In this paper, a touch trigger probe using one- and five-boss cross-shaped membranes is proposed, which can be used in coordinate measuring machines for three-dimensional measurements. Silicon bulk micromachining is utilized to fabricate force sensors. Four different piezoresistor layouts are characterized in this work. A maximum sensitivity of 3.01 mV V−1 mN−1 and 11.29 mV V−1 mN−1 is obtained, respectively, when vertical and lateral loads are applied on one-boss design. The horizontal to vertical stiffness ratio is decreased from 1:37.5 to 1:2.25 when a five-boss design was used compared to a one-boss design. The sensors' ability to measure both normal and shear forces with high linearity is demonstrated by means of tests performed by applying forces between 0 and 25 mN.

No abstract

In this paper, the concept, fabrication, activation and testing of a novel synchronous micropump based on microfabricated copper coils and polymer magnets are presented. The pump works by the synchronized rotation of two polymer magnets in an annular SU-8 microfluidic channel. Magnet rotation is achieved by sequentially activating a set of planar coils to repel or attract the first magnet (traveling magnet) through the channel, while the second one is anchored between the inlet and the outlet ports. At the end of each pumping cycle, the magnets exchange their anchored and traveling functions. The synchronization of magnet rotation has been achieved through programming two activation schemes that proved the high dependence of the pump operation and performance on employed activation scheme parameters. The magnetic forces exerted from electroplated coils on the polymer magnet were tested experimentally using a three-dimensional force sensor. Different coil dimensions have been investigated. A maximum force of 658 μN at an applied current of 138 mA was achieved. The micropump has successfully pumped water with rotational speeds up to 83.33 rpm. Water flow rates in the range of 17.3 μL min −1 at 31.25 rpm to 158.7 μL min −1 at 83.33 rpm were achieved.

A 3D force sensor is developed using bulk silicon micromachining for measuring force in the sub-µN range. It is intended for use in high precision coordinate measuring machines. Full and cross-shaped boss membranes are fabricated, where the total chip size is 6.5 × 6.5 mm 2 . The full membrane is 3000 × 3000 µm 2 and the beams of the cross-shaped membrane are 900 × 700 µm 2 with 16 p-diffused piezoresistors in transversal strain configuration. The strains detected by the piezoresistors are measures of the three orthogonal components of the force applied at the tip of the stylus, which is glued on the center of the boss. When a vertical load is applied to the stylus, higher sensitivity is obtained for the cross-shaped membrane than for the full membrane.

In this contribution, we report on different miniaturized bulk micro machined three-axes piezoresistive force sensors for nanopositioning and nanomeasuring machine (NPMM). Various boss membrane structures, such as one boss full/cross, five boss full/cross and swastika membranes, were used as a basic structure for the force sensors. All designs have 16 p-type diffused piezoresistors on the surface of the membrane. Sensitivities in x, y and z directions are measured. Simulated and measured stiffness ratio in horizontal to vertical direction is measured for each design. Effect of the length of the stylus on H:V stiffness ratio is studied. Minimum and maximum deflection and resonance frequency are measured for all designs. The sensors were placed in a nanopositioning and nanomeasuring machine and one point measurements were performed for all the designs. Lastly the application of the sensor is shown, where dimension of a cube is measured using the sensor.