Thin specimen in a variety of ways, including:

• Mechanical cutting and grinding (for sample preliminary preparation step)
• Electrolytic polishing (usually used for the thin end of the metal)
• Ion milling (for metal and insulation).

Must be in the subsequent electrochemical polishing or ion in the process of milling pin, thoroughly remove any introduced during the preparation of the initial mechanical damage layer.

When grinding disc center near the first hole, can stop the final grinding operation, then immediately stop electrolytic polishing or ion milling processing.At this point, the hole near the conical part of the material usually has thin enough, enough to make the electron beam penetration.

On electrolytic polishing or ion milling pin time is too long, will remove the hole near the electronic can penetrate thin section, and the rest of the material may be too thick, makes the beam cannot penetrate.