# hi help me please friends

• posted

Hi folks, I need a help. As I am basically an electrical engineer I have succeeded in micro-stepping a stepper motor by 128 micro steps of step angle 1.8degrees which mean it can at one instance move by as small as

0.014degrees. Well the problem now is that I need to convert this angular motion into its equivalent linear motion(i micron) so that I get a micron level motion. As not many were able to help me out in this regard, I started browsing the net for some way of achieving this conversion. I hit upon something on which I need your help. In a compact disk there is a rack and pinion arrangement which is capable of moving by 0.5micron (maybe, 0.05 micron...me not pretty sure). There is an optical arrangement of infra red beam which runs on this rack and pinion and which is reflect on to the ridges of a cd so as to store data in cd's. as the distance between adjacent ridges of cd is in the order of 0.5 micron(or maybe 0.05 micron) so this rack and pinion must support such minute movement of 1 micron that is required in my project,I feel. Cant this apparatus satisfy my need? Respond as soon as possible friends suchi
Loading thread data ...
• posted

The slider is only a rough positioner to get the head into the area of interest. As such it positions to within 20 microns or so. A secondary system that servoes in displacement and focus is carried on this slider and uses the tracks themselves for feedback. These are typically Lorentz motors on flexures. Positioning to a micron is a non-trivial task. Since you are trying to do it cheaply, take a look at capstan drives. Also, it would be good to remember that just because you are dividing the current between steps with a granularity of 1/128th of a step, this has no relationship to the actual angles you are achieving, especially if there is any friction whatsoever in your system.

• posted

take a look at differential micrometers (Thorlabs is a good source). In combination with a good linear slide, you may be able to achieve what you want more easily than you describe below.

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.