A mirror coating system that was put into operation six years ago by the Russian plant operator Guardian Steklo in Ryazan, failed to work satisfactorily in production. There were consistent, non-reproducible quality variations of the starting product, which were no longer acceptable, either to the operator or customers.

Since complete replacement of the still relatively new system from a third party provider at the then expected high cost was not a viable option, a ‘cure’ was looked for as a way to overcome existing shortcomings. The goal-oriented and necessary approach was to gain better control over the production process to ensure that each piece of glass adheres to precisely defined process parameters. This should reduce the variability of the paint drying, which leads to an improvement in the corrosion resistance of the mirror.

Dortmund-based KLÖPPER Maschinentechnik was awarded the contract to modernise or strengthen the existing plant in accordance with the specifications, ie to carry out a retrofit exercise. Another requirement of the operator was that the necessary business interruptions should be as minimal as possible.

Goals and benefits of retrofitting

Why should relatively new machines and production facilities be disassembled and disposed of expensively, just because some process parameters are not met? Why should one-shot production processes be completely changed if they can no longer be optimally designed? The answer often lies in the responsible balance between a possible new investment or the partial retention of existing, still functioning components. Especially with expensive and extensive systems, a suitable retrofit could be very interesting with regard to the second.
Retrofit stands for the meaningful modernisation, subsequent expansion or conversion of existing, mostly older systems and equipment for the successful continuation or acceptance of an existing system. Depending on the initial situation, the following goals may be relevant for the planned retrofit, for example:

• Increasing production volume and efficiency.
• Increase product quality.
• Increasing the degree of automation and embedding in modern IT environments.
• Long-term supply of spare parts.
• Fulfillment of legal requirements.
Companies that have already carried out a successful retrofitting of their system report the following advantages:
• Short downtime, as only partial renewals necessary.
• Lower investment costs compared to reinstallation.
• Existing infrastructure, eg foundations, constructions or drives could be taken over.
• Low training costs, as the system is mostly known.
• Modernisation of the controls and IT connection.

Project realisation

KLÖPPER Maschinentechnik was commissioned by the Russian plant operator Guardian Steklo to carry out a retrofit of the mirror production plant of a competitor. The principal concrete expectation of the client was to ensure better control of the entire process in terms of paint drying and paint curing by giving each piece of glass the same controlled infrared radiation. Better control of the overall process and significantly increased flexibility in paint heating and curing should result in improved paint temperature curves. In particular, compliance with these temperature curves is important with regard to the dependence on glass entry, continuity pauses, glass thickness and glass temperature.

After a thorough analysis of the production processes and the ongoing technical processes, it became clear that the focus of the desired retrofit must lie in a revision of the thermal process. Therefore, the complete regulation in the topcoat oven was replaced by installing a new system; the old mechanical components did not have to be disassembled. For the integration of this fully automatic temperature control, minimal interruptions of the current production operation were necessary, the pure downtime being just two weeks. The control with the determined operating parameters was designed so that the heat input for each produced pane could be dosed and monitored individually with the required accuracy.

Results after completion of retrofit
After completion of the plant retrofit, ie with commissioning and a few trial runs, the client confirmed that the specified customer requirements were successfully and effectively implemented and that a clear increase in product quality had been achieved from the first glass produced. All panes of glass are now monitored so that traceability and sorting has become much improved.

The temperature control, which has been proven at KLÖPPER for many years, allows a very precise temperature profile in the production process, which corresponds to the relevant and individual recommendations of the paint manufacturer, thus optimising the quality of the paint surface.

The client is also able to adapt parameters independently for different paint manufacturers or to optimise them based on in-house experience. Because of the better lamp arrangement and better power control, there were also advantages in terms of energy savings, because less radiant heaters are used than previously. In addition, energy is saved by switching between glass surface and air temperature control when there is no glass in the oven.

Strong reputation

For more than five decades, KLÖPPER Maschinentechnik has been a trusted and internationally active machine manufacturer in the field of glass processing systems, as well as a service provider for the professional retrofitting of plants. The company’s expertise is supported by an experienced team of engineers and technicians from the fields of mechanical engineering, electrical engineering and computer science. Thanks to this inter-disciplinary competence, all technical interfaces can be processed directly under one roof. The customer thus receives all necessary services from a single source with the following range: Technical and economic advice in advance; on-site analysis as a qualified engineering service; manufacturing and testing of components in the factory; assembly and commissioning on-site; on-site service after commissioning; telephone support; and maintenance and service.

Depending on the functional and needs analysis, the professional refitting of an entire system can take place at agreed time intervals and thereby, the module-wise replacement of affected system components, including temperature control, drive technology and sensor technology. In addition, the modular functional extension of existing plants can be interesting for some operators, including:

• Disc tracking in the oven.
• Spotlight failure detection.
• Custom data documentation for quality control.
• Connection to enterprise resource planning (ERP) systems.
• Compliance with Distributed Control Systems (DCS).

Conclusion

All types of glass processing machines can be optimised and modernised relatively inexpensively with minimal disruption because often, only a few critical components need to be replaced.