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How Does Chemical Machining Work?

What Is Chemical Machining?

Chemical machining is the clean removal of metal using a photochemical technique from pre-defined locations without affecting the integrity or characteristics of the metal. With no burns or pressure on the pieces, this method is typically utilized to produce small, thin metal parts of intricate designs.

Chemical machining is the clean removal of metal using a photochemical technique from pre-defined locations without affecting the integrity or characteristics of the metal. With no burns or pressure on the pieces, this method is typically utilized to produce small, thin metal parts of intricate designs.

Cleaning the metal of any debris and oil is the first step in the procedure. To ensure an even coating, a photoresist is applied and baked. Once the artwork is over the ready-made metal sheet, it is exposed to ultraviolet radiation to get the appropriate resolution and etch requirements.

The artwork has been taken down, and the site is now prepared for development or removal. By dipping the sheet in a chemical solution that dissolves all the material that is not a part, the metal is now ready to be etched. After the etching is finished, the resist is taken off, and the metal components are cleaned, examined, and packaged.

The Chemical Machining Process

  • Cleaning

Cleaning effectively completes the subsequent processing; the workpieces are cleaned to eliminate any oil, grease, dust, or other substances.

Cleanings are required to guarantee that the masking material adheres to the workpiece properly. Stray etching happens when masking debugging.

Depending on the work material and the necessary machining depth, various cleaning operations, such as vapor degradation, alkaline etching, etc., like maskants, are carried out. Porous workpiece materials are challenging to clean.

Mechanical and chemical procedures are the two basic types of cleaning. Because it does significantly less harm than the automated method, the chemical method is more commonly utilized.

The thinner or chemically cleansed portions of the mask are refined if it is thicker and thinner. It is beneficial to heat the cleaning process.

  • Masking

Masking is carried out using masks. These masks don’t interact with the machining chemicals because they are naturally inert. Employing a simple stripe mask is recommended.

Any one of the three approaches listed below is given a mask:

  • Cut-and-peel method
  • Screen technique
  • Photoresist method

In this masking procedure, the non-machinable parts of the workpiece are covered with a mask so that the machined part is exposed to the machining chemical. However, the entire workpiece is protected during the masking procedure.

  • Scribing

Following the masking procedure, removal is done from the workpiece’s area, which will be mechanized so that a chemical reaction may occur. Only the portions that will be automated are subjected to chemical machining after the scribe process.

  • Etching

The workpiece is filtered before being submerged in a container containing a chemical that reacts chemically with the workpiece.

The masked part of the workpiece does not experience any chemical reactions when it is submerged in the chemical. In contrast, the unmasked area of the workpiece experiences chemical reactions with both the chemical and the material. I’ll begin to back away from it.

Typically, etching is carried out at a high temperature. To prevent uneven machining, gas bubbles shouldn’t be permitted to become trapped during the procedure.

  • Demasking

After the etching procedure, the masks are removed from the workpiece’s mechanized and non-mechanized areas, and the oxide layer is removed from both.

  • Washing

The workpiece is extensively rinsed under fresh water after the demasking procedure to eliminate all contaminants from its surface.

In addition to all these stages, the Etchant of heating and cooling is also utilized. Depending on the temperature, a heating or cooling rod is used to maintain the waiter’s temperature in the container.

Types Of Chemical Machining Process

A wide range of processes, including milling, blanking, and engraving, can be done with this method. The numerous chemical machining techniques can be divided into the following categories:

  • Using Chemical Mills
  • Chemical Engraving
  • Chemical Blanking

Reactive gases, such as jets of chlorine, can also be used in the machining area to achieve chemical machining for specific specialized uses. Metal parts can be debugged using this technique, also referred to as hot chlorine machining or gaseous chemical machining.

Chemical Milling

Chemical milling, also known as industrial etching, is a subtractive manufacturing technique that involves removing material in baths of etching chemicals at a controlled temperature to produce an object with the desired shape.

Chemical etching is sometimes referred to as photochemical etching, chemical etching, or photochemical machining. Although other materials are becoming more significant, metals are the primary substances it employs. It was created from printing etching techniques and armor decoration techniques developed during the Renaissance as alternatives to metal engraving.

In essence, the procedure entails soaking the cutting sections in an etchant, a corrosive chemical that reacts with the material in the cutting area and dissolves the solid material; inert chemicals, known as maskants, are employed to protect particular areas of the material as resists.


The production of semiconductors and printed circuit boards both use etching. Removing shallow layers of material from significant aircraft components, missile skin panels, and extruded parts for airframes is another application in the aerospace sector.

Microelectromechanical systems and integrated circuits are also frequently produced via etching. Plasma etching is commonly used in the semiconductor industry in addition to conventional liquid-based methods.

Chemical Blanking

Chemical milling can include chemical blankets, blanking, photo-making, photo vibration, or photo etching. In this method, chemical activity eliminates the materials from several locations.

Their sheets and foils are the primary products of this procedure. This procedure can work for almost any metal, but it is not advised for materials that need to be thinner than 2 mm.

Acid or alkali is used to clean, reduce, and choose the workpiece. After thoroughly cleaning and drying the metal, the photoresist material is sprayed, dipped, or whirled onto the workpiece. Afterward, it is dried. Degradation-resistant pictures on photoresist materials have been created using photography materials.

This mask is only sensitive to ultraviolet radiation, which has a specific frequency, and not ambient light. As with developing drawings, this surface is now visible to light through a negative, or instead, a photographic plate with the desired design. Following exposure, the picture is created. Unexpected pieces fall away while being developed, exposing bare metal.

The metal is maintained in a machine and either added to the slurry or sprayed with chemicals. Hydrofluoric acid (for titanium) or any other number of chemicals can be used as the etching solution. The undesired metal has been ingested after 1 to 15 minutes, and the final product is ready to remove the ashes immediately.

Chemical Engraving

Printed circuit cards, various engraving processes, and cuttings of intricate designs can all be chemically blanked.

  • Metals as thin as 0.005 mm can be mined effectively.
  • It is possible to maintain high precision with orders of +0.015 mm.
  • A photographic process that is automated can produce work at high rates.

Application of Chemical Machining

  • CHM has been used in a variety of applications where tight tolerances and metal removal depth are required.
  • The procedure results in a surface finish between 0.5 and 2 microns thick.
  • During this process, a section of the entire surface of formed or irregularly shaped items, such as forgings, castings, extrusions, or formed wrought stock, is also partially removed from metal.
  • The creation of detailed, burr-free stampings is one of the primary uses of chemical machining.

Advantages and Disadvantages of Chemical Machining

  • The benefits include that it is simple to use on even the most complex materials to machine and does not deform the product or leave burrs behind.
  • However, because of how slowly the process works, it is rarely used to generate significant amounts of material or to machine materials thicker than 2 mm.
  • Some small pieces speed up production, allowing 10 to 100 to be produced on a single plate at a time.

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