A universal model for ruled surface's linear cutting with four-axis linkage machine
At present, the ruled surface's multi-axis manufacture is a hot research direction, but its universal mathematic model as key theory problem hasn't been established so far. To solve the problem of ruled surface's manufacture with four-axis linkage machine, we worked out the intersection line between the lateral surface and the horizontal plane of upper-lower guiding device through geometry method, and then established the universal mathematical model to manufacture the lateral surface of the work pieces under the condition that the lower guide is fixed. To verify the exactness of the model, we took the four-edge frustum and triangle-circle frustum as example. The model has universal use value in guiding practical manufacturing.
The general geometrical models of the design and 2-axis NC machining of a helical end-mill with constant pitch
Abstract This paper presents general geometrical models of the cutting edge and groove section of a helical end-mill with constant pitch. The section profile and relative feeding speeds of the grinding wheel used in 2-axis NC machining of the end-mill are deduced. The actual groove and cutting edge of a taper toroid-shaped end-mill are simulated. The approach of eliminating the remaining revolving surface is introduced. This paper presents a reliable method for the design and 2-axis machining of a helical end-mill.
Effects of Equipment Dimensions on Liquid Mixing Time of Bubble Column with Draft Tube
The liquid mixing time of a bubble column with a draft tube is experimentally studied. The diameter and height of the column, the diameter and length of the draft tube, and the mode of sparging gas were changed and the liquid mixing time was measured.The lengths of bottom and top clearances have significant effects on the liquid mixing time. The liquid mixing time increases with increasing column aspect ratio of height to diameter. The liquid mixing time of the bubble column with a draft tube is longer than that of a standard bubble column when the column aspect ratio is relatively high. The liquid mixing time has a minimum when the diameter ratio of draft tube to column is 0.5 to 0.6. These effects of equipment dimensions are expressed by an equation. In the experiment using different solutions, the liquid mixing time becomes shorter with increasing liquid surface tension, or with increasing liquid viscosity.