The sintered NdFeB magnet is the permanent magnet with high magnetic performance. The hardness is high. It is crispy. When we machine the magnet, it is easy to crack. Normally we have several production techniques to produce the magnet.
- The wire-electro cutting machine: It could be devided into slow wire electrical discharge machine and fast wire electrical discharge machine. The accuracy of the slow one is ±0.01mm, cutting speed is about 2-5mm²/min. It is suitable for the complex shape of the magnet.
- Laser cutting equipment: It is suitable for the thin slice of the magnet(Thickness<3mm), the power is above 500W.
- Grinding and chamfering: We use diamond wheel to grind and chamfer. The speed is about 0.1-0.3mm/s. In this process, we need to avoid the high temperature inside of the magnet to make the magnet demagnetized.
- Drilling and threading process: We take ultrasonic assisted drilling to dig holes. It could reduce the risk of the crack on the magnet. The minimum diameter of the magnet is about 0.5mm. The tapping need to use the hard alloy cutter. The speed is above the 200rpm.
- Surface coating: Normally we use standard nickel, Zn and epoxy. The thickness of the standard nickel is 15-25μm. The salts spray could be above 72h.
