NONTRADITIONAL MACHINING AND THERMAL CUTTING PROCESSES Flashcards
Why are the nontraditional material removal processes important?
Reasons for importance of nontraditional material removal processes are (1) the need to shape new metal alloys and non-metals that are difficult to machine by conventional processes; (2) the requirement of unusual and complex work part geometries; and (3) the need to avoid surface damage which is often associated with conventional machining.
There are four categories of nontraditional machining processes, based on principal energy form. Name the four categories.
The four categories are (1) mechanical, but not including conventional machining; (2) electrical; (3) thermal; and (4) chemical.
Describe the water jet cutting process.
Water jet cutting uses a high-pressure, high-velocity stream of water directed at the work surface to cut the work.
What is the difference between water jet cutting, abrasive water jet cutting, and abrasive jet cutting?
WJC cuts with a narrow, high velocity water stream; AWJC adds abrasive grits to the water stream; and AJM cuts with abrasive particles that have been added to a high velocity air stream.
How does increasing discharge current affect metal removal rate and surface finish in electric discharge machining?
As discharge current increases, metal removal rate increases and surface finish is degraded.
What is meant by the term overcut in electric discharge machining?
Overcut refers to the gap between the electrode (tool) in EDM on each side of the tool and the machined hole, cavity, or kerf (in wire EDM).
Name the four principal steps in chemical machining.
The four steps are (1) cleaning, (2) masking, (3) etching, and (4) demasking.
What are the three methods of performing the masking step in chemical machining?
The three masking methods are (1) cut and peel, (2) screen resist, and (3) photographic resist.
What is a photoresist in chemical machining?
A photoresist is a masking material that is sensitive to light. When exposed, it chemically transforms and can be removed from the surface of the work, leaving the desired surface unprotected by the maskant.
