Thursday, March 13, 2014

My Fiber Optic Polishing Machine

I do research with lasers and fiber optics, and I needed a polishing machine customized to meet my needs.  I started with an old Fibertek machine, which could only polish standard fiber connectors.


 I need to be able to keep my parts perfectly vertical, and also have control over how hard the parts pressed on the polishing pad.  I made a guide using 4 hardened stainless posts with linear bearings. A dial indicator measures the polish depth, and counterweights in the rear control the pressure.






This circular cut was made on the mill using a rotary table. 





The accuracy of the rotary table cut approaches that of a lathe.  Here a lathe cut part fits inside with about 0.002" clearance.
 Here is a partially completed fixture that will hold 10 items in the polisher.   The pie shaped pieces will each hold a single part, and they can be removed without disturbing the other parts.  They are held by a single screw at the small end, and a dovetail at the big end.  All of the holes were done with the bolt hole function on my Shumatech DRO.  Here I did not use the rotary table at all, for it was much easier to program the Shumatech.

The outside diameters and the dovetails were cut on the lathe.  Then I cut the upper disc into the pie shaped pieces using a bandsaw, and then I milled the saw cut edges smooth.
 My high powered lathe has no trouble turning these diameters, even in steel.  However, it puts about 300% more stress on the drive belt pulley as does a 7x10 or 7x12 lathe.  The pulley finally failed, so I ordered a replacement from Little Machine Shop.   Here is a picture of how the belt connects to my gear reduction unit.   Someday I will make a metal replacement pulley.




I needed a way to hold an optical fiber connector, known as an MT connector, very accurately, and with no free play.  The MT's measure 3mm high x 6 mm wide.  Here is one in a rectangular hole I made with tolerances of 0.1mm


I began by milling a slot slightly smaller than the MT's dimensions.  Then I drove a rectangular punch I made from a hardened steel bolt into the slot.  Even though my method was crude - I drove the punch in with a ball pein hammer - I had good repeatability from one part to the next.

2 comments:

  1. Your blog held my interest right to the very end, which is not always an easy thing to do!!
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  2. I am thankful to you because your article is very helpful for me to carry on with my research in same area. Your quoted examples are very much relevant to my research field.

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