Understanding Precision Photo Etching Costs

Precision vs. Decorative: Important Differences

Precision photo chemical etching is characterized by detailed specifications that call for conformance to identified dimensions, tolerances and inspection requirements. These factors have implications with regard to pricing. By contrast, decorative etching is all about appearance and as such, we are able to run decorative on large sheets with minimal inspection at very predictable sheet prices.

Precision metal etching also encompasses a very wide range of alloys and metal thicknesses, both of which have direct bearing on costs. Generally, the mid range of thickness values runs from .010″ to .030″. At these gauges, metals are easily handled and run through the process with excellent yields. At metal gauges under .010″, more care is needed to avoid bends and kinks so the handling needs to be more mindful. And, as metals get thicker than .030″, the metal etching time, which is the most expensive time in the shop, gets longer and more costly.

Metal Thickness Drives Dimensional Tolerances

Dimensional tolerances also play a significant role in the costs of chemical etching. The etching process can achieve dimensional tolerances of +/-15% of the metal thickness, with a practical minimum of +/-.0015″. Location tolerances are typically within +/-.001″ of drawing nominal. In the significant majority of cases, the standard tolerance of +/- .005″ on 3-place decimal dimensions is going to be quite comfortable and economical for metal thicknesses up to .030″. Tighter tolerances also reduce yield, which has an impact on costs, as well.

The inspection requirements for precision manufactured parts are more extensive, even with standardized sampling plans. Most precision etched parts are removed from the sheet and require special packaging. These steps entail additional labor beyond the etching process itself.

Quantity also plays an important role in costs as it bears directly on the cost of the materials, as well as on the amortization of set up over a range of quantities.

Sheet Sizes have Significant Impact on Etched Piece Prices

The table below illustrates the impact of tolerances and sheet sizes on photo etching costs. The premise is based on a 1-inch part on .010″ thick metal and does not include metal cost. The major variable in this example is the labor. In chemical etching, the unit of labor is the sheet. The amount of labor per sheet varies very little with the size of the sheet. Therefore, the number of sheets becomes a decisive factor in calculating costs.