Technology of extruding of aluminium alloy nicety

4 Mm, its public errand asks to be ± 0.

04mm. Extruding production process asks to comparative to pattern of equipment, industry, craft strict. Call skill of this kind of extruding normally accurate extruding [1-3] . Example of profile of 1 accurate aluminous extruding has the public errand of aluminous profile of a few small-sized nicety to compare the public errand of special class in JIS standard to return above of small in part, the dimension public errand that general and accurate aluminous profile asks is in ± 0.

04 ～ ± 0.

Between 07mm. The section of aluminous profile of small-sized and accurate extruding shows the share at the graph 1. Graph voltage of citing of section of 1 small-sized and accurate aluminous profile plan section of used accurate aluminous profile is " ︼ " M of ／ of profile weight 30 G, limits of section dimension public errand is ± 0 07 Mm. The section of accurate aluminous profile that loom uses is " ■ " , section dimension public errand is ± 0.

04mm, angle deviation is less than 0.

5 ° , flexibility is 0.

83 × L. A1050, A1100, A3003, A6061, A6063 (low, medium intensity alloy) the least wall of profile of small-sized and accurate extruding is large 0.

5mm, the least section accumulates 20mm2. A5083, A2024, A7075, (aluminium alloy of medium, high strenth) the least wall of profile of small-sized and accurate extruding is large 0.

9mm, the least section accumulates 110mm2. Citing of public errand of dimension of small-sized and accurate aluminous profile is shown 2 times like the graph. Graph dimension of citing of public errand of dimension of 2 accurate aluminous profile / Mm dimension allows common difference / special class of JIS of Mm 　 　 is small-sized, accurate 　 A 2.

54 ± 0.

15 ± 0.

B 1 of 07 　 　 .

78 ± 0.

15 ± 0.

C 3 of 07 　 　 .

23 ± 0.

19 ± 0.

Requirement of technology of 2 accurate extruding says 07 　 　 commonly, deformation of aluminium alloy hot extruding is big, of pattern of pair of neutral of equipment of the change of extruding temperature and speed, extruding, industry be out of shape wait to be opposite easily the precision of profile dimension produces an effect, and they mutual influencing factor is overcome very hard. Graph the influencing factor that 3 listed nicety squash. 2.

The requirement mould of pattern of 1 pair of industry is the element with the directest precision of measure of influence extruding product, should assure dimension of section of extruding goods aborning changeless or change is very little, must make the tigidity of the mould, hear resistance, wearability achieves particular demand. Graph influencing factor of precision of 3 extruding profile should assure a mould to be out of shape not easily below high temperature high pressure above all, have very tall hear resistance, to accurate extruding character is more strict, the requirement is working temperature (500 ℃ are controlled) below, of mould material succumb intensity is not less than 1200N/mm2. Need to have tall wearability next, this basically changes a hardness and ply on nitrogen definitely, the hardness that asks nitrogen changes a layer commonly is in 1150HV above, nitrogen changes a deepness to be in 0.

25 Mm ～ 0.

Between 45mm, and the change of dimension of the mould after nitrogen is changed should be in 0.

02mm less than. Have the sincere profile that hangs a wall and hollow profile to section, the flexibility that considers a pattern even is out of shape, to make the mould assures certain stiffness, can consider to add the ply of the mould or the special pad that match appearance likeness appropriately. To control the change of profile mouth dimension, can control metallic flow in launder of the channel on matrix, if pursue,4 are shown. The scheme leaves diversion chamfer 　 on 4 matrix 2. Method of extruding of requirement of craft of 2 pairs of extruding is influential to the precision of goods. Appearing easily commonly to extruding front (begin to push a share) the wall that compares back end is large bigger phenomenon, the profound change of around end wall of retrorse extruding goods is very little, if pursue,5 are shown. Because this is used,squash to control the precision of product measure more easily instead. Extruding products falls cooling meeting to produce systole to be out of shape in hot condition. S% is its deflection: The extruding of alloy of 5 A7075 of graph of positional ／ M of edge extruding direction dimension of material changes in type: S ％ -- shrinkage; Lt -- the section dimension of hot condition; L0 -- the section dimension after refrigeration; A -- hot coefficient of expansion; Te -- extruding temperature; Ts -- surroundings temperature. By (L) type is knowable, the change of temperature can cause the change of product measure, temperature change is bigger, its deflection is bigger, what should assure product measure accordingly is accurate, extruder is due Tips controls a system (isothermal extruding system) . Use isothermal extruding namely. If extruder does not have this kind of device, to aluminium the club can use gradient to heat, accomplish approximate and isothermal extruding, temperature of the back end before anyhow should assure goods agrees or differ lesser. Additional, from (1) type can see, extruding temperature is higher, of generation be out of shape bigger, because this is in,make sure products is mechanical below function circumstance, will use inferior extruding temperature as far as possible. The change of extruding speed also can make the dimension of goods produces change, especially ringent goods makes the change of dimension of step aside mouth easily, should use wait for fast extruding, contemporary extruder to commonly Fi controls a system (wait for fast extruding to control a system) . The refrigeration that goods comes out from extrusion die aperture is crucial, must keep even, constant cooling rate, make the systole of goods keeps consistent. 2.

The character of the requirement extruder of 3 pairs of equipment affects the precision of extruding goods. Column of tension of general requirement extruder is the integral structure of prestressing force, the stiffness of equipment and be close friends to neuter, canister of general extruding axis, extruding, mould, send the biggest tolerance is less than between makings manipulator 1.

5mm, normally control is in 1.

2mm less than. To accurate extruding, deviation of center of lever of canister of mould, extruding, extruding should is less than 0.

System of control of due and isothermal extruding mixes the extruder that 2mm uses at accurate extruding wait for fast extruding to control a system, at least due wait for fast extruding control. Besides, the mould is due and cooling device, the stability of the tigidity that ensures the mould falls in constant temperature, wearability and dimension. 2.

The composition of the requirement casting club with great qualitative ability of 4 pairs of casting, organization is inhomogenous, have be mingled with, slant analyse, grain is bulky the flow that waits for blemish to be able to affect a metal and be out of shape, make the dimension of goods produces mutation. To accurate extruding, qualitative to the material of casting club requirement is more strict, must handle through be being changed equably, grain should be controlled in one class less than. Nicety of 3 last words squashs is an omnibus technology. The material of requirement mould qualitative, design, make very strict; Extruder must be advanced equipment; Choose different extruding method and technology according to different goods section; Aluminous club needs to be handled via be being changed equably, its organization, function must even. Only such ability satisfy the requirement of accurate extruding. CNC Milling