A modern plant means not only perfect production equipment, competent staff and well-established technology. One of the main components of high-quality products is raw materials’ and finished products’ strict quality control.
Conventionally, we can divide measures of control into three main stages – raw materials inspection test, the maintenance of optimal parameters on the line, as well as the control and testing of the product that comes off the assembly line. In this section we are going to tell you how we provide high quality of Döcke shingles.
The main components of shingles are SBS-modified asphalt, high-strength glass-fibre wrapping material, as well as stone granulate and sand, covering the exterior surfaces of the finished product.
Our laboratory’s specialists take samples and decide whether it is possible to use the components in the production process. Only after that the compounding materials are brought to the line.
Test method for softening point of asphalt, GOST 11506-73 0C
This method helps us to define asphalts’ physical-chemical properties and decide if they can be used in shingles production.
Softening point of asphalt is the temperature at which it passes from relatively solid state to fluid and liquid state. Indirectly the softening point characterizes asphalt’s flow characteristics.
The material’s samples fill two rings, and on each of them are steel balls. The specialists place these samples on the upper plate of the apparatus’ bearer. They immerse the device into a reservoir, filled with glycerin, where heating begins at a certain speed. The apparatus records the temperature at which asphalt squeezed by a ball touches the bottom of the plate.
The depth of needle penetration at 250C, 0.1 mm, GOST 11501-78
We conduct this test using a special device which is called penetrometer. The aim is to measure the depth of penetration of a standard needle under a load of 100 g at a temperature of + 25 ° C. The test lasts 5 seconds.
Conventionally, the method of penetration characterizes asphalts’ degree of hardness. This is an important characteristic that allows us to create an asphalt blend that is resistant to high temperatures.
Bases quality control
We produce fiberglass-based shingles, and underlayment is made on a base of polyester. The specialists control their mass per unit area and rupture resistance.
Breaking load in both the longitudinal and lateral directions is the main characteristic that confirms the quality of underlayment and polyester that directly influences the strength of asphalt shingles and underlayment. In this process we use the tensile test machine "Instron".
Mineral dressing quality control
Mineral coloured dressing (basalt granulate) is responsible not only for the aesthetic appeal of your future roof, but it also protects the asphalt coating from the environment influence.
Granulate quality inspection test is conducted on several parameters:
The granulate is examined by the sieve system on a vibrating table. We put some granulate samples into the upper sieve. Then they gradually spill through sieves of different diameters from highest to lowest. We assess the percentage of different factions by weighing the samples on scales.
An optimal balance between different fractions makes it possible to achieve the finished products’ coverage by the granulate and to prevent a shining effect, when the parts of asphalt that are not covered with granulate glisten in the sun.
The granulate’s colour fastness
The specialists boil the sample within a specified time. They evaluate the granulate’s colour invariance and the absence of discoloration of the water in which the sample is examined.
The mineral filler’s analysis
The mineral filler (dolomite powder) is one of the asphalt compound’s components that rigidify shingles.
We control humidity and granulometric texture.
The mineral filler’s humidity
The quality of the finished shingles depends on this characteristic. Humidity is examined by means of high-precision scales with a heating element. The sample is weighed before and after drying by the heating element.
CURRENT CONTROL IN THE PRODUCTION PROCESS
The strict observance of recipes and technology, as well as optimal characteristics of the production line guarantee the finished products’ high and stable quality. That is why we control the current characteristics of the asphalt-polymer blend and the finished compound at the stage of production. We also conduct for compliance with the standard colour mix.
The quality of mixing the polymer modifier with the asphalt is controlled using a fluorescent microscope.
The asphalt polymer compound’ viscosity control
The viscosity of the asphalt-polymer compound at different temperatures is an important characteristic for the optimization of the production line. This index is determined by using the Brookfield rotational viscometer.
The colour mix conformity with the standard
The formulation and the percentage of granulate of different colours in the mix composition is the producer’s commercial secret. It takes many months to make it up. Our designers and engineers get the desired combination and create the colour mix standard sample. We keep it in a laboratory and insert its formulation into the computer that controls the mixing equipment. Although all operations at the Döcke plant are automated, laboratory specialists regularly check the granulate’s conformity with the formulation and the collections’ colour palettes. That is why standard deviations in different batches of roof are absent or minimal.
The determination of the filler’ contents
This test is designed to determine the actual amount of filler in the final asphalt-polymer compounds.
Laboratory specialists put the compound’s sample into a heat-resistant cell and place it into a muffle furnace. At a certain temperature the asphalt and polymer modifiers burn out, leaving in the cell only dolomite powder that is not susceptible to fading.
The difference between the sample’s mass before and after the burning helps us to calculate the actual amount of filler in the asphalt-polymer compound.
Tests of finished products
We conduct approval and recurrent tests on each batch of finished shingles.
We control the following characteristics: appearance, linear dimensions, heat resistance, flexibility in cold, loss spreading, breaking load under tension, tearing strength, water absorption, waterproofing.
We place the samples into an oven. They stay there upright for some time at a predetermined temperature.
Tests on heat resistance confirm that you can use Döcke shingles in all regions.
Flexibility in cold
We keep the samples in a cooling chamber at a temperature, predetermined according to quality requirements. After that we bend the samples on a special beam.
The samples should not have cracks. The binding substance and the dressing compound should not exfoliate.
The loss of dressing compound
We weigh the control sample of the finished shingles and place it on an apparatus in order to determine the loss of dressing compound. On the upper surface of the shingles we install a metal broom with weighting material. After we turn the equipment on, the broom execute reciprocal movements. After 50 cycles we remove the sample and weigh it again. The difference in weight before and after the test and shows us the loss of dressing compound. Döcke products have a minimal loss of dressing compound in comparison with other Russian producers.
Besides, there are other tests, for example, UV- and swelling resistance tests, the determination of bonding strength. All these tests are conducted in comparison with other producers’ shingles.
The glue joint’s breaking load under tension
We conduct this test on a tensile machine. It shows the force that should be applied in order to tear apart the glued shingles. The tests of breaking load under tension show that our glue strips firmly stick shingles together, surpassing the best samples of domestic and foreign shingles producers.
Such results are an argument for applying our glue strips on the shingles’ front side.
Every day Döcke Home Systems quality laboratory’s specialists conduct a full set of tests. Professionalism, strict observance of technology and formulations guarantee our roofing materials’ high quality and long inning.