But the dislocation precision of dislocation razor blade

  • Time:
  • Click:128
  • source:OURLOVE CNC Machining
To but for razor blade of dislocation hard alloy, high accuracy dislocation adds man-hour to just need in medium precision only normally, this listens go up to have some of contradiction it seems that. (in the article, gotten precision is measured after dislocation precision definition is the cutting blade that changes bit. ) the reason that produces this kind of contradiction is very simple, because there are a lot of elements to affect treatment precision besides bit, so accurate dislocation is to not have to the treatment of extremely strict public errand very of the meaning. That is to say, if treatment public errand is very close, as a result is opposite every time a dislocation hind must make adjustment word, use common bit more economical. On the other hand, if treatment common difference is very wide, bit precision is not big to its influence, use accurate bit undeserved. Have an exception only, reach workpiece rough machining namely when next tolerancepublic errand dimension (as a result of below the need of working procedure) , must use accurate bit, lest cut a size too small and cause discard as useless. Influence but the element of dislocation precision has a lot of, include the factor that be concerned with bit directly and has nothing to do with bit. One, of arbor wear away or damage the problem of arbor makes bit loses precision very easily. If bit chamfer greatens because of wearing away or produce any forms be out of shape, criterion the bit position after dislocation can have bigger difference. 2, the arbor with the different type of arbor its tool cutting edge angle is different also, this also can affect dislocation precision. Graph 1 in arbor A is 90 ° tool cutting edge angle, compare with arbor D photograph, dislocation precision suffers the effect of bit error easily. Of course this differentia is not very small, but accumulate with other error rise to also can become very considerable. Graph 1 graph 2 graphs 3 3, the bit chamfer on arbor of knife chamfer horn also has range of its public errand. The knife chamfer horn of triangular razor blade is 60 ° normally - 1 ° , and square razor blade is 90 ° - 1 ° , limits of this public errand already was proved to restricting bit ambulating is the most appropriate. From the point of the influence to dislocation precision, knife chamfer part is small compare for a time be close friends for a time greatly, can refer to a graph 2. Knife chamfer horn of Zun Tu is + 1 ° , bit is met with point of a knife is runner shaft and ambulating ever since, get generation of cutting point of a knife to be more than - the shift when horn of chamfer of 1 ° knife (right graph) . Latter razor blade swings in its back end only, shift undertook around what approach a center only, cutting point of a knife turns rarely. When tool cutting edge angle greatens (because arbor style is differ) , because the turn and produces effect inside bit chamfer also will greaten. ' 4, heat expands steel qualitative arbor and horniness contain golden razor blade to all be met be heated expands, coefficient of its linear expansion is the flat carbonization tungsten of typical brand 2.

F of ° of 66 × 10-6in/in (note: ＝ of 1 ° F 0.

556K) . When using cooling fluid, normally working temperature amounts to 750 ° F. Below room temperature, the height that picks trigonometry bit is 0.

19in. Because this has: 750 ° F - 72 ° F (room temperature) temperature rise of 678 ° F and 2.

678 × of 66 × 10-6in × 0.

719 ＝ 0.

0013in.

Stretchy quantity (0.

033mm) if 60 ° tool cutting edge angle is formed on arbor of bit park lathe, come when bit temperature rise when 750 ° F, workpiece diameter will decrease in the begining than cutting 0.

0026in. (0.

066mm) . Coefficient of linear expansion of steel qualitative arbor about 2 times at carbonization tungsten, heat expands the effect arises only at arriving from bit the part between bolt of clamp of the first arbor. Bit of unlike of arbor temperature rise is so old, but the heat of arbor expands to change to also have bigger effect to working measure. 5, stand or fall of tigidity of rigid machine tool is one is evaluated hard, more the element that predicts hard. Bit, arbor, tool carrier, workpiece and machine tool have " abdicate " phenomenon, make whole system becomes elastomer thereby. If it were not for is had because of the knife wear away phenomenon, do not consider this kind to play commonly be out of shape. But as cutting tool wear away, cutting force can add, if workpiece is long and thin sleeve, increscent cutting power can make workpiece generation deflective, make its diameter greatens thereby. According to systematic tigidity and tolerancepublic errand requirement, the sequential possibility that this one element creates is important, likely also not important. However, this is an element that does not suffer bit precision effect completely. 6, dirty content and the factor with cut bits influence to make over precision the mainest the quality of likelihood and arbor or razor blade it doesn't matter concerns. When treatment, spoil and cut bits to always exist, they can send bit when dislocation below. The trouble that they cause and clear the difficult easy degree of bit chamfer becomes direct ratio, with the attention of machine tool handlers degree becomes inverse ratio. Handlers may think he clears bit chamfer is very careful, but stay very easily still at the back of bit 0.

001 or 0.

The dirt of 002in or fine-cut bits. This meeting makes bit advanced to be measured certainly relative to workpiece, mean in turning from time to tome 0.

002 ～ 0.

The diameter of 004in reduces an amount. Complex arbor clears hard, more make this kind of state exasperate. 7, bit error razor blade must be made by tolerancepublic errand, what choose tolerancepublic errand to must provide economic feasibility. If want to make tolerancepublic errand is reduced, cost can raise a lot of. Manufactory home does not send exorbitant foundation to go up to use more severe common difference as far as possible in cost normally. The dimension of triangular razor blade and public errand are classified according to inscribed circle diameter, square razor blade is classified by the dimension between subtense and public errand, this is a few kinds measure what maneuverability provides most in means. Will classify by inscribed circle public errand and do not express it to be able to be mirrorred right piece but dislocation precision, because other bit dimension common difference are in final precision,also having main effect. A B C pursues 4 8, the trigonometry razor blade of ideal of inscribed circle error is the complete equilateral triangle that an acme is circular arc form. However the dimension of inscribed circle can not show whether complete this triangle is equilateral, because a circle can be mixed,cut inside aleatoric triangle. All directions razor blade should be complete square, but the size between flank can not state whether this square is perfect, the parallelogram because of equilateral its subtense dimension is equal also. Purificatory razor blade has very tall geometry precision, but a few difference also is inevitable. 9, the circular arc that point of a knife changes the point of a knife of bit must agree by dimension is formed, these circular arc should locate accurately, accurate ground and razor blade each edge is tangent, see graph 4A. If symmetry is poor, may cause certain error; Too outstanding or circular arc of point of a knife is big shrink (graph 4B) . Circular arc of point of a knife may slant left or slant right (graph 4C) . 10, bit and blade holder ply this, the drop is not too large to the action of dislocation error, because it adopts a point of view,will produce an effect. Blade holder ply can be taken no account of commonly, because be in arbor is whole during service life, change the frequency of blade holder is very few. The change that after the razor blade of deviation be gettinged on by replaces the 5 razor blade that make clear a next deviation, the plan produces. The height of bit coping increases 0.

010in, the horn before be being lost with 6 ° is opposite in the razor blade when central place cutting the effective feed of workpiece increased 0.

001in. If cutting tool is before horn, if change the smallest bit into the thickest, cutting deepness can decrease, if pursue medium,be shown. Graph 5 graphs 6 11, the influence of time pursues 6 increase and increase what make clear a few main factors to let cutting time to machining the influence of dimension, total effect is cumulative normally. "Factitious " when the element includes to be like dislocation, fail to clear blade holder clean, when buy puts bit, ambulate etc. Some elements are constant when cutting like bit public errand, but of cutting blade wear away, the addition of cutting force greatens along with the addition of cutting time. The last word establishs an all-purpose formula impossibly, in order to is informed accurately when should use accurate bit, treatment of avery kind of must try to consider according to respective characteristic. But, this is a domain that be worth to consider and can pay off. CNC Milling