Onsrud claims that keeping cutter chiploads within their specified ranges is critical for cutter life. As shown in the attachmentGWizard and Onsrud.pdf (1.1 MB)
, their 1/4" endmill with the smallest chipload (0.002") is a single flute solid carbide.EM. Forcing GWizard to provide that chipload at the maximum router speed (to maximize MRR) results in a 11.9 lbf force on the workpiece and router (since the cutter’s shank is the same diameter as the cutter). That force would likely cause about 1/64" of added cutting error on a Stepcraft D840.
IMO GWizard would be a lot more useful if users could enter minimum chipload (cutter dependent), spindle speed, and maximum machine force. To be meaningful, those calculations need to properly account for the characteristics of the material being cut. Users would also need to know how much error they’re willing to accept and what force causes it.