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Nantong WEG: High efficiency, high standards, and high requirements / Specialized in electric motor industry

2022-03-10

Abstract:

Founded in Brazil in 1961, WEG Group is a company specialized in providing customers industrial electric motors, automation, and energy equipment manufacturing. They offer a wide range of products supporting mining machinery, chemical, air blower, and pump industries. The China divisions include WEG (Nantong), WEG (Jiangsu), WEG (Changzhou), and Yatong Jiewei Electromotor. WEG (Nantong) is the first wholly-owned subsidiary of WEG Group in China and Asia.

In 2014, WEG Group established WEG (Jiangsu) Electrical Equipment Co., Ltd (“WEG”) in Nantong, focusing on high/low voltage industrial motors and parts of first stage projects. The company has an annual production capacity of 700,000 high/low voltage industrial motors and 100,851 parts.

In recent years, WEG has purchased several sets of die-casting cells from YIZUMI. By introducing intelligent die-casting units, the company has comprehensively improved the automation level of the existing die-casting production lines for higher productivity.

Challenge 1

The molds for motor housings require deep cavities as the surface of the housings is covered with heat radiation fins. The spraying distance of the flat spray nozzle cannot meet the demand of spraying inside the cavity. In addition, as the space between the mold center cavity and outer cavities is limited, it creates a great challenge for the design of the profiling spray nozzle.

YIZUMI has designed a special profiling spraying nozzle for motor housings, which extends the water-vapor mixing spray nozzle of the atomizer through a double-layer pipe, allowing the spraying outlet of the release agent to directly enter the cavity for spraying. This approach effectively improves the spray efficiency and quality, ensuring the spray effect in the mold and avoiding product defects due to uneven spraying.

Challenge 2

The characteristics of the deep cavity motor housings also pose a challenge to the design of the extractor gripper. Due to the length of the product and the thickness of the mold, the space available for grippers is very limited. If only one gripper was needed to extract the product and place it on the conveyor, the space would be sufficient. However, in addition to the product extraction, this die-casting cell also needs to cut the ingate system and trim the overflows, which requires the extraction robot to be equipped with a dual function (biscuit/part) gripper to extract and place the product in the hydraulic press after ingate cut.

After repeatedly simulating the 3D drawing of the customer's mold and YIZUMI's preliminary design of the gripper, the engineers found that no matter how to change the design, the product gripper would always interfere with the mold when the ingate cutter picks up the part. The design work ran into a deadlock. The design of the gripper plays a key role in the design of the peripheral devices. Eventually, through the use of a quick-change plate, the robot carries the main plate to first connect the sub-plate on the ingate cutter to extract the product, allow the product to cool down, and place it in the cutting device. The ingate cutter is then released and replaced by a product extractor that can easily extract the product after ingate removal.

Challenge 3

The diameter of a large motor housing can exceed 300mm. The commonly used disk saw will need custom-made over-sized saw blades to handle the job. This poses a great challenge to the positioning accuracy of the tooling, the difficulty of adjustment, and the stability of cutting.

YIZUMI designed a special ingate cutting device for motor housing products. In addition to moving along the sawing direction, the fixture that holds the product can also rotate by using an indexing plate so that a smaller saw blade can be used. It not only ensures the cutting accuracy and operation stability, but also ensures that the product stops after a cycle of cutting at the exact angle where it was placed to facilitate the precision positioning in the next stage when it is placed into the hydraulic press for edge trimming.

In order to cope with the fierce market competition, WEG invested CNY 35 million to further optimize and adjust its internal production structure and capacity in February 2020. The company continues to expand the production capacity by adding 125 units of equipment including painting lines and aluminum motor housing press assembly lines at the plant under construction as well as making adjustments to the environmental protection facilities. Upon the completion of the project, the plant will increase its annual production capacity of high/low voltage industrial motors by 300,000 units, raising the total annual output of the whole plant to 1 million units.