UniDisc MK2, 3mm disc punch

The Model 508 is an accessory for Twin Jet Electropolisher Model 501B. Designed to produce 3mm diameter discs for electropolishing, and subsequent TEM examination, from sample strips.

The UniDisc is designed to produce 3mm diameter discs for electropolishing, and subsequent TEM examination, from sample strips.

Sample strips are fed into the side of the UniDisc. When the handle is pulled, the strip is trapped between two rigid metal die faces. The punch then pierces the tightly held sheet and ejects the disc into the collection tray. Deformation is confined to a much localised shear zone at the edges of the disc away from the central region which is later thinned using either the twin jet electropolisher or the single jet electropolisher. The punch and die are replaceable items made from hardened tool steel. The standard model produces 3mm discs for TEM from sheet/foil samples with minimum distortion.

Optional models produce discs from 1mm to 6mm in diameter. Examples of the use of these includes the production of 1mm discs of highly radioactive materials which are pressed into holes punched in non-radioactive 3 mm discs and the composite disc thinned. This reduces the radiation dose to the personnel involved. The larger disc specimens are used in SEM.

Ordering information

• The standard UniDisc Mk2 is used for making 3mm disc from samples 0.10 to 0.15mm thick i.e. the optimum for electro polishing.
• If the thickness of the sample is outside the 0.004 to 0.006: range, the same punch is used but the die has to be changed because a different clearance between the punch and the die is required to make good flat discs without any flash around the edges.
• Discs can be made from materials up to and including 1mm thick stainless steel. To order non-standard 3mm die quote: the source material and thickness.
• Punch and die sets and/or individual punches and dies can be supplied to produce discs in the range of 1 to 6mm in diameter. To obtain advice on the feasibility of your project quote: the diameter of the disc required, the thickness and type of the source material.