Preheating device for surfacing of plastic mold

Abstract

The utility model discloses a preheating device for surfacing of a plastic mold, which comprises a plurality of independent first-type heating units, a heating device with a resistance wire arranged on a support component of a ceramic structure, a bottom spliced and arranged on the mold, and a plurality of independent second-type heating units, and the heating devices of heating resistance wires are embedded in the fireproof asbestos and are spliced and arranged at the periphery of the mold. According to the actual size requirement of the mold, the first type of heating units and the second type of heating units are selected, the plastic mold is placed in a space defined by the two types of heating units, and the top of the mold is covered with fireproof asbestos for heat preservation. The preheating device disclosed by the utility model is simple in structure, can simultaneously realize heating, heat preservation and surfacing operation, and ensures the stability of surfacing preheating temperature.

Description

Technical Field

[0001] This utility model relates to a preheating device, and more particularly to a preheating device for plastic mold overlay welding. Background Technology

[0002] To create specific textures on the surface of injection-molded products, plastic molds typically require surface etching before use. Achieving consistent etching results necessitates a uniform microstructure in the molded plastic. However, in actual production, issues frequently arise, such as machining errors, impacts or wear during transportation or service, leading to dimensional inconsistencies and unusable molds. Since the cost of a medium-sized mold can often reach millions of yuan, repairing unusable plastic molds is essential.

[0003] Laser welding and argon arc welding are widely used for the localized repair of plastic molds. However, in the process of repairing plastic molds by welding, due to the large size of the mold, the mold itself acts as an infinitely large cold body during the cooling of the weld seam. This results in a very rapid cooling rate of the molten weld metal, forming an ultrafine-grained martensitic structure. This microstructure is significantly different from the original structure of the plastic mold, leading to inconsistent textures during etching and severely affecting the surface quality of the injection molded product. Preheating before welding can effectively inhibit the martensitic transformation of the weld metal and promote grain growth, and is therefore widely used in the repair of plastic molds by welding. However, currently, the preheating of plastic molds usually involves placing the entire mold in a muffle furnace, heating it to the set temperature, removing it, and then performing the welding. Because the molds vary in size, multiple muffle furnaces of different sizes or a very large muffle furnace are required for preheating. In addition, when the heated mold is removed from the muffle furnace, the mold surface cools down rapidly, making it difficult to perform the welding at the preset temperature. Utility Model Content

[0004] The purpose of this utility model is to provide a preheating device for plastic mold overlay welding.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The preheating device comprises a plurality of independent first type heating units and a plurality of independent second type heating units, wherein the first type heating unit is a heating device with resistance wires arranged on a ceramic structure support part, serving as a bottom of the plastic mold build-up welding preheating device, and the second type heating unit is a heating device with heating resistance wires embedded in refractory asbestos, serving as a periphery of the plastic mold build-up welding preheating device, and the space surrounded by the first type heating units and the second type heating units is used for placing the plastic mold; according to the size requirement of the plastic mold, a plurality of first type heating units are selected to be spliced, and a plurality of second type heating units are selected to be spliced, so as to jointly form the plastic mold build-up welding preheating device.

[0007] The edge length of the first type heating unit is 15-50 cm, and the edge length of the second type heating unit is 15-30 cm; and the top of the plastic mold is covered with refractory asbestos.

[0008] The plastic mold build-up welding preheating device has the following effects: (1) according to the actual size of the plastic mold, the preheating device with the actual size required by the mold can be assembled by using the heating units, which is convenient and simple, and can effectively reduce the equipment investment of the heating furnace; (2) when the preheating reaches the required temperature, the build-up welding operation can be performed while heating and keeping warm, so as to ensure the stability of the build-up welding preheating temperature. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a schematic view of the shape of the plastic mold build-up welding preheating device in the utility model.

[0010] Among them, 1 is the length of the cuboid, 2 is the width of the cuboid, 3 is the height of the cuboid, 4 is the top of the cuboid, and 5 is the bottom of the cuboid.

[0011] Figure 2 is a schematic view of the front projection of the plastic mold build-up welding preheating device in the utility model.

[0012] Among them, 6 is the first heating unit, 7 is the second heating unit, 8 is the plastic mold, and 9 is the refractory asbestos.

[0013] The utility model will be further described below in combination with the embodiments. DETAILED DESCRIPTION

[0014] Embodiment 1

[0015] The heating surface of the first heating unit and the second heating unit is square. Assuming that the length, width and height of the mold are 150 cm, 100 cm and 50 cm respectively, the bottom (150 cm x 100 cm) is selected to be spliced by 6 first heating units with a side length of 50 cm, wherein 3 are spliced in the length direction and 2 are spliced in the width direction; the front and rear sides (150 cm x 50 cm) are selected to be spliced by 24 second heating units with a side length of 25 cm, wherein 6 are spliced in the length direction and 2 are spliced in the height direction on the front and rear sides respectively; the left and right sides (100 cm x 50 cm) are selected to be spliced by 16 second heating units with a side length of 25 cm, wherein 4 are spliced in the width direction and 2 are spliced in the height direction on the left and right sides respectively; and the top of the mold is completely covered with refractory asbestos.

[0016] Example 2

[0017] The heating surface of the first heating unit and the second heating unit is square. Assuming that the length, width and height of the mold are 150 cm, 120 cm and 45 cm respectively, the bottom (150 cm x 120 cm) is selected to be spliced by 80 first heating units with a side length of 15 cm, wherein 10 are spliced in the length direction and 8 are spliced in the width direction; the front and rear sides (150 cm x 45 cm) are selected to be spliced by 60 second heating units with a side length of 15 cm, wherein 10 are spliced in the length direction and 3 are spliced in the height direction on the front and rear sides respectively; the left and right sides (120 cm x 45 cm) are selected to be spliced by 48 second heating units with a side length of 15 cm, wherein 8 are spliced in the width direction and 3 are spliced in the height direction on the left and right sides respectively; and the top of the mold is completely covered with refractory asbestos.

[0018] Example 3

[0019] The heating surface of the first heating unit and the second heating unit is square. Assuming that the length, width and height of the mold are 150 cm, 120 cm and 45 cm respectively, the bottom (150 cm x 120 cm) is selected to be spliced by 80 first heating units with a side length of 15 cm, wherein 10 are spliced in the length direction and 8 are spliced in the width direction; the front and rear side surfaces (150 cm x 45 cm) are spliced by 20 second heating units with a side length of 15 cm and 10 second heating units with a side length of 30 cm, wherein the front side surface and the rear side surface are spliced by a second heating unit with a side length of 15 cm and a second heating unit with a side length of 30 cm along the height direction respectively, then 9 second heating units are spliced along the length direction behind the second heating unit with a side length of 15 cm, and 4 second heating units are spliced along the length direction behind the second heating unit with a side length of 30 cm; the left and right side surfaces (120 cm x 45 cm) are spliced by 48 second heating units with a side length of 15 cm, wherein 8 are spliced along the width direction and 3 are spliced along the height direction on the left side surface and the right side surface respectively; the top of the mold is completely covered by refractory asbestos.

Claims

1. A plastic mold build-up preheating device characterized by, The preheating device comprises several independent first type heating units and several independent second type heating units, wherein the first type heating unit is a heating device with resistance wires arranged on a ceramic structure support part, serving as the bottom of the plastic mold build-up preheating device, and the second type heating unit is a heating device with heating resistance wires embedded in refractory asbestos, serving as the periphery of the plastic mold build-up preheating device, and the space surrounded by the first type heating units and the second type heating units is used for placing the plastic mold; according to the size requirement of the plastic mold, several first type heating units are selected to be spliced, and at the same time, several second type heating units are selected to be spliced, to jointly form the plastic mold build-up preheating device.

2. A plastic mold build-up preheating device according to claim 1, wherein The heating surfaces of the two types of heating units are all square, and the side length of the first type heating unit is 15-50 cm; the side length of the second type heating unit is 15-30 cm.

3. A plastic mold build-up preheating device according to claim 1, wherein The top of the plastic mold is covered with refractory asbestos.

Images