The main difference between the two is the type of work that they will do. The engineer will be in charge of knowing how things should be done based on science and based on the items that will be used. The technician will know how to do the tasks but will not exactly understand the process behind or it or why certain things should be done the way that they are being done.
There are also differences in the types of tasks that will be done. Engineers will work on the problems and designing processes and products. Technicians, on the other hand, will be in charge of performing the tests. They will also collect the data that will be passed on to the engineer.