Along the same vein as Why do consoles explode in Star Trek?
Why is it that whenever anything hits something in the Power Rangers, sparks fly?
There seems to be no explanation for it other than a cool special effect.

Along the same vein as Why do consoles explode in Star Trek?
Why is it that whenever anything hits something in the Power Rangers, sparks fly?
There seems to be no explanation for it other than a cool special effect.

The idea is that the suits are "power weapons" themselves, they materialize with their offensive "power weapons". When they get hit the power that keeps them somewhat safe will spark. It's the same idea when you see the glow of shielding being hit by other weapons in Star Trek.
In response to the comments I'd like to add that all weapons on the show used post-transformation are intended to be "power weapons". If it looks like a sword or staff, it is a power sword/staff. The sparks don't typically fly when they are not "transformed" into their power-forms. In the rare event that sparks fly when something non-power hits something else that is non-power (and can't explode on its own) the reason is special effect consistency.
Actually there is a canonical explanation for the sparks flying off of the Rangers whenever they get hit. The reason it's sparks and not their suits getting ripped or burned is because of a thing called the "Morphin Grid" that the Rangers channel their powers from. Comparable to something like the "Speed Force" in DC comics, it's an extra-dimensional force from which all Power Rangers draw their abilities and, whenever they're morphed, it shields them from potential damage. It's not infinite though, which is why when Rangers take enough abuse they've been shown in some stressful battle scenes to have ripped suits, singe marks, and broken helmets on occasion. Usually when they hit that point though the Rangers are just knocked out of their powered up forms as a sign that "Hey, maybe you shouldn't keep fighting this guy."