The focal length printed on the lens, is always the focal length (not counting small inaccuracies).
Placing the lens onto a camera with a 'crop sized' sensor, does not change the focal length of the lens. "DX" or "EF-S" lenses etc., which are designed for digital bodies, are still exactly what is printed on them.
An 18-55mm does not become a 27-83mm.
The 'crop factor' is simple a comparison. It compares the field of view (FOV) of a camera & lens, to the FOV that you would expect with a certain focal length on a 35MM FILM SLR. The reason is because 35mm film SLR cameras were the 'standard' for a few decades before digital SLR cameras became the norm.
So unless you are quite familiar with using a 35mm FILM SLR, you should not be concerned with the crop factor. 18mm on your "1.5 crop factor" camera is what it is, a fairly wide FOV. That won't change and you aren't actually getting 28mm.
Of course, there are 'full frame' DSLR cameras, where the sensor is the same size as 35mm film, and thus they have no 'crop factor'.