The quality of tinned copper stranded wire must be strictly inspected before packaging. The specific inspection standards must be strictly carried out in accordance with relevant requirements. It mainly involves the appearance inspection, wire diameter inspection, elongation inspection and resistivity inspection of tinned copper stranded wire, which are the contents that must be verified as a qualified tinned copper stranded wire.
When inspecting the appearance of tinned copper stranded wire, it is required that its surface is smooth, without black lines, no messy lines, no pitting, no oxidation, no puncture, no scratches, no tinning defects, no oblique lines, no hand joints, and no handprints. At the same time, the wiring should be good, uniform, without heaping edges, lacking edges, and no stranding; and the tension should be moderate; there should be no dust sticking on the surface of the copper wire after rolling.
The wire diameter of tinned copper stranded wire should be in accordance with the general standard, and the customer should strictly control it according to their requirements when they have special requirements. Before testing, you need to adjust the micrometer to zero; then put the tinned copper strand to be tested outside the micrometer clamp, twist the end of the micrometer with appropriate force; when you hear the micrometer beep three times, you can observe its reading. This should be repeated two or three times until the reading is consistent.
When testing the elongation of tinned copper strands, you need to use an elongation tester. When the displayed reading returns to zero, gently open the clamp, put one end of the tinned copper strand into the induction clamp, press the induction clamp, then gently straighten the tinned copper strand and put the other end into another induction clamp, press the induction clamp to clamp the copper wire firmly, and press the test key. Wait until the induction clamp breaks the copper wire and stops moving. The reading at this time is the elongation of the tinned copper strand.
Of course, the resistivity of tinned copper strands is tested with a resistivity tester. Clamp the induction clamps on both sides and observe whether the reading is zero. When the reading is 0, take a 1-length section of tinned copper stranded wire and clamp the two ends of the copper wire with two induction clamps. The copper wire to be tested must not come into contact with any metal objects, and press the test button. The reading obtained at this time is not the resistivity, and it needs to be calculated according to the relevant formula.
