CN116288333A - Laser cladding method for manufacturing cladding layer on side surface of screw rib of screw - Google Patents

Abstract

A laser cladding method for manufacturing cladding layers on the side surfaces of screw edges of screws comprises the steps that laser cladding devices capable of carrying out laser cladding on screw edges with set sizes are placed on two sides of the screw edges, then screw rotation and laser beam translation are controlled, continuous laser beams are synchronously carried out laser cladding on the surfaces of the two sides of the screw edges by the laser cladding devices through program control, and cladding layers with different performances are respectively manufactured according to different working surfaces on the two sides of the screw edges of the screws, and the laser cladding method has the advantages that: the surface of the screw rib of the injection molding machine is modified by the laser cladding technology, and compared with the traditional flame surfacing technology, the defects of air holes, poor combination and the like of the coating are eliminated. And the efficiency of screw surface strengthening is improved by a laser synchronous cladding mode. Aiming at different working surfaces on two sides of the screw, metal powder with different functions is synchronously clad, and a high-hardness wear-resistant coating and a corrosion-resistant coating are respectively prepared, so that the service life of the screw is greatly prolonged, and the surface strengthening cost of the screw is reduced.

Description

A laser cladding method for making the cladding layer on the side of the screw flight

technical field

The invention relates to the technical field of laser surface cladding on the side of a screw flight, in particular to a laser cladding method for making a cladding layer on the side of a screw flight.

Background technique

The barrel and screw are the key parts of the injection molding machine. During the production of plastic products, plastic particles and fillers enter the barrel of the injection molding machine from the tail, and the screw rotates at high speed in the barrel to push the plastic particles and fillers forward. Mixed and plasticized, injected into the cavity from the head of the screw. At this time, the barrel and the screw are subjected to certain high temperature and high pressure, and the working temperature of the screw is different for different plastics. The screw and the barrel are often scrapped due to the excessive gap caused by wear and tear, which cannot be squeezed and injected normally. Abrasion increases the gap between the screw flight and the barrel, which reduces the melting rate and pumping capacity, causes uneven material temperature and pressure fluctuations, reduces product quality, reduces productivity, and increases energy consumption. Compared with the barrel, the screw is more prone to damage and failure.

Laser cladding technology refers to the technology of using laser as a heat source to heat and melt the powder to be clad, and cladding a layer of fused layer on the surface of the substrate through preset or synchronous methods. The cladding layer can improve the friction and wear resistance, corrosion resistance and oxidation resistance of the base material. This cladding method has the advantages of concentrated energy density, the formation of a metallurgical junction between the prepared cladding layer and the substrate, an interdiffusion transition layer, high bonding strength, and a relatively low dilution rate of the substrate to the cladding layer. The front and rear ends of the screw blade are damaged at the same time, but because the front end of the screw pushes the extruded molten plastic forward, the front end is mainly damaged by abrasion, while the rear end is relatively damaged by corrosion. Therefore, it has become a very urgent task to carry out different emphases on cladding repair and strengthening for the front and rear ends.

Contents of the invention

The technical problem to be solved by the present invention is to provide a laser cladding method for making a cladding layer on the side of the screw flight in view of the above-mentioned current state of the art; Cladding layers with different properties are simultaneously clad on the main and secondary working surfaces of the screw flight, increasing the wear resistance and corrosion resistance of the side of the screw flight.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: the laser cladding method for making the cladding layer on the side of the screw flight, which is characterized in that it includes a laser cladding method that can carry out laser cladding on the screw flight of the set size The laser cladding device is placed on both sides of the screw flight, and then controls the rotation of the screw and the translational movement of the laser beam. The laser cladding device performs laser cladding on the two sides of the screw flight with the continuous laser beam through program control, and presses the screw flight. Cladding layers with different properties are made on different working surfaces on both sides of the rib. The cladding layer with different properties refers to the high-hardness and wear-resistant cladding layer on the main working surface of the screw rib, and the cladding layer on the secondary working surface of the screw rib. Make corrosion-resistant cladding layer on it.

As an improvement, the cladding layer can be selected as a high-hard wear-resistant cladding layer first, and then the corrosion-resistant cladding layer is made after the high-hard wear-resistant cladding layer is produced, or the cladding layer is selected as the first Make a corrosion-resistant cladding layer, and then make a high-hard and wear-resistant cladding layer after the corrosion-resistant cladding layer is completed.

As an improvement, the cladding layer can first be selected as a high-hard wear-resistant cladding layer and a corrosion-resistant cladding layer, and the laser cladding device for making the high-hard wear-resistant cladding layer and the laser cladding device for making the corrosion-resistant cladding layer are combined. The covering devices are respectively arranged at corresponding positions on both sides of the screw rod.

As an improvement, the two-side synchronous laser cladding device is designed from the traditional single laser head cladding device, and uses dual laser heads to couple and synchronize laser cladding on both sides of the screw flight.

As a further improvement, the continuous laser beam performs laser cladding on both sides of the screw flight synchronously. The screw is a rotating body, and all the flight are located on the side of the screw cylinder. The metal powder used for cladding is based on performance requirements. Iron-based powder is used for the hard wear-resistant cladding layer, nickel-based powder or cobalt-based powder is used for the corrosion-resistant cladding layer, and the particle size of the metal powder is selected to be 100-150 μm.

As an improvement, the coaxial powder feeding method can be used for laser cladding on both sides of the screw flight. The powder feeding method adopts the carrier gas powder feeding method. The included angle with the normal direction of the side surface of the screw rib is 45°～60°.

As an improvement, the main parameters of the laser cladding device can be selected as follows: scanning speed 6mm/s, shielding gas flow rate 12L/min, welding rate 40%, cladding 3 layers on both sides of the screw edge, 5 layers per layer, each layer The thickness is 300-500μm, and the laser power and powder feeding amount are determined by the metal powder composition.

As an improvement, the screw is preferably an injection molding screw or an extrusion screw, and the base of the screw is 38CrMoAl metal material.

As a further improvement, the screw is pretreated before laser cladding of the screw flight, and the steps of the pretreatment are:

1. First remove the oxide layer on both sides of the screw edge;

2. Clean the screw with acetone;

3. Dry the screw after cleaning with acetone;

4. Place the dried screw clamp in the laser cladding device;

5. Preheat the screw in the laser cladding device, and then perform laser cladding on the side surface of the screw edge.

Compared with the prior art, the present invention has the following advantages: 1. The present invention uses laser cladding technology to modify the surface of the screw flight of the injection molding machine. Compared with the traditional flame surfacing technology, it eliminates the pores of the coating and the bonding Bad and other defects. 2. The present invention improves the efficiency of the surface strengthening of the screw by means of laser synchronous cladding. 3. The present invention aims at different working surfaces on both sides of the screw, simultaneously cladding metal powders with different functions, and preparing high-hard wear-resistant coatings and corrosion-resistant coatings respectively, which greatly improves the service life of the screw. While increasing the service life of the screw, it reduces the cost of surface strengthening of the screw.

Description of drawings

Fig. 1 is a schematic diagram of a cross-sectional structure of a screw according to an embodiment of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the embodiments of the accompanying drawings.

As shown in Figure 1, the laser cladding method for making the cladding layer on the side of the screw flight in this embodiment is characterized in that it includes laser cladding that can laser clad the screw flight of the set size The device is placed on both sides of the screw flight, and then the rotation of the screw 1 and the translation of the laser beam 41 are controlled. The laser cladding device performs laser cladding on the two sides of the screw flight with the continuous laser beam 41 through program control, and presses the screw. Cladding layers 3 with different properties are made on different working surfaces on both sides of the screw flight. The cladding layer 3 with different properties refers to the high hardness and wear-resistant cladding layer made on the main working surface of the screw flight 2, while the cladding layer 3 on the screw flight 2 Make a corrosion-resistant cladding layer on the secondary working surface. The screw base is 38CrMoAl metal material.

The above-mentioned cladding layer 3 is to make a high-hard and wear-resistant cladding layer first, and then make a corrosion-resistant cladding layer after the high-hard and wear-resistant cladding layer is completed, or the cladding layer 3 is to make a corrosion-resistant cladding layer first. After the corrosion-resistant cladding layer is made, the high-hard and wear-resistant cladding layer will be made. The cladding layer 3 is a high-hard wear-resistant cladding layer and a corrosion-resistant cladding layer. The laser cladding device for making the high-hard wear-resistant cladding layer and the laser cladding device for making the corrosion-resistant cladding layer are respectively arranged on Corresponding positions on both sides of the screw. The two-side synchronous laser cladding device is a traditional single-laser head cladding device designed to use dual-laser head coupling to simultaneously perform laser cladding on both sides of the screw flight. The continuous laser beam performs laser cladding on both sides of the screw flight synchronously. The screw 1 is a rotating body, and all the flight 2 are located on the side of the screw 1 cylinder. Iron-based powder is used for the wear-resistant cladding layer, nickel-based powder or cobalt-based powder is used for the corrosion-resistant cladding layer, and the particle size of the metal powder is selected to be 100-150 μm. The laser cladding on both sides of the screw flight adopts the coaxial powder feeding method, the powder feeding method adopts the carrier gas powder feeding method, the powder feeder and the protective gas use 99.99% high-purity argon, the laser beam 41 and the screw flight 2 The angle between the normal direction of the side surface is 45°～60°. The main parameters of the laser cladding device are: scanning speed 6mm/s, protective gas flow rate 12L/min, welding rate 40%, cladding 3 layers on both sides of the screw edge 2, 5 layers per layer, and 300-500μm thickness per layer , The laser 4 power and powder feeding amount are determined by the metal powder composition to adjust. Before the laser cladding of the screw flight, the screw is pretreated, and the steps of the pretreatment are:

1. First remove the oxide layer on both sides of the screw edge;

2. Clean the screw with acetone;

3. Dry the screw after cleaning with acetone;

4. Place the dried screw clamp in the laser cladding device;

5. Preheat the screw in the laser cladding device, and then perform laser cladding on the side surface of the screw edge.

Below in conjunction with accompanying drawing 1 embodiment the present invention is described in further detail

1. The base material of this embodiment is 38CrMoAl metal sheet material commonly used in injection molding machine screws. After cutting, a strip sample with the same width as the screw flight is obtained, and the oxide layer on the surface of the material is removed by grinding. After passing the inspection, it is placed Below the laser cladding head.

2. Device preparation: choose the same type of laser cladding head and place them on both sides of the above-mentioned plate, adjust the position of the laser head so that the angle between the laser beam and the normal direction of the side of the screw edge is 45°~60°, and set the path of the movement structure to execute Program, so that the laser equipment and powder feeder on both sides start synchronously.

3. Metal powder selection: For the powder coated on the high-hardness and wear-resistant side, use iron-based alloy powder with 6.0wt% vanadium and 2wt% carbon; for the coating powder on the corrosion-resistant side, use 17~ Nickel-based alloy powder with 20wt% chromium.

4. Parameter setting: The required laser process parameters are: high hardness and wear-resistant layer) laser power 1500W, scanning speed 6mm/s, powder feeding amount 12g/min, protective gas flow 12L/min; corrosion-resistant layer) laser power 1800W , scanning speed 6mm/s, powder feeding rate 14g/min, protective gas flow 12L/min, cladding overlap rate is 40%, each powder cladding layer, each layer cladding 5 layers, each layer thickness 300 μm.

5. Conduct metallographic analysis on the cooled and formed sample, and perform surface Rockwell hardness testing on the coatings on both sides of the sample. The results show that the coating on both sides is metallurgically bonded to the substrate, and the coating is dense, with almost no defects such as pores and cracks. The hardness of the high-hard wear-resistant coating is HRC=73.8, and the surface Rockwell hardness of the corrosion-resistant coating is HRC=50.

Claims (9)

1. A laser cladding method for making a cladding layer on the side of a screw flight, characterized in that it includes a laser cladding device capable of carrying out laser cladding with a screw flight of a set size placed on both sides of the screw flight side, and then control the rotation of the screw (1) and the translation of the laser beam (41), the laser cladding device will carry out laser cladding on the surface of both sides of the screw (1) with the continuous laser beam (41) synchronously through program control, and press Cladding layers (3) with different performances are made on different working surfaces on both sides of the screw flight. The cladding layers (3) with different performances refer to the production of high-hardness and wear-resistant melting layers on the main working surface of the screw flight (2). cladding, and make a corrosion-resistant cladding layer on the secondary working surface of the screw flight (2). 2. The laser cladding method according to claim 1, characterized in that, the cladding layer (3) is a high-hard wear-resistant cladding layer made first, and then made after the high-hard wear-resistant cladding layer is completed The corrosion-resistant cladding layer, or the cladding layer (3) is to make the corrosion-resistant cladding layer first, and then make the high-hardness and wear-resistant cladding layer after the corrosion-resistant cladding layer is manufactured. 3. The laser cladding method according to claim 1, characterized in that, the cladding layer (3) is a high-hard wear-resistant cladding layer and a corrosion-resistant cladding layer, and the high-hard wear-resistant cladding layer will be made The laser cladding device and the laser cladding device for making the corrosion-resistant cladding layer are respectively arranged on the corresponding positions on both sides of the screw. 4. The laser cladding method according to any one of claims 1 to 3, characterized in that: the two-side synchronous laser cladding device is designed as a traditional single laser head cladding device, and is carried out synchronously by coupling of double laser heads Laser cladding on both sides of the screw flight. 5. The laser cladding method according to any one of claims 1 to 3, characterized in that: the continuous laser beam simultaneously performs laser cladding on both sides of the screw flight, and the screw (1) is a rotating body , all screw edges (2) are located on the side of the screw (1) cylinder, and the metal powder used for cladding is iron-based powder for the high-hard wear-resistant cladding layer according to performance requirements, and nickel-based powder or nickel-based powder for the corrosion-resistant cladding layer. For the cobalt-based powder, the particle size of the metal powder is selected to be 100-150 μm. 6. The laser cladding method according to any one of claims 1 to 3, characterized in that: the laser cladding on both sides of the screw flight adopts the coaxial powder feeding method, and the powder feeding method uses the carrier gas powder feeding method , the powder feeder and the protective gas all use 99.99% high-purity argon gas, and the included angle between the laser beam (41) and the normal direction of the side surface of the screw edge (2) is 45°-60°. 7. The laser cladding method according to any one of claims 1 to 3, characterized in that: the main parameters of the laser cladding device are: scanning speed 6mm/s, shielding gas flow rate 12L/min, welding rate 40%, 3 layers are respectively cladding on both sides of the screw edge (2), 5 layers per layer, and the thickness of each layer is 300-500 μm. The power and powder feeding amount of the laser (4) are adjusted according to the composition of the metal powder. 8. The laser cladding method according to any one of claims 1 to 3, characterized in that: the screw is an injection molding screw or an extrusion molding screw, and the base of the screw is 38CrMoAl metal material. 9. The laser cladding method according to any one of claims 1 to 3, characterized in that: the screw flight is pretreated before laser cladding, and the pretreatment steps are: 1. First remove the oxide layer on both sides of the screw edge; 2. Clean the screw with acetone; 3. Dry the screw after cleaning with acetone; 4. Place the dried screw clamp in the laser cladding device; 5. Preheat the screw in the laser cladding device, and then perform laser cladding on the side surface of the screw edge.

Images