What are the differences between optical glass perforated sheet and step sheet in processing technology?

The core difference of processing technology between optical glass perforated sheet and step sheet lies in the different molding objectives, key processes and precision control points. The perforated sheet focuses on the size/verticality of the hole, while the step sheet focuses on the flatness/height difference of the step surface.

Core process difference

1. The molding core processes are different.

Perforated sheet: the core is "hole machining", which requires laser drilling, ultrasonic drilling or diamond drilling to form the basic hole, and then reaming, fine grinding and polishing to meet the accuracy requirements.

Step piece: the core is "step forming", and the step structure is directly made by milling and grinding in layers (machining the datum plane first, then machining the step surface), or by using diamond grinding wheel to form and grind.

2. The focus of precision control is different.

Punched sheet: The diameter tolerance of the hole (usually ±0.001~±0.005mm), the roughness of the hole wall (Ra≤0.01μm) and the perpendicularity between the hole and the glass surface (≤0.002mm/m) are mainly controlled.

Step piece: the height difference of step (tolerance ±0.002~±0.008mm), flatness of step surface (≤0.001mm/m) and verticality of step side surface and datum plane are mainly controlled.

3. Auxiliary process differences

Perforated sheet: after hole processing, it is necessary to clean the hole wall (remove residual debris from the hole) to avoid impurities in the hole from affecting subsequent assembly or optical performance; In some scenes, it is necessary to chamfer the orifice (R0.01~0.05mm) to reduce stress concentration.

Step piece: after the step is formed, the edge of the step should be trimmed and chamfered to prevent edge collapse; At the same time, it is necessary to control the parallelism of the upper and lower surfaces to avoid overall warping.

General basic process (no difference)

Both of them need to go through basic processes such as blank selection, rough grinding and leveling, datum polishing, cleaning and drying, and the processing environment, material protection and equipment accuracy requirements (such as spindle runout ≤0.002mm) are consistent.