their operation principle as well as their reported performance characteristics is given unfortunately not all the information relevant within the scope of this chapter has been reported by the respective authors. At the end of the section, a comparison between the most promising actuators or platforms for planar micromanipulation is made in a concentrative table and the most suitable of them are determined based on the criteria proposed in the previous paragraph. 

Pneumatic microconveyor platforms are contact-free systems since pneumatic force fields are used to create a cushion to separate the object from the surface. Figure 2.14 illustrates... 

Various implementations of actuators and actnator microconveyor platforms that could potentially be nsed for planar manipnlation of microparts have been presented so far. Table 2.1 shows a comparison of the most indicative of these implementations, along with all the reported information regarding their design and performance characteristics, i.e. actuator dimensions, maximum velocity achieved, force or torque per actuator or pressure, the load of the object used for conveyance experiments, the horizontal displacement per actnator as well as the actuation frequency, the power consnmption per actuator and finally an estimation of the fabrication and the operation complexity. 

Manipulation of parts on microconveyor platforms an integrated approach for programmable force field design and platform programming... 

Field diffusion, actuation principles and programming of microconveyor platforms... 

An application has been developed that simulates the motion of a part on a microconveyor platform under the derived planar force field. The platform s dimensions are 4.2x4.2mm, containing 21x21 motion pixels of dimensions 0.2x0.2mm each. The period of actuation according to Bohringer et al. (1997) is 2s, which corresponds to four actuation rates of 2s, 4s, 8s with three strokes and 8s with four strokes. 

A variety of microconveyor platforms based on microactuators has been presented in the last two decades. The reported conveyance velocities range from jum/s up to around a hundred mm/s and are a correlation of the respective actuator deflection (stroke) and its actuation frequency. In general, large deflections with at least a frequency of a few Hz tend to give faster manipulation speeds. In most of the presented cases, the reported velocities can be deemed quite promising. 

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