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Frequently asked questions - FAQ

Here you will find frequently asked questions and associated answers all relating to the technology of KNOTH Automation GmbH. You could not find an answer to your question? Then please contact us directly.

Can residual contamination values be guaranteed with dry cleaning systems from KNOTH?

We would like to answer this question with an all-embracing “YES”. However, in the past 8 years alone, we have supplied more than 1,800 cleaning systems and devices, and no situation was entirely the same. Therefore, to name general residual dirt values without knowing the workpiece and all process parameters is highly questionable.
Based on parameters specified by customers, KNOTH plans and delivers a cleaning solution which will definitely deliver the previously agreed degrees of cleanliness. It is clear that a specific residual contamination value can then of course also be guaranteed.

What does a cleaning degree of 98% mean


The definition of the cleaning result in percent is common above all for our dry cleaning systems.
For intermediate cleaning processes, residual contamination values are rarely requested. What is rather important here is the minimisation of contaminations being carried over to subsequent process steps.
So when a workpiece is transported to our system following its final machining, it is 100% contaminated with chips/coolants. 98% of this contamination is then removed (in this case) by us in the system. This can be proven by means of the total weight of the workpiece. 1) Weighing of the contaminated workpiece (100%)

2) Weighing after the KNOTH intermediate cleaner (x %)

3) Weighing of the completely cleaned workpiece (0%).
90-98% being cleaned off is quite common for pure dry cleaning (without flushing or washing). Usually, these results are even better in automatic operation. However, a ratio of 100% for purely dry cleaning can simply not be achieved. Even if the weight proportions were to result in a ratio of almost 100%, there can still be small contaminations, chips, coolant residues on the workpiece and above all inside it – these can barely be determined with this test method.


How is a process-reliable dry cleaning despite a cleaning ratio of below 100% possible?

For process-relevant dry cleaning processes, our PrecisionAircleaner cleaning systems are used in principle. For the function/assembly/measuring surfaces on the workpiece, own nozzle assemblies on independent air circuits are always used. So if the total ratio on the workpiece is 90%, we can still guarantee the cleaning quality for the relevant areas.
In principle, we offer all our customers the option of cleaning tests at our premises. This allows us to test, determine and confirm the required systems and the cleaning result empirically and precisely upfront.

Is compressed air expensive?

Yes! Compressed air is expensive! This is the result of production, storage and conduction of air. There are 4 significant places of energy loss up to the consumer:

  • Compensation of air
  • Conduction up to the consumer
  • Leaks in the compressed air system
  • Resistances during control on the consumer
  • Expansion of air on the consumer

Compressed air is thus a valuable medium! For this reason, nozzle assemblies have always been used by KNOTH which are particularly characterised by strong forces and at the same time minimum consumption. The individual compressed air jets as well as compressed air settings are precisely adapted to the workpiece and the cleaning requirements. 
In comparison, SurfaceAircleaner and PrecisionAircleaner cleaning systems thus need a lot less air than when the same workpieces are blown off manually with hand blast pistols.
Furthermore, all our cleaning systems are designed for use with low-pressure networks. An economical compressed air production at up to 3 bar would thus be possible.