для заказа - kyocera@kyocera-tools.ru Technical
Information
D rilling Basics
Drilling
Proper drilling involves proper machine setup, coolant delivery, insert selection, and a basic understanding of the drilling process.
Indexable drills are not the same as twist drills in application or performance.
BASIC DRILLING
Drilling a hole from solid stock is a tough job for a variety of reasons. Chip and heat evacuation are tough, the actual cutting action is
hidden from view, and the surface footage varies from the programmed speed at the outer cutting edge to zero at the center of the
tool. A drill doesn’t actually cut at the center, it pushes the material out of the way. Cutting forces are high and other factors such as
coolant delivery and machine alignment can combine to cause a drill to deflect and cut off-size, or fail catastrophically.
MACHINE SETUP
This is an important consideration when using indexable drills. In drilling, shorter is always better. Use the shortest drill and the
shortest adapter possible. This will always improve performance. The machine spindle and bearings should be in good condition,
and the fixturing must be adequate and rigid.
In lathes, alignment is crucial. The tool must run within 0.003” TIR to the spindle, or insert failure could occur. If the center insert
continually chips, check the alignment. Chuck jaws should be in good condition as well and provide adequate clamping pressure.
The workpiece should not extend from the chuck excessively either.
COOLANT DELIVERY
Coolant thru-the-spindle should be used wherever possible. Coolant improves tool life by lubricating the cut and removing heat and chips
from the work area. Chip evacuation is very important when drilling.
INDEXABLE VS. TWIST DRILLS
Indexable drills are very different than twist drills. Replaceable inserts eliminate drill regrinding. Because of higher surface footages,
indexable drills generally out-feed twist drills.
DRILLS VS. CORE DRILLS
Kyocera drills are designed to put holes in solid material. Kyocera core drills are used to open a pre-existing hole. Core drills,
because of their design, can attain two times the feed rate of insert drills. As a result, core drills provide an excellent means of enlarging
an existing hole.
APPLICATION CONSIDERATIONS
Feed and Speeds
Proper cutting speeds and feeds are obviously important considerations. The recommended cutting feed and speeds shown in
this section are starting points derived through testing in our Tech Center and in the field. Adjustments are frequently required for
optimum results based on specific application configurations. Call your local Kyocera Sales Engineer for assistance as necessary.
Rigid Setups
No tool will perform at maximum potential in a poor setup. Workpieces must be held securely and in accurate alignment (.XXX or
less for non-DRC drills and .XXXX for DRC drills).
Tombstones must be mounted properly, and workholding must be adequate. Worn jaws can introduce chatter, and possibly mis-
locate parts, or even release parts during the cut. The machine itself must be in good condition, and tool gage lengths should
be as short as possible. Shorter gage lengths result in higher feed capabilities with less deflection and chatter, and longer insert
life.
Machine Horsepower vs. Spindle Horsepower
There can be a great difference between the spindle motor rating (machine horsepower) and the horsepower at the tool tip
(spindle horsepower). Typically, spindle horsepower is around 75% of rated horsepower. As a good rule of thumb, drills require
approximately 5hp per inchof diameter when cutting steel. The machine's power curve should be referenced to determine the
power available at various speeds in order to determine capability. 82
kyocera@kyocera-tools.ru
www.kyocera-tools.ru
