Second Lesson for Mechanical Engineering
Q1) Why does Mr.Lehman only buy HSS Endmills for his courses? What does
HSS stand for?
Ans) High speed steel is a great tool as it isn't as expensive as the other types and it
provides good wear resistance. It provides withstanding resistance to high temperatures
while maintaining its hardness. It has slower cutting speeds than carbide but it can still
last you a long time. The reason Mr. Lehman uses a HSS tool because it is cheaper to
replace which is important as lots of students can damage the tool.
Q2) What is the benefit of having the roughing style end mill over a standard end
mill?
Ans) Rough end mills have a jagged cutted edge which cuts smaller chips than the
standard end mill. The Smaller chips allow us to have smoother machining and it helps
us remove the metal more efficiently. Standard end mills cut larger chips and therefore
the surface is semi-finished and not as smooth.
Q3) What do I mean by flutes? Does the angel of the helix matter?
Ans) The flute is the cutting edge. The flute is basically the spirals that cut the material.
Flutes provide A path for the removal of chips. The flute also helps provide a path for
the coolant to flow directly to the part that's being machines and it helps chips to be
flushed away. There are different amounts of flutes for different materials. Less flutes
are for softer material while the more flutes are for harder materials. A higher helix angle
helix is used for finishing (For example 45 Degrees) Wraps around the tool a little faster
and makes a more aggressive cut. A lower helix angle (For example 35 Degrees) wraps
slower and has a stronger cutting edge. These are used for the toughest roughing
applications. It also changes your desired finish on the material.
Q4) Why is coolant important especially during adapted machining?
Ans) Coolant is an essential function of machining. Coolant helps reduce the heat from
the piece and cutting tool and at the same time it lubricates them giving us a smoother
finish. The lubrication also helps reduce friction too. It also flushes away chips and small
abrasive particles.
Q5) Why would you need to do a finishing pass after machining traditional or
adaptive?
Ans) The reason we do a finishing pass after machining is because we want to smooth
out the rough cuts. Traditional machining and adaptive machines both leave a rough
finish and leave burrs so running a finishing pass would help smoothen the surface and
remove the burrs.
By: Taha Qureshi