Liner

In liners there are products to be inserted underneath on machines with the purpose of tolerance compensation, Eng. shims or packaging materials Layer pads, mostly made of corrugated cardboard or plastic.

Intermediate layers (machine element)

definition

Intermediate layers (machine element) correspond to the English term shims. This refers to products for underlay that compensate for manufacturing tolerances of mechanical components and are intended to simplify the function of the clearance adjustment during the assembly of mechanical components. If these tolerances are not compensated, there is, for example, increased wear. The use of intermediate layers eliminates the need for mechanical (re) processing, for example by re-turning the screw-on flange or subsequently grinding a spacer. For this reason, intermediate layers are used in many areas of industry, particularly in the aviation and aerospace and for large machines (for. Example, as an engine material or ball bearings pass rings). There are intermediate layers in different designs. They are adapted to the requirements of technical applications as required.

variants

Three or four variants with different advantages have emerged in the industry. In addition to the type of production and the materials used, they also differ in their possible applications: The most common are solid or solid intermediate layers, which consist of a single layer and can be combined with one another in order to create a tolerance compensation by adding different solid intermediate layers. In addition, there are intermediate layer concepts which, instead of adding additional intermediate layers, create the necessary tolerance compensation by removing existing sheets or foils (e.g. by pulling off or peeling off superfluous sheets):

Solid / solid intermediate layers

The most common is the use of solid intermediate layers, which i. d. Usually consist of a single layer. The advantage of these intermediate layers compared to packaged or laminated intermediate layers is primarily their cost-effective production, since the metal processing of the sheet metal, ie. H. the cutting of the semi-finished product, the production process is finished. In special cases, massive intermediate layers are produced in any and mostly small thickness increments and with low thickness tolerances, usually by grinding: For example 1.00 mm / 1.03 mm / 1.06 mm etc. If these are sold together, they can be used as an assortment become. However, there are also precision foils with a thickness of one or several hundredths of a millimeter.

Packaged intermediate layers

In the case of packaged intermediate layers, individual foils are connected to one another by gluing on the front sides. For example, in the sense of book spines or tear-off calendars, possibly with adhesive edges all around. Compared to the massive or solid intermediate layers, several foils are bundled or glued to form a package; It is therefore not necessary to produce a solid intermediate layer that fits exactly for the individual case, but the thickness of the intermediate layer can be adjusted on site to the existing difference. Several foils can therefore be glued to one another at one edge using a specific adhesive at one or more points and then precisely adjusted to the required thickness by tearing off the unneeded foils. Bundled intermediate layers also combine bundles with sheets or foils made of different materials and thicknesses. Although this method is more complex in terms of the manufacturing process due to the adhesive bonding, it has the advantage when used that the intermediate layer packages can be adapted to the required tolerance on site by simply tearing off the foils. Another form of grouping is bundling, e.g. B. by cable ties.

Laminated shims

In contrast to packaged intermediate layers, laminated intermediate layers are completely glued using special adhesives. The result is a multi-layer, fully laminated so-called "sandwich structure". The bonding allows individual or multiple layers to be detached without destroying the remaining part of the intermediate layer or even impairing its function. Laminated peeling sheets are high-precision intermediate layers. In contrast to packaged or solid or solid intermediate layers, these intermediate layers are made as a seemingly massive intermediate layer according to customer drawings and provided with the necessary holes so that they are ready for installation. Contrary to their massive appearance - and unlike conventional shims - they consist of a large number of glued individual foils a few hundredths of a millimeter thick (0.1 mm - 0.025 mm), but can also be glued in combination with solid foils. The fitter or maintenance technician can pull off the film layers by hand up to the measured thickness.

Laminated intermediate layer made of plastic

So-called non-metallic peelable intermediate layers, based on polyethylene terephthalate (PET), which consist of several laminated plastic films from 0.025 mm to 0.10 mm thick. The plastic films that have already been peeled off can also be reused. This results in several advantages over conventional metallic, laminated sheet metal:

• Low density of around 1.3 kg / dm³ and belongs to the group of flat insulation materials of insulation class B (up to 130 ° C)
• Good electrical insulation (dielectric strength approx. 180 V / µm).
• Reuse of plastic films that have already been peeled off.

Plastic interlayers are particularly suitable for lightweight constructions in which electrical insulation is important, such as in vehicle construction, aviation as well as electrical and measurement technology, but also in generator and transformer construction, because the laminated sheet metal made of plastic there, in addition to tolerance compensation, also the Can take on insulating function. The laminated plastic intermediate layers, however, have lower mechanical strengths than the metallic variants and can therefore only be used to a limited extent.

Materials

1. Starting material - The starting material used for the production of intermediate layers is essentially metallic precision strips and precision metal foils made of stainless steel, unalloyed steel, brass and / or aluminum, but also PET and possibly composite material . Solid intermediate layers can generally be made from all conceivable semi-finished products that are suitable for tolerance compensation due to their material properties.
2. Additives - Depending on the intermediate layer (for example, packaged, solid or laminated), certain additives are used, in particular different adhesives that bind the different metal foils or strips together.

Manufacturing

Interlayers can be manufactured in different shapes. In general, all separating manufacturing processes can be used. The following can be named as examples:

• Punching
• CNC punching or nibbling
• Water jet cutting
• Laser cutting
• Fine lasers
• Chemical etching process
• Machining
• Wire EDM

In addition, different adhesive processes are used during lamination.

Heat dissipation

Type-specific metal plates, which are often made of titanium , are offered for vehicle brakes . These are intended to improve the stability of the brakes by reducing the heat transfer from the occasionally red-hot disc to the brake calipers and the brake fluid. The long-term durability should also be increased.

Intermediate layers (packaging material)

Furthermore, in the packaging industry, intermediate layers (called “layer pads” here) are used to separate bottles, glasses, cans and the like stacked on pallets. Corrugated cardboard is traditionally used here .

For some years now, however, more and more plastic has been used because these plastic interlayers (in contrast to corrugated cardboard) can be cleaned and are therefore suitable for multiple uses. The material "CARTONPLAST" is particularly suitable for this, as it combines the advantages of corrugated cardboard (low weight, flexibility, recyclability) with those of plastic (insensitivity to moisture, stability).

In the packaging industry, intermediate layers are mainly used in the area of END-OF-LINE packaging (end of the packaging line). As the name suggests, this is a layer between two stacked product layers. Starting with the lowest layer (on the pallet), either cardboard / cardboard / corrugated cardboard is coated, uncoated or non-slip, and plastic blanks are used to separate the individual layers. In English, these intermediate layers are called slip sheets .

Individual evidence

1. ^ [1] , Georg Martin: advertising film. Instructions for peeling M-Tech®L. Accessed September 21, 2011.
2. ↑ Alkomposit Laminated Peelable Shims ( Memento from January 25, 2016 in the Internet Archive ) (PDF file; 708 kB), Jicey: Peelable Shims Alkomposit. Retrieved September 12, 2011.
3. ↑ http://www.ebay.de/itm/TITANIUM-BRAKE-PAD-SHIMS-SUBARU-IMPREZA-TURBO-WRX-STI-/280919452376?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item41681aaad8
4. ↑ http://www.google.de/patents/about?id=jGg3AAAAEBAJ  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.