Sheet metal parts manual correction process
◆ Extension method
The extension method is mainly used for deformations such as concave and convex in the middle of the metal sheet and wavy edges and warping.
◆ Twisting method
The twisting method is used to correct the torsional deformation of the strip. During operation, clamp the strip in a bench vise and use a wrench to twist the strip back to its original shape.
◆ Bending method
The bending method is used to correct various bent bars and strips bent in the width direction.
◆ Stretching method
The stretching method is used to straighten various slender wires.
(1) Correction of convex drum surface:
Place the convex side of the sheet upward on the platform, hold the sheet with your left hand, and hold the hammer with your right hand.
The tapping should start from the edges around the sheet and gradually move towards the center of the drum surface.
After the sheet is basically corrected, use a wooden hammer to perform an adjustment knock to make the entire tissue stretch evenly.
(2) Correction of edge warping:
Place the wavy edge sheet on the platform, hold the sheet with your left hand, and hold the hammer with your right hand.
Start tapping from the middle of the sheet and gradually spread to all sides.
After the sheet is basically corrected, use a wooden hammer to perform an adjustment knock to make the entire tissue stretch evenly.
(4) Slapping correction of sheet metal:
Use a clapper (throwing iron) to slap on the sheet material, so that the convex part of the sheet material is compressed and shortened, and at the same time, the tensioned part is compressed and elongated, thereby achieving the purpose of correction.
(6) Correction of surface depression and deformation:
The jacking iron should be placed slightly away from the hammering point, and the hammering point should be a higher part of the uneven surface. This allows the steel sheet plate to receive force between the top iron and the hammering point.
(7) Correction of large concavities:
First, you can use a blowtorch to heat the middle part of the concave surface to a pink hot state, and then lift it up with a jacking iron on the lower side of the middle part, so that the original depression can be initially reset. Then use the hammer and jacking iron to gradually flatten the surrounding higher parts and restore the original geometric shape.
(8) Correction of large curvature surfaces:
When trimming parts with large surface curvatures (high convex surfaces) such as fenders and fenders, you can first heat them with flames, then lift them up with a jacking iron, and finally hammer them flat to achieve the original shape.
(9) Correction of small dents:
Use the tip of a pick hammer to flatten the depression from the inside out. Use a crowbar to reach into the narrow space and pry the dent out. This method is generally used to pry out dents in car doors, rear fenders and other enclosed body panels. Use a dent puller to smooth out the dent. Mainly used for closed body panels or creases that are inaccessible from behind. Use a pulling rod to flatten the dent, and tap and pull to lower the bulge and raise the dent.
(10) Correction of flat steel distortion:
Clamp the flat steel in a bench vise.
Clamp the other end of the flat bar with a wrench and twist it in the opposite direction of the twist of the flat bar.
After the distortion is basically eliminated, use the hammering method to correct it.
When hammering, place the flat steel at an angle, with the flat part resting on the platform, and the twisted and warped part extending outside the platform.
Use a hammer to tap the upwardly warped part slightly away from the outside of the platform. The distance between the tapping point and the platform is about 2 times the thickness of the metal sheet. While tapping, move the flat steel into the platform. Turn it 180° and perform the same tapping again until it is corrected.
(11) Deformation and correction of angle steel:
Place the outer and inner curved angle steel on the cylindrical anvil or platform with holes.
To bend the angle steel outward, tap the edges of the two right-angled sides, and tap inward from the edge. To bend the angle steel inward, tap the roots of the two right-angled sides.
Clamp one end of the twisted angle steel in a bench vise. Use a wrench to twist in the opposite direction.
(13) Correction of welded parts:
◆ Correction of the angle of L-shaped welding parts
Correction method: For L-shaped weldments composed of two angle steels welded together vertically, the welding angle will change after cooling.
◆ Correction of rectangular frame
Correction method: Figure shows a rectangular weldment. When sides AD and BC of the frame are bilaterally bent, the frame can be erected on the platform with the outer curved edge AD facing up. Pads are placed on both ends of side BC and the convex point E is hammered.
When the size error isn’t too large, stand the frame up and hammer the end of the longer side to shorten its overall length. If ∠B and ∠D are less than 90°, tap point B to expand it.
