Running a production batch of 12"x12" 6061 plates on a ROC-TECH 4x8 router, cutting 0.25" deep pockets. 2-flute carbide endmill, tool #17, 12k RPM, 120 ipm, climb milling. First 8 parts held ±0.002" depth. Last 4 came out 0.004" to 0.006" shallow. Fixture’s tight, spindle runout checked under 0.0005" yesterday, no visible tool wear. Old habit says blame tool deflection first, but it’s consistent across the bad parts. What should I measure first to rule out setup vs machine?
Did you re-measure the Z work offset after the first 8 parts? Had this bite me last month. Swapped in a tool that looked the same but was about five thou shorter and never rechecked the offset. Same shallow depth on the last batch. I check mine every two parts now.