Of spare parts of body of thin wall cup outside round treatment

Spare parts of body of thin wall cup is to show one aspect of the matter starts to talk, another end is underside, and the wall is large the than be less than 1/20 cup body spare parts with the diameter. Round treatment has two difficulty outside the spare parts of this kind of type: It is mural Bao Rong changeful form, of workpiece outside round circularity or coaxial spend out of tolerance; The 2nd is the circle outside treatment when, because flexibility is out of shape, the mouth appears to carry big, bottom to carry small horn degree of lip-rounding after treatment, diameter of the circle outside making the bus parallelism out of tolerance of two end. 1.

The craft of spiracle tappet asks to the spiracle tappet of form of a kind of cup is used in great quantities on the car now, my company produced the tappet of cup form valve of a few breed, its material uses mild steel, cementite quenchs processing. The wall of cup form tappet is large very thin, have 0 only.

75~1mm, but external the dimension of columnar face and appearance error demand are higher, round figure sketch map of tappet of 1 cup of type spends diameter of the circle outside mixing the parallelism demand of two upright generatrix is higher, it is 0.

005mm, if pursue,1 is shown. Graph 1 　 carries out summary through much production, we mastered the treatment craft of this kind of tappet gradually, of the circle outside was being satisfied relatively high accuracy. The craft course of round treatment is outside: → of cold extruding semifinished product goes outside thick car of stress anneal → outside round → kibble round → cementite quenchs half essence of → temper → is ground outside round → essence is ground outside round. 2.

Craft point analyses 　 (1) go stress anneal the take out in working procedure of the round outside follow-up car, circle outside grinding exterior metal, leftover stress lost metallic interior to balance, make the circle outside semifinished product happens to be out of shape certainly. For this, before the circle outside the car, answer semifinished product to undertake anneal, in order to eliminate internal stress. (2) cementite quenchs tappet of form of Bao Bi cup is extremely changeful when quench form, for this, we use sealed type to be able to accuse atmosphere multi-purpose furnace, assume cementite to quench working procedure, this is multi-purpose furnace hermetically sealed, heat continuously (warm-up, heat, quench, temper is finished inside a furnace) , aeriform protection undertakes cementite quenchs, the deflection that can assure workpiece is very small. The circle outside the tappet of form of a few kinds of cups that produces via measuring us deflection ≤ 0.

05mm.

The workpiece when quenching must be made the same score put, had been out of shape in case big, follow-up working procedure is indelible deflection, namely the axis of tappet is vertical put at horizontal. (3) essence of life is ground outside the circle is with the cup form tappet of external diameter 31mm exemple, the reservation before quenching (radius) ply is made an appointment with 0.

The mental allowance of 15mm, essence of life is ground outside round working procedure divides grinding, the first grinding surplus is 0.

015~0.

02mm, the 2nd surplus is 0.

005~0.

007mm.

Because the wall is thin, when the circle outside grinding, workpiece is very incidental inside grinding area flexibility is out of shape, and buccal end carries deflection than the bottom big, after giving grinding division, workpiece spring back, carry measure with respect to the mouth big and end end is small, diameter of the circle outside mirrorring tappet the out of tolerance of parallelism regular meeting of space of two end mother, the biggest when can amount to 0.

015mm. To achieve circularity and parallelism requirement, we use MGT1050 of high accuracy cylindrical grinder, undertook a series of adjust an experiment. 3.

Adjust an experiment when workpiece of inadvertently grinder grinding, influence geometry precision and outside the element of round grinding precision basically has work find a place for height (the center is high) , the geometrical appearance of guide pulley and its position angle. (1) the center of the central expensive work that adjusts workpiece is high press type calculates: H= γ π / 360 × (D guides + D) (D is arenaceous + D) / (D guides + D is arenaceous + 2D) choose emery wheel model to be P450 × 150 × 250WA/SA80LV, guide pulley model is P350 × 225 × 203A80PR.

Reach emery wheel diameter, guide pulley diameter workpiece diameter (it is with 31mm workpiece exemple) take the place of to go up form calculation, get a work center tall H=12.

98mm, after if emery wheel reachs guide pulley nap,be 400mm and 300mm respectively to the diameter, calculate again its height H=11.

43mm, the workpiece in type and grinding annulus, the tangential role γ that guide pulley contact nods takes 7 ° . We reach the center of workpiece high from 10mm after 14mm is adjusted respectively, the effect that measures it to be spent all right to circularity peace, if the result expresses 1 to show: Nextpage 　 from the watch 1 be pleasant to the eye the place of optimal center perch that gives Bao Biting staff, the computation that compares general columnar shape spare parts wants highly tall. Because thin wall spare parts is more sensitive to pressure,this is, more incidental flexibility is out of shape. Rise high as the center, workpiece and emery wheel center connect line and decrescent of horizontal included angle β , to the law of workpiece from emery wheel and guide pulley Xiang Lizhong decomposes the extruding force decrescent of the horizontal way that give, the flexibility of workpiece is out of shape also decrescent, end of such mouth of cup form tappet and the flexibility that the bottom carries are out of shape difference also as narrowed (see a picture 2) , advantageous to improving parallelism, also improved circularity at the same time. But, the adjustment with high center has the limit, exorbitant when work will be not steady inside grinding area and start. 1.

Guide pulley 2.

Splint 3.

Emery wheel 4.

Workpiece pursues analysis of extruding force of round grinding level increases workpiece outside 2 workpiece after the center is high, because horizontal thrust is reduced, the grinding force of workpiece of arenaceous wheel pair also was reduced. Because this improves work while the center is high, the other parameter such as working rotate speed does the fore-and-aft feed rate that also wants pair of work, guide pulley to be adjusted accordingly, will increase grinding time. (2) the adjustment of appearance of guide pulley geometry and positional angle is perforative when grinding, to make workpiece has fore-and-aft feed rate, guide pulley has one banking angle to spend α in vertical plane a person operating from within in coordination with outside forces, α also affects grinding precision. To make workpiece and guide pulley still satisfy line contact, increase grinding stability, need guide pulley prune implement diamond pen slide carriage, also had turned accordingly inside horizontal ′ of an angle α (α of α ′ < ) .

In addition, as a result of workpiece find a place for height compares H of central tower above two rounds, and make the osculatory dot of workpiece is in slightly the ′ of some position H under high H, also answer because of position of slate pencil of this King Kong value of deflection H ′ . Main shaft of ① adjustment guide pulley is in the banking angle α inside perpendicular plane. ② correspondence adjusts guide pulley nap implement the circumgyrate horn inside horizontal. D of × of =h of ′ of H of quantity of deflection of slate pencil of ③ computation King Kong guides / (D guides + D) =[13.

350 ÷ of 5 × (350+31) ] Mm=12.

4mm adjusts guide pulley of the nap after parameter, again grinding tappet, if express,measure parallelism outcome 2: From the watch 2 in the result sees, guide pulley is mixed in the banking angle α inside vertical plane guide pulley nap implement when ′ of circumgyrate horn α takes lesser cost, most be helpful for tappet of form of thin wall cup outside round grinding. Should adjust guide pulley and workpiece to achieve when be close to line contact, workpiece circularity and parallelism are best. Such adjustment should be according to different equipment in practice specific fumble. We discover when the experiment, the working rotate speed of guide pulley rises a few, round parallelism also is improved somewhat outside cup form tappet. This explains as guide pulley the banking angle α inside vertical plane is reduced, the working rotate speed of corresponding guide pulley also should be increased a few, be helpful for the improvement of parallelism. 4.

The technique that processes spare parts of body of thin wall cup was discussed in epilogue article, discuss and solved tappet of form of thin wall cup outside in round treatment, incidental outside the circle is out of shape and the problem of bus parallelism out of tolerance, the hope can give a person of the same trade a bit help. CNC Milling