![<?echo $_SERVER['SERVER_NAME'];?>](/template/twentyseventeen/skin/images/header.jpg)
Selection of materials and materials The material is initially used as the material. The first process is roughing the outer circle and the car is <40H8 hole. The second process uses the tensioning sleeve to make the outer circle. However, due to the force of the force, the workpiece is deformed to a large extent, resulting in waste. And because of the different positioning criteria, the coaxiality is difficult to guarantee. Then use the component.
The change of the diameter of the inner and outer walls caused by the temperature rise of the workpiece after hot deformation processing can be estimated by the following formula: ΔD=αDΔt where: the increase of the inner and outer diameter of ΔD???, mm; the coefficient of linear expansion of α?, mmΠ°C ; (α steel = 1.07 ~ 1.22 × 10-5mm Π° C; α cast iron = 1.0 ~ 1.10 × 10-5 Π° C) D ??? medium diameter, D = (inner diameter + outer diameter) Π2, mm; Δt ??? temperature The amount of change, °C.
For example, in the actual machining process, α steel = 1.1 × 10 -5 Π° C, ΔD = 43, Δt = 20, then ΔD = 1.1 × 10 - 5 × 43 × 20 = 0.0095 mm. Therefore, when processing thin-walled parts, a large amount of cooling It is also very necessary.
Process equipment Because CNC lathes and standardized tools greatly reduce human factors, we only study two factors. The jacket can be used to prevent deformation of the part caused by the clamping force when machining the end face, and can also be used for positioning.
Rod Deflection Deformation The sleeve part has a hole depth of 77 mm and an inner diameter of 40 mm. A <25 x 4 or <30 x 3 boring knife can be used. During the process of fine inner bore, the arbor must be bent, and the formula for calculating the deflection of the mast: f=64pl33EÏ€d2 where: f???flexibility, mm; P??? radial cutting force, N; l??? mast Effective use length, mm; E??? mast elastic modulus, GPa; d??? mast diameter, mm.
When using ordinary mast, p=120, l=80, E=210, d=25, then f=64×120×8033×210×106×3.14×252=0.0064mm The operation and operation problems are mainly concentrated on finishing. Feed rate, removal of internal hole chips, and three aspects of tool setting.
Finishing feed F (mmÎ r). During the finishing process, due to Ra=3.2 or 1.6, the rounded r(mm) value of the finishing insert is 0.4 and 0.8, and the depth of cut is about 0.5 to 1. The feed amount F can be determined theoretically.
F = 8Rar If Ra = 3.2, r = 0.4, then F = 8 × 3.2 × 10 -3 × 0.4 = 0.1 mm Πr storage area is indicated. 3.3 pairs of knives. In the process of knives, the operator needs to have rich operational experience. In addition to the normal operation, the above factors of thermal deformation and shank deflection must be fully considered, and the tool tip compensation adjustment should be carried out on the basis of trial cutting. When the workpiece and process equipment reach the heat exchange balance, the tool nose compensation data can be stabilized.
Step: Determine the brief procedure for machining the part. Qi end face, borehole waste; rough car <46h6 outer circle, <40H8 inner circle; fine car <46h6 outer circle, <40H8 inner circle, chamfer and cut. Qi left end face, chamfered.
In summary, we can theoretically estimate the main factors affecting the machining accuracy when processing thin-walled parts. In practice, many detours can be avoided. Some of the empirical formulas, the craftsman and the operator can make the best calculation results by making appropriate modifications according to different materials, different tools and cutting parameters.
(Finish)
Wire Mesh Decking,Decking Mesh,Steel Mesh Decking,Metal Mesh Decking
Nanjing Chinylion Metal Products Co., Ltd , https://www.clrack.com