Technology driven design

We talk to dozens of engineers and designers who are looking for new ways to solve their most challenging design efforts. Sometimes, the parts they want to make are too complex for the processes they’re accustomed to using. Other times, they need parts in batch sizes that are impractical for other fabrication methods: perhaps too few for stamping or too many for laser.

Photo chemical machining has characteristics that make it an effective option for some of these problems. Here are four benefits that engineers and designers should know about:

“At its hottest point, the etching process reaches temperatures of about 125℉. “

No stresses or deformations on the finished part

The cutting- and stamping-based fabrication methods are more well-known, but they have some shortcomings that give designers pause. For example, laser cutting and wire EDM exposes the workpiece to extremely high temperatures, leading to heat affected zones or recast layers that can change the characteristics of the metal alloy.  Stamping and punching can create work hardening that requires remediation through annealing. Stamping and CNC milling can lead to mechanical distortions, burrs and uneven edges.

Photo etching has none of these problems. At its hottest point, the etching process reaches temperatures of about 125℉. And because the parts are chemically etched out of the sheet metal, there are no cutting or shearing actions that lead to burrs or other deformations.

Well-suited for complex geometries and features on flat parts

Today, screens, meshes, sieves and other parts that require many small holes or design features are finding their place in industrial, medical, electronic and scientific applications. For most of the conventional fabrication processes, these parts are either nearly impossible to make, or are completely impractical in terms of tooling, cycle time or costs.

A phototool is a stencil used to imprint the pattern of the parts on the metal. All of the features, including as many holes as may be needed, are etch all at once at no additional cost. This saves time and ensures the uniformity of each hole on the part. The photo etching process produces consistent, burr-free holes as small as 0.004″ in 0.002″ thick material. As a rule, minimum hole size is 110 percent of the thickness of the material. On 0.010″ thick material, the smallest hole we could make would be 0.011″.

Designers and engineers today need precise component parts and are looking for new processes that help them solve design problems.

Tight, consistent tolerances are built in

The phototool is extremely accurate because light is its only working exposure. Thus, there is there is no “tool wear” that could lead to tolerance variations. Because of this, the locational tolerances for design features generally meet the nominal dimensions of the specification.

Dimensional tolerances are dictated by the thickness of the metal. We can typically hold these to within +/-15% of the sheet’s thickness.

Design changes are quick and easy

Phototools are inexpensive, generally about $400 and can be made in about 2 days. This means that designers can change their designs without incurring substantial costs or delays.

For detailed information, our newly updated Comprehensive Guide to Photo Chemical Machining offers engineers and designers technical information to assist their projects:

Check out the “Minutes with Max” video series.  All about etching in bite-size chunks.

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