A welcome to the forum is usually how things start off not just dive into a question for help ppl get rather annoyed at that . And a location in your profile.......that aside You would be lucky to get a laser to do that unless the ties were black as a start. Second you need very good safety googles OD5 as the power needed to do that will be very high unless you want to wait 10 seconds per tie.You will not get a legal laser out of the box that will do that, you would need about 3 watts plus of 445nm blue, you would be better off using a pair of cutters its just to dangerous even if you had safety googles and the very high powered laser ,the laser would have to be made up from parts not off the shelf no such beast exists to my knowledge, maybe an industrial C02 laser but to big and bulky ....basically its not safe or practical