In more and more industrial companies, it is becoming necessary to design the environment to minimise or ‘clean’ particles, as the increasingly sensitive products can be severely damaged by such particles. Even if the production environment is located in a cleanroom, this is no longer a guarantee that the integrated machines will achieve the same air cleanliness class as its surroundings.
The initial situation
One of our customers faced the same challenge: a machine manufacturer that produces measuring devices for non-contact and non-destructive characterisation of surfaces and coatings for double-sided sample inspection. After analysing the production processes in detail, it was determined that the clean air flow from the clean environment could not reach the machine's interior when the machine was closed. It also produced particles during operation. It is therefore quite possible that there is a higher concentration of particles inside a machine than in the cleanroom environment outside the machine.
This ‘’uncleanliness‘’ of the machines can cause major problems. An unwanted particle on one of these samples can significantly affect the test result or increase the reject rate.
The solution
In order to develop a suitable solution, measurements first had to be carried out inside the machine for the necessary analysis. The measurements finally proved that the actual concentration inside the machine only corresponded to an ISO class 8 (particle purity class of the air according to DIN EN ISO 14644) and thus confirmed the fears of ‘impurity’.
Test phase 1
The first solution was to integrate a fan-filter-module (fan-filter-unit) into the machine, which can also ensure a clean air supply inside the machine. To test the idea first, standard fan-filter-modules were connected to the machine, which were not yet customised to the machine's requirements.
Although the modules were not precisely customised for the machine, this short-term solution already led to a reduction in the number of particles and thus to an improved air cleanliness class in accordance with ISO 6.
Test phase 2
After the first successful initial tests, the problem of precisely adapting the fan-filter-module to the machine now arose. Firstly, the filter-modules were integrated into the machine surface, allowing the modules to be permanently installed and the machine to be supplied with a vertical air flow.
In addition, the fan-filter-module had to be fitted with ion bars to counteract the issue of electrostatics. However, this resulted in a further ‘cleanliness problem’, as these ion bars also had to be cleaned. In order to minimise this cleaning effort, the ion bars were processed in a type of drawer. As a result, they can be cleaned quickly and easily at any time.
Final solution
However, the first solution approach was rather unsuitable for the machine manufacturer and its surface measuring devices, as they are used to inspect samples on both sides and therefore have to be surrounded by clean air on both sides. Consequently, only a horizontal air flow could be considered as a solution.
In collaboration with the customer, a solution was finally implemented in which the back of the machine, which is sealed with sheet metal, was connected to a fan-filter module.
Here you will find interesting facts about cleanroom technology.
The result
A significant advantage of this solution is that the customer can easily integrate the module themselves with two closures. The horizontal integration allows a horizontal air flow to be generated, which surrounds the top and bottom of the sample with clean air.
The final result of the solution we realised together was optimal air purity for the sensitive samples inside the machines and thus a particle- and error-free measuring process for the machine manufacturer. As this example shows, the construction of a cost-intensive cleanroom can often be replaced by this fast, simple and cost-effective variant in the machine interior.
As both customer requirements and technical machine specifications change, continuous adaptation of the solution concept is necessary for successful realisation of the solution.
If you would now like to find out to what extent such a solution would also be advisable for your machines, please contact us without obligation. We will be happy to advise you at any time!