If you get a patent for your invention, does that mean that your invention does not infringe on anyone else’s patent?
While unusual, it is entirely possible for an issued patent to infringe on another patent. Remember, a patent grants the holder the right to “exclude others from making, selling, offering for sale and importing.” It does not grant the patent holder the right to make the device or perform the method described.
Say someone has patented a process comprising steps A, B and C. You invent a process that adds a step D to this process. Your process may very well be patentable. However, performing it would, in fact, infringe on the original process.
In such a case, the parties would likely work to come to a licensing agreement — whereby one party would purchase the right to perform the process covered by the claims from the other. Alternately, they might engage in a cross-licensing agreement so that both parties can practice the processes disclosed by the claims.