Summary: The dimension of silk of double head of novel tap ― that the article introduced a kind to be used at luring steel material tap, construct through comparative awl (geometry) parameter and coating material and method have logical choice, make can efficient ground, economy ground undertakes to stainless steel tap is machined. Stainless steel serves as a kind admirable anti-corrosive material, have the exceedingly good performance characteristics of the respect such as stock intensity and tenacity, make wide application receives in each domains such as equipment of machine spare parts and pharmacy, chemical industry. But, increase of dosage ceaselessly as stainless steel, the treatment issue that stainless steel regards difficult cutting as material is increasingly outstanding. Because stainless steel has good plasticity and certain tenacity,reach intensity just about, bring about treatment so sclerotic phenomenon is serious, be opposite easily point of cutting tool cutting causes loss. Because the intensity below its high temperature is tall, hot conductivity is low, cutting temperature is accordingly high, wear away to cutting tool the impact is very big, having quite big tenacity and strength because of it, outspread rate is old, reason forms the tumour that accumulate bits extremely easily. These circumstances are machined to stainless steel, especially tap will bring very great difficulty. We are in effective treatment process, the high-speed steel tap that developed ion of Co of infuse of a kind of surface (the 1) that be like a graph, have logical choice to the structural parameter of cutting tool, can better land finishs stainless steel tap. Graph tap of 1 pair of heads pursues 2 special fixture the structural brief introduction of tap of 1 pair of heads is current our commonly used tap has one aspect of the matter to have thread only, and another end is knife handle. This kind of structure makes arbor rear must be designed set prescription body or cone, with can delivering torque. And the significant portion of the whorl of tap takes tap length only 40% the left and right sides, tap material is used at knife handle part for the most part, waste material quite. The double head tap that designs now has same appearance in its both ends, can make tap is secured go up in clamping apparatus, make torque OK deliver another end from aleatoric one aspect of the matter. The knife handle part that this kind of structure is equivalent to a tap of two only heads incorporates an organic whole, reduced petiole length thereby, saved stuff. In the intermediate part of double head tap, namely knife handle part, can mill gives more shallow circular arc slot, the thimble opening that uses both ends of double head tap locates, circular arc chamfer can assure to locate clamp mask has taller fixed position precision after classics grinding. The logical choice test of parameter of 2 tap structure makes clear, tap chamfer number has bigger effect to tap effect. What we choose is 3 chamfer tap, it and photograph of 4 chamfer tap are compared, the dimension of cross section increased, the intensity of tap gets rising, can prevent tap effectively to break off below the action of tap torque, also was the horn after the horn before increasing is mixed to create advantageous condition. And, the tap torque of 3 chamfer tap can reduce 10% than 4 chamfer tap, consequently force of unit area cutting also is reduced subsequently. As a result of tap cutting muscularity, it is those who reduce tap to wear away speed, think the horn before tap should take small cost commonly, but the character according to stainless steel material, its tensile strength is not too tall, and high temperature intensity, outspread rate and section shrinkage are bigger however, bits is cut when tap not easy depart, curly and break off, cutting is out of shape big, tap torque is big, cutting temperature is high. Because this is out of shape to reduce cutting, make cutting light, the horn before should increasing appropriately, and can make area of the chamfer that hold bit increases so, make not easy and curly cut bits with what break off can of short duration puts the chamfer that hold bit in, unapt because cut bits,jam and make tap breaks off or tooth collapse blade. Accordingly we chose Bp=20 ° bigger before horn. The horn after the tine of ministry of awl of standard tap cutting supports is Ap=6 ° ～ commonly 8 ° , but because stainless steel tenacity is bigger, so we were chosen bigger hind 12 ° of ～ of horny Ap=10 ° , undertake shovelling grinding to whorl profile when make, shovel the horn after wearing whorl cut look namely, in can avoiding tap process so, restore as a result of flexibility, be narrowed after cutting by treatment surface, make Machalidada increases, also can avoid tap to be in invert when exiting, be cut bits blocks a place of strategic importance. Form of chamfer of the chamfer that hold bit chooses the groovy body that two circular arc make point-blank, the direction of groovy form had better use helix chamfer, but it is quite difficult that its are made, cutting tool production cost is higher, accordingly we choose the form that there is blade inclination in the cutting awl ministry of linear chamfer, in order to improve its cutting performance. The tap material with the logical traditional choice of 3 tap material all is common high-speed steel. The data shows, treatment stainless steel can have TiN coat in high-speed steel surface, in order to reduce cutting torque, prolong tap life, improve whorl quality. The experiment proves, tiN coating can make the attrition force between tap surface and stainless steel material drops, make cutting torque drops 1/3 ～ 1/2, what TiN coating still can restrain tap and stainless steel effectively is close with action, prevent the felt between stainless steel and tap apparently, make whorl surface quality rises thereby. Graph ion of 3 infuse bogus and not the material that the tap cutting of infuse Co ion ages we choose wear process is ion of exterior infuse Co, because it has afore-mentioned characteristics of TiN coating not only, still have a few more excellent features. Because the crystal lattice of high-speed steel surface of element of exterior infuse Co produces serious distortion and aggrandizement, exterior organization and Co ion produce chemical combination to react, form metallic compound and photograph of dispersion metal horniness, make exterior hardness can be amounted to 1, 600 ～ 2, 000HV, and this horniness layer is mixture body, without the apparent interface of TiN coating, so horniness layer and high-speed steel have extremely strong union strength, raised the wearability of tap surface thereby, impact resistance and corrosion resistance. We undertake Co ionic infuse to tap and made cutting function contrast experiment with the tap that handles without infuse, the material of infuse Co ionic tap is W6Mo5Cr4V2, dimension takes blade dip) for M10 × 1(, test specimen is 1Cr18Ni9Ti stainless steel, hardness HB190, tensile strength 642MPa, choose cutting career 3. 6m/min, pouring emulsification cutting fluid, discharge 5L/min. When length of general attack silk is 4m, on face of the knife after the tap cutting of infuse Co ion ages grind classics caustic to measure for 0.
15mm, not the wear extent of infuse Co ion is 0.
4mm. (Ke Yanxian grows the cutting life of the tap after graph 3) experiment proves infuse Co is ionic 1.
5 ～ 2 times, and of edge of edge of face of the knife after tooth wearing away is even, and usually face of the knife after tap tooth is located in edge corner office to often can arise to wear away badly to die even blade, after this explains infuse Co is ionic adequately, the wearability of tap and impact resistance got rising significantly. Because the special fixture of tap of 4 pairs of heads is double head tap is a kind of new-style structure, general clamping apparatus cannot hold clip, so we designed the special fixture of double head tap, graph 2 for clamping apparatus appearance, graph the 4 structural sketch map that are placed in special collet for outfit of double head tap. Double head tap is in the impaction below the action of oblique plane by steel ball inside the circular arc chamfer among double head tap, should drive pressing of degree of tightness to cover what can go to the lavatory namely to tear open tap only outfit and turn around. Tap is sold by the fixed position in central aperture and clamping apparatus have centering effect, tap clamping apparatus can drift somewhat inside whole housing, so that aim workpiece aperture. And there also is a few allow to move in axial, in order to facilitate when tap advance and retreat, allow to there is some of deviation a bit on pitch. Graph sketch map of structure of 4 special fixture the double head tap with 5 conclusion original structure, changed traditional tap petiole workmanship, saved cutting tool stuff, reduced cutting tool to make cost, if both ends is parted,awl of make it head is mixed 2 awl, can turn around quickly use. The special fixture of the design can make tap location exact, deliver torque bigger, outfit tear open fast, save auxiliary time, improve manufacturing efficiency. The structural parameter of logical choice tap, can improve treatment quality, improve the cutting performance of tap. Use the high-speed steel tap of ion of exterior infuse Co, can raise tap durability 1.
5 ～ 2.
0 times, and of tooth wear away evener. CNC Milling