They are the small tool that is necessary, essential, and invisible that is a critical part of industrial applications.
There is an endless list of applications that depend on the precision and accuracy of metal shims. Produced and manufactured using different types of metal shaping processes, metal shims are carefully engineered to provide exceptional performance. Unlike the typical household shims, metal shims are produced to meet the highest tolerances and precision measurements, which is essential and necessary to meet the needs of engineering designs.
Metal shims are designed to adjust clearances, tolerances, and alignments as well as act as spacers to fill gaps, openings, and misalignments between parts. The term metal shim is a generic term that covers several different configurations of shims that include laminated shims, horseshoe shims, circular shims, and round shims. Although there are several standard types of shims, shim manufacturers are frequently asked to create custom shims to fit the needs of a unique designs.
Types of Shims
As a small, simple, and convenient component, shims have become an incredibly useful tool that has found use in so many sectors of business. They can have a gauge as low as 0.0005 inch with an exceptionally high degree of accuracy. The types of metal shims cover ones made in layers to thick ones to hold heavy machinery.
Laminated shims, or surface bonded shims, have a stack of peelable layers, which is like a post it note pad. They are made of layers of metal foil with the layers connected into a rigid shim that functions like a piece of solid metal. The thickness of a laminated shim is adjusted by peeling off pieces of the lamination to reach the appropriate height. Once a laminated shim is placed, it can withstand shearing forces and machining.
The layers of laminated shims are pressed together to cure with unwanted and deformed layers removed in order to have a smooth even surface. Laminated shims make it possible to use a single shim to fulfill the needs of an application and eliminate the need to have a warehouse of different sized shims.
Slotted shims, known as horseshoe shims and “U” shaped shims, have a “U” shape such that they can fit around fasteners, screws, and shafts. They provide a snug fit for more accurate alignment and tighter tolerances. Metal slotted shims come in several different shapes with variations in the length of their legs and the number of slots. They are made of stainless steel, steel, galvanized steel, and aluminum.
The various shapes of slotted shims includes ones that have multiple slots, which are special ordered such that the slots have the correct dimensions.
Arbor shims, known as slitter shims, are washer-like shims used to prevent the axial movement of connected components. Although they have the shape of washers, arbor shims are manufactured to meet specific tolerances for perfect alignment. They are used for spacing milling cutters, saws, and grinding tools. Arbor shims are manufactured in thicknesses of 0.001 inch up to 0.018 inch.
Edge Bonded Shims
Edge bonded shims are a form of laminated shim with a slight difference. With laminated shims, full layers can be removed as needed to reach the appropriate thickness. With edge bonded shims, the layers above and below the edge of the shim can be removed, which makes this type of shim easier and more convenient to use. Additionally, edge bonded shims have layers of different thicknesses that make it easy to adjust the final thickness.
Tapered shims, known as wedge shims, are made to support heavy loads and help balance tools, machinery, and equipment. They are used for applications that have a tapered surface and can make assemblies tighter by pushing pieces apart. The design of tapered shims allows engineers to make minute, slight, and precision adjustments.
Flat Sheet Shims
Flat sheet metal shims are used in applications where hardness, flatness, smoothness, and accuracy are essential. They may be used with other types of shims such as slotted shims, tapered shims, and round shims to serve as a platform or spacer. Flat sheet metal shims are made from cold rolled low carbon steel in various sizes and thicknesses with the standard size being 6 inches by 18 inches in thicknesses that can accommodate any application.
The applications that make use of flat sheet metal shims are tool and die set up and machine alignment, assembly, repair and maintenance.
Different sized shim rings are used to fill gaps between machines and components alongside retaining rings. They are defined by their thickness, inner diameter (ID), and outer diameter (OD).
Uses for Metal Shims
The small invisible metal shim is an essential part of several industrial applications. Their key factor is how precisely and accurately they are able assist in the development of a project.
Fill Gaps: Shims are used to close gaps and make materials level, which is especially true for construction projects.
Leveling: Shims are placed or driven between surfaces and equipment to level them.
Adjust Clearance: For the sake of precision and accuracy, shims are placed between components to reduce or increase clearance.
Protection: Copper and aluminum shims are used to protect computer processors from heat sinks.
How Metal Shims are Manufactured
In the majority of cases, metal shims have to be cut to custom dimensions before they can be used. As with the manufacture of any metal product, there are a few ways that metal shims can be made to meet the exacting requirements of industrial applications.
CNC processing has become a vital part of modern manufacturing and is used to create shims of different shapes. CAD designs of shims are downloaded into CNC machines and converted to different codes that guide the milling tool. CNC milling is a high precision process with tight tolerances and the ability to produce any geometric shape.
A stamping machine, with a die that has the geometry of the shim, uses tons of force to cut coiled metal. The process of stamping can produce large quantities of shims in a short time. The limitation to stamping is the need to create dies for custom shims and only one size shim can be produced.
Laser cutting uses directed thermal energy to cut through sheet metal to create shims. It is a precision process that can be programmed to manufacture complex geometries with tight tolerances. All forms of metals can be cut using laser cutting and different geometric shapes can be cut from the same sheet.