my previous post on how to pierce small
holes on a thin strip, I mentioned about polishing a 0.5mm
diameter punch. Since these punches are very tiny and very
hard to polish to such a high degree of surface finished,
I felt a need for me to elaborate on how I did it.
of all, you have to machine the small diameter punch carefully
to ensure the surface is finished as smooth as possible. One
should also try to maintain a good roundness and prevent dig
marks remain on the surface. Any digging mark remaining on
the surface are not removable away during the polishing process.
Dent marks will be left on the part and would eventually creates
problems during future usage.
you should also consider adding some allowances on the diameter
to allow material removal for the polishing process. In this
case, 0.03mm diameter allowance is sufficient for small parts.
In this case, the diameter of the punch is 0.52 mm. Adding
0.03 mm will give it a total of 0.55mm in diameter.
I am using
a 0.005mm grade Diamond polishing compound, an ultra-sonic
polisher and a mini lathe machine to do the job.
the tiny punch on the machine chuck. Adjust speed to 500 rpm.
2. Set the polisher to medium speed.
3. Apply diamond compound to the wooden polisher tip.
4. Move the polisher lip front and back along the punch diameter.
Apply gentle force to the polisher, do not push too hard,
or the punch may just give way.
5. Clean up the area and make measurement by a micrometre,
make sure diameter is within the specification.
Polish small punch on the lathe machine with diamond compound
and ultra-sonic polisher
down the diameter and to obtain a good & smooth surface
finished, it took only estimated 5 minus for one punch.
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