Target horsepower is the ideal [horse] power for the specified width/depth of cut and feed rate on the specified stock material type. By default, it is set on a 2.5D milling operation when a flat-end milling tool is used. The calculation is simple. The stock material has a property which specifies the [horse] power per unit material removal rate. All we need is to calculate the material removal rate from the width/height of cut and the feed rate. Then multiply this value and the stock's [horse] power per unit material removal rate.
During feed optimization, FeatureCAM calculates the sampled material removal rate along the whole toolpath. If the rate is faster than the target feed rate, it is decreased. If the rate is slower than the target feed rate, it is increased.
Set this milling attribute to the required horsepower for the operation. This number is then used in feed optimization to even out the tool loads. This attribute is automatically set to the estimated horsepower for 2D roughing passes performed with flat end tools. For 3D roughing passes performed with flat end tools, this attribute is also set to the estimated horsepower as long as the Z increment attribute is set. For all other operations, this attribute has no default value.
When toolpaths are generated, the estimated horsepower required for each operation is calculated by using the depth of cut, width of cut, feedrate and stock material. The actual shape of the feature is not taken into account. Instead just a simple straight cut is assumed when calculating the estimated horsepower. This number is reported in the Operations list of the Details tab as the Est HP. The estimated horsepower is only calculated for operations that are cut with flat bottom tools with a fixed depth. This includes 2.5D milling features, and 3D Z level roughing and other 3D features with Z increment set.
If the Target horsepower is not set for an operation, then its feedrates are not modified by feed optimization. This means that if you do not explicitly set the target horsepower for individual operations, feed optimization will only affect 2D roughing operations and 3D roughing operations with flat end mills and the Z increment parameter set.