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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:  

bullet Superior performance with ordinary drill bits.
bullet Very little breakage.
bullet 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:  

bullet Radically straighter short slots (about 90%).
bullet 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:  

bullet Much straighter short slots (about 85%).
bullet Slot drills are still recommended for this application.
bullet Moderate feedrates are recommended.

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Last modified: 2017-11-09