Optical Comparator Selection Guide
Optical comparators come in an often bewildering variety of shapes and sizes. Benchtop, floor model, in-line, side-screen, side-table. How do you know what type of system to get, and which options to specify? As is the case with most capital equipment purchases, the answer is to know what your needs are today and to plan for changing needs tomorrow.
We have arranged this selection guide to help you through this decision making process. If you have any questions, feel free to email us for assistance.
Screen Size?
How large of a viewing screen should you get? Depending on manufacturer, you will find systems with screen diameters of 10", 12", 14", 16", 20", 24", 30", and even larger. How big is big enough?
The answer is based on the type of measurements you plan to make.
Measurement by comparison (with overlay charts or screen templates) can use the entire viewing screen. A larger screen means you can see more of the part at any one time, perhaps measuring many features at once with the same chart. Measurement by motion (with visual alignment or edge detection) uses the movement of the worktable assembly and screen rotation to measure the part. How large of a part you can measure is based solely on the overall travel of the worktable.
If you need to use overlay charts, for thread or form measurement for example, then a larger screen may be needed depending on the size of the parts. The table below shows the field-of-view (how much can be seen at one time) for some common screen sizes and magnification levels. For other combinations, simply divide the screen size by the lens magnification.
Field Of View
| 14" | 16" | 20" | 30" | |
| 5x | — | 3.20" | — | — |
| 10x | 1.40" | 1.60" | 2.00" | 3.00" |
| 20x | 0.70" | 0.80" | 1.00" | 1.50" |
| 50x | 0.28" | 0.32" | 0.40" | 0.60" |
| 100x | 0.14" | 0.16" | 0.20" | 0.30" |