Metallized film capacitor process Flow
Process 1
Slitting process to slit the semi-finished film into finished film Semi-finished metallized film Required equipment Slitting machine
Process 2
Winding process to roll the finished film into cores. The core is the most basic and important component of the film capacitor finished film, mandrel Required equipment Winding machine
Process 3
Spraying process will be the core of the two end surfaces sprayed with metal layer, easy to weld the lead core, zinc wire, zinc and aluminum alloy gold wire Required Equipment Spraying Machine
Process 4
Enabling process after the core gold spraying, the core for charging and discharging test. Test its capacity, loss, self-healing and withstand voltage is in line with the design requirements / equipment required Fusing machine.
Process 5
Welding assembly process will be welded on the core lead, and its series, parallel combination of solder, a variety of wires, copper foil equipment required automatic welding machine, soldering iron
Process 6
Core, core group test process on the core, core group for voltage, capacity, loss test. Required equipment capacity tester, voltage tester, insulation resistance tester
Process 7
Impregnation process at high temperature, vacuum state, the core, core group impregnation, to remove the core of air, water, insulating oil Required equipment impregnation machine
Process 8
Assembly process will be assembled into the shell core assembly, do insulation, installation of leads and other insulating film, insulating paper, shell, insulators, lead columns and so on.
Process 9
Semi-finished product testing process for semi-finished product voltage, capacity, loss, insulation test. Required equipment capacity tester, voltage tester, insulation resistance tester
Process 10
Encapsulation and painting process for semi-finished products encapsulation, grinding, cleaning and painting treatment paint. Required equipment argon arc welding machine
Process 11
Finished product testing process for semi-finished products for voltage, capacity, loss, insulation test, as the case may be, but also for the life test, accurate capacity, loss test and internal resistance and inductance test, need to use the equipment capacity tester, voltage tester, insulation resistance tester, precision high-voltage bridge, AC and DC withstand voltage test devices, oscilloscopes, Luo times the coil, high-voltage capacitance test device.
Process factors that cause deviation in capacitance during manufacturing process
Capacitance of a wound capacitor C = 0.177ε s / d
ε is the dielectric constant of the dielectric s is the effective area of the pole plate d is the thickness of the dielectric The capacitance is directly proportional to ε and s and inversely proportional to d. The capacitance of a wound capacitor is determined by the capacitance of the capacitor.
The capacity is directly proportional to ε and s and inversely proportional to d. Although precisely specified in the document, all three parameters can change during the process, resulting in capacity deviations. The focus of the process is to minimize these deviations and increase the capacity hit rate.
a. Winding process
There are inherent errors in the film width, thickness, or edge retention.
Changes in film tension from large to small turns, errors in tension of each winder.
Pressure of rollers is too small. The winding process runs off, wrong edge error.
High humidity in the air leads to large core capacity.
b. Hot pressing process
Uneven force on core thickness error, resulting in uneven core tightness.
Capacity dispersion.
Unevenness of hot pressing plate.
Temperature error.
c. Heat treatment time or temperature error
d. Contained dip
Vacuum error
Time error
Curing temperature error.
Process points to solve the deviation
1. Accurately determine the winding capacity center value (also known as the correction value), must be hot (cold) pressure, heat treatment and wrapping and other processes capacity
The rate of change of capacity of hot (cold) pressing, heat treatment and wrapping must be included in the capacity correction value of the core. The correction value is different for different models, specifications and even for different winders.
2. the capacity and height of the core are measured regularly during the winding process to control the dispersion of the electric capacity.
3. randomly measure the capacity of the core after flattening and shaping, and adjust the value of winding center in time if any deviation is found.
4. track the capacity distribution of finished products, and find out the over-difference timely feedback, in order to adjust the capacity correction value.
If the product is tested after a short period of time after wrapping and sealing, as a result of storing the product for a period of time, the capacity will change, resulting in capacity overshooting, which is more obvious for polyester capacitors, and is generally shifted in the positive direction.
There are several ways to solve the problem:
Heat treatment of the product after sealing.
After packaging and natural storage for a week before testing.
According to the law of change in the test to control the deviation value, such as polyester capacitors in the positive deviation card tight, negative deviation relaxation.
UF Capacitors is an ISO9001-certified manufacturer in China, founded in 1995. We hold military qualifications for tantalum capacitors, MLCC, film capacitors and other products. Additionally, we have a UL-recognized test laboratory located at our factory site.
Our marketing position is to provide a superior alternative to first-tier brands such as TDK, Murata, AVX, EPCOS, Vishay, and Panasonic. We offer similar quality but at better prices, with faster lead times and excellent service. With extensive experience working with renowned international companies like GE, Philips, Jabil, and Flex, we have built a strong reputation.
If you are looking for film capacitor factory in China, please contact us: carey@ufcapacitors.com
Or want to find more capacitor datasheet, please visit our website: www.ufcapacitors.com.
