Evaluation criteria of square tube sheet
In the inspection process of tubesheet, the main inspection indexes are hole position,hole tolerance, hole finish, burr, grooving position, etc. for double tubesheet,more attention is paid to hole position in the inspection process,and the hole position matching degree of two tubesheets is very important.
Generally, it can be guaranteed by CNC drilling machine.Compared with thick plates, the perpendicularity of holes above 300mm is very important.These large-diameter thick plates need more precise tools and equipment,and the application of special gantry machining centers will be more and more common.
Advanced square tube sheet processing method
In fact, a major problem restricting tubesheet processing is equipment.In the traditional tubesheet processing, the rocker drill is its main equipment.Because of its manual operation characteristics and fixed operation methods,it is difficult to tap its potential. Although drilling jigs and other methods can be used to improve efficiency,they can not solve the fundamental problem.
Only by finding a way from the equipment can we fundamentally solve the problem.Multi axis NC drilling machine has been widely used in pipe hole processing abroad, instead of rocker drill.NC plane drilling machine can replace manual marking and drilling,which can greatly improve the processing accuracy and efficiency.
China has also begun to realize the localization of this kind of drilling machine in recent years,but the products of most manufacturers have small bed (2m ~ 3M) and few spindle (one or two). Large tubesheets cannot be machined. It cannot completely replace imported products.Therefore, large tubesheets (more than 7m) requiring high machining accuracy can only be processed abroad. Imported CNC machine tools are expensive, long installation cycle and difficult to maintain. They are not necessarily suitable for China's national conditions.There is an urgent need for domestic machine tool manufacturers to produce super large CNC drilling machines to meet the needs of tubesheet manufacturers.
