Failures

Possible causes

Unsmooth

chip-discharging

1. leakage of cutting liquid 2. improper geometric dimension of cutlery 3. cutting liquid over-viscose 4. wrong parameter set for feeding

Poor

chips generated

1. improper geometric dimension of cutter 2. low linear speed for cutting 3. uneven distributing of material on workpiece

Damaged drill bit

1. abnormal feeding 2. clogged chip-discharging 3. poor co-axiality between spindle and guiding support 4. inappropriate cutting liquid 5. higher or lower feed rate 6. excessive axial endplay on the spindle 7. poor materials of cutters

Short life for cutters

1. over-temperature of cutting liquid 2. poor co-axiality between spindle and guiding support 3. improper geometric dimension of cutter 4. inappropriate cutting liquid 5. higher linear speed for cutting or higher feed rate 6. inferior cutting liquid 7. lower precision filtration for cutting liquid 8. unstable feeding

Excessive deflection of workpiece central line

1. poor co-axiality between spindle and guiding support 2. inappropriate size of guide sleeve of drill bit 3. curved drill bar caused by high feed rate 4. uneven distributing of material on workpiece 5. inappropriate geometric angle of cutters

Poor surface finish

1. low linear cutting spead 2. inappropriate geometric dimensions of guide pad 3. improper pressure of cutting liquid 4. wrong cutting liquid 5. higher or abnormal feed rate 6. lower precision f iItration for cutting liquid 7. large hole for guide sleeve of drill bit or drill bar 8. vibrating 9. uneven distributing of material on workpiece

Hole is not round-shape

1. poor co-axial ity between spindle and guiding support 2. inappropriate geometric angle of cutters 3. incorrect rotary precision of spindle