Общий каталог ZCC-CT 2019 - страница 1113

Technical information Technical information – drilling Solid carbide drills A Drill specification and cutting parameters Chip pocket The chip pocket ensures that the chips are removed out of the hole during processing. The helical angle describes the pitch of the flute. It's specified according to the to be machined material. Turning Helical angle hardened materials small helical angle large tough materials The cutting edge length needs to be specified according to the drilling depth, guide bushing length and the whole regrinding Cutting edge length length. The larger the helical angle, the lower the stability. Since it greatly influences the tool life, it should be as small as pos- or spiral length sible. The recommended min. spiral length is the drilling depth plus 1.5 times of the hole diameter. B Point angle Generally the point angle is 140°, for special applications it should be set differently. tough materials, easy to machine small point angle large hardened materials and high-performance drilling The core diameter is an important factor and influences the stability and the chip flow. Milling low axial cutting force high axial cutting force Core diameter low stability small core diameter large high stability for easy to machine materials for hardened materials or cross holes The chamfer width influences the guidance and friction of the drill during machining. Chamfer width low friction and high friction and C bad drill guidance small chamfer width large good drill guidance The drill diameter is slightly reduced from cutting edge to shank to reduce friction during machining. Back taper The area behind the chamfer width. The body clearance is necessary to reduce friction during machining. Drilling Body clearance Deep hole drilling 1 Preparation of the pilot hole with 1534SP03C* D – Point angle of pilot drill must be bigger than SL drill. – Diameter of pilot drill must be 0.01–0.04 mm bigger than SL drill. – The pilot hole should be 1–3×D. Information Technical 2 Entering the pilot hole with SL drill – Entering the pilot hole with low cutting speed. (VC: 20–30 m/min) – Stop 1–3 mm before end of pilot hole. (Vf = 0) – Increase cutting speed up to recommended parameter and then start drilling at feed rate. 3 Manufacturing the deep hole E – Drilling with suitable cutting speed and feed rate. In case of cross holes feed rate should be reduced to 0.05 mm/rev.. 4 Pulling out the drill Index – After reaching the required depth reduce the cutting speed (VC: 20–30 m/ min) and pull out the drill at high feed rate. (Vf: 2000 mm/min) C 172