Wire Drawing Machine with In-line Annealer

Selection criteria

Number of dies, line speed, annealing voltage / current control.

Supply chain

Wire drawing lines are led by German and Italian makers (Niehoff, SAMP), several with plants in China, alongside many Chinese builders around Jiangsu, Zhejiang and Anhui. Motor makers buy wire rather than drawing it; the takeaway is that diameter tolerance and surface quality start here.

Buyer FAQ

Which conductor properties set on the drawing line should I check?

Check bare-conductor diameter tolerance and minimum elongation against IEC 60317-0-1, and resistance against the annealed-copper value (resistivity 1/58 Ω·mm²/m at 20 °C). Elongation for common motor sizes is typically required in the 20–35 % range, rising with diameter. Also inspect for slivers and drawing marks, which become enamel faults later.

Why does in-line annealing matter for winding?

Under-annealed wire is harder and springs back, causing loose turns, poor slot fill and enamel cracking on tight bends. Over-annealed or unevenly annealed wire stretches under winding tension and loses diameter. Ask whether annealing current is controlled against line speed and whether elongation is measured on every spool.

ETP or oxygen-free copper rod?

Most magnet wire is drawn from electrolytic tough-pitch (Cu-ETP) rod with about 100 % IACS conductivity. Oxygen-free copper (Cu-OF) draws better to very fine sizes with fewer breaks and is required where hydrogen embrittlement during brazing or welding is a risk. Ask the wire supplier which rod grade and source they use for your size.

Where it is used