Using epoxy to mount a sample before processing is an effective way to provide additional support to samples during subsequent grinding and polishing and is especially important with delicate and porous samples. However, to get this important internal support, the sample must be penetrated as fully as possible. Vacuum impregnation has been widely recognized as an effective way to improve penetration of the epoxy resin by removing air entrapped in the pores of the sample, enhancing capillary action and reducing the barriers for the epoxy to move into the specimen pores. Pouring epoxy under vacuum is a proven method of reducing this resistance and increasing epoxy penetration.
Though mounting under vacuum inarguably assists with epoxy impregnation, there are some limitations regarding excessive vacuum levels or duration, due to partial pressure changes causing the epoxy to boil. These limitations can prevent the epoxy from fully impregnating the sample and can lead to poor results in the grinding & polishing process. So how do you work around these limitations to further penetrate samples?
Buehler’s application engineers have studied this issue and identified a solution: running multiple vacuum cycles with each mount. Multiple vacuum cycles can help extract additional air from the sample and further improve sample impregnation. But how much does cycling help with sample penetration? Turns out, it’s a lot! And this difference is substantial, even when the total time under vacuum is the same. Not only does cycling improve epoxy impregnation in samples, but the penetration continues to improve with additional cycles!
However, vacuum cycling has largely been a manual process even with the most sophisticated and “programable” equipment on the market; requiring user intervention between each vacuum cycle before moving on to the next, resulting in extra technician time to process samples. Until now! Buehler has developed the only fully programable unit for vacuum impregnation that allows cycling with continuous sealing, requiring no user interaction over multiple cycles. With the SimpliVac, users can run up to 10 cycles without touching their unit, freeing up valuable time.
With the SimpliVac optimizing your epoxy mounted samples by allowing you to pour under vacuum and program multiple vacuum cycles you will get higher quality samples, faster while reducing user involvement. The only questions is, what will you do with that extra time?