Journal qt'Neuroscience Methods, 28 (1989) 225-227 225 Elsevier NSM 00937 Improving performance of motorized slides for micromanipulation Xiaoqing Gao and Frederick Sachs Department of Biophysical Sciences, SUNY, Buffalo, N Y 14214 (U.S.A.) (Received 1 July 1988) (Revised 7 December 1988) (Accepted 17 December 1988) Key words: Vibration; Microinjection; Microscopy; Patch clamp; Microelectrode Motorized linear slides used as micromanipulators for biological use suffer from 3 problems: vibration at low speed, poor ergonornic design of the controller and slow coarse positioning. These problems are not hard to solve by minor modifications to the controller and the slides. Motorized slides made by a variety of manufac- turers, including Newport Corporation (18235 Mt. Baldy Circle, Fountain Valley, CA 92708), have gained popularity as manipulators for biological experiments. The slides provide a low drift, build- ing-block system that allows a manipulator to be constructed to match individual requirements. The slides and controllers were designed to match the requirements of work in laser optics but the re- quirements of micromanipulators for biological applications are not identical. As biological micromanipulators, the slides suffer from a number of problems the most seri- ous of which is vibration during fine positioning. Additionally, they suffer from an abysmally slow coarse positioning and poor ergonomic design of the 3-axis controllers. Fortunately, none of these problems is difficult to solve and the resulting manipulators provide excellent high-resolution, low-drift, performance. We used three precision linear slides (No. M-425-OMA) with 0.5 in. travel and the No. 860SC controller to build an XYZ manipulator. A fight angle block (No. 360-90) held the vertical axis on top of the XY pair. Correspondence: X. Gao, Department of Biophysical Sciences SUNY, 105 Parker Hall, Buffalo, NY 14214, U.S.A. 0165-0270/89/$03.50 © 1989 Elsevier Science Publishers B.V. The coarse positioning problem was solved by mounting a small, 3-axis, coarse positioner (Brink- mann MM-33) on the vertical slide. The problem of vibration is somewhat more complex. The motor controllers for the Newport slides have two modes of movement: a continuous, or slew, mode in which a velocity servo controls the speed and a jog, or step, mode in which individual pulses are applied to the motor but the servo is not effective. The continuous mode is used for relatively rapid movements while fine positioning is accomplished in the jog mode. Once started, movements in the slew mode are smooth. How- ever, starting from rest and during motor reversal there is a large amount of vibration which is easily felt simply by touching the motor. The vibration causes a micropipette to shake as much as a few microns and can easily destroy a nearby cell. The vibration can be reduced by stiffening the micro- electrode holder system, but in practice, the need to gain access to the stage of the microscope limits the degree of stiffening that is practical. The vibration originates in the design of the controller. At startup, the error signal in the veloc- ity servo is maximum and the motor is being driven with a maximal step of current. This prob- lem is most severe in "jog" mode in which current pulses are applied discretely so that a continuous Biomedical Division)