What hole diameter design rules apply to photochemical etching of stainless steel parts?

For photochemical etching of stainless steel parts, the primary hole diameter design rule is to avoid specifying holes smaller than the material thickness, and to target a hole diameter of at least 1.0 times thickness as a baseline, with 1.1 to 1.5 times thickness or larger being easier to produce consistently. Round holes are the most stable geometry in etched stainless steel. A round opening distributes etchant action more evenly than slots, squares with sharp corners, elongated holes, or complex decorative openings. If a design requires holes below the 1:1 diameter-to-thickness ratio, manufacturability should be checked early because process feasibility then depends on the specific stainless steel grade, temper, sheet flatness, grain direction, surface finish, hole pattern density, required opening cleanliness, and whether the part is etched from one side or both sides. In some thin-gauge applications, smaller features may be possible, but they should not be assumed without engineering review. Hole diameter cannot be judged independently from adjacent features. A common practical check is to review hole diameter together with web width, bar width, land width, and edge distance. If holes are very close to each other or very close to the part edge, the etched material between them can be undercut more aggressively, which may change effective opening size, reduce straightness, or create fragile sections. For precision mesh, filter screens, speaker grilles, encoder discs, fluidic plates, and other perforated stainless steel components, the relationship between open area, hole size, pitch, and material thickness directly affects both etching stability and part function. Through-hole quality should also be defined clearly on the drawing. In photochemical etching, hole edges are typically burr-free, but the opening may show a slight etch radius or corner break depending on thickness, exposure control, and etch time. Designers should state whether the drawing dimension refers to the etched top side, the etched bottom side, or a functional mid-point diameter, because etched openings are not always perfectly straight-walled in thicker material. If the hole is used for alignment, fluid control, optical transmission, screening, air flow, or assembly clearance, the functional critical dimension should be marked so the etching process can be controlled to the relevant feature. Pattern density is another important condition. A single isolated hole and a dense array of hundreds or thousands of holes do not present the same process window. Dense hole fields can create local differences in etchant exchange across the sheet, which may shift hole size from the edge of the panel to the center or from one region of the part to another. Material selection affects hole design limits as well. INNOETCH provides photochemical etching for stainless steel along with copper, nickel, molybdenum, aluminum and other metals, and different alloys etch at different rates and with different edge characteristics. When preparing a design for quotation or prototype review, include the stainless steel grade, sheet thickness, finished part dimensions, hole diameter and tolerance requirements, hole-to-edge distance, hole pitch or spacing, surface requirements, burr or edge expectations, quantity range, and application conditions. If a sample exists, it is helpful to identify which dimensions are functional and which are general reference. For precision components, flatness requirements should also be noted because very thin perforated parts with high open area can be more sensitive to handling and inspection method. A practical design review sequence is: first confirm material thickness; second check that hole diameter is not below thickness without special review; third verify that spacing between holes and spacing from holes to part edges are not excessively narrow; fourth mark critical dimensions separately from non-critical dimensions; and fifth define the inspection method for hole size, such as optical measurement, pin gauge use, or functional assembly criteria. This reduces iteration time and helps avoid drawings that look acceptable on paper but require adjustment for stable etching. For prototype and production projects, INNOETCH supports custom etched metal components based on customer drawings, samples, dimensions, materials and application needs, with engineering review covering design optimization, process control, quality inspection and stable batch production. Quality checks for etched stainless steel hole features typically include dimensional review, surface condition, edge quality, opening consistency, flatness and batch-to-batch uniformity, in line with the company’s ISO 9001 quality management approach. For project review, drawings, material specifications, dimensions, tolerances, quantity and application requirements can be sent to nico@innoetch.com.