Abstract. 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.

Print publication: Issue 12 (December 2009)
Received 22 June 2009, in final form 16 September 2009
Published 20 October 2009