How To Cut Plastic Without Melting It

here is a idea kinda close to what they use at factory ,like where i work and desgign using platics,sensor and more for in-house tester what i made i took a old wet saw and replace the blade with a stainless steel fine tooth blade and made shore plenty of water is inside the machine,can also make your own too go very slow cut stop and go again,cuts a very smooth cut hard to do with a dremel,but can be done using like a water spray on blade and long extension cable that comes with most dremel kits