Tham khảo tài liệu 'high speed machining episode 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Safety precautions are necessary Use machines with safety enclosing -bullet proof covers Avoid long overhangs on tools. Do not use heavy tools and adapters. Check tools adapters and screws regularly for fatigue cracks. Use only tools with posted maximum spindle speed. Do not use solid tools of HSS An example of the consequences of breakage at high speed machining is that of an insert breaking loose from a 40 mm diameter endmill at a spindle speed of rpm. The ejected insert with a mass of will fly off at a speed of 84 m s which is an energy level of 53 nM - equivalent to the bullet from a pistol and requiring armour plated glass. Some typical demands on the machine tool and the data transfer in HSM ISO BT40 or comparable size Spindle speed range Block processing speed 40 000 rpm 1-20 ms Spindle power Increments linear 22 kW 5-20 microns Programmable feed rate Or circular interpolation via 40-60 m min NURBS no linear increments Rapid traverse Data flow via RS232 90 m min 19 2 Kbit s 20 ms Axis dec. acceleration Data flow via Ethernet 1 g faster w. linear motors 250 Kbit s 1 ms High thermal stability and rigidity in spindle - higher pretension and cooling of spindle bearings Air blast coolant through spindle Rigid machine frame with high vibration absorbing capacity Different error compensations - temperature quadrant ball screw are the most important Advanced look ahead function in the CNC Some specific demands on cutting tools made of solid carbide High precision grinding giving runout lower than 3 microns As short outstick and overhang as possible maximum stiff and thick core for lowest possible deflection Short edge and contact length for lowest possible vibration risk low cutting forces and deflection Oversized and tapered shanks especially important on small diameters Micro grain substrate TiAlN-coating for higher wear resistance hot hardness Holes for air blast or coolant Adapted strong micro geometry for HSM of hardened steel Symmetrical tools
