Blog

A fascinating city is formed

The historical Czech town of Jablonec nad Nisou (German: Gablonz an der Neiße) was first mentioned in the 14th century. The glass industry in the town however had its origins a couple of centuries later. We can assume that the first glass professionals settled in the area in the 16th century. Above all, the existing rich resources that are necessary for the production of glass, were a major factor in the settlement.

Destruction and new beginnings

In the fourth and last part of our series From idea to finished product we are informing you about a few ways of product refining.

„Refining“ of the glass article

Can be an already processed article yet to be refined (glass refining), that is to say the example of a customer logo is applied by means of sandblasting or that special colour effects (e.g., rainbow colours, etc.) being vapour deposited. There is not only the rainbow colour effect but also a whole series of other colours. The sheer exotic names like vitrail medium, peacock, golden shadow or bermuda blue spark curiosity even more. These colour effects are especially popular in our glass pyramids. These are ideal as corporate gifts for clients or as an eye-catcher at a presentation or decorations. Any design is possible with certain easily customizable articles according to the customer’s wishes. Therefore we listen to exactly what the customer wants.

Continuation of the article „From the idea to the finished product part 3 ….

In part 3 of our article „From the idea to the finished product“ we discuss the further processing of pressed glass articles.

Removal of excess glass

…. Continuation of  From idea to finished product from glass Part 1

The production process of the pressed glass article begins

The mould is built in to the press. Now the actual production process begins. It can be sweaty work at the furnace, with temperatures reaching up to 1300 degrees. According to the shape and size of the material of the pressed glass product, the appropriate raw glass rods must be selected. There are glass rods with different diameters. The bigger the glass article, the thicker the glass rods. The diameter of the glass rods can be as high as 44 mm. Depending on the type of glass or even the colour of glass, there are different requirements to be considered when processing. The glass rods are then heated in the oven. As soon as the glass rod is soft and is suitable for the pressing operation, it can be kept in the open press. The press closes and presses the product accordingly. Throughout this process, the mould is permanently heated by flame so that you have an appropriate temperature necessary for the successful finalisation of the product. During the pressing process, there can be excess glass from the edge of the article. When the item is then pressed, the connection to the glass rod is broken with a special pair of scissors. The glass rod is then held to the heat for the next pressing operation in the oven. The pressed article is then removed with forceps from the opened mould.

The first part of this section deals with implementing an idea right up to the production of a prototype – it creates a new glass product. Regardless of whether it is a glass lens, glass ball or ……..

The idea is the beginning for a new glass product

To start with, there is an idea of us working together with our customers right up to the finished product. The first step is a drawing with all the necessary details like, for example, precise measurements, tolerance specifications, description, etc.. We should also be informed of the intended use or purpose, such as the exact requirements set by the customer for the pressed glass product. These requirements also decide on the type of raw glass needing to be used. There is usually the choice of either soda lime glass or borosilicate glass.

Fusing (Fusion) is a sophisticated technology, in which various pieces of glasses are fused together. The melting temperature is among other things, dependent upon the composition of the glasses which are to be fused together. There is even the possibility of other temperature-dependent items such as metals to merge together with the glass. Glass fusion also works with colored glass powders, frits and fragments.

In our current blog we describe the manufacture of raw glass (lime soda glass). Normally the following raw materials are used for the glass mixture:

• Quartz sand
• Potash
• Sodium carbonate
• Lime
• Dolomite
• Feldspar

The ingredients change according to the type of glass being made. This list therefore only features the most important components. As soon as the batch is made, the melting begins with 3 different phases:

• Phase 1 is the preliminary melting phase. This is when the batch is melted and homogenized
• Phase 2 is refining  (removing gas bubbles).

A lens is an optically effective element with two light-refracting surfaces. Of which a surface is usually curved as concave or convex. The most important characteristic of a lens or a so-called lens system is the optical image. The critical size of a lens is the focal length the unit is specified in meters, depending on the intended use etc. Thus the distance from the focal plane or the focal point of the lens is defined. The simplest lenses are optically active at both spherical surfaces (surface sections of a sphere). From a historical perspective it is assumed that the first glass lenses were used in the field of optics. They were used as lenses to correct short sight or long sight. Later, the first binoculars and also microscopes were developed. Materials which are suitable for the production of lenses must be made of transparent materials. In addition to glass are also some plastics suitable, such as Polycarbonate. The name of the lenses is defined by the curvature of their surfaces. Each of these surfaces can be concave, convex or flat (plan). Convex lenses have curved surfaces outwards, concave lenses, however, have inner curved surface. With lenses having a flat surface no curvature is present. A very important characteristic of a lens is the principle of reversal of the light path. The focal length is dependent on the curvature radii of the two lens surfaces. There are many different types of lenses. We want to enumerate only a few at this moment.

Glass beads play a prominant role in our wide-ranging assortment. Just the variety of possible applications are an indication these days that glass is an important component of daily life. If we look at our assortment, it’s easy to miss the smallest glass beads left in our production sites all over the world. Each one has exactly a 1 mm diameter and we make them in Germany following a traditional process. The scale of these small borosilicate beads can also be expanded – 2 mm, 3 mm, 4 mm etc. There are several possible applications for these beads. Among other things, they are found in ball bearings, as a mixing ball for insulin, as a ball valve in a dosing pump and in dispensers in the grocery and cosmetics industries, etc. Our outstanding quality and precision is valued around the world.

Glass is a material with a long history. By about 5000 BCE, natural glass called obsidian, was used as a working material. Blades, wedges and scrapers were fashioned and used to make other objects for daily use.

Glass was fashioned into containers in Egypt from approx. 1450 BCE. The Egyptians were the ones who first discovered how to make glass.  From that point on, glass making developed in leaps and bounds. In the Roman Empire, villas for the upper-classes were outfitted with window glazing. This was made possible by the invention of the glass blowing pipe in approx. 200 BCE.