Electro Spark Deposition (ESD) is the international term for the cold welding machine, which was developed by former Soviet experts through research into the circuit principles of electro discharge machining.
Its main purpose is to coat mold/metal surfaces with high hardness materials such as tungsten carbide to improve wear resistance, heat resistance, anti-sticking and other properties.
Initially, the maximum coating thickness of the machine was only 30 μm, so it could not meet the repair needs.
After extensive research and development, its output power has been improved, and the structure of the welding gun and the material composition of the welding rod have been improved.
In response to the previous front-rear vibration electrode, a rotating electrode was used and argon shielding was used to prevent oxidation and nitriding of the molten metal, achieving continuous multi-layer repair welding, improving the thickness of the repair welding and pushing it to market as a mold/metal repair machine.
For injection molding manufacturers without mold manufacturing departments, if traditional welding methods are used to repair molds when burrs appear on molded products, the molds will deform or even crack due to the heat generated.
If there is no equipment such as EDM or milling machines to cut off excess weld metal, only high repair costs can be incurred to entrust the repair to the mold manufacturer. During the repair period, machine downtime will cause delays in delivery.
On the contrary, if our company's mold repair cold welding machine is used for repair, there will be no deformation, sharp edge and other defects, and the mold can be easily repaired.
Excess weld metal can be controlled by a few wires. There is no need for special precision machining machines, just small polishing machines, grinding machines, files, oil stones and other tools for manual precision machining.
Injection molding manufacturers can easily repair the mold cutting surface where burrs appear by themselves, which is time-saving and cost-effective.
Introduction to self-made mold repair cold welding machine:
1. Working principle:
The principle of mold repair cold welding machine is to use a charged capacitor to discharge with a period of 10^-3 to 10^-1 seconds and an ultrashort time of 10^-6 to 10^-5 seconds.
The electrode material and the contact part of the mold will be heated to 8000-12000°C, and the molten metal in the plasma state will transition to the surface layer of the workpiece in a metallurgical way.
Figure 1 shows a schematic diagram and various features (welding, coating). Area A is the coating or layer of weld welded to the surface of the workpiece.
Due to the alloying effect between it and the base material, it diffuses and infiltrates the interior of the part, forming a diffusion layer B and obtaining a high-resistance bond.
2. Achieve cold welding (low heat input):
Why can cold welding be achieved? As shown in Figure 2, the discharge time (Pt) is extremely short compared to the interval time (It) until the next discharge, and the machine has sufficient relative stopping time.
Heat will diffuse through the mold base to the outside world, so there will be no heat buildup in the processed part of the mold.
Although the temperature rise of the mold remains almost at room temperature, due to instantaneous melting, the temperature at the electrode tip can reach about 1000°C.
3. High bond strength:
When using the mold repair cold welding machine for repair welding, since the heat input is low, why is the bonding strength still very high?
This is because the welding rod produces metal droplets instantly, transitions to the metal contact part of the base material, and at the same time, due to the high temperature effect of the plasma arc, a strong root-like diffusion layer is formed at the deep surface (as shown by B in Figure 1). It shows high binding capacity and will not fall off.
Figure 3 is a schematic diagram of the processing principle:
4. Features of mold repair cold welding machine:
Achieve true cold welding and the workpiece does not need to be preheated or insulated during the repair process. There is no heat input during the instantaneous welding process, so the workpiece will not deform, anneal, edge bite or have residual stress, and will not change the status of the metal structure of the workpiece.
High bond strength for repair welding. Because the welding rod is instantly ionized by the arc and transferred to the workpiece in contact with it, the bonding strength is high and will not drop.
High repair precision. The thickness of the coating can vary from a few micrometers to several millimeters, requiring only polishing. It can also be machined by turning, milling, planing, grinding, electroplating, etc.
Multifunctional use. It can perform functions such as repair welding and surface strengthening.
High economic practicality. It can be repaired online on site, improve production efficiency and save time and costs. It's also easy to use. Anyone can operate it after a short period of training.
Wide range of applicable substrates, including various types of mold steel, stainless steel, tool steel, cast iron, cast aluminum, aluminum alloy, copper alloy, nickel alloy and all conductive conductors.
Good environmental performance, no noise, dust, liquid residue, strong light or odor.
Even if the repaired weld layer is worn out, it can be repaired several times in the same location.
By using inert gases such as argon for shielding, high-quality weld layers can be obtained.
Since a rotating welding rod is used, there will be no wire stuck phenomenon. It is easy to operate and can obtain high-quality weld layers, and the excess weld metal can be controlled to a small amount, saving precision machining time.
The principle of spark welding repair machine:
Our company's spark welding repair machine adopts advanced German cold welding repair and strengthening technology. It uses the principle of high-frequency electric spark discharge to perform heatless welding on the workpiece to repair surface defects and wear of metal parts, ensuring the integrity of the workpiece.
It can also use the reinforcement function of the spark welding machine to carry out reinforcement treatment on the workpiece, achieving wear resistance, heat resistance, corrosion resistance, etc.
After the metal part is repaired by the spark welding repair machine, it does not deform, anneal, has high welding strength and is wear-resistant. It can be tested by metallography, tensile strength and hardness tests.
The metallurgical combination of the welding material and substrate guarantees the firmness of the welding. This compensates for the shortcomings of ordinary argon arc welding and electric welding.
The spark welding machine can be used to weld narrow parts, parts with deep cavities and extremely hard materials without cracks or sand holes, nor does it cause deformation or concave phenomenon around the weld pool of the workpiece.
The spark welding machine uses argon gas protection and the welded area does not oxidize or turn blue. Using a microscope to observe the operation, even small parts are clear at a glance.
After welding, the surface can be mirror polished, suitable for welding and reinforcement repair of various materials.
The welding point of the spark welding machine can be adjusted from 0.2mm to 2.0mm, and it can weld metal sheets as thin as 0.2mm without breaking the sheet, and the weld is uniform and beautiful.
Spark welding repair machine is an indispensable repair and reinforcement tool for all processing, manufacturing, maintenance and surface treatment enterprises.
At the same time, spark welding machine is also a good helper for individuals involved in the special repair industry to get rich quick.
Disadvantages of traditional repair:
After traditional repair, the workpiece may deform, reduce hardness, have sand holes, local annealing, cracks, holes, wear, scratches, bitten edges or insufficient bond strength, internal stress damage and even scrap. The resulting losses in manpower, material resources and financial resources cannot be calculated.
Features of Electric Spark Pile Welding Repair Machine:
- No annealing and deformation of the mold/workpiece: No preheating is required for the mold and there is no heat input during the instantaneous stack welding process, so there is no deformation, undercutting, residual stress, no local annealing and no change in the organization of the mold or metal product.
- High welding strength: Fully penetrates the surface of the mold material, producing strong bonding strength.
- High repair precision: The welding thickness of the pile ranges from a few microns to several millimeters and can be polished and repaired without color difference.
- Multifunctional: It can perform pile welding and surface strengthening functions.
- Environmental protection: No pollution during the working process.
- Easy to Operate: Anyone can use it easily, and stack welding can be carried out in difficult-to-weld areas. By adjusting the discharge power and frequency with the regulator, the thickness and smoothness required for welding and pile reinforcement can be obtained.
- Economical and convenient: Immediate on-site repair, improving production efficiency and saving costs.
Adaptation range of electric spark pile welding repair machine:
Punching dies, forging dies, injection molds, casting molds, pressure casting molds, metal products, machine parts, tools.
Materials applicable to electric spark pile welding repair machine:
Aluminum, aluminum alloy, copper, copper alloy, low carbon steel, medium carbon steel, die steel, carbon steel, stainless steel, full steel, semi-steel, cast steel, cast iron, cast aluminum, gold carbon tungsten and all conductive conductors.
Defects that can be repaired by a spark pile electric welding repair machine:
Holes, air holes, burrs, burrs, bumps, scratches, broken corners, collapsed corners, sand holes, cracks, wear, interior, manufacturing errors, manufacturing defects, welding defects.
Defective parts that can be repaired by a spark pile electric welding repair machine:
Corners, sharp edges, grooves, side walls, bottoms, deep cavities, planes, parting lines, on-site repairs during production operations.
Electric Spark Pile Welding Repair Machine Specifications:
| Model | XKS-01 | KS-02 |
| Input voltage (V) | 220V single phase 50Hz/60hz2 | 220V single phase 50Hz/60Hz |
| Maximum output power (W) | 1800 | 1800 |
| Secondary output voltage (V) | 20-160 | 20-160 |
| Maximum capacitor capacitance (uf) | 480 | 560 |
| Variable frequency range (discharge frequency/second) | 40-2100（HZ） | 40-2100（HZ） |
| Part temperature during welding repair (℃) | 20-85 | 20-85 |
| Solder joint temperature (℃) | 8,000-10,000 | 3,000-10,000 |
| Welding wire (mm) | 1.0-3.2 | .10-3.2 |
| Dimensions (length * width * height) | 460*300*360 | 465*315*385 |
| Weight (net weight kg) | 28 | 30 |
| Main consumables. | Protective lenses, welding wires, argon gas, electricity. | |
Comparison of various repair methods:
Comparison of electric spark pile welding repair machine with other argon arc welding and laser welding.
| Item | Electric Spark Surface Repair Machine | Argon Arc Welding | laser welding | |
| 1. Heat entry into the mold | low | Very high | low | |
| 2. Mold deformation and undercut | anything | big | Small | |
| 3. Bond strength with base metal | good | good | good | |
| 4. Thickness that can be overlapped (mm) | <3 | >1 | >0.3 | |
| 5. Overlap welding thickness control | Very easy. | Very difficult | hard | |
| 6. The difficulty of overlapping welding at edges and corners | Very easy | easily | Very easy | |
| 7. Hole Filling | easily | easily | easily | |
| 8. Surface welding of the bottom surface of the pore groove side wall | Very easy | hard | hard | |
| 9. Overlap welding speed | fast | Very fast | fast | |
| 10. Fine processing | Method | Handmade | EIM – Mechanical Processing | Handmade |
| Time required | short | far away | secondary | |
| 11. Total time for paving+finishing | fast | far away | secondary | |
| 12. Dimensions of repairable molds | Big Small | Medium to large | Small | |
| 13. Dimensions of the welding machine | Small and medium size | average size | big | |
| 14. Can be repaired on site | he can | Should not | Should not | |
| 15. Overlap welding direction | Both forward and up and down options are available | below | below | |
| 16. Need for preheating and isolation of the mold | there is no necessity | to need | there is no necessity | |
| 17. Applicable Materials | Steel, aluminum, copper alloys, etc. | Steel, aluminum | Steel, aluminum | |
| 18. Consumables | metal bars | Welding Wire | Welding Wire | |
| 19. Protective gas | argon | argon | argon | |
| 20. Precision manual processing can be carried out | he can | Should not | he can | |
| 21. Hard material coatings can be applied | he can | Should not | Should not | |
| 22. Total Cost Required for Welding Repair | Low cost | Dear | commonly | |
| 23. Price | Low | Average | high | |
| 24. Operator Safety | security | Intense ultraviolet radiation | Irradiation | |
Application range of electric spark pile welding repair machine:
- Large mechanical equipment
- Cylinder body, seals
- Cast iron parts, cast steel parts
- Aluminum molds, aluminum alloy products
- Steel molds and their products
