Convection technology in glass tempering gives an edge
The growth in demand for architectural glass is boosted by the increased use of safety glass in construction. Another factor in the background is the need created by climatic change to develop safer and more energy efficient constructions. On the other hand people are battling, for example, with an increase in hurricanes, on the other they are looking for ways to save energy. Safety glass has several challenging properties that must be taken into account in the development of glass processing machines.
New types of glass and coatings are entering the market. When combined with the continuing efforts of customers to achieve higher quality, greater productivity and extremely low energy consumption, they are opening the way for modern convection technology.
With a convection heating system, the glass is heated with a stream of hot air without direct radiation. This means it does not matter what coating is on the glass.
The RoboTemp™ full convection tempering machine is the flagship of Glassrobots. The company has delivered close to thirty RoboTemp™ flat tempering machines to glass processing companies worldwide. Its largest full convection flat tempering furnace, handling a maximum glass size of 3.2 m x 8 m, was delivered to a European customer for façade glasses.
When selecting a tempering machine, there are a number of things that should be considered For example whether the machine is capable of adjusting temperature distribution over large glass sheets during treatment (this is especially important when it comes to low-E glass). Furnaces should also be capable of sustained heavy loading without loss of power, keeping the same capacity with back-to-back loadings and maintaining quality. Operating software for the furnace should be robust and companies should possess a good track record in glass processing and thus knowledge about developing its own software. In addition, the quality and type of components used with the machine should be considered, whether you can save energy and labour costs with the furnace and whether the furnace offers the potential for more profit compared to other furnaces on the market.
Windscreens go deeper
Car windscreens are undergoing considerable changes in design and even continue directly into a roof window. On the automotive glass technology side, Glassrobots TFA3evolution™ bending furnaces are especially designed for mixed production of ARG windscreens, but also suitable for serial production enabling to achieve the highest OEM standards.
In the furnace, the patented control system FuzzyBendÔ gives an excellent repeatability and the automatic bending process requires less manpower for operating than the traditional systems. This system and the bending control is based on continuous measurement of glass temperature by IR-pyrometer. There are TV-cameras at the bending end enabling the operator to monitor the final bending at the control panel. The PC and PLC (programmable logic control) together control and monitor the operations of the furnace. Operators can easily call different bending programs to each wagon separately from the PC. Each heating element is divided into three individually controlled parts enabling complex heating profiles. Also vertically adjustable heating elements can be used.
With the FuzzyBendÔ control system the glass is always bent under same bending time and uniform bending conditions. The control system eliminates the effects of change in the production mix, the heat balance of the furnace, external temperature conditions and variation of supply voltage. An integrated condition monitoring and maintenance system facilitates the preventive maintenance and ensures minimum of downtime. Also remote diagnostic software can be provided so Glassrobots’ engineers can communicate with the furnace’s PLC/PC.
In order to meet the special requirements of each customer, Glassrobots has innovated package solutions like the Complex Shapes-option, the Deep Sag-option and the Special Features-option for enhancing the furnace capability in terms of difficult bending and furnace capacity.
Other products: LTFBA bending furnaces for large windscreens, vacuum de-airing equipment, autoclaves, flat laminating lines.
For further information, contact Anders Holmqvist or Juha Karisola