Stamping is a technological method that applies pressure to the material by using the die on the press at room temperature to separate or deform the material so as to obtain the required parts. Stamping die is a special process equipment that makes metal materials into parts during stamping.
The die is usually made into the basic shape of the die by forging process, and then is finished by ultra-precision milling process by numerical control machine tools. The performance of the stamping die determines the workpiece precision and process efficiency.
What are the performance characteristics of the lower die briefly introduced by Yixin Precision Metal and Plastic Ltd.:
First, the characteristics of mold performance
(1) wear resistance
When the blank is deformed in the mold cavity, it flows and slides along the surface of the mold cavity, causing severe friction between the surface of the mold cavity and the blank, thus causing the mold to fail due to wear. Therefore, the wear resistance of the material is one of the most basic and important properties of the mold.
(2) Strength and toughness
The mould often bears large impact load, which leads to brittle fracture. In order to prevent sudden brittle fracture of mold parts, the mold must have higher strength and toughness.
(3) Fatigue fracture performance
Under the long-term action of cyclic stress, the die often leads to fatigue fracture. It takes the form of small energy multiple impact fatigue fracture, tensile fatigue fracture, contact fatigue fracture and bending fatigue fracture.
(4) high temperature performance
When the mold temperature is high, the hardness and strength will decrease, leading to early wear or deformation of the mold and failure.
(5) cold and hot fatigue resistance
Some molds are in a state of repeated heating and cooling, which causes the surface of the cavity to be pulled and the pressure to change stress, causing surface cracking and peeling, increasing friction force, hindering workpiece deformation and reducing dimensional accuracy, thus leading to mold failure.
(6) corrosion resistance
Some dies are affected by the process environment, which erodes the surface of the die cavity, increases its surface roughness and intensifies wear failure.
(7) geometric parameters
The shape, fit clearance and fillet radius of the die not only have great influence on the forming of stamping parts, but also on the wear and life of the die.
Second, the type of mold material
(1) composite materials
Composite materials are extremely wear-resistant and tough, so it is difficult to use conventional milling tools to make molds. It can be easily handled by using a hard, sharp and integral hard alloy milling cutter with a special surface coating. In addition, fiber content and fiber direction also have a significant impact on the process (determining cutting speed, feed rate and optimal tool path).
(2) titanium alloy
The main factors that titanium alloy has lower machinability are its lower thermal conductivity, higher adhesion and hardening. The tool for titanium alloy mold has excellent performance, but its universality may be poor when dealing with many different materials. When the workpiece geometry is extremely complex, or if a large cutting depth is required, an integral hard alloy tool should be used.
Inconel (nickel-based superalloy) is the most difficult material to make moulds. They have extremely low thermal conductivity and extremely high strain hardening, even higher than titanium alloy. Therefore, the longer the contact time between the tool inclination angle and the material, the greater the abrasion of the tool. In order to further reduce the friction between the tool and Inconel, an aluminum titanium nitride coating is adopted. The coating has been polished and has extremely smooth and fine surface roughness.
These are the performance characteristics that the stamping die must have. The die milling process is to a large extent restricted by the tool material, workpiece hardness, cutting oil performance, etc. Therefore, many adjustments are required to make it fully applicable to meet the process requirements when milling the die.
We are yixin precision metal and plastic ltd, specializing in the production and processing of various small stamping parts. If you need to customize some small parts, you can always find us. No matter what the order is, we can do it in quantity.