1. Careful selection of raw materials
The first step in manufacturing the rear wiper is to carefully select the appropriate raw materials. The bracket of the rear wiper is usually made of high-strength metal materials, such as aluminum alloy or special steel. Aluminum alloy has the advantages of light weight, high strength, and corrosion resistance. It can effectively reduce the overall weight of the rear wiper and reduce the motor load, while ensuring that the performance will not be affected by rust during long-term use. Special steel, with its excellent rigidity, provides solid support for the stable operation of the wiper in various complex environments.
As a key part that directly contacts the rear windshield and realizes the wiping function, the rubber strip has extremely high requirements for raw materials. Generally, natural rubber or synthetic rubber, such as EPDM, is selected. Natural rubber has good flexibility and elasticity, can fit the glass surface tightly, and effectively remove rain and stains; EPDM has excellent weather resistance, ozone resistance and aging resistance. It can maintain stable physical properties in harsh environments such as high temperature, ultraviolet rays and humidity, and extend the service life of wipers. In order to improve the wear resistance of the rubber strip, an appropriate amount of fillers such as carbon black will be added to it, and it will be processed through special formulas and processes to achieve the best wiping effect and durability.
2. Fine processing of parts and components
2.1 Bracket processing:
The selected metal material is first cut into a blank that meets the design size. For aluminum alloy brackets, CNC cutting technology is often used to ensure that the cutting accuracy reaches the millimeter level to meet the strict requirements of the shape and size of the rear wiper bracket of different models.
The cut blank enters the bending process. Through high-precision bending molds and equipment, the metal strip is accurately bent into a specific arc and angle, so that the bracket can perfectly fit the contour of the vehicle’s rear windshield.
For some brackets with complex structures, welding operations may be required. Advanced welding processes, such as argon arc welding, are used to ensure that the welds are firm and smooth, avoid defects such as cold welding and leaking welding, and ensure the overall strength and stability of the bracket.
After welding, the surface of the bracket is treated, such as anodizing (for aluminum alloy brackets) or electrophoretic coating (for steel brackets). Anodizing can form a hard and dense oxide film on the surface of aluminum alloy, enhancing its corrosion resistance and wear resistance. At the same time, it can also be dyed according to needs to give the bracket different appearance colors; electrophoretic coating covers the steel surface with a uniform paint film, which has a good anti-rust effect and improves the appearance and durability of the bracket.
2.2 Rubber strip production:
Based on the selected rubber raw materials, the mixing operation is first carried out. Rubber and various compounding agents, such as vulcanizers, accelerators, antioxidants, fillers, etc., are added to the internal mixer according to the precise formula ratio, and fully mixed under high temperature and high pressure to make the components blend with each other to form a stable performance compound rubber. The mixed rubber is further processed by the open mill to adjust its plasticity and uniformity, and to form a film of a certain thickness and width.
Subsequently, the film is fed into the extruder and extruded through a specific mold to form a rubber strip embryo with a specific cross-sectional shape. In order to obtain better physical properties of the rubber strip, the embryo needs to be vulcanized. The rubber strip embryo is placed in the vulcanization mold. Under high temperature and high pressure, the rubber molecules and the vulcanizer undergo cross-linking reactions, and the molecular structure changes from linear to mesh, thereby improving the strength, hardness, wear resistance and aging resistance of the rubber. The vulcanization time and temperature are precisely controlled according to the rubber formula and product requirements to ensure the best vulcanization effect.
The vulcanized rubber strip also needs to be processed later, such as surface polishing and coating with special coatings. Grinding can make the surface of the rubber strip smoother and flatter, reduce the friction resistance with the glass during wiping, and reduce noise; coating special coatings, such as graphite coating or fluoride coating, can further improve the lubricity and antistatic properties of the rubber strip, making it smoother during wiping and reducing the adhesion of dust and dirt.
2.3 Motor manufacturing (if it is an electric rear wiper):
The motor of the electric rear wiper is used as the power source, and its manufacturing process is also fine. The motor housing is usually made of aluminum alloy die-casting. The die-casting process can make the housing have good dimensional accuracy and surface quality, while having sufficient strength and heat dissipation performance.
Inside the housing, the stator and rotor are installed. The production of the stator requires the enameled wire to be wound on the iron core according to a specific number of turns and winding method. The winding process requires high precision to ensure the stability of the electromagnetic performance of the motor. After winding, the stator is dipped in paint to make the enameled wire tightly combined with the iron core, enhance the insulation performance, and improve the reliability and service life of the motor. The rotor is composed of an iron core and a permanent magnet. The iron core is formed by stamping, and then the permanent magnet is accurately installed at a specific position of the iron core to ensure that the rotor can generate a stable magnetic field during rotation. The brushes and commutator of the motor are also key components. The brushes are generally made of metal graphite materials with high conductivity to ensure good contact with the commutator to achieve stable current transmission and commutation functions.
During the motor assembly process, the installation accuracy of each component is extremely high. For example, the installation of the bearing must ensure that the concentricity is within a very small error range to reduce friction and vibration during motor operation, reduce noise, and improve the efficiency and service life of the motor.
3. Precision assembly process:
After all parts are processed and inspected, enter the assembly link of the rear wiper.
First, accurately embed the rubber strip into the groove of the bracket to ensure that the rubber strip fits tightly with the bracket without looseness or offset. In order to ensure that the two are firmly connected, some auxiliary fixing measures may be adopted, such as applying special glue to the contact part between the rubber strip and the bracket, or using specific buckles, clips and other fixing devices.
Next, install the transmission mechanism between the motor (if it is an electric rear wiper) and the bracket. The transmission mechanism usually includes gears, connecting rods and other components. The installation must be carried out strictly in accordance with the design drawings to ensure the matching accuracy between the components so that the rotational motion of the motor can be accurately and smoothly converted into the reciprocating swing of the wiper. For some rear wipers with automatic control functions, it is also necessary to install electronic components such as rain sensors and control circuit boards, and to connect and wire the lines to ensure that the signal transmission between the electrical components is accurate and the control function operates normally.
Finally, install the connection interface of the wiper, which is used to connect the rear wiper to the wiper arm or mounting base of the vehicle. The design of the interface must meet the standardization requirements to ensure that it can be quickly and reliably installed and removed with the corresponding components of different models.
4. Testing stage:
After the rear wiper is assembled, it must undergo a series of rigorous tests to ensure that its performance and quality meet the standards.
4.1 Check the appearance
Appearance inspection is the first step. Check whether the overall appearance of the rear wiper has any defects, such as whether the bracket surface is scratched or deformed, whether the rubber strip surface is smooth, whether there are bubbles or impurities, and whether the installation of each component is firm and neat.
4.2 Measuring dimensions
Dimension measurement is also very important. Use high-precision measuring tools to measure the key dimensions of the rear wiper, such as the bracket length, rubber strip width, and overall installation dimensions of the wiper, to ensure consistency with the design drawings and relevant standards.
4.3 Test performance
The performance test simulates various working conditions of the rear wiper in actual use. In the wiping performance test, the rear wiper is installed on a simulated rear windshield test bench, and the motor drives the wiper to wipe back and forth. Observe the wiper’s removal effect on simulated rain and stains, and check whether there are problems such as missed scraping, incomplete scraping, or uneven scraping marks.
4.4 Durability test
Durability test requires the rear wiper to perform long-term cyclic wiping under certain wiping frequency and load conditions, usually tens of thousands or even hundreds of thousands of wiping times, to test its reliability and stability during long-term use, to ensure that the rubber strip will not wear out prematurely, the bracket will not deform, and the motor and transmission mechanism will not fail.
4.5 Electrical performance test (electric rear wiper)
In addition, for electric rear wipers, electrical performance tests are also required, including motor current, voltage, power and other parameter tests, as well as rain sensor sensitivity tests, control circuit function tests, etc., to ensure that the electrical system works properly and the coordination performance between various components is good.
Only rear wipers that have passed all tests can be identified as qualified products and enter the market circulation link to provide reliable rear vision protection for vehicle users.
If you want to know more about other processes in the manufacturing of rear wipers, or the manufacturing processes and differences of different types of wipers, please feel free to contact us! Novoflow has its own wiper manufacturing plant, and its manufacturing technology covers hybrid wipers, boneless wipers, truck wipers, bus wipers, conventional wipers, multi-function wipers, winter snow wipers and so on.
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