 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
ABOUT SLOT DRILLING
IN NC-CAM 6
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
NC-CAM 6 offers three of the most advanced slot drilling algorithms
known to the PWB manufacturing industry. Two of these utilize multiple
tool diameters to machine the slots with pilot drilling. The other uses
an innovative algorithm to straighten short slots.
Note that all FASTechnologies slot nibbling algorithms offer
user-settable edge roughness! This feature can be used either way:
By setting the slot cusp to a higher value, i.e. 0.002", the number of
hits needed to create the slot is dramatically reduced. This speeds up
drilling, and also makes the slots easier to plate (less smear).
The opposite end of the scale is achieved by reducing the slot cusp to a
very small number, i.e. 0.0001". This will result in tremendously smooth
slots, albeit with a commensurate increase in total hits required.
The slotting algorithms described here are available as a standard
feature of FASTechnologies
NC-CAM 6 Drill package. They
are also available in FASTechnologies
SmartParts Client/Server+DNC
networking product. |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
FLONG-SLOT
MULTI-DIAMETER ALGORITHM
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
This
algorithm uses a small drill (less than 80% the slot width) to
pilot-drill alternate holes in the body of the slot. These pilot holes
present a superior "bushing effect" to the full-diameter drill on its
second pass down the slot. |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
NET
EFFECT:
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Superior performance with ordinary drill bits.
|
 |
Very little breakage. |
 |
Very straight, smooth slots.
|
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
SHORT-SLOT MULTI-DIAMETER ALGORITHM
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
This
algorithm uses a small drill (less than 50% the slot width) to create a
"chip-breaker" hole at one end of the short slot. This small hole breaks
the chip formed on each plunge as the full-diameter drill nibbles its
way from one end of the slot to the other. |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
NET EFFECT:
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Radically straighter short slots (about 90%).
|
 |
Slot drills are still recommended for this
application. |
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
"S3" STRAIGHT SHORT SLOT ALGORITHM
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
The
original short-slot-straightener algorithm. In this algorithm, the hits
in the slot are pre-compensated to directly cancel the cutter deflection
caused by the asymmetrical side thrust on the drill on the second
through last hits. The exact scheme is proprietary, as it involved a
tremendous amount of research, but suffice it to say that our default
algorithm typically cuts slot deflection by about 85%. Surprisingly, our
testing showed that the straightness does not vary much from the top to
the bottom of the stack on drills larger than about 0.026". |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
NET EFFECT:
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Much straighter short slots (about 85%).
|
 |
Slot drills are still recommended for this
application. |
 |
Moderate feedrates are recommended.
|
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |