Metal Shim Manufacturing: Chemical Etching or Laser Cutting?

Shims can be found in most factories that are a best fit for spacing alignment found in aerospace, automotive, electronic, and medical industries. In such industries, they serve as a spacer that gives the right deviation with fine tuning and calibration between two objects. Small system failure or breakage caused, largely, by the smallest deviation in one of the components will certainly lead the management to a corrective action. Since the major requirement of shimming is the presence of precision, dealing with thinner materials will require a more precise way of shimming.

For advanced metal shim manufacturing techniques such as chemical etching and laser cutting are good options.

This blog post will discuss these two metal shim manufacturing techniques and help understand when to laser cut or chemically etch custom parts manufacturing based on part designs.

Shims Made by Means of Chemical Etching

Chemical Etching is a subtractive technique. It is a suitable technique that involves using a chemical solution to selectively etch away unwanted material from a metal sheet’s surface.

The metal sheet is coated and then exposed to design or pattern with a photolithographic technique. It is followed by the selective etch of the metal exposed areas, thus leaving the desired shape or pattern of a shim.

One of the significant advantages of photo chemical etching is the ability to create shims having precision tolerances as fine as +/- 0.01mm. This kind of precision would set the base for making specialized shims by a manufacturer solely for one application. Further, since the process of etching requires no dies on tooling, the process also assures exceptionally low lead times and, more importantly, low costs related to prototyping and production.

Metal Shim Manufacturing

Many metal applications utilize photo etching to create shims that reflect an extremely fine surface finish. Here are some examples:

Optical instruments: Precision optical components of optical equipment, such as mirrors, lenses, prisms, to be used in automotive applications, require shims with near-perfect surface finishes so that light scattering is minimized and optimal performance is guaranteed. These are generally produced in highly-polished stainless steel, aluminum, and sometimes even gold custom gasket manufacturing.

Medical devices: 

Due to tissue irritation aspects and proper functioning, surgical instruments, implants, and other medical devices are performed using extremely smooth-surfaced metal shim manufacturing service. The metals used for these types of shims are usually the following:

Titanium is a great material for implants, surgical instruments, and other critical components due to its higher-order strength, corrosion resistance, and biocompatibility.

In contrast, Nitinol is a nickel-titanium alloy deformed under stress, which because of its superelasticity, can return to its original shape, making it ideal for shims in dynamic applications such as stents or joint replacements.

Stainless steel is a rather inexpensive material with decent strength and resistance to corrosion; it can therefore find application in less demanding fields of this industry. Very excellent properties of such a material in an implant, surgical instrument, or other important component could exist in the application area because of the enhancement that titanium gives to the original metal by its addition.

Semiconductor packaging: 

Very accurate shims should be made because high-performance electronic products need to do proper thermal management, as well as ensure good electrical contact. Mostly metallic or other highly conducting materials, such as copper or aluminum, and equally smooth surfaces, are adopted to keep the thermal resistance and electrical impedance down to the minimum level.

Aerospace and defense applications The level of performance and reliability expected of critical components in the construction of aircraft, spacecraft, and military equipment generally demand shims with exceptionally fine surface finishes. Shims from such materials are generally fabricated as high strength titanium, inconel, beryllium with surfaces polished to near-mirror quality.

Laser Cutting Shims

 

Laser cutting, like the latter, is similarly a subtractive metal shim manufacturing process, but in this case, the laser beam is used in cutting the sheet metal to the shape of the shim. A vector image or a CAD file will be loaded to the laser cutting machine, which will in turn project the laser beam to the metal sheet.

One of the attractive features of fiber laser cutting is its capability to cut different sorts of materials such as stainless steel and aluminum into very speedily high-precision standard product manufacturing. 

In laser cutting, the process can realize tolerances of approximately +/- 0.05mm. Whens a greater degree of precision is necessary, laser cutting can be combined with other processes, such as metal photo etching, to achieve the correct level of accuracy in a part.

When to apply to a Shem Chemical Etching or Laser Cutting

When trying to determine the application of chemical etching or laser cutting, the following factors should be key: shem thickness, design complexity, and industry.

For instance, etching the metals is recommendable on the manufacturer of shims with tight tolerances of high precision since there is the need for maintaining accuracy ion micro feature designs. 

Example:

Micro shims:

• Purpose: To fill the micron gaps with fragile components, such as small ICs or sensors, keeping correct alignment and spacing.
• Size: Mostly, they are of the order of sub-millimeters, and the thickness may be thicker than a human hair.
• Thickness: In micrometers to tens of micrometers.

In the other case, when the cut is for a thicker material, then the best way is by using laser cutting. The reason is that if chemical etching is employed, it may not be appropriate to get a desired shape, because thickness cannot go deeper int his etching process.

Example: 

Big shims

• Function: Supports heavy module, or makes good the offset of alignment due to bulky components like heatsinks/ transformers
• Size: Several cm, to even tens of cm – depending on the device size.
• Thickness: often the thickest among electronic shims; of the order of the mm to a few cm.

Laser cutting is more economical when production runs are small because setup time is much faster. Chemical etching becomes a viable option when runs are moderate to larger with complex features on parts.

Conclusion

The decision of what to select either chemical etching or laser cutting for metal shim manufacturing will be defined by the thickness of the shim, its complexity of design, and the industry application. Either way, significant cost and time savings are achievable over and above conventional machine parts manufacturing methods using chemical etching or laser cutting, and these differences often make it a preferred metal shim manufacturing choice in the aerospace, automotive, and electronics businesses.

Manufacturers should always consult the professionals of a certain technique so as to consult the manufacturer which method to use for their requirement.

We can provide metal shim manufacturing ways. We have over 30 years’ experience with all kind of Custom Industrial Manufacturing Services applications and Metal Shim Manufacturing. 

FAQ’s

How is metal shim manufacturing?

Chemical Etching Shims

 

The process involves applying a photoresist over the metal sheet and then exposing it to the design or pattern through a photolithographic process. Selective areas of the exposed metal sheet are then etched, and this process leaves the desired pattern or shape of the shim.

What are the materials used in shim?

Materials for a shim

Made from Polypropylene (PP), High-Impact Polystyrene (HIPs), and ABS, plastic shims are the most versatile of the three common shim materials.

What is a Metal Shim Manufacturing process?

A shim is a library that intercepts API calls transparently, changing the arguments passed, handling the operation itself, or redirecting the operation elsewhere. Shims can be used to support an old API in a newer environment, or a new API in an older environment.

 

What’s the formula for shims?

The formula to be used to compute for the new shim size is: New shim size = Measured valve clearance – Specified valve clearance + Old shim size

 

How thick is a shim?

Smaller shims, usually 0.020″ and less are ground stock. Almost all of these shims are on tolerance +/-.0005″ Thicker shims, usually those 0.025″ and up are rolled stock.