Shim (spacer)

For intermediate layers, there are products to shim on machines with the aim of the tolerance compensation, Eng. shims or packing of goods, engl. Layer pads, usually made of corrugated cardboard or plastic.

Intermediate layers ( machine element )

Definition

Intermediate layers ( machine element ) corresponds to the English term shims. There are here Products meant to shim that compensate for manufacturing tolerance of mechanical components and also to facilitate the function of the game setting in the assembly of mechanical components. If these tolerances are not balanced, it comes for example to increased wear. Through the use of intermediate layers is unnecessary to machine ( re-) processing, for example by the returning of the Anschraubflanschs or subsequent grinding a spacer. For this reason, liners are used in many industries, particularly in the aerospace industry as well as at large machines (eg as motor mounts or ball bearing shims ). Liners are available in different designs. They will be adapted to the requirements of industrial applications as needed and can thereby reduce the cost of the positioning of the pinion housing from 8.5 % up to 2.6%.

Variants

There have been in the industry three or four variants emerged with different advantages. They differ not only Production method and materials used by their applications: On most conventional are solid or solid intermediate layers that consist of a single layer and with each other can be combined to make by adding different solid liners tolerance compensation. In addition, there are intermediate layer concepts ( eg by pulling off or peel off unnecessary sheets ) rather than by adding additional intermediate layers by removing existing plates or foils produce the necessary tolerance compensation:

Solid / solid liners

Most commonly, the use of solid liners that usually consist of a single layer. The advantage of this intermediate layers compared to packaged or laminated interlayers is mainly in its cost-effective production, since, with the metal processing of the sheet ie of cutting the semi-finished product, the production process is ended. In special cases, massive liners in any and mostly small Dickenstufungen and with small thickness tolerances, grind - usually by made ​​: for example, 1.00 mm / 1.03 mm / 1.06 mm, etc. If these are sold together, they can be used as a range be. However, there are precision slides having a thickness of one or several hundredths of a millimeter.

Packaged Liners

In packetized interlayer individual sheets are joined by adhesive bonding to the end faces with each other. For example, within the meaning of spine or decalcomanias, possibly even with circumferential adhesive edges. In comparison to the massive and solid intermediate layers several sheets are bundled or glued and thus result in a packet; It is therefore not a solid intermediate layer are precision-made for the individual case, but the thickness of the intermediate layer can be adjusted on site to the existing difference. It can therefore be bonded to each other, and then adjusted by the tearing off of unnecessary films precisely to the required thickness of a plurality of sheets at an edge of a particular adhesive at one or more locations. Packaged interlayer combine packets with sheets or films made of different materials and thicknesses. Although this method is more complicated due to the bonding in terms of the manufacturing process, but provides in applying the advantage that the intermediate layer packages can be customized by simply tear off the sheets to the required tolerance on site. One other form of summarizing provide bundling, eg by cable ties, dar.

Laminated shims (german laminated shims )

In contrast to packaged liners laminated interlayers with special adhesives are completely glued. The result is a multi-layered, full-surface laminated so-called "sandwich structure ". The bond allows detachment of single or multiple layers without destroying the rest of the liner or even compromising its function. When laminated peel sheets are high-precision liners. Unlike packaged or massive or Solids liners these liners are manufactured tailored as a seemingly massive liner according to customers drawings and provided with the necessary holes, so they are ready for installation. Contrary to your massive appearance - and unlike conventional washers - they consist of a variety of bonded single films of a few hundredths of a millimeter thick (0.1 mm - 0.025 mm), but can be combined with solid foils are glued. The installer or maintenance engineer can remove the foil layers to the thickness measured out by hand.

Laminated intermediate layer of plastic

So-called non-metallic peelable shims, based on the polyethylene terephthalate ( PET), made ​​thick laminated plastic sheets from a plurality of 0.025 mm to 0.10 mm. The already peeled plastic films can be reused also. This results in several advantages over conventional metallic layer laminated sheets:

• Low density of about 1.3 kg / dm ³ and belongs to the group of the surface insulating materials insulation class B ( 130 ° C)
• Good electrical insulation ( dielectric strength about 180 V / micron ).
• Reuse of already peeled plastic films.

Plastic liners are ideal for lightweight constructions in which electrical insulation is important, such as in automotive, aerospace and electrical and measurement technology, but also the generators and transformers, as the laminated layer sheet of plastic there beside tolerance compensation and the can take over insulation function. The laminated plastic - but intermediate layers have lower mechanical strength than the metal versions and are therefore of limited use.

Materials

Production

Liners can be manufactured differently molded. In general, all the divisions of the manufacturing process can be used. Example there may be mentioned here:

• Punch
• CNC Punching and Nibbling
• Water jet cutting
• Laser Cutting
• Fine lasers
• Chemical etching
• Machining
• Wire EDM

In addition, in the lamination add different bonding processes come into play.

Heat dissipation

For vehicle brakes type-specific metal plates are offered that are often made ​​of titanium. This should improve the stability of the brakes by the heat transfer from the occasional red-hot plate on the brake calipers and the brake fluid is reduced. The long term durability is to be increased.

Intermediate layers ( for packing )

Furthermore, in the packaging industry intermediate layers ( here "layer pads" called ) used to separate stacked on pallets bottles, jars, cans and the like. Traditionally, here corrugated cardboard used.

For several years, however, since these plastic liners (as opposed to corrugated cardboard ) can be cleaned and are therefore suitable for multiple use of reinforced plastic. Especially the material " CARTONPLAST " is suitable for this purpose because it combines the advantages of corrugated cardboard ( light weight, flexibility, recyclability) with the plastic (moisture insensitivity, stability).

Liners are used in the packaging industry, especially in the field END -OF -LINE packaging ( end of the packaging line). As the name says, this is a situation between two stacked layers of products. Starting with the bottom layer (on the range ) are either cardboard / cardboard / corrugated board coated, uncoated or anti -slip coated and plastic blanks used to separate the individual plies. In English, these liners are referred to as slip sheet.

Demarcation

A distinction is made ​​possible by the choice of raw materials and semi materials.