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Thermal processing for the ophthalmic industry.Download
Why is thermal processing an important topic in ophthalmology?
The most important products of the ophthalmic industry include intraocular lenses (IoL) and contact lenses. Thermal processing is mostly involved in the production of both types of lenses. Depending on the production method adopted, these products are mostly subjected to thermal processing for either curing or sterilisation. Curing for instance is commonly used in the production of moulded intraocular lenses. In this process, the mould is heated beyond the phase of transition, held at a certain temperature long enough to achieve uniform heating. In the process, the chemical properties of the monomer/s are processed to achieve specific results. A similar process is used in the production of contact lenses.
How present is Weiss Technik in this industry?
We have a long working history with the key players in ophthalmology, providing customised solutions for batch and continuous thermal processing. In recent years, we have supplied over 300 ovens to the US, Singapore, and Puerto Rico to name just a few. Above all, manufacturers need reliable mechanical engineering partners in order to be able to guarantee identical products and uninterrupted production at different locations. With our vast experience, we can offer them just that. Our customers also enjoy direct round the clock service worldwide irrespective of the location.
How will you describe the requirements of ovens for the ophthalmic industry?
In both chamber and continuous ovens, thermal processing affects product quality. The temperature must therefore be quite uniform, especially in the oven and during the curing process even when several curing zones are required. A uniform air flow is also quite important. The solutions are thus not trivial. With our ovens, we adapt the maximum temperature deviation to the customer’s requirements. A common challenge in the series production of contact lenses is sometimes the residual oxygen. Here, we have been able to exceed our customers’ expectations thanks to our engineering experts, gas-tight design and special door sealing solutions. Solutions for the monitoring and recording of all process related data according to the strict rules of the medical industry must always be considered.
In the field of industrial heating technology, we implement customised process-integrated solutions across all industries. Manufacturers in the ophthalmics industry can benefit from our many years of experience and our holistic solutions:
We do not only supply customised ovens but also equip them with the required hardware and software. It is particularly important that this meets the strict data processing requirements of the pharmaceutical industry. You are free to choose the control system: weisstechnik Simpac, Siemens S7 or Rockwell Allen Bradley. With the cooperation of other subsidiaries of our parent company OptoTech, we also integrate automated solutions for sorting products after the end of line test. We are thus a one contact partner and supplier for all central components of a thermal processing system.
For the curing cycle of cast wafers in the production of IoL, we have a unique tunnel oven in our portfolio. Its specially developed air flow guarantees a temperature uniformity of ±0.5 K on the product at any position in the oven. For reliable production, the product transport in the oven is very smooth and closely monitored. The accompanying data management system of the processing assessment fulfils the documentation obligation in the pharmaceutical industry. Our complete package also includes the automatic sorting and stacking of the processed product.
The Nitrogen gas oven is designed according to EN 1539 Dryer Type B. Here, the residual oxygen content in the oven is monitored according to industry standard so that the amount of combustible material to be processed at a time is not limited.
A residual oxygen content of 0.006% can be achieved with this system. The integrated heat exchanger in the oven enables a constant starting state and rapid cooling. The maximum temperature variation with this is ±1 K but optimisation is achievable, if required.
The shielding gas oven is used during the monomer curing process in order to polymerise monomer from a liquid into a contact lens. The UL-certified oven with electrically driven doors can be integrated into an automated production process. It has a maximum temperature variation of ±2 K, which can be optimised on request. For perfect conditions during the process, the oven is equipped with a residual oxygen control and an adjustable air flow management system. This guarantees a consistently high quality of the contact lenses.
If you would like to learn more about our thermal processing solutions for the ophthalmic industry, we will be happy to advise you personally and develop an individual solution for your requirement.