Chemical etching has come on leaps and bounds in recent years thanks to the industry’s quick response to meeting the incredible demand for precision metal parts. As our home electronics and appliances become increasingly sophisticated, the technology and manufacturing processes to produce them also has to keep up in order to meet the strict demands. So nowadays, the chemical etching process is able to produce incredibly accurate results that are used across a number of different industries including aerospace and medical.
In this article we’ll take a look at the benefits of using chemical etching to produce precision metal parts. It’s thanks to the manufacturing process that means chemically-etched parts are so practical, reliable and applicable.
What is the Manufacturing Process?
In this section we’ll go through the chemical etching production technique and how it helps to make such robust final products. The first stage of the process is to ensure a clean metal surface with which to work on. In order to accomplish this, we clean the sheet metal in a class 6 clean room to make sure that the process isn’t negatively affected by any unwanted contaminants. At Tecan we have experience with a variety of different metals, some of which include:
- Stainless Steels: Ferritic, Austenitic and Martensitic
- Copper, including C101 (oxygen Free) and C110
- Mild steel, tool dteel, carbon steel and spring steel
- Nickel alloys: Mu-Metal, inconels, alloy 42 (nilo 42)
- Aluminum which includes aircraft/aerospace grades
- Nickel silver, brass, beryllium copper, phosphor bronze
Once the metal is rigorously cleaned, then the photoresist can be applied to the metal. The photoresist is the lacquer that will protect the desired parts of the metal later down the production line. After the photoresist is applied across the entire sheet metal, it’s then exposed to ultra-violet light which hardens the photoresist to the shape or stencil we require. The unexposed areas are then developed away to reveal the exposed metal underneath. Once this is done, then the chemical etching process begins as we spray the entire sheet metal with our carefully formulated chemical spray that dissolves away the unwanted parts of the sheet metal. Finally the photoresist that protected the desired parts is stripped away and we’re left with the final product.
As the process is controlled by computer, we have total control over the stencil which means our designs can be incredibly accurate, as small as 25 µm in some instances. This also means that thanks to the precision of the stencils, the etchant only goes to work on the unwanted parts of metal so creating fine mesh speaker grilles or sieves are no problem at all. This intricacy obviously extends into other areas like medical where the need for precise and structurally in-tact metal parts is essential.
This is another incredible feature of chemically-etched parts; the metal’s inherent properties are unaffected where in other manufacturing processes, such as laser cutting or micro stamping, the process is so high energy that it can affect the metal’s properties. This is a big advantage that chemical etching has which is that it produces precision metal parts that finish the production process burr and stress-free, unaffected structurally and this process is replicable on an industrial scale.
A Versatile Process
As mentioned previously, the process is so precise thanks to the stencil being applied via computer software so the designs can be as complex as you can make them in a computer-aided design software. This also means that the lead times are greatly reduced because the prototyping period is also reduced from weeks to just days in many instances. The journey from testing prototypes to finished product is so quick thanks to the fine adjustments all being done on computer. There’s no re-tooling or adjusting any machinery, the process is all done and carried out via computer control for absolute precision.
A recent example of chemical etching’s versatility are bipolar fuel plates. These require channels etched into the surface of the metal which can then be stuck together to create a seal for the channel which then distributes gases or liquids. The advantage of manufacturing these fuel plates with chemicals is that the channels don’t have any aberrations or burrs from the manufacturing process which could affect the passage of gases or liquids. By using chemical etching, we’re able to create the channel grooves within the metal without any deformation. They need to be absolutely precise for their intended function which means that the chemical etching process is ideally suited for this.
For these reasons and more, chemical etching has become an industry standard because of its precision and repeatability across a large production scale. The fact that there’s no post production in terms of deburring or tidying up the parts at the end means that the production time is reduced which is also reflected in the cost. Chemical etching is an industry-leading manufacturing process for precision metal parts that are now required by so many industries.