The phenomenon of floating material is a common and bad phenomenon in the hardware mold. The reasons for the production of floating material are various, so the solutions are also diverse. Some of the waste is due to poor hardware mold design, some are due to poor materials, some are due to stamping operators. To make an effective and quick solution, one should first carefully study the types and causes. The following precision metal stamping companies in the hardware mold design experience and friends to share exchanges, improper or inadequate please advise.
I. The type of material
Today, I will first talk about the types of tallow. For tallow, I divide it into three types according to its size and formation factors.
1. Uptick in waste
Scrap is the part that is separated from the product in a single punching (forming) process. Its size is generally the same as the shape of the lower die edge. Its area and harm are the largest among the three phenomena. When this phenomenon occurs, it is possible to make the punch or the knife edge crack or even break, it is possible to make the product lead needle fracture, and it is possible to make the template crack.
2. Poplar on waste debris
Waste is the non - integral product or non - integral waste produced in a single process. Its size is relatively small, like the product of the burr edge (burr) off the formation; cut waste wire and so on. This situation is reflected in the appearance of scratches, scratches, pits or dents in the product. This situation is mainly bad for the product, but this situation is the most common and relatively hidden in mold production.
3. The rise of waste powder
Waste powder refers to the fine powder generated by the friction between the punch and the product in a single process. This phenomenon is generally difficult to find with the naked eye in the early stage of production, and only when the accumulation of a degree, the punch and into the small when the color change is easy to identify. When the waste powder reaches a certain degree, it is easy to cause the punch fracture or the die into the crack. It is most likely to occur in brass and aluminum substrates.
Ii. Reasons for floating materials
1. Scrap on the rise
Waste up first to analyze the cause of the dint, the sources of waste due to the general or lower die and punch edge shape is the same, as a result, the waste within the hardware mold inserts should have certain friction exists, from the principle of the die cutting, waste after cut off because of the existence of material plastic or elastic deformation will get its organizational structure, In OTHER WORDS, THE UNCONSTRAINED ACTUAL shape SHOULD BE LARGER THAN the blade SHAPE of the LOWER DIE, which IS WHY it IS no longer easy to refill the waste material into the lower DIE after it is removed from the INPUT. There should be an upward force that is greater than the sum of friction and tension if the waste is pushed up. This force may come from two directions. One is the tension or elastic force of the scrap material itself. As the scrap material is bent (simply put) and deformed during punching, when the punch is removed from it, the tension inside it will have a rebound force, either downward or upward. The second is the external force, which also has two aspects. When the punch is cut away from the lower die entry, the punch surface and the raw materials (and waste) are closely attached together to form a closed space with the lower die entry to produce a vacuum state. When the punch rises, Destroy this one under the action of vacuum negative pressure of the air inducing waste, with the punch up the phenomenon of waste up, second, in general stamping process, the mould into the son has the waste, overlapping phenomenon, when the latest piece of waste to join, the internal force of other waste itself (rebound) will also be prompted new waste up. So when the stamping speed is very low and there is no scrap accumulation phenomenon, scrap type scrap phenomenon rarely occurs. That's one of the reasons.
2. How is waste debris generated when waste debris rises? There are several cases, one is the product or waste burr (or called hair) off; first, the punch or other parts of the metal mold and the raw material of the abnormal scratch or collision caused by fine waste. This is mainly because the punch in the need to make excessive action on the raw material when there is no corresponding structure; three is due to the raw material has been done before the stamping surface treatment, and the surface treatment layer and the material itself or there is a certain phenomenon of non-structural fusion will make the edge of the material separation off; another is due to the unreasonable design of the mold, there is a second punching (heavy cutting) or too small scrap cutting. Generally speaking, the width of the punching should not be less than 1/3 of the thickness of the material, these too small cutting scrap is easy to break away from the main body of large scrap or due to hardening collapse to form scrap.
3. Reasons for the rise of waste powder
Waste powder is caused by the structural reasons for raw materials. It has been said that aluminum base and brass base materials are prone to this situation. There is no way for raw materials, and the reason for this is that the surface of the punch or the entry has roughness, that is to say, there are pits on its surface under a certain degree of amplification. When the punch or insert touches the raw material, it rubs the raw material (like a file files iron) and creates waste.
Three, floating material countermeasures
1. Through the phenomena and causes of the above two tests, the countermeasures of hardware molds can be analyzed. First, a description of each method of floating waste material.
A. Floating material caused by improper discharge design
This kind of floating material mainly appears in the process of discharging, most of which produce a relatively simple punching shape. Such as square, smaller edge heterorow scrap. This time should be deliberately made in the design process gap; such as trapezoid, dovetail shape. Make the simple punching shape complex, increase the friction of waste material to prevent the rebound of waste material and vacuum suction.
B · Punch hole itself is simple in shape.
Such as round holes, square holes and so on. In this case, the reason for the formation of floating material is to change the rebound direction and reduce the vacuum area. Common methods such as,
1. The punch is ground into a unilateral bevel or a bilateral bevel, which can deform the material, reduce the rebound force inside and outside the material, and reduce the vacuum area.
2. You can also grind a small boss in the center of the round punch when punching the round hole, which has the same effect as the inclined plane, but this method is more effective for the round hole.
3· When the cutting edge is three sides or two sides, it is not necessary to cut off the punch edge to make a certain step, so that when stamping, you can first do a little bending action to make the waste material downward deformation is conducive to the waste material blanking.
4. Cut the punch off the surface to make a corrugated or rough surface, which can be processed by file or electric mill to increase the amount of air and reduce the amount of vacuum.
C · Punch shapes for all possible or floating materials