Renault D47 1234 Plastic Element Parts - Heat Behavior in a Dry, Non-Radiant Oven

The standard “Renault D47 1234 Parts with plastic elements - Heat behavior in a dry, non-radiant oven”, developed by the French automobile company Renault, describes a procedure for evaluating the behavior of plastic parts exposed to long-term dry heat in terms of shrinkage, deformation and change in appearance. This test should be performed only to check molding stresses. It applies to all parts containing plastic elements such as dashboards, steering wheels, grilles, lamps, door handles and the like, installed in vehicles.

In principle, this test method consists of placing the parts to be examined in a ventilated oven brought to a pre-selected temperature for a specified period of time. The temperature and duration of the test are determined by the documentation.

Major equipment used in testing includes:

• The oven shall consist of a forced ventilation device which enables good temperature uniformity to be achieved throughout the usable area and to maintain the selected temperature throughout the test period. The oven shall include a regulating device which shall ensure that the temperature does not vary more than plus/minus 2 degrees around the selected value during the test and plus/minus 1 degree from one end of the part to the other. The internal dimensions of the oven shall be such that the part under test shall not come into contact with the walls or floor of the oven in any way and shall not impair air circulation.
• The grill is positioned so that the part does not touch the walls or floor of the oven and provides good air circulation.
• With digital thermometers, the thermocouples connected to the temperature recorder are calibrated to plus/minus 1 degree.
• Mounting allows the part to be fixed to a vehicle under conditions as close as possible to the method of fixing it.
• The material is required to draw visible marks on the part to be examined.
• Suitable measuring instruments are, for example, rulers graduated to the nearest 0,5 mm, measuring instruments, calipers, rod compasses, palm gauges, 3D measuring devices or others.

When performing the test, the part to be inspected is fixed to the assembly according to the conditions specified in the documents or, if this is not possible, according to the known service conditions (in particular, the tightening torques of the fastening screws). Reference lines are drawn at intervals of a certain length in the main directions of the part (e.g. length and width), measured to the nearest 0,1 percent using a suitable tool. The part is preconditioned at 2 degrees plus/minus 23 degrees for at least 2 hours. In addition, measurements are made to the nearest 1/2 mm using the most suitable tools depending on the shape of the part, dimensions play an important role for good performance in service (e.g. in the dashboard, dimensions of the meter opening, ashtray housing, etc.).

If previous measurements are not representative of certain types of parts, their functional dimensions are measured with appropriate equipment.

The oven temperature is set to the value defined in the documentation. The part to be examined is allowed to stabilize before being placed in the oven.

When the part to be inspected has several areas exposed to different temperatures in service, the part is subjected to a test at each of these temperatures in turn, if possible following a gradation of 10 degrees at 10 degrees.

In this case, it is recommended to perform a test on another part by bringing it directly to the maximum temperature.

The part is placed in the furnace under suitable conditions and without subjecting it to unexpected restrictions on its function. In the case of free parts, they are positioned in a way that reduces the restrictions due to their weight and are observed for defects.

The part is removed from the oven and allowed to return to room temperature. Its appearance is then observed and the dimensions taken before testing are measured again.

Among the numerous tests, measurements, analyses and evaluation studies that our organization has carried out for businesses in various sectors, our organization also provides testing services defined in the “Renault D47 1234 Plastic element parts - Heat behavior in a dry, non-radiant oven” standard with its trained and expert staff and advanced technological equipment.