Laser flue gas filtration Laser flue gas filtration for additive production methods

HYDAC – your partner for flue gas filtration in additive production, preferably with SLM technology.

4 min reading time

Customer Success Story Engineering Hydraulics

Laser flue gas filtration for additive production methodsHYDAC – your partner for flue gas filtration in additive production, preferably with SLM technology.

Selective laser melting (SLM) is an additive production method that involves parts being manufactured in layers directly from a material in powder form.

In the SLM method, the material powder is fused directly to the processing point by the heat energy of a laser beam. To prevent the material from oxidising, the working chamber is filled with a protective gas. This causes flue gases to develop in the machine’s working chamber, which could impair the fire point of the laser. For this reason, the flue gas needs to be filtered. The dusts that are thus generated are combustible if they react with oxygen. Some of the dust particles are so small that they are respirable. With current technology, when the filter is changed, the filter is therefore either flooded with water or brought to an inert state with slake lime.

The disadvantages of this method:

  • The disposable filter elements can sometimes have very short service lives (in some cases only lasting for one construction job)
  • High running filter costs and extensive filter change workload
  • Complex inertisation is needed when the filter is changed, as the entire housing needs to be
  • Frequent filter change results in a large disposal volume
  • Occupational health and safety is unsatisfactory
  • removed, flushed with water and cleaned.

Optimisation of the filter solution with the innovative laser flue gas filter solution from HYDAC

Our customer is a global player among machine tool manufacturers. With its solutions, it serves the huge trend of additive production, using selective laser melting (the SLM method) in its metal 3D printers. One major challenge that this poses is the filtration of the laser flue gas that is generated.

The existing filtration solution required very frequent filter changes, as new disposable filter elements were needed for almost every construction job. This resulted in a large and costly filter element disposal volume for the machine owner.
Another disadvantage in the complex filter change process was the inadequate occupational health and safety caused by the fire hazard posed by the metal powder in the event of a reaction with oxygen. On top of this, the particles were very small and respirable. Every time a filter was changed, it was therefore necessary to flood the filter housing with water. Then the entire housing was removed, flushed out with water and elaborately cleaned. With this method, it could take up to 2 hours to change the filter.

The entire filter change process was inefficient and entailed health risks. The customer therefore came to us with the following requirements:

  • Improve occupational health and safety

  • Develop a filter system with long filter life and cost-effective operation

  • The high disposal costs for the end user should be eliminated

  • A filter that can be used universally for all types of powder material in the additive production method

Based on this goal definition, a requirement book was developed together with the customer. A test of the first prototype of the HYDAC filter was performed directly on the customer’s premises, naturally with support from our skilled filter experts. After some adjustments, the customer approved series production.

FlushPACK – the laser flue gas filter solution from HYDAC

HYDAC took up the challenge of filtering laser flue gas particles – the result is the innovative filter system FlushPACK.

The principle of passivation

First, the particles are filtered out of the protective gas in a gas filter (1). A hydraulic accumulator (3) charged by a compressor (2) performs backflushing in the filter, causing the dirt to fall to the filter base. There, it combines with a passivation fluid, which is extracted into a separate container (4) where it is stored. The particles are thus bound. Optionally, a HEPA filter (5) can also be installed.

The result

As the dirt is passivated directly inside the filter, no PPE (personal protective equipment) is needed for the filter change. At the same time, the occupational health and safety of the method is increased. Thanks to the very long filter life, the filter system can be operated cost-effectively. Thanks to the change system, the high disposal costs are eliminated – used filters can be returned to HYDAC. Because of the use of the passivation fluid, the filter system can be used for all types of powder material. The powder material can even be changed without changing the filter.

Customer quote:

“The long service life of the filters and the simplicity of the filter change and the disposal fully convinced us. We are now going to retrofit an existing machine with the FlushPACK.”

Your advantages with the FlushPACK laser flue gas filtration solution

Occupation safety

Occupational health and safety improved, thanks to patented passivation of the reactive dirt, elimination of the need for additional personal protective equipment (PPE) and prevention of fire hazard when filters are changed.


Simple spent filter reutilisation, thanks to reutilisation concept via HYDAC.


Cost reduction in operation, thanks to long service lives, rapid and safe filter change and elimination of additional disposal costs.

Improved component quality, thanks to stable process parameters (constantly low temperatures and high gas cleanliness) and intelligent cleaning cycles.


Filters can be used for any powder material, thanks to material-independent filtration concept.

We are always happy to give advice!

Contact our HYDAC expert team and arrange your consultation appointment today!

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