Objective Lens Focusing Device
Project Description
This device is used to focus an objective lens for a medical imaging device. It moves the objective lens vertically in order to focus on a slide. The biggest design challenge was the extreme tolerances that needed to be held. This device has to move the objective lens by increments of 1/3 of a micron (0.0000003m).
Project Skills
Product Design, Engineering Analysis, Prototyping
Conceptual Development
The gear train was designed to an AGMA quality of 14, which is used for such instruments. An anti-backlash gear was of importance in the design. This kind of gear eliminates the play between meshing teeth by using two half-thickness gears spring loaded against each other.
Product Design
The screw used to turn the rotary motion into linear motion was 80 threads per inch, and the nut rotating about the screw was a double nut. This was done to allow the two halves to be pre-loaded to eliminate linear play between the nut and screw.
The Finished Product
All of the components in this design were machined/ground out of 304 Stainless Sleet and Aluminum Bronze to very high tolerances ±0.0005 in many cases.