What round canal cuts principle and radius of cutting tool round horn is affirmatory

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Round canal is cut off use strong dismiss a method very general already. Of radius of circular arc of the geometrical appearance of the analysis getting power that cuts about round canal, cutting blade, cutting tool decide or those who wait for a problem is contact to solve between arc radius and tubal radius, cut off modular edge design to have important sense to round canal one, the condition that round canal cuts off extrapolate force is in charge of material to be in to assure cut a process not to produce inward cave in, must make cutting blade produces from beginning to end to tube wall by the thrust outside introversion. The graph is in charge of 1 times if the graph is shown 1 times,suffer strive. When the 1st quadrant, produce the condition of extrapolate force to be: 90 ° of θ ＜ - β - α (the θ in 1) type -- the tube wall on square canal and α of Y axis included angle -- because angle of friction is square ＝ tubal β 45 ° , criterion 45 ° of ＜ of 0 ＜ θ - α (2) is when the 4th quadrant (graph 2) , produce the condition of extrapolate force to be: (- 90 ° - (α ` - β ` ) 90 ° of ＜ of ＜ θ ` - (α ` -  of the θ in β `)(3) type -- cutting blade and  of β of Y axis included angle -- the tube wall below square canal and α of ＝ of  of α of Y axis included angle are angle of friction because, reason has 135 ° of ＜ of ` of 0 ＜ θ - α (4) pursues 2 through comparing (2) type and (4) type can see θ  includes θ , and (4) type is compared (2) type condition is comfortable, contented (2) type will surely be satisfied (4) type, because this reachs the condition of extrapolate force is integratedly: 45 ° of ≤ of 0 ＜ θ - when α canal is cut, produce the condition of extrapolate force, the inference according to above is knowable should satisfy type only (1) can, nevertheless the θ in type and β horn must change, and θ definition is tangent of cutting tool appearance and Y axis included angle, β is tube wall tangent and Y axis included angle, α still is angle of friction, α ＝ Arctan μ . μ is opposite for steel the kinetic friction coefficient of steel, in have when lubricating, be 0.

05 ～ 0.

1, in without when lubricating, be 0.

15; Steel is in to mild steel have when lubricating, be 0.

1 ～ 0.

2, in without when lubricating, be 0.

2. For safety, take μ ＝ commonly 0.

2, criterion 11 ° of α ＝ 12 ° of 19  ≈ , condition of geometry of the thrust outside can getting round canal to cut is 90 ° of ≤ of 0 ≤ θ - 12 ° - β namely 78 ° of ≤ of 0 ≤ θ - β (6) by the graph 90 ° of β ＝ of ＋ of 3 knowable γ namely 90 ° of β ＝ - γ (, if edge appearance can produce extrapolate power, criterion 45 ° of γ ＞ can produce extrapolate power likewise, reason needs to be calculated only 45 ° of γ ＝ can. 2, the geometrical requirement that must satisfy the thrust outside generation of cutting tool appearance and round horn radius according to cutting a course certainly, the figure that if the graph is shown 4 times,becomes the point of a knife that cuts bit and circular arc design. A, H and bit ply δ must satisfy intensity to ask to reach be helpful for cutting a condition. When the appearance parameter that cuts bit certainly, the key is R1 of radius of affirmatory circular arc, the others parameter can decide according to experience. Graph 4 graphs 5 show went out to cut the position when be being nodded to A, if plan institute is shown,coordinate is fastened. By the geometry of the graph the relation can get: The R in type of γ of Rcos of ＝ of OB of γ of AB ＝ Rsin, round canal radius pursues 5 pairs of edge, a nods coordinate to be: θ of R1sin of ＝ of Y1 of θ of X1 ＝ R1cos can get α of Rsin γ ＝ by relation of the geometry in the graph + R1(1-cos θ ) criterion the R1 in type -- 0 ＝ of γ of Rsin of ＝ of α of radius of cutting blade circular arc Rsin α (11) by (10) type is knowable, cutting radius of circular arc of bit cutting blade is change, not be calm value, namely the appearance curve of edge is not a circle. It is nevertheless solve this problem, can use another approach, take some radius R1 to be worth era to enter namely (10) type, the point of view that can seek a γ is worth, next checking computations looks to whether can be satisfied (9) type, if can be satisfied, feasible, if be no good, the specification must try other curve additionally. Nevertheless other curve cannot be satisfied (7) , (8) type. It is in order to cut the round canal of R ＝ 10mm exemple have consideration. Mix with R ＝ 10mm above all 12 ° of α ＝ take the place of (11) type, get A ＝ 2.

97mm. Next with R ＝ 10mm, a ＝ 2.

1mm, r1 ＝ 135.

9mm generation enters Sin γ ＝ [R1(1-cos θ + A] ／ R, except in θ ＝ 5 ° ～ get γ value to cannot be satisfied inside the limits of 8 ° (outside 9) type, the value that gets below other θ value all very good and can contented (9) type. According to above analysis, cut off bit to be able to choose radius of one big arc to serve as the radius of edge. Graph the appearance that 6 pictures gave bit of radius of horn of a few kinds of different circles. Graph 6 from cut off face quality to ask to look, r1 of circular arc radius wants big; From the point of strength demand, r1 of round horn radius wants small. Be in charge of to cutting the circle of R ＝ 10mm for, choose R1 ＜ 59.

32mm is advisable. 3, conclusion (1) passes an analysis, the geometrical condition of extrapolate force produces when deriving round canal is cut. (2) offerred a kind of train of thought to cut R1 of radius of circular arc of blade the crucial point certainly. CNC Milling