How Does HDT/ Vicat Tester work ?

General Description

DW5340J series table type HDT/Vicat tester is mainly used to do the HDT test and Vicat test for non-metal materials: such as plastic, rubber, nylon and electrical insulating material. They are the perfect test tools for chemical industry, R&D department and academies or colleges. The operator must read this document carefully before commencing any activities on the HDT/Vicat tester.

Principle 

Vicat Softening Temperature Test Method

Determination of the temperature at which a standard indenter under a force, penetrates 1mm into the surface of a plastic test specimen.

HDT Test Method

A standard test specimen is subjected to a bending stress to produce a nominal surface stress. The temperature is raised at a uniform rate, and the temperature at which a specified deflection occurs is measured.

Specimen preparation and installation

Vicat test specimen

At least two test specimens shall be used to test each sample. The test specimens shall between 3mm and 6.5mm thick and at least 10mm by 10mm in area or 10 mm in diameter. They shall be made in accordance with the specifications, if any, for the material under test. In the absence of such specifications, any suitable procedure may be used for the preparation of test specimens.

For sheet materials, the thickness of the test specimens shall be equal to thickness of the sheet, expect as follows:

a) If the thickness exceeds 6.5mm, the test specimens shall be reduced in thickness to 3mm to 6.5mm by machining one surface (See ISO 2818), the other surface being left intact. The test surface shall be the intact one.

b) If the thickness of the sheet is less than 3mm, not more than poeces shall be stacked together in direct contact to give a total thickness between 3mm and 6.5mm and the thickness of the upper piece shall be at least 1.5mm. Stacking of pieces of lesser thickness does not always give the same test result.

HDT test specimen

At least two test specimens shall be used to test each sample. Each test specimen shall be a bar of rectangular cross-section (Length l, width b, thickness h). The dimensions of the test specimen shall be as specified in the relevant part of ISO75.

Notice: The standard dimension is : (80×10×4）mm

Specimen installation

1 Take the test station out of the bath by holding the two handles. Turn the knob and place the specimen on the plane of the station. Turn back the knob to lock the specimen

2 Hold the two handle and immerse test station into Oil bath, specimen should be located 35mm under oil.

3 According to the standard and specimen to calculate the weights and put them on the loading carrying plate.

For VICAT test, place the test station to the bath and wait for about 5mins, then place all the necessary weights, last power on. .

For HDT test, place the test station to the bath and place the necessary weights at once, next wait for about 5mins. Last step power on.

CAUTION: Do not turn the knob after installing the specimen to avoid weights falling off.

Weights and deflection settings

Weights calculation for HDT test：

Pisition	Method	Dimension （l×b×h）	Stress （MPa）	Load F （N）	weight （g）
Flat-wise （recommend）	A	80mm×10mm×4mm	1.80	3	238
B	0.45	0.75	8
C	8.00	13.33	1291
Edge-wise	A	120mm×10mm×4mm	1.80	4.8	421
B	0.45	1.2	54
C	8.00	21.33	2106

If the dimension of your specimen is not including in the above form, please calculate the load according to the following formula:Notice: “74g” in the table above means the total weight of load carrying plate & the loading rod and the micrometers”

F＝2×δ×b×h×h/(3×L)………………………………….………. (1)

F1 = F×1000/9.81 – 68………………………………..………(2)

Where:

F— The total force, in Newtons, applied to the test specimen;

F1—The weight you should add;

δ—The nominal surface stress, in megapascals, in the test specimen; such as Method A 1.80Mpa, Method B 0.45Mpa, Method C 8.0 Mpa;

b—The width of the test specimen, in millimeter;

h—The thickness of the test specimen, in millimeter;

L—The span of the test specimen support, in millimeter

g—9.81 m/s2

Note:The span between the test specimen supports is 64±1mm if the specimen is tested in the flatwise position, and 100±1mm if the specimen is tested in edgewise position.

If you need more information HDT/ Vicat Tester price and theory , please send email to [email protected].