The Application

Additive production processes already have many uses when it comes to manufacturing prototypes, mock-up and exhibition models and spare parts in very small series. As product development and time-to-market periods keep getting shorter, 3D printing is also increasingly becoming a major component in the area of rapid manufacturing. One specific method used in additive production is selective laser melting (SLM). This involves fine layers of metal powder being applied to the powder bed and melted by lasers. This process is carried out in a protective gas atmosphere as the laser smoke particles that are created are highly charged and reactive. They must not under any circumstances come into contact with oxygen as this would pose a fire hazard. 


The gas filtration has to meet very high requirements in order to remove these particles. As a filter specialist, HYDAC has decided to tackle this exceptional challenge and has developed an innovative filter system: the FlushPACK.

HYDAC Flushpack

FlushPACK stands for Flushing, Passivating And Cleaning Kit – an innovative filter system from HYDAC. The unique concept, specially developed for laser welding fume filtration in additive production processes, impresses with its passivation of hazardous welding fume particles. This involves the respirable and highly reactive particles being wetted with a special passivation fluid, which prevents them from being released into the ambient air.

The Special Features of the System

Improved occupational health and safety

Previous filter concepts

  • Filter change with complete personal protective equipment (PPE) incl. respiratory protection mask
  • Respirable dry particles can be released into the ambient air → health risk
  • Fire hazard


  • Patented passivation of the reactive dirt
  • Need for additional personal protective equipment (PPE) eliminated 
  • Prevention of fire hazard when filters are changed

Simple spent filter reutilisation

Previous filter concepts


  • Previous disposal costs for some filter concepts up to €2,000 per year per printer (lab sludge)





  • Used filters are returned to HYDAC. We take care of the reutilisation!
  • No additional disposal costs


Cost reduction in operation

Previous filter concepts

  • High costs as maintenance intervals short
  • High disposal costs


  • Long service lives, up to 1 year
  • Rapid and safe filter change in less than 30 minutes
  • No additional disposal costs

Improved component quality

Previous filter concepts

Filters without backflush cause the pump power, and thus the gas temperature, to increase → bad print quality



High print quality, thanks to constantly low temperatures and high gas cleanliness

Filters can be used universally

Previous filter concepts

Filter type may need to be adjusted to suit the powder material



  • Filter system functions independently of the powder materials used
  • Changing the powder material does not pose a problem
  • FlushPACK can be retrofitted at any later date without any change to the material



  • Health and safety at work improved, thanks to
    • patented passivation of the reactive dirt
    • eliminating the need for additional personal protective equipment (PPE) 
    • avoiding the fire hazard when filters are changed


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


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


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


  • Filters can be used for any powder material, thanks to
    • special filtration concept


  • Improved profitability and product quality