The standard “MAN M 3150-5 Surface quality - Assessment of the primer coat” developed by the automotive company MAN describes a procedure for assessing the surface quality primer coat of vehicles.
Essentially, the MAN M 3150 series of standards was designed to enable uniform assessment of surface quality and structure and colour harmony of coatings on MAN commercial vehicles (cabin, cabin add-on parts, chassis and bus exterior coating). The requirements are derived from customer requirements and state-of-the-art technology.
This series of standards applies to both in-house parts and purchased parts, regardless of the quality and type of component material (sheet metal, plastic).
The MAN M 3150-5 standard applies to trucks and buses. Special regulations may apply to military vehicles.
The basic requirement is that the desired surface quality, surface structure, color and surface tension must be within the desired tolerance ranges for both buses and trucks.
The requirements for the substrate primer coating (structure, colour, tension) are specified in the technical delivery conditions of the coating materials (M 3094, M 3031, M 3022 and similar standards). In particular, it must be ensured that the filler colour of the cabin is the same as that of all additional parts.
The contact angle measurement method in surface tension measurements is an optical method. The contact angle is determined by means of the tangent at the 3-phase point. If certain fluids with known properties such as free surface energy or density are used, it is then possible to determine the surface energy of the solid body to be examined. For this purpose, the dispersion and polar components of the surface tension on the surface are determined. A distinction is made between dynamic and static contact angles. The measurement time and the specified parameters are specified in the tables in the standard.
The coating thickness measurement must be carried out using a paint penetrator thickness gauge or similar measuring device for plastic parts and a different device for metal insert parts, for example. The requirements of the technical delivery conditions (e.g. standards M 3022, M 3086, M 3162) apply. Unless otherwise stated, the tests must be carried out after 7 days of storage at room temperature. All parts of the MAN M 3150 standard series are valid for surface quality.
The possible types of defects and their permissible tolerances are defined in the tables provided in the standard, depending on the place of occurrence (evaluation zone 1, 2, 3 or evaluation zone A, B or C). The evaluation zones for trucks are defined in the company standard MAN M 3150-3. The evaluation zones for buses are defined in the standard MAN M 3150-4.
The following criteria must be taken into account for the defect assessment: The assessment of surfaces/components shall be carried out in the assembly position or assembly conditions, as far as possible, under diffuse daylight or artificial light similar to daylight (1000 lx) and at a viewing distance of at least 0,5 m. A longer viewing distance may be required depending on the defect pattern. In case of doubt, consultation with the responsible technical department is required. No adhesive residue is allowed which would affect the surface quality of the components. If no comments are made on frame longitudinal members and chassis attachment parts in the tables, assessment zone 2 or assessment zone B applies if there is no effect on corrosion.
In this standard, the evaluation defect types and evaluation methods for trucks are explained in a table on the following basis:
In this standard, the evaluation defect types and evaluation methods for buses are explained in a table on the following basis:
The handling, packaging, transport and storage of primed components must be carried out in such a way that no defects occur on the surfaces in Zones 1 and 2 or on the surfaces in Zones A and B. In particular, the MAN M 3338 standard applies to packaging.
Among the numerous tests, measurements, analyses and evaluation studies carried out for businesses in various sectors, our organization also provides testing services defined in the “MAN M 3150-5 Surface quality - Evaluation of primer coating” standard with its trained and expert staff and advanced technological equipment.
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