M-Tech®L
Laminated peelable shims
When assembling components, tolerances can be compensated quickly and easily using M-Tech®L shims.
M-Tech®L laminated shims (original name Laminum®) are peeled off to the required material thickness. In this way, the construction tolerance can be compensated with one single compensation element. Laminated shim stock consists of a multitude of thin metal foils laminated onto one another over their full surface. Overall thickness can be reduced by peeling off each layer by hand, foil by foil, in the hundredths of a millimetre range.
New! M-Tech®L PET
The new laminated shim M-Tech®L PET from Georg Martin GmbH is made of polyethylene terephthalate (PET) Mylar® from DuPont® and consists of several, only 0.10 mm thick laminated plastic foils. The PET is counted among the surface insulating of the class B and is characterized by;
Light-weight, low density of about 1.3 kg / dm3
Heat and cold resistant (-70°C to 150°C)
High tensile strength
Tear resistance
Chemical, mechanical and thermal stability.
Good electrical insulation (dielectric strength around 180 V/μm)
Numerous applications for M-Tech®L PET;
In automotive, aerospace, electrical and measuring techniques
Ideal solution for lightweight construction in which different functional units must be electrically insulated
In the construction of generators and transformers which M-Tech®L PET shims perform here dual function, as tolerance compensation and the insulating effect
Choice of Shim
Determining the thickness
The theoretical maximum gap between the components is decisive for determining the thickness of the shim. A little should be added to this theoretiacal value before selecting the corresponding shim thickness.
Example, If the theorectical thickness ist 3.1 mm, we can choose M-Tech®L with standard thickness of 3.2 mm.
In practical applications, these values are measured with the help of a feeler gauge or by embossing the component tolerance on to the material.
Determining the material
Five different base material types in two differnt film thicknesses can be selected from the shim range. In addition to the commonly used materials aluminium 99.5, mild steel, stainless steel, and brass, an aluminium wrought alloy AlMg3.0 is also available, the strength of which is similar to that of steel shims.
To compare material strength, you wil find test results on the E-module and Rp0.2 values in the following document.
Mechanical strength values (115 KB)
Handling
A knife or a file can be used to catch the edge of the shim backing film. Scrape along the rounded punched edge, then try tp peel the top film in a lifting motion. Working safetly and speed can both be improved b ywearing gloves to perform this task. M-Tech® gloves provide increased protection against cuts and greater sensitivity when handling these extremely thin metal films.
The gloves and the knife can be ordered as accessories. Click here for an overview of articles.
Accessories and aids
The peeling instructions provide a better understanding of the peeling process. our materials are constantly checked for their good peeling properties. The instructions are available in the follwing formats.
Peeling film in FLV Format, 5.6 MB
Peeling instructions in PDF Format
(131 KB)
Processing
M-Tech®L can be punched, nibbled, machined and wire-eroded. The cutting speeds, web widths of the product (approx. twice the thickness of the material) and processing forces must be adjusted to suit the material.
Punching is used mainly in our own production process. Machining can be done in special cases. Punching and nibbling produce a round edge which is particularly easy to peel.
Structuring of joints
The shims do not permit any curved surfaces. Care should be taken to ensure that no web width smaller than the material thickness result. It is best if the shims are always completely covered by the components, otherwise film particles can detach themselves during unfvourable, long-term load processes.
see the following section on pressue types.
Load Notes
Temperature: Load tests should be conduced on a case-by-case basis at temperature well below 0∧C and above 120∧C.
Pressure Types: As a rule, this shim should always be kept under initial tension. Static and dynamic loads are both possible, but the strength values for the shim can only be determined for static loads. Dynamic loads, such as impact strokes where there is no initial tension at times, are not advisable. M-tech®S materials (solid shims) should be used here.
An overview of the precise base materials for immediate layers is listed here.
Material list M-Tech®S (30 KB)
Because shims are more flexible than solid materials they can have damping effect in several cases. Their elasicity limit (Rp0.2) lies just below that of hard-rolled sheet steel of the same thickness, however. This means that it is possible to use them im most applications - even under heavy loads. In special instances, testing on the customer's premises is recommended on a case-by-case basis.
You will find an overview of the results of material strength testing in two tables, subdivided by the thickness of the individual metal films in the laminated shim.
Mechanical strength values (115 KB)
