Mold plays an extremely important role in modern industry, and its quality directly determines the quality of the product. Improving the service life and accuracy of the mold and shortening the manufacturing cycle of the mold are technical problems that many companies urgently need to solve. However, the failure modes such as collapse, deformation, wear, and even breakage often occur during the use of the mold. So today, the editor will give you an introduction to four ways of mold repair, let’s take a look.
Argon arc welding repair
The welding is carried out by using the arc burning between the continuously fed welding wire and the workpiece as the heat source, and the gas shielded arc sprayed from the welding torch nozzle. At present, argon arc welding is a commonly used method, which can be applied to most major metals, including carbon steel and alloy steel. MIG welding is suitable for stainless steel, aluminum, magnesium, copper, titanium, zirconium and nickel alloys. Due to its low price, it is widely used for mold repair welding. However, it has disadvantages such as large welding heat affected area and large solder joints. Precision mold repair has been gradually replaced by laser welding.
Mold repair machine repair
Mold repair machine is a high-tech equipment to repair mold surface wear and processing defects. The mold repairing machine strengthens the mold to have a long life and good economic benefits. Various iron-based alloys (carbon steel, alloy steel, cast iron), nickel-based alloys and other metal materials can be used to strengthen and repair the surface of molds and workpieces, and greatly increase the service life.
1. The principle of mold repair machine
It uses the principle of high-frequency electric spark discharge to repair the surface defects and wear of the metal mold by non-thermal surfacing welding on the workpiece. The main feature is that the heat affected area is small, the mold will not be deformed after the repair, without annealing, no stress concentration, and no Cracks appear to ensure the integrity of the mold; it can also be used to strengthen the surface of the mold workpiece to meet the performance requirements of the mold’s wear resistance, heat resistance, and corrosion resistance.
2. Scope of application
Die repairing machine can be used in machinery, automobile, light industry, household appliances, petroleum, chemical and electric power industries, for hot extrusion molds, warm extrusion film tools, hot forging molds, rolls and key parts repair and surface strengthening treatment .
For example, the ESD-05 type electric spark surfacing repair machine can be used to repair the injection molds of wear, bruises and scratches, and to repair the rust, fall off and damage of die-casting molds such as zinc-aluminum die-casting molds. The machine power is 900W, the input voltage is AC220V, the frequency is 50~500Hz, the voltage range is 20~100V, and the output percentage is 10%~100%.
Brush plating repair
Brush plating technology uses a special DC power supply device. The positive pole of the power supply is connected to a plating pen as the anode during brush plating; the negative pole of the power supply is connected to the workpiece as the cathode during brush plating. The plating pen usually uses high purity fine graphite blocks as The anode material, the graphite block is wrapped with cotton and a wear-resistant polyester cotton sleeve.
When working, the power supply assembly is adjusted to the appropriate voltage, and the plating pen filled with the plating solution is moved at a certain relative speed at the contact part of the surface of the repaired workpiece. The metal ions in the plating solution diffuse to the workpiece under the action of the electric field force. On the surface, the electrons obtained on the surface are reduced to metal atoms, so that these metal atoms are deposited and crystallized to form a coating, that is, to obtain the required uniform deposition layer on the working surface of the plastic mold cavity to be repaired.
Plasma surfacing machine, plasma spray welding machine, shaft surfacing repair
Laser surfacing repair
Laser welding is a welding in which a laser beam is used as a heat source by focusing on a high-power coherent monochromatic photon stream. This welding method usually includes continuous power laser welding and pulsed power laser welding. The advantage of laser welding is that it does not need to be carried out in a vacuum, but the disadvantage is that the penetrating power is not as strong as electron beam welding. Accurate energy control can be carried out during laser welding, so that the welding of precision devices can be realized. It can be applied to many metals, especially to solve the welding of some difficult-to-weld metals and dissimilar metals. It has been widely used for mold repair.
Laser cladding technology
The laser surface cladding technology is to rapidly heat and melt the alloy powder or ceramic powder and the surface of the substrate under the action of a laser beam. After the beam is removed, the self-excited cooling forms a surface coating with a very low dilution rate and a metallurgical combination with the substrate material. , So as to significantly improve the surface of the substrate abrasion resistance, corrosion resistance, heat resistance, oxidation resistance and electrical characteristics of a surface strengthening method.
For example, after carbon-tungsten laser cladding of 60# steel, the hardness is up to 2200HV or more, and the wear resistance is about 20 times that of the base 60# steel. After laser cladding CoCrSiB alloy on the surface of Q235 steel, the wear resistance and the corrosion resistance of flame spraying were compared, and it was found that the corrosion resistance of the former was significantly higher than that of the latter.
Laser cladding can be divided into two categories according to different powder feeding processes: powder preset method and synchronous powder feeding method. The effects of the two methods are similar. The synchronous powder feeding method has easy automatic control, high laser energy absorption rate, no internal pores, especially cladding cermet, which can significantly improve the anti-cracking performance of the cladding layer, so that the hard ceramic phase can be The advantages of uniform distribution in the cladding layer.