What Is a Shim Plate?
A shim plate is a component that is inserted between components and equipment or locations to adjust the position, level, and spacing between them.
Types of Shim Plates
Shim plates are a type of “shim,” and include plate-type “shim plates,” ring-type shims “shim rings,” and thin tape-like metal sheets.
1. Shim Plate
There are various types of shim plates, depending on the shape of the plate, mounting method, material, and specific use. Typical shim plates are rectangular plates with holes drilled in the base shim plates and are classified by plate size, thickness, number of holes, and material. Some shim plates have slots (grooves) instead of holes.
There is a plate shape alignment shim that facilitates multiple installations and removals, and it has a brim and holes for hooking tools, etc. The laminate type (laminated peel-off type) consists of multiple thin plates of the same thickness that have been laminated together in advance with adhesive, and each plate is peeled off for use, allowing the thickness to be adjusted freely and easily to match the gap and height of the actual product.
Dimensions are available with commonly used external shapes and hole diameters in advance, or dimensions can be ordered. Thicknesses, which are particularly important for shim plates and applications, vary from t0.005 to t6.0 mm and so on. The material is generally austenitic stainless steel SUS304, and other materials include iron-based SPCC, SPHC, brass C2680P, C2801P, aluminum sheet material, PET resin, etc.
2. Shim Ring
Ring-type shim rings are classified by their perforated ring shape, C-shaped slit shape, and material. Shim rings have specific applications, such as for bearing inner and outer rings and flanges.
As with shim plates, there are two types of shim ring dimensions: those with commonly used outer diameters and bore diameters, and those that can be ordered in advance. Plate thicknesses for bearings are also dimensioned according to the bearing type. The material is generally austenitic stainless steel SUS304.
3. Tape Type
Thin metallic tape is rolled like general adhesive tape. It is characterized by the fact that it can be used at any length. It is sometimes called “shim tape.” Dimensions are mainly based on tape width and thickness. Materials include SUS304 and brass.
Uses of Shim Plates
Shim plates are used to adjust the height and position between machine parts.
1. Shim Plate
An example of shim plates for base use is to adjust the level (height direction) of a fan (blower) motor. The motor is mounted on a base with legs, and the motor output shaft is connected to the fan via a coupling. The base is designed and manufactured so that the motor and fan are properly aligned, but in reality, there may be some misalignment due to machining and manufacturing accuracy.
In this case, the left and right directions of the motor can be adjusted by the motor position, but if there is a gap in the vertical direction, it cannot be adjusted as it is. In this case, shim plates are inserted into the gap to adjust the height of the motor. By using multiple shim plates of different thicknesses in combination, fine adjustment becomes possible.
2. Shim Ring for Bearing
A type of shim ring, shim rings for bearings are, as the name suggests, shim rings specialized for bearings, and are available for bearing outer rings and inner rings. They are used to adjust the position of bearings. By adjusting the thickness and number of shim ring inner ring plates, the axial position of the bevel gear is changed. This allows precise adjustment of the engagement with the bevel gear on the mating side.
3. Tape Type
Tape-type shim rings are also available in the form of a sheet wound on a roll, which can be pulled out and cut to any length. It is versatile because of its flexibility in size, shape, and thickness.
4. Laminate Type (Peel-And-Strip Type)
As described in the shim plates section, the laminate type (peel-and-stack type) is stacked into a single sheet, which can be peeled off one at a time for use, allowing flexibility in the required plate thickness. The laminated shim plates allow for shim adjustments to be made in actual products without the need to consider the thickness and number of shim plates precisely at the time of design. Also, it eliminates the need to prepare multiple shim plates, thus reducing costs. Laminated shim plates are widely used in the aerospace industry.
Other Information on Shim Plates
Shim Plates Standards
There are no applicable standards for shim plates themselves. These standards can be used as a reference when selecting shim plates.
- SAE AMS-DTL-22499 Shim Stock, Laminated (American Aerospace Standard)
- DIN LN29557 Aerospace; Laminated shim of corrosion resisting steel; dimension, masses (German Aerospace Standard)