Nov 2019 - 3: Cutting out the crashes

Published: Nov. 25, 2019, 8:56 p.m.

As part of the global BMT Group, BMT Aerospace is a multinational designer and manufacturer of gears and mechanical components for the aerospace industry. Active in five key market segments that include high lift actuation gears, turbine engine gearboxes, shafts and couplings, high-precision detail gears and gears. To produce these precision components to tight deadlines while avoiding expensive mistakes, BMT Aerospace relies on CGTech\u2019s VERICUT machine simulation software. No workshop wants to crash any of its CNC machine tools, as production suffers while the machine is down for repairs. Additional costs include the scrapping of parts, broken cutting tools and even toolholders and workholding vices being damaged. The cost and downtime can be enough to disrupt a company\u2019s growth trajectory, sometimes permanently. This is especially true for a Swiss-made, 5-axis machining centre that is one of only a few in the United States. Vitaliy Tsisyk, gearbox engineering manager for BMT Aerospace International, a division of the Belgium-based BMT Group, was part of the team that decided to install the high-end machine tool. He knew the stakes were too high for the traditional \u2018push-the-green-button-and-hope\u2019 approach to program prove-outs, so he contacted CGTech for help Based in Michigan, Illinois, BMT Aerospace is one of three plants responsible for precision machining of gears and transmission components for the aerospace industry. With the other sites in Romania and Belgium the customer list includes names like Airbus, Boeing, Embraer, GE Aviation, Rolls-Royce and United Technologies Corp (Raytheon Technologies Corporation). These customers demand zero defects and have no tolerance for supply chain disruption. Two of BMT\u2019s three plants use VERICUT toolpath simulation software from CGTech, with the third coming online shortly. \u201cWe were the first ones to launch VERICUT,\u201d Vitaliy Tsisyk recalls. \u201cThat was five years ago. Belgium began using it a couple years after that, and we are currently working with the Romanian plant to get it implemented there. For us, the main reason was to avoid any issues on our 5-axis machining centres. You simply cannot afford any mistakes when you are producing expensive parts on very expensive machinery.\u201d A DMG-Mori Dixi DHP 80 II horizontal machining centre (HMC) installed on the shop floor boasts a volumetric accuracy of 25 micron and positioning accuracy of 0.9 micron. The HMC primarily machines gearbox housings such as the gearbox mounted accessory drive (GMAD) used on Saab 2000 twin-engine passenger jets and Lockheed Martin C-130 military transport aircraft. It also machines other parts from aluminium, magnesium, stainless steel, and titanium that demand extreme accuracy. Bought for the Dixi machine, the use of VERICUT software has expanded to other CNC machine tools at BMT Aerospace, including a recently installed UMC-750 5-axis HMC from Haas Automation. Vitaliy Tsisyk says the machine cuts chamfers on the bevel gears used in power take-off (PTO) boxes and similar gearbox assemblies \u2013 applying extremely complex kinematic motion that would have been difficult to visualise without VERICUT. The software also prevented a near certain crash after a drive block for a right-angle head was improperly mounted on the machine tool. \u201cLuckily, I have a very experienced guy on the shop floor who told me he didn\u2019t think it would clear the part,\u201d Vitaliy Tsisyk says. \u201cI brought the program into VERICUT, updated the model to reflect the block\u2019s placement and size, and sure enough, it would have crashed.\u201d In one example, an angle head was set-up to mill a series of internal grooves within a cylindrical part. Vitaliy Tsisyk had the accessory\u2019s specified dimensions validated on one of the shop\u2019s co-ordinate measuring machines, then used those values to model the head in VERICUT. \u201cIn this case, the gap between the two was especially critical, because if you crash a head like that, deep inside a workpiece, it only takes one small mistake to break a machine, break confidence levels and disturb the production that could delay final product delivery to our customers,\u201d Vitaliy Tsisyk explains. \u201cWith VERICUT, I don\u2019t have to worry about those situations.\u201d