Photochemical Machining

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Photochemical Machining
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Synopsis

• Photochemical Machining For Electronics
• Photochemical Machining and Etching Processes
• How Photo Etching Works
• Chemical Etching of Surgical Saw Blades

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Photochemical Machining For Electronics

• Photo-etched microelectronic parts are usually
  shiny and can at times look chrome plated, flat
  and dull. It might take any of the mentioned
  forms depending on the photo-etching process it
  has undergone. However, you can get regular
  photo-etched parts that can be attached to
  frames. This type is quite easier to make and
  also remarkably less expensive than the
  rubber-backed parts. But note that, it's a lot
  harder to work with compared to the rubber-backed
  parts that are far easier to remove, very
  expensive and also difficult to come across.
• When it comes to QFN and LD-MOS leadframes, photo
  etching is guaranteed to do the perfect magic and
  not just on it alone but also on other custom
  platforms too.
• As a result of its amazing low attenuation loss,
  the QFN otherwise known as "air-cavity" packages
  are perfect for use in RF and microwave
  communications applications. Due to its complex
  and also fragile designs, the leadframes are just
  perfect for the capabilities of chemical etching.

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Photochemical Machining and Etching Processes

• The first step towards photo-chemical machining
  process is the manufacturing of a photo-tool,
  this can be achieved by using a laser photo
  plotter to selectively expose a photographic film
  based on computer-aided design data.
• The next step involves the selection and
  preparation of the metal for photochemical
  etching. In order to ensure that the metal has
  good adhesion to the photoresist, the sheet metal
  has to be thoroughly cleaned with electrolytic
  alkaline, the cleaning process makes the metal
  free from dirt, grease, rust, and oil thus making
  it possible for it to be laminated with the
  photo-resist.
• After undergoing lamination, the surface of the
  metal which has now been covered with photo
  artwork will then be exposed to a UV source.
  After this process you will realize that the
  un-exposed negative working photo-resist will be
  washed away, leaving only the exposed photoresist
  on the surface to produce the required protective
  layer for the etching process.

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How Photo Etching Works

• Let's look at it this way when engineers receive
  either of the following drawings, sketches, or
  electronic files, the first thing they do is make
  use of the CAD software to produce a pattern of
  repeated part designs. During this process, the
  repeated designs are laser plotted on the
  photographic film, thereby producing a photo
  tool. This tool has the capacity to hold a
  countless number of images although this
  capability is entirely dependent on the part
  size. Then the next step involves using the UV
  light and photo tool to send the images to a
  photoresist which is primarily a photosensitive
  polymer. The photoresist, therefore, covers the
  sheet of material. However note that, while this
  process is ongoing photoresist that notices UV
  light is instantly polymerized thereby leaving
  resist that is in unclear areas of the photo tool
  uncured.

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Chemical Etching of Surgical Saw Blades

• This machining method of saw blade production is
  less expensive than the stamping, punching, laser
  and waterjet cutting method. And not just that,
  it also has numerous benefits too that includes
  shaping, blade tooth offset, surface marking of
  graduation lines, logos and insignias among
  others. And the interesting thing is that all
  these benefits can be achieved in its smoothest
  and best forms without any burr within a short
  period of time and also at a low cost.
• Chemical etching is economical when compared to
  other traditional methods like stamping because
  of the fact that, it primarily relies on digital
  tooling which is far more economical than the
  hard tooling that the stamping method is known
  for.
• When it comes to the iteration of designs, this
  is one area where you will appreciate the beauty
  of the photo-chemical etching method. This is
  because of its ability in an iteration of design
  prototype in a single sheet at no extra cost.

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