What should we pay attention to when we are doing hardware stamping of electronic products?

The core of hardware stamping processing of electronic products is to ensure product precision, surface quality and production safety. It is necessary to adapt to the characteristics of small size, high precision and thin wall of electronic products around five core links: material control, mold precision, process parameters, surface protection and safe operation. The specific precautions are as follows:

Strictly control the quality and pretreatment of raw materials

Common materials for stamping electronic products are stainless steel strip, copper strip, aluminum strip, cold-rolled steel strip, etc. It is necessary to ensure that the material thickness tolerance is ≤±0.01mm (suitable for precision terminals, shrapnel and other parts) and the surface is free of scratches, oxidation and oil stains. Incoming materials should be verified to avoid mixing (for example, copper tape conductive parts can not be replaced by steel tape).

Cleaning the materials before processing: use degreasing agent to remove oil stains on the surface, and then dry them before feeding; Aluminum strip and copper strip should be treated with anti-oxidation to avoid oxide chips during stamping. The coil should be leveled to prevent the size deviation of stamping parts caused by material warping.

Ensure high precision and maintenance of molds.

Die is the core of precision stamping, and the gap between punch and die should be designed accurately according to the material thickness (the gap value is usually 8%~12% of the material thickness), and the edge roughness Ra is less than or equal to 0.4 μ m to ensure smooth and burr-free punching surface. The mould locating pin and guide post shall be matched accurately, and the repeated positioning accuracy shall be ≤ 0.005 mm..

For tiny parts of electronic products (such as connector terminals and mobile phone hardware supports), progressive dies are preferred to realize the integration of feeding, stamping, trimming, bending and unloading, and reduce process errors.

Regular maintenance of the mold: grinding the cutting edge in time after wear to avoid burr; The surface of the mold should be coated with antirust oil and stored in a dry environment; During the stamping process, the waste and dust in the die are cleaned regularly to prevent the die from being stuck.

Precise control of stamping process parameters

Adjust the stamping speed and pressure: the thin material (thickness < ＜0.5mm) is stamped at a low speed (100~300 times /min) to avoid material stretching deformation; The pressure of thick materials or bending parts is appropriately increased to ensure that the molding is in place. The stroke should be accurately controlled to prevent the die from being damaged or the product from being deformed due to excessive stamping.

Attention should be paid to the bending process: bending radius ≥ material thickness (to avoid brittle fracture), and there is no indentation at the bending place; For the parts with rebound requirements (such as shrapnel), it is necessary to adjust the compensation amount of the die through repeated trial punching to ensure that the size reaches the standard after rebound.

Feeding accuracy control: automatic feeder is adopted, and the feeding step error is ≤±0.01mm；; When the coil is fed, a deviation correction device is installed to prevent the stamping parts from being short of materials and out of tolerance due to material deviation.

Strengthen surface protection to avoid secondary damage.

Hardware of electronic products requires extremely high surface smoothness, so it is necessary to coat special lubricating oil (such as volatile stamping oil) on the die surface during stamping to reduce friction scratches; When stamping soft materials such as copper strip and aluminum strip, a protective film can be attached to the surface of the material.

The unloading device should adopt elastic unloading plate to avoid scratching the product surface by hard contact; The finished products should be placed in layers with anti-static trays to prevent scratches or electrostatic damage caused by stacking friction.

Remove burrs in time after stamping: adopt grinding, polishing or tumbling technology to ensure that the height of burrs is ≤0.005mm to avoid short circuit of electronic product assembly caused by burrs.

Do a good job in quality inspection and process control

First article inspection: After each shift starts or dies are changed, full-scale inspection (using precision instruments such as secondary elements and projectors) is required for the first article to confirm that the size, appearance and bending angle meet the requirements of the drawings.

Inspection and sampling: sampling once every hour during production, focusing on key dimensions and surface defects; Sample batch products for salt spray test and hardness test (such as elastic fatigue test of shrapnel).

Establish traceability system: record raw material batch, mold number, process parameters and test data, so as to facilitate the traceability of quality problems.

Standardize safe operation and equipment maintenance

Equipment should be equipped with safety grating and two-hand start button to prevent misoperation during stamping; It is forbidden to clean up the waste or adjust the mold when the equipment is running.

Check the clutch, brake, slider and other parts of the punch regularly to ensure stable operation; The hydraulic system needs to check whether the oil pressure is normal to prevent the pressure fluctuation from affecting the stamping quality.