The precision chip resistor adopts the manganese-copper strip as the raw material. It is relatively complex to manufacture the resistor of the package size 2512 within ±1% tolerance. First of all, the manganese-copper strip is stamped into the required resistance pattern by precision stamping. The target resistance value is set, correcting the center value according to the upper and lower limits of the target resistance value so as to ensure that all products are controlled within the upper limit of the specification.
 
To modify the center value is to intentionally adjust the target center value below the actual center value so as to ensure that the printed alloy pattern sheet resistivity must not exceed the target upper limit. In the practical stamping process, the actual resistance value should be measured after each batch of graphics chips are impacted. Once it is found that there is an out-of-range resistance values, different punches or different batches of strips are replaced to meet the central value range of the target resistance value. Manganese-copper strip is only one type of resistance material. Resistance manufacturers can also use other suitable alloy materials to make precision chip resistors.


Precision chip resistor adopts resistance tester and special tool to measure resistance value.
According to the level of stamping process, the resistance graphics whose resistance value is less than the lower limit of the target are divided into N groups. Chemical etching solution for resistive adjustment needs to be prepared before resistive adjustment, adding a proper amount of tap water to the tank body 3, heating it to 30-50°C with a heater, adding etching salt with a mass ratio of 5%-10% and a strong acid configuration with a volume ratio of 1% - 5% to form the chemical liquid 1.
 
The precision chip resistor is made by adding 5% potassium bisulfate compound salt, opening the gas pump cycle, dissolving the etched salt completely, then adding 5% sulfuric acid in volume ratio. When the composition of the chemical liquid is uniform, the chemical liquid 1 can be put into production when the liquid level is stable. The volume of the chemical liquid 1 accounts for 80% of the total volume of the tank. The bath body may use a common plating PP bath, such as acid-resistant, alkali-resistant, aging-resistant, and high-temperature-resistant body, and a general electroplating PP bath shall be used for the heater. The heater shall be acid-resistant, alkali-resistant and leakage-proof. The present embodiment adopts a ferrolon heater for electroplating purpose.