RU2240925C1 - Method for manufacture of decorative products of natural amber - Google Patents

Abstract

FIELD: manufacture of decorative products.

SUBSTANCE: molding of heated starting raw material in a vacuum-treated mould is accomplished with a simultaneous pressure release and stopping of vacuum treatment.

EFFECT: enhanced quality of products.

9 cl, 2 dwg

Description

The invention relates to the production of artistic, decorative and technical products, as well as souvenirs made from natural amber.

A known method of pressing amber, carried out in an inert atmosphere of nitrogen at 150-170 ° C with a longitudinal pressing force of 7-15 kg (AS USSR No. 1283106, MKI B 28 D 5/00, publ. 15.01.87). This method ensures the preservation of high decorative properties of the original amber, however, the anisotropy of the properties of amber products limits its scope in terms of pressing large-sized products.

Closest to the proposed method is a method of manufacturing large-format products from a small fraction of natural amber (RF patent No. 2191704, MKI B 44 C 5/06, publ. 27.10.2002). This method involves loading raw materials of a fraction of ~ 10 mm into sealed molds, heating to a temperature not higher than 140 ° C and pressing with a smooth increase in pressure from 0 to 100 atm with holding force for a specified period of time. This method allows to obtain products that retain the physical, chemical, aesthetic properties of natural monolithic amber. However, a prolonged exposure to amber of the longitudinal pressing pressure creates internal stresses in it, which in turn can lead to cracking and even destruction of products.

The proposed method allows to improve the quality of jewelry obtained from natural amber by reducing the possibility of cracking. This ensures the receipt of both small and large products.

In addition, this method allows you to adjust the transparency and color of the resulting products, which greatly affects their decorative and artistic properties.

This result is achieved by the fact that the manufacture of decorative products from natural amber is carried out as follows: the feedstock is loaded into a matrix of a sealed mold, the heated raw material is pressed into a vacuum mold, the volume of the forming cavity of the matrix is fixed while the pressure is released and vacuum is stopped, and then cool the mold.

The specified technical result is also achieved by the fact that the feedstock and the mold are heated before loading the feedstock into the mold matrix, or the feedstock loaded into the mold matrix is heated before pressing together with the mold.

The feedstock is heated to a temperature of 110-130 ° C, and the mold is heated to 160-230 ° C, which allows you to change the color of the finished product.

To regulate the transparency of the finished product, the volume of the feedstock is taken less or more than a fixed volume of the mold cavity of the matrix.

The main difference of the proposed method from existing methods of manufacturing products from natural amber is the absence of longitudinal pressing pressure after fixing the volume of the forming cavity of the matrix at the time of sintering.

This pressing method uses a mold with a mechanism for fixing the volume of the mold cavity of the matrix.

The method is implemented as follows.

Fraction of natural amber of various sizes is used as the initial raw material: large pieces of amber, amber pebbles, fragments of amber, defective amber products, amber that has been crushed (it is possible to add secondary raw materials up to 15%). The feedstock may be different in transparency and size. The total amount of feedstock may vary slightly from the volume of the resulting product.

The feed is loaded into the mold matrix. In this case, it is possible both separate heating of raw materials and molds, and joint. Raw materials can be preheated to 110-130 ° C. The mold is heated to 160-230 ° C. You can heat the raw materials together with the mold. In this case, heating takes place in a muffle furnace in a mold. The difference in thermal conductivity of the material of the mold and amber is used.

The color of the finished product depends on the temperature of amber and the mold: from natural to dark cognac.

After reaching the operating temperature, the mold is installed in the hydraulic press. The punch under pressure from the press, sufficient for the destruction of amber, is quickly lowered (within 30-40 seconds) until it stops. In this case, the mold is evacuated. After the mold is completely closed and the feedstock is destroyed, the volume of the mold cavity of the mold matrix is fixed by fixing the punch with a fixing mechanism. After fixing the volume of the forming cavity of the matrix, the press pressure is completely relieved and the process of evacuation of the mold is stopped. Under the influence of pressure in the heated amber, intermolecular bonds are destroyed, and it turns into a heterogeneous mass. The heated amber mass is heated to the temperature of the mold, increases in volume and fills the volume of the mold cavity of the matrix. The sintering process occurs due to the internal reaction of the material in a fixed volume of the mold cavity of the matrix. After cooling below 90 ° C, the product can be removed. Free cooling is applied. With artificial cooling, the product can be fragile.

In the claimed method, the source material is expanded in a fixed volume of the mold cavity of the matrix when it is destroyed in the process of reaching the technological temperature range. Unlike the prototype, there is no smooth increase in pressure. Moreover, the possibility of internal stresses is much lower than with prolonged exposure to the longitudinal pressure of the press.

Figure 1 shows one of the possible variants of the device for implementing the method in its original state (mold placed in the press).

Figure 2 - the same device when reaching a fixed volume of the forming cavity of the mold matrix.

1 - press

2 - mold matrix

3 - feedstock (amber pebbles)

4 - hole for evacuation

5 - emphasis

6 - punch

7 - fixing mechanism

8 - forming cavity of the matrix

The method is implemented in the device as follows.

The heated feedstock 3, located in the mold matrix 2, is placed in the press 1 and quickly, under the pressure sufficient to destroy amber, for example, about 50 tons, lower the punch 6. Simultaneously vacuum the working chamber through the hole for evacuation 4. After reaching the punch the stop 5 is fixed by the fixing mechanism 7. At the same time, the volume of the mold cavity of the matrix is fixed 8. At the same time, the pressure is released and the evacuation is stopped. Maintain in a fixed position until the temperature reaches below 90 ° C.

The proposed method allows you to further adjust the transparency and color of the resulting products. Natural amber is heterogeneous in its density, which leads to its difference in transparency. More “transparent” fractions are correspondingly more dense than “white” or “smoky” ones. If individual fractions, different in their transparency, are subjected to destruction in a fixed volume of the mold cavity of the matrix equal to the volume of the feedstock, while giving the desired shape at the required minimum technological temperature for sintering amber, the material during the expansion process occupies the entire free volume of the mold cavity all free voids. After cooling, sintered amber in its bulk retains its original transparency properties, i.e. the density of the feedstock, but there are traces of fluidity.

If the fixed volume of the mold cavity of the matrix is less than the total volume of the feedstock (not more than 15%), then the obtained pressed amber will be more transparent, i.e. more dense.

If, on the contrary, the fixed volume of the mold cavity of the matrix is greater than the volume of the feedstock (by no more than 10%), then opaque inclusions appear in transparent amber.

To determine a fixed volume of the forming cavity of the matrix, the volumes of the matrix and punch are pre-calculated, and then the fixed volume is determined. Knowing the average density of natural amber and determining the weight of the feedstock, you can determine the amount of feedstock. By changing the ratio of these volumes, you can change the transparency of the finished product.

Claims (9)

1. A method of manufacturing decorative products from natural amber, including loading the feedstock into an airtight mold matrix, compressing the heated feedstock into a vacuum mold, fixing the volume of the mold cavity of the matrix while relieving pressure and stopping the evacuation and subsequent cooling of the mold. 2. The method according to claim 1, characterized in that the feedstock and the mold are heated before loading the feedstock into the mold matrix. 3. The method according to claim 1, characterized in that the feedstock loaded into the mold matrix is heated before pressing together with the mold. 4. The method according to claim 2, characterized in that the feedstock is heated to a temperature of 110-130 ° C. 5. The method according to claim 2, characterized in that the mold is heated to a temperature of 160-230 ° C. 6. The method according to any one of claims 1 to 5, characterized in that the volume of the feedstock is less than a fixed volume of the mold cavity of the matrix. 7. The method according to claim 6, characterized in that the volume of the feedstock is less than a fixed volume of the mold cavity of the matrix by no more than 10%. 8. The method according to any one of claims 1 to 5, characterized in that the volume of the feedstock is greater than the fixed volume of the mold cavity of the matrix. 9. The method according to claim 8, characterized in that the volume of the feedstock is greater than the fixed volume of the mold cavity of the matrix by no more than 15%.

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