Here are five crucial tips to consider when buying a used scanning electron microscope (SEM):
1. Contact Everyone
Contact as many used equipment suppliers as you can to build up an accurate picture of which used SEMs are on the market.
2. Conduct a “Desirability Assessment”
Survey all staff that will be involved with using the SEM. People that only use the microscope occasionally who want features that increases the cost of purchase should be have limited input. Once the list of required features has been compiled, award each a score out of 10. This ‘desirability score’ needs to be cross referenced against a ‘performance score’. This assessment often reveals the fact that highly desirable features that do not perform well score low, whereas less desirable features that perform well score higher.
3. Arrange Demonstrations
Use the ‘desirability assessment’ to make up a short-list of SEM’s for the purposes of a demo. Eliminate any equipment that falls short of requisite minimum standards.
4. Rate the Photographs Produced by Each Machine
Examine the photographs from each machine, arranged in lines reflecting the procedures used. Locate the best micrograph in each section and award it 10/10. Similarly, rate the fastest times 10/10. Give lower scores to poorer quality micrographs and slower times. Multiply the two scores together for each manufacturer and divide them by the maximum score for the test. Then multiply by the ‘desirability assessment’ score and total the final score for each short-listed SEM.
Once you’ve made your choice, don’t be shy about negotiating hard. A used SEM doesn’t come cheap but most suppliers have a 5-10% discount built into their original asking price.