Stretch-bending and roll-bending processing
Stretch-bending and roll-bending processing are two commonly used stretch-bending processes for aluminum profile bending manufacturers.
Stretch-bending process
The stretch-bending process requires higher precision, larger length and curvature radius requirements, and smaller transverse dimensions for bending parts. Stretch bending is performed on a dedicated stretch bending machine.
During stretching and bending, the entire thickness of the plate is subjected to tensile stress, so only elongation deformation occurs, and the deformation caused by spring-back after unloading is small, which is easy to ensure accuracy.
If you want to compare the process methods between stretch bending and roll bending, you need to compare the following aspects:
Suppress straight profile sinking
Using a universal sinking die to suppress sinking for straight profiles.
Make holes
There are a lot of pilot holes on the profile parts that need to be processed. The drilling method is relatively flexible and can be used for parts of different sizes and thicknesses. The quality of the holes obtained is higher, and it is currently the most widely used.
The punching method is more efficient than drilling, and it is worthy of promotion.
Make bevel
The oblique angle of the general straight profile can be stamped with an oblique die.
The bevel angle of the profile part with curvature is generally made simultaneously in the bending process.
Making gaps
The edge milling work of the long stringer and the beam edge is generally processed by vertical milling or arm milling according to the template (model).
The structure of the die for punching the small corners of the pillar and other end shapes is simple and simple.
Profile inspection
The inspection items of profiles are surface Quality, appearance, length, angle, sag, etc.
Surface Quality:
In addition to the surface of the profile, there should be no deep hammer marks and shrinkage machine tooth marks. The most important thing is that no cracks are allowed.
Profile shape:
The shape can be inspected according to the shape template, inspection template, or three-dimensional inspection mold.
The shape template is used for the inspection of general single-curvature profiles;
The inspection template is used for the inspection of mass production parts with large output and high-quality requirements;
Hyperbolic complex profiles generally require special inspection equipment. A combined template frame or a rubber-sand reverse mold tire can be used according to the different component coordination systems.
Poor profile outside description
The allowable deviation of profile shape is:
±0.2- 0.3mm related to the shape of the aircraft ±0.5mm not related to the shape of the aircraft
The unevenness of the profile web:
The gap between the flat or curved web of the straight profile and the inspection platform should not exceed 0.5mm when the profile length is less than 500mm, and should not exceed 1mm if the length is greater than 500mm.
The bevel angle of profile:
The angle (bevel) tolerance of contour parts is ±30′, and that of non-contour parts is ±10.
Profile length:
The deviation of the length of the profile relative to the sample plate or drawing is ±1?1.5mm.
Thickness and width of the profile:
When the relative bending radius is less than 5, the thinning of the edge strip is allowed up to 30%, and the width change is allowed up to 10%.
Sag depth and length:
The allowable deviation of the profile sink depth H: +0.3mm for depths below 1.5mm; +0.5mm for depths above 1.5mm;
The tolerance of the sag length l is +1~2mm.
Notch depth:
The allowable deviation of the profile edge milling notch depth is ±0.5mm.
Offset
The offset of the center of the assembly hole relative to the template is 0.3mm, and the offset of the pilot hole is 0.5mm.