① Piston anodizing ② Chromium-based ceramic plating ③ Piston ring long cylinder rotary chromium plating ④ Electroless nickel plating ⑤ Aluminum tin plating ⑥ Chromium mist recovery purifier ⑦ Temperature and liquid level control ⑦ Piston pin chromium plating ③ Special piston ring chromium plating ③ LCD panel etching