White paper illustrates how advanced machines, tooling help machine tool builder improve productivity
This white paper illustrates the immediate productivity gains resulting from the combination of an advanced third-generation machining centre and optimized tooling. The machine is the Mazak Horizontal Centre Nexus (HCN) 8800, a mid-sized horizontal machining centre with a 31.5 in. (800mm) square pallet, and the tooling is from Seco Tools.
In 1989, Mazak Corp.’s manufacturing plant in Florence, KY, installed a Palletech Manufacturing System with 140 pallets and three loading stations that served eight units of first-generation Mazak FH-800 horizontal machining centres.
In 2001, the eight machines were replaced with four units of second-generation Mazak FH-8800 horizontal machining centres. And while the amount of machining centres within the system was reduced by half, the same production volumes were maintained. In fact, additional workpiece components were added to the system’s production output without having to increase the number of pallets in the system. The number of pallets remained at 140 within the system.
Currently in the Kentucky plant, the FH-8800s in the system do process machining of the turret base and carriage castings for the company’s Quick Turn Nexus 300 and 350 turning centres. These medium-sized castings were used as test pieces for the comparison of the FH-8800 to the HCN-8800.
In the test cutting with HCN-8800, optimized tooling from the company’s VIP program partner Seco was incorporated in place of the existing tools used on the FH-8800. The result was immediate increases in machining performance and drastic reductions in part cycle times for both casting componentsâ€“from 8.25 hours down to 5.45 hours for the turret base and from 8.5 hours down to 4.25 hours for the carriage.
Seco Square 6 shoulder mill.
Seco’s Super Turbo helical cutting tool.
The third-generation machine brought higher performance in terms of speed, power, machining capacity and CNC control capability. As compared with the FH 8800, the HCN 8800 provides 25 per cent faster machine acceleration, a 50 per cent increase in rapid traverse speed, 10 per cent faster tool change time and 75 per cent quicker worktable indexing. More aggressive metal removal is also achieved with over 10 per cent more machine torque, and part size machining capacity is over 15 per cent larger due to increases in axis travels of 6 per cent in X, 9 per cent in Y and 32 per cent in Z. Critical to optimizing cutting toolpaths, the HCN 8800 features an advanced CNC control that includes functions to increase quality, productivity and operability.
Castings made from FC 300 and FCD 450 irons.
Medium-sized turret base castings for Mazak’s Quick Turn Nexus 300 and 350 turning centres were used as test pieces for the comparison of the FH-8800 to the HCN-8800 machining centres.
Over 30 tools total are used for machining each of the two components. Operations include face and end milling (roughing and finishing), center drilling, hole drilling, boring, chamfering and tapping. Most milling tools used are run dry.
Turret Base and Carriage Machining Summary
Mazak worked with Seco for optimizing the machining processes, specifically the rough milling operations. The combination of the HCN 8800-II and Seco tooling that allowed for higher metal removal rates, as well as optimized part programs and toolpaths, was key in reducing cycle times and part-processing costs.
With part programs revamped and toolpaths optimized, the Square 6 face mill cutters had the most significant impact in reducing cycle times by allowing for increased chip load per cutter revolution and higher surface footage metal removal rates. For certain tools, metal removal increased from a previous rate of 400 sfpm to between 1,000 -1,200 sfpm when machining approximately 0.125 in. to 0.171 in. per pass. These increases were due to the power of the HCN 8800, the additional number of cutting inserts on the Seco tooling and the use of shorter tool lengths. The tooling also provided a lower cost per cutting edge and thus lowered cost per part for the castings. Additionally, using Seco inserts that are periphery ground and have built in wipers further improved surface finish quality, and their perfect 90Â° setting angles ensured true 90Â° square cuts in single milling operations to further save valuable production time.
For the rough castings, between 0.203 in. and 0.250 in. of stock is removed during rough machining operations. Fluctuations in the raw castingsâ€“deviations in the amount of stock to be removed and in hardness of the overall castingsâ€“are all overcome with the Seco tooling.
In the test cutting with HCN-8800, optimized tooling from the company’s VIP program partner Seco was incorporated in place of the existing tools used on the FH-8800. The result was immediate increases in machining performance and drastic reductions in part cycle times for both casting components â€“ from 8.25 hours down to 5.45 hours for the turret base and from 8.5 hours down to 4.25 hours for the carriage.
For several face milling operations, Seco Square 6 face mills were used instead of the previous helical-type mills. The previously used two- and three-fluted helical mills were also replaced by Seco’s six-fluted helical face mills that put additional teeth in the cut, allowing for doubling of feedrates and running higher surface footage amounts as well as reducing tooling costs.
Several major milling operations for turret bases and carriages also required long tool reaches. For this reason and to handle the new aggressive machining operations, Seco Steadyline anti-vibration tooling adaptors were incorporated. These allowed for higher tool speeds and feeds while also maintaining tool life and part surface finish integrity.