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SMC Electric Meter Box Production Process Standard

Jun 10, 2020

1. Weighing

The shape and size of the sheet material cutting are determined according to the structural shape of the product, the feeding position, and the flow, and the model cutting material is produced. The shape of the cut is mostly square or strip, and the size is usually 40%-80% of the projected area of the product surface. In order to prevent contamination by external impurities, the upper and lower films are only removed before loading.

2. Hot pressing

After the material block enters the mold cavity, the press goes down quickly. When the upper and lower molds coincide, slowly apply the required molding pressure, and after a certain curing system, the molding of the product is completed. During the molding process, various molding process parameters and press operating conditions should be selected reasonably.

1. Molding temperature

The molding temperature depends on the curing system of the resin paste, the thickness of the product, the production efficiency and the complexity of the product structure. The molding temperature must ensure that the curing system initiates and crosslinks smoothly, and achieve complete curing.

In general, the forming temperature of thick products should be lower than that of thin-walled products, so as to prevent excessive heat accumulation in thick products due to excessively high temperature. If the thickness of the product is 25-32mm, its forming temperature is 135-145℃. And thinner products can be formed at 171 ℃.

Increasing the molding temperature can shorten the corresponding curing time; conversely, when the molding temperature decreases, the corresponding curing time needs to be extended. The molding temperature should be selected between the highest curing speed and the best molding conditions. It is generally believed that the SMC molding temperature is between 120-155°C.

2. Molding pressure

SMC molding pressure varies with product structure, shape, size and SMC thickening degree. Simple shape products only need 25-30Mpa forming pressure; complex shape products, forming pressure can reach 140-210Mpa. The higher the degree of SMC thickening, the greater the molding pressure required.

The size of the molding pressure is also related to the mold structure. The molding pressure required by the vertical parting structure mold is lower than that of the horizontal parting structure mold. Moulds with smaller clearances require higher pressure than those with larger clearances. Products with high appearance performance and smoothness require high molding pressure during molding.

In short, the determination of molding pressure should consider many factors. Generally speaking, SMC molding pressure is between 3-7Mpa.

3. Curing time

The curing time (also called holding time) of SMC at the molding temperature is related to its properties and factors such as curing system, molding temperature, product thickness and color.

The curing time is generally calculated at 40s/mm. For thick products above 3mm, some people think that for every additional 4mm, the curing time increases by 1min.

Three, integer

1. Use a file to polish off the flash.

2. Correct the perforation and blinds according to the requirements.

4. Housing installation

1. The standard bolts used in the assembly of the shell must be pre-tightened, that is, a flat spring pad is added, and the tightness between the standards is based on the flatness of the spring pad. The flat state of the spring pad indicates that the standard room is tightened and the spring pad The bounced state indicates that the standard room is not tightened.

2. The standard self-tapping screws used in the assembly of the housing must be screwed into the housing 8-10mm.

3. When the door is installed on the door shaft, there must be an elastic device on the door shaft to facilitate the loading and unloading of the door.

4. There should be "a little danger, pay attention to safety" and logo, "National Grid" logo and service hotline on the door.

5. When there is screen printing, the handwriting of the screen printing should be clear and free of skew.

6. There must be standard parts for users to install meters and cabinets in the cabinet.

7. Prepare the corresponding accessories according to the installation method of the body. Prepare the corresponding hoop for the rod installation. The box body should have a rain cover when installed outdoors.

8. There should be cable entry and exit holes on the box, and there should be a threading sheath on the cable entry and exit holes.

5. Device assembly

1. Components should be selected according to the rated current and parameters given by the customer or power department.

2. Check the rated current and parameter index of the components before installing the components. The parameters of the components must correspond to the parameters and installation requirements of the bidding technical requirements.

3. The layout of the components should be reasonably distributed according to the size of the box to ensure that the user's access lines and the wiring in the box are easy to install.

4. When installing components, the components should be fixed firmly.

6. One time wiring

1. When the incoming line is a three-phase four-wire system, the colors of the corresponding conductors of A, B, C, and N are yellow, green, red, and blue, and the color of the ground wire is yellow and green.

2. The area of the conductor prepared in the box should be according to the cross-sectional area of the customer's requirements. When the customer has no requirements, select the cross-sectional area of the conductor according to the rated current of the switch: 50A-60A, 10mm², 80A-100A, 16mm², 100A-160A, 25 mm² .

3. When the wire needs to be crimped, the wire should pass through the wire hole of the wire nose 1-2mm, press it tightly with hydraulic pliers, and be treated with sugar tin. After the sugar tin treatment, the surface of the wire nose should be uniform, bright and smooth , And to protect the hydraulic part with a threaded sheath or an insulating tube.

4. The wire should be horizontal and vertical when installed in the box. When bending is required, be careful not to damage the insulation of the wire.

5. The terminal of the switch can not press the insulation layer of the wire when installing the wire.

7. Finished product inspection

1. Verification of technical requirements

2. According to the technical requirements provided by the Technology Department, gradually check the specifications and models of circuit breakers, wires, junction boxes, and technical requirements of copper bars.

3. To verify whether the screws are tight, each screw must be equipped with a flat washer and a spring washer, and the torque of the screw should be more than 5Nm.

4. The wire arrangement is uniform and orderly, and the position is correct.

5. According to the technical requirements, the material package is correct.

8. Packaging

1. Packing of SMC cabinet

(1) Packed in packaging bags first.

(2) Packed in a carton again, the name and number of products and stacking requirements should be on the carton.

2. Packaging of transparent box

(1) On the PC cover of the PC box, there is a packaging film to protect the PC box cover.

(2) Packed in packaging bags first.

(3) Repack in a carton. The carton should have the product name, model number, and stacking requirements.

Nine, finished products, sales

After the packaging is completed, the product should be put into storage and wait for the product to be released.