We use the manufacturer's suggested chip load and use industry accepted calculations for chip thinning for both radial depths (width of cut) less than 50% of the cutter diameter and for axial depths of cut below the corner radius of the cutter (up to a full ball). The Dashboard slider bar allows for feed rates from zero to three times the manufacturer's suggested chip load to allow for chip thinning, but this is not an endorsement of using the maximum available value on the slider bar. Anything above the manufacturer's suggested value will appear yellow
A dynamically stable cutting tool may be able to accept a higher feed rate than the manufacturer's recommended parameter, but that can only be determined experimentally. Boeing Advanced Research and Development recommends using our technology for determining speed and cutting depths:
As for feed rate they recommend starting at a value (the 1% of diameter shown here is for aluminum) and then increasing the feed rate until surface finish degrades or power is exceeded:
Care must be taken not to overload the machine spindle, which the power bar on the Dashboard will estimate and the load monitor on the CNC control will show in real time, by over feeding.
The cutting tool itself has limits. Tools with larger numbers of teeth have less chip evacuation capabilities that could be exceeded by chip loads in excess of the manufacturer's recommendation.Long flute length, long overhangs and high length to diameter ratios, especially in smaller diameters, increase the flexibility of the tool and puts stress at tool and holder connection point. This can lead to failure (tool breaking off at the toolholder) for high cutting loads. In these cases the manufacturer's chip load may require decreasing by 25% or more.
SPEED VS. CHIP LOAD
Because of design limits of the tool, chip load recommendations from the manufacturing should be closely adhered to as the above states. Speed is dynamically limited so the manufacturer's recommended SFM are typically very conservative. Having the Dashboard showing where stable speed zones are, above the manufacturer's suggested SFM, allow you to be more aggressive.
Our recommendations are:
- Use the Dashboard to calculate a stable spindle speed, depth and width of cut.
- Start at the manufacturer's suggested chip load (feed per tooth).
- Adjust for chip thinning if applicable.
- If desired and cut is stable, increase feed rate in 10% increments until surface finish degrades or power is exceeded.