Decryption of Buick Envision ＂Digital Talk＂ SAIC-GM Dongyue Factory

On December 27, 2015, the SAIC-GM Buick Envision was officially loaded and shipped out of the port in Yantai, Shandong Province, and exported to the North American market including the United States, Canada and Mexico for the first time. The Envision was launched in China in October last year, and the models exported overseas this time are all produced at the SAIC-GM Dongyue base. Wang Yongqing, general manager of SAIC-GM, said: "Envision’s entry into the country is not only the excellent strength of the product itself, but also highlights the new sublimation of Dongyue base, SAIC-GM manufacturing and even Chinese manufacturing." On the occasion of Envision’s export to North America, Netcom was invited to visit the SAIC-GM Dongyue production base. Next, the editor will use a set of "numbers" to decrypt the birthplace of Envision, which is known as the "four-star general" in the factory.

Shanghai GM Dongyue Base is composed of SAIC GM Dongyue Automobile Co., Ltd. and SAIC GM Dongyue Powertrain Co., Ltd. and is jointly built by SAIC Group, GM (China) and SAIC GM with 25%, 25% and 50% investment respectively. Now it has four complete vehicle production processes of stamping, body, painting and assembly and powertrain workshops such as casting, forging, engine and gearbox. The products cover Buick Envision, Oncola and Chevrolet Chuangku, New Aiweiou, Sail 3 and Lefeng RV6 models. The powertrain includes 1.2L-1.8L S-Tec, Ecotec two series engines and four series of S6 automatic gearboxes.

The annual production capacity of Dongyue production base is 600,000 units, the annual production capacity of engines is 1.17 million units, and the annual production capacity of gearboxes is 720,000 units. Since the establishment of the vehicle factory in 2003, the cumulative production has exceeded 3.50 million units as of August this year, and since the powertrain factory was put into operation in 2005, the overall powertrain production has reached 10 million units.

Stamping workshop – lean production, stamping three parts at a time

The stamping workshop of Dongyue South Plant has a total of 5 through-type, fully enclosed automatic stamping lines and 2 uncoiling blanking lines, which are responsible for the stamping production of more than 160 kinds of body panels. The average indicators of production time and automatic mold change time have reached the advanced level of the same type of equipment in the world.

The three parts of Envision’s front/middle/rear floor are produced in one mold and three pieces in Line 1 of the stamping workshop. The molding process of the three parts is completed simultaneously in one stamping, which implements the concept of lean production and is efficient and energy-saving. Stamping process of aluminum front cover: The density of Envision’s aluminum front cover is 1/3 of that of steel plate, which reduces the weight of 7.5 kg compared with the traditional steel cover, which reduces the weight of the vehicle and reduces fuel consumption. Front cover inner plate process – three-sequence forming and one-time trimming: Envision’s front cover inner plate mold adopts three-sequence forming process. The trimming process of the parts adopts one-time trimming process. The floating waste knife design is free of debris, which makes the appearance of the front cover smoother, more beautiful, and improves the product quality.

Body shop – providing "10% more" safety

The body workshop of Dongyue North Factory integrates today’s advanced body manufacturing concepts. For the first time, it adopts high-density robots, GEO-pallet high-speed conveyor system, and 5 + 1 model’s total gate design. It has 465 robots of various types. Here, the high-flexibility and high-automation manufacturing system creates the Buick Envision’s "four vertical and eight horizontal" body safety structure, which covers the member cabin in all directions. At the same time, the Envision body uses a large number of high-strength steel and galvanized sheet, and the proportion of high-strength steel in the body reaches 75%. It not only realizes the lightweight of the body, but also has excellent anti-corrosion performance, providing "10% more" safety performance.

The body workshop uses the large/small accompanying tooling system to carry out floor splicing and assembly and body-in-white transmission, which has the advantages of strong flexibility, fast transmission speed and high precision, and has the function of quality traceability to ensure production efficiency and production quality. Envision’s Small GEO Pallet in the engine compartment uses high-density robot stations. 14 robots perform welding operations at the same time, and each production beat can complete 200 solder joint welding, which takes up less space and is more efficient. At present, this process has been promoted and used in the production bases of SAIC-GM Yantai Dongyue North Factory, Shenyang Beisheng Phase III, and Wuhan Branch.

Two welding processes: roof laser brazing, Arplas welding

The Envision roof uses an advanced laser brazing process to ensure that high-strength steels are combined with each other in an optimal structure, making the product more beautiful. At the same time, it enhances the sealing and the strength of the welded area, further enhancing the safety of the cockpit.

Envision’s water guide tank and rear cover license plate use advanced Arplas welding technology, using special equipment to punch out a protrusion on the single-layer board of the parts to be welded, and then use a special welding torch to weld the parts at the protrusion. Compared with traditional exposed solder joints, the application of this technology can ensure the welding strength, make the outer surface flat without welding marks, and save up to 70% of energy consumption.

Painting workshop – 10% improved sound insulation

The Envision uses a LASD (Liquid Applied Sound Damper) liquid sound insulation pad that combines new materials and new technologies. It is a liquid body sound insulation and shock absorption material that uses robots for construction. It replaces the traditional solid asphalt sound layer in the car. While improving the performance of the vehicle, it has the characteristics of green environmental protection, light weight, good sound insulation and shock resistance. The Envision is also one of the first domestic models to use LASD materials. The application of this new material improves the sound insulation effect of the Envision by 10%.

The paint workshop of Dongyue North Factory adopts advanced body anti-corrosion technology and technical equipment, including water-based paint. Compared with the traditional coating process, the VOC (volatile organic compound) emissions of the water-soluble paint process can be reduced by more than 80%, which is more green and environmentally friendly. At the same time, the Envision paint process implements the industry’s leading film thickness standards, providing the vehicle with excellent appearance performance, while greatly improving the vehicle’s ability to resist atmospheric corrosion and chemical corrosion, and improving the service life of the vehicle.

Final assembly workshop – 100% quality inspection

The final assembly workshop uses glass robots to automatically coat and glue, and spare tire robots to automatically install spare tires. In addition, SAIC General Motors took the lead in using a multi-platform flexible machine transportation system that can lift and lower both the interior plate and the chassis hanger. Among them, the two-way liftable large plate of the interior line is adopted for the first time in China. It can choose the appropriate height according to the assembly process to realize multi-platform flexible production.

The final assembly process will complete the assembly of all parts of the vehicle and carry out 100% quality inspection. It is from here that the Buick Envision gets off the production line and starts its journey to the domestic and overseas markets. The Envision uses the Pin-through net positioning method for chassis assembly. Through the fine positioning pin, it directly penetrates the chassis parts to locate the body baseplate. During the assembly process, it is precisely synchronized to achieve precise positioning and splicing of the body and chassis, thus ensuring the excellent handling performance of the chassis and enhancing the customer’s driving experience.

In the final quality inspection line, the visiting group also happily boarded the new off-line car and followed the quality inspector to experience the vehicle rain test and bad road test. In the rain test area, 360 nozzles were all-round sealed test, within 70 seconds, 5 tons of water, 70 times the simulation of natural rainstorm rainfall, to ensure the excellent sealing of the car; in the bad road test area, the quality inspector controlled the steering wheel, and the whole vehicle traveled according to the "figure 8" route to detect the directivity of the steering wheel and ensure that there was no abnormal sound. These have quality inspection links, so that the editor has a deeper understanding and experience of the excellent quality of SAIC-GM. (Network News Agency, December 28, 2015, Yantai report)