The rigidity and metal-removal capability of the CM6000 mill let HCI machinists cut machining time by up to 75%, taking only 4 h to machine large flanges compared to 12 to14 h when using single-point machining tools.

A portable mill can machine wind towers that now have diameters from 10 to 14 ft, and to a surface-flatness tolerance of 0.002 in. The Climax CM6000 mill can also create a 60 rms micro finish, exceeding the current requirements of the wind-power industry and in particular tower fabricator Hitachi Canadian Industries Ltd., Saskatoon, Saskatchewan, Canada.

Thanks to the modular design of the CM6000 from Climax Portable Machine Tools, Newberg, Oregon, when it is not machining out-of-spec flanges on the assembly line, it can stores in HIC’s fabrication shop until needed, reassembled within 60 min and moved into position by an overhead crane. Its in-situ machining eliminates the time and work required to build subassemblies at a machine shop for re-machining, and the cost of subcontracting with field service companies.

The hunt for the portable mill began when HCI found that work for a particular customer was a challenge because of its short delivery schedule and also, once its larger towers were assembled, the machine shop’s boring mills were not large enough to machine the whole tower to the tight specs required. It had two manufacturing shops including a large machine shop with stationary vertical-boring mills, where subassemblies could be built and towers turned to true-up out-of-spec flanges. But such machining requires hauling tubes from a fab shop to a machine shop, mounting tubes, do the work, and taking them back to the fab again.

As a result, the shop subcontracted the work to field-service companies that used portable machine tools to grind the towers outdoors at the plant. Although the subvendors could meet the precision specs, it was often costly and difficult to schedule them. As a cost-reduction measure, HCI decided to bring the machining in-house. When Chief Engineer Rob McEachern began to research his portable machine-tool options, he contacted Climax Portable Machine Tools.

McEachern and the Climax sales engineer discussed minimum and maximum capabilities of the machine he needed

The Climax mill is used to true-up flanges on tower sections.

including its precision, portability, and fast metal removal rate, as well as the range of tower sizes and demanding specifications HCI had to meet. The sales engineer recommended the CM6000 circular mill which had the power, precision, and portability the fab plant needed so it could be used outdoors at the plant as well as set up for use in a work cell. Climax engineers are also designing a fixture to improve the portable mill’s use.