Zawiercie Crystal Glass Factory Ltd.

Zawiercie Crystal Glass Factory Ltd.

Manufacturing technology

Blown glass

The technological process of production:

The technological production process of crystal glass products is a multi-phase process which requires maintenance of many parameters in such a manner that the final product meets the visual as well as technical requirements. The most important manufacturing parameters, which decide upon the quality of crystals are:

  • the temperature of the melting the raw material,
  • glass oven atmosphere,
  • the quality of the raw material used in the manufacturing process
  • other factors, which allow to obtain the glass mass of the proper quality and homogeneity.

The first manufacturing phase constitutes of proper preparation of the raw materials, which upon melting create a plastic mass, which in the later stages is used to form appropriate shapes of the final glass products. The so-called "glass set", which is the mixture of components, is being homogenised and fed into the glass oven (glass bath), where physical and chemical processes take place within high temperature, allowing to obtain mass of desired quality. The particular raw material which the mixture consists of, constitute the highly protected manufacturing secret.

The product part of the oven constitutes its important element, where the glass mass that has been processed to achieve required viscosity to form the product, is being drawn from.

At this manufacturing phase, what is extremely important is the attainment of the proper melting temperature, the removal of any impurities, which may influence glass purity as well as the elimination of gas bubbles created as the result of the occurred chemical processes.

To the major extent our products are still manually blown. This is the most interesting and at the same time the most difficult manufacturing stage. It is done by performing the following steps:

  • Attainment of a portion of the glass mass – first the glass-blower forms a bubble (first upon the heated tool a small portion of the glass mass is placed and then a bubble is blown out), next the proper portion of mass is added,
  • The initial forming of the portion,
  • Blowing out of the given portion of glass through oral blowing of air through the blow-pipe, the glass-blower then juggles the blow-pipe in order for the portion to obtain the required shape,
  • Manual formation or formation with the use of a form – during the manual forming (free forming process) the glass-blower manually forms the shape and it is his skill and imagination that guarantees the final effect. The formation of the product with the application of the form requires blowing in the air through the mouth piece in order for the mass to obtain the shape provided by the inside of the form.

This allows for the formation of shapes possessing various curvatures impossible to be obtained by means of mechanical manufacturing processes.

The formed but still hot glass products are adhered with all of the functional elements, such as handles, or other decorative elements.

The formed products are de-stressed with the application of the special ovens referred to as the de-stressing devices. This process is aimed at the removal of stress created within the product as the result of formation. The proper execution of this phase has the decisive importance on the durability and wear factor of the glass products. They are placed within the de-stressing device therefore they cool off in a controlled manner. The de-stressing device is the sort of an oven. It has the length of several metres with a conveyor belt placed in the middle, where all of the products are placed. The belt transports the products with very small speed throughout the whole bowels of the device, which are subject to the influence of various temperatures.

After the execution of the de-stressing process all of the products are passed to the decorative department. The patterns cut and engraved by our specialists constitute our products' trademark. The traditionally rich and frequently placed cuts from the city of Zawiercie require a huge dose of craftsmanship well as patience from our specialists. It is thanks to their work that our products are highly valued and wanted on numerous foreign markets.

Chemical polishing constitutes the final decoration phase. All of the products are polished using a mixture of sulphuric and hydrofluoric acids, in order to give them the right gloss. The polishing process is conveyed automatically in the baths which have been designed specifically for that purpose. Once this process is finished,the majority of the products are additionally decorated by means of shading, matt or engraving processes. Engraving constitutes the highest degree of the art of glass decoration and it is mastered by very few, gifted professionals.

The ready products are subject to the detailed, final quality control in order to eliminate any faulty products.

The ready, decorated products are subject to the manual quality control, before they are sorted and manually packed. This procedure allows to eliminate any faulty or damaged items and therefore to achieve much higher manufacturing quality. All of the crystal products are packed into decorative boxes and shipped to the warehouse, where they await to be sent to the domestic and foreign clients.

 

Hale stalowe PW Pasek