Ninth Institute Project Case | FAW-Volkswagen Tianjin Coating Workshop Waxing Line

The car body cavity wax injection anti-corrosion technology originated from the Volkswagen Group in Germany, significantly improving the anti-corrosion performance of the vehicle chassis. In 2007, the Ninth Institute successfully developed the production line equipment for car body cavity wax injection independently, becoming the only domestic supplier capable of providing a complete set of wax injection production line equipment. To date, it has successfully implemented more than a dozen newly built wax injection production lines and over seventy wax injection renovation projects for FAW-Volkswagen and SAIC Volkswagen. The wax injection line project in the FAW-Volkswagen Tianjin painting workshop has a capacity of 300,000 vehicles, consisting of two lines with a capacity of 150,000 vehicles each. The project started design in September 2016 and completed acceptance in December 2018, and the wax injection line has been running well since then. In this project, the Ninth Institute relied on mature professional technical capabilities and a complete project management system to provide users with reliable equipment and high-quality services.

The equipment of the wax injection production line mainly consists of non-standard thermal equipment, mechanized conveying equipment, electrical control equipment, and wax injection machinery. The main characteristics of the production line equipment are as follows:

1. Energy-saving and environmentally friendly heating system To achieve the wax injection process, it is necessary to inject hot wax at 120°C into the bottom cavity of the car body, forming a uniform wax film on the inner surface of the cavity to isolate metal from the external environment, reduce corrosion, and improve the anti-corrosion properties of the car body. The heating system is an important component of the wax injection line equipment. This project uses a heat transfer oil boiler to provide stable thermal energy for the system. The heat transfer oil boiler has precise temperature control and comprehensive safety protection measures, achieving higher heat exchange efficiency and meeting higher environmental protection requirements. (During project construction, Tianjin's local environmental protection regulations required nitrogen oxide emissions not to exceed 150 mg/m3; tests showed that this project's boiler emissions were less than 80 mg/m3). To avoid impacts on production from annual boiler inspections and other work, this project's boiler is configured with one in use and one standby to provide stable thermal energy for production 24 hours a day.

2. High-pressure airless manual waxing equipment The manual waxing station in this project uses high-pressure airless waxing equipment. Through a high-pressure pump, liquid wax is pressurized and sprayed out through a round nozzle, forming an extremely thin and uniform wax film inside the car door, providing users with better waxing quality.

3. Efficient car body preheating system To ensure that liquid hot wax can form a uniform wax film in the bottom cavity of the car body, it is necessary to heat the bottom of the car body before waxing to increase the fluidity of liquid wax in the cavity. The air nozzles at the bottom of the preheating station blow hot air into the bottom cavity of the car body, quickly raising its temperature to process temperature. To reduce wax mist's impact on the car body, the Ninth Institute developed a special filter to achieve efficient air filtration. The preheating system adopts modular design for modular production and transportation, enabling quick assembly on-site while improving installation quality and significantly shortening installation cycles.

4. Completely independently designed car body waxing fixture The waxing fixture is key equipment for performing waxing work in the bottom cavity of the car body. In this project, the Ninth Institute completed all work from defining waxing holes in the bottom cavity of the car body to detailed design, manufacturing, installation, and debugging of fixtures. The structure of the bottom cavity is complex with numerous holes and dense spatial layout. When designing waxing fixtures, it is necessary to select suitable holes as waxing holes from over 100 process holes at the bottom of the car body while blocking other holes with fixtures to ensure that each cavity's wax film quality meets standards. To better design waxing fixtures and check for static interference and dynamic interference conditions in fixture structures, the Ninth Institute design team used three-dimensional forward design combined with motion simulation to excellently complete design tasks. This project replaces manual spraying with automatic door waxing, saving labor costs in production and improving working conditions for production personnel while advancing towards environmentally friendly goals.

5. Stable and reliable mechanized conveying system The waxing process is the last step in painting workshops; it requires transferring painted bodies from paint racks to hanging devices to complete waxing processes. The Ninth Institute provides a complete mechanized conveying solution; in the waxing process area, an overhead roller bed combined with inverted sleds and hanging devices is used to complete mechanized conveying for all waxing processes. The entire set of mechanized conveying equipment operates stably and reliably, meeting a dual-line production pace of 62JPH while fully ensuring painting production line capacity. It also provides a reliable equipment foundation for future increases to 65JPH. The FAW-Volkswagen Tianjin factory's painting waxing line produces FAW-Volkswagen's first medium-sized SUV model; to support users in launching new models as soon as possible, project teams worked together with users to overcome tight schedules. To shorten project timelines for waxing lines and ensure earlier vehicle delivery times, before construction began on-site, project teams used three-dimensional interference checks to eliminate inter-module interference and reduce rework on-site while lowering unnecessary communication costs; during early stages before equipment entry into site construction units had not fully delivered installation work areas; under user coordination, project teams meticulously divided work area scopes with construction units to minimize subsequent construction impacts on equipment installation; project teams reasonably arranged installation sequences for various specialized equipment while increasing modular prefabrication work within Ninth Institute factories to enhance product quality while shortening on-site installation cycles ultimately ensuring that painting production lines achieved first vehicle rollout ahead of schedule meeting user acceleration goals.

Waxing equipment has become a flagship product of the Ninth Institute; after more than ten years of practical experience implementing main lines with capacities ranging from 50,000 to 600,000 vehicles has accumulated rich experience and received unanimous recognition and praise from customers. The Ninth Institute will continue to uphold its values of 'technology-based business development, integrity service, value innovation, collaborative sharing' while continuously providing customized waxing solutions for customers and growing together with them.