When the general drawing shape is a square tube, near the center of the straight side wall, there may be a large-scale drawing cracking phenomenon.
①drawing height is too large:
For the use of reducing the depth of drawing to prevent cracking, other reasons must be checked first. After all the conditions are checked and there is no problem, the problem still occurs, and the method of reducing the stretching height can be used, and a set of stretching and shaping procedures can be added.
②die fillet radius is too small:
When the square tube is deep-drawn, the measure to prevent the springback sag on the side wall of the straight side is generally to use the method of drawing the bead, but this method has the defect of causing the bead scar.
Therefore, when drawing without using drawbeads, as a measure for drawing forming, make the gap slightly smaller than the plate thickness, and at the same time, select the drawing method in the state where the angle is too small. If cracks occur beyond the tensile limit, the angle can be slightly increased and then a trial drawing can be performed.
2: Stamping conditions
①. Excessive blank holder force:
The flange surface is all shiny, indicating that the blank holder force is too large, and the blank holder force can be reduced to the point where the material is allowed to flow in without wrinkling.
② Poor lubrication of the die surface:
To make it easy for materials to flow in, it is necessary to check the type and amount of lubricating oil.
3: Mold problem
①Die surface processing and coordination is not good:
While the product is cracked, there are scratches on the flange surface, so it is necessary to use a grinding wheel to polish it well to achieve the condition that the material flows easily.
②the gap is too small:
When the side wall of the product is shiny and cracked, it is because the side wall is too thin, so the gap needs to be adjusted.
③the position and shape of the deep drawing bead are bad:
Due to the excessive force of the drawn bead, there are many cases of rupture, so the force of the drawn bead should be reduced.
④poor mold precision:
The precision of the mold is poor, and the core is offset; the parallelism and verticality of the punch and the die are not good. If the mold is checked in advance, there will be no problems in the trial drawing
⑤ Insufficient rigidity of blank holder:
When the rigidity of the blank holder is insufficient, only a few buffer pins will be violently stretched and cracked.
⑥Poor precision of the press:
When the precision of the press is not good, it will produce the same defects as the poor precision of the mold. Before the test drawing, the machine tool must be kept in a high-precision state, and the test drawing must be carried out.
①. When the defect is caused by insufficient tensile strength of the material and excessive grain size, it is necessary to change the material
②. When defects occur due to insufficient thickness of the plate, it is necessary to increase the thickness of the plate.
Balford has passed ISO9001 in 2017. We has over ten years experience on manufacturing motor housing, solenoid valve housing and sensor housing, focused on auto parts.Now Balford enter into solenoid valve housings and sensor housings industry that are mainly based on difficult deep drawing process.
We employ documented procedures for every step in the manufacturing process from initial program launch through steady-state production in order to ensure consistent performance. We engineer our processes to produce the desired results, monitor those results, and use what we learn to regularly refine our processes as part of our commitment to continuous process and efficiency improvement.
Many of our customers have been with us for 5-8 years or more. Year after year, they experience zero late deliveries and zero returns.