Ultra­sonic Net Sealing Machine GKV 6000

The GKV 6000 was developed for pack­aging small products in the low weight range and optimized for pro­cessing standard-sized fat balls / suet balls. The func­tional scope of this net pack­aging machine has been reduced to the bare essen­tials, enabling the most cost-effi­cient pack­aging of identical products. For example, this machine fea­tures a pneu­matic net take-off system, which can be manually adjusted in length. In addition, the wear com­ponents have been reduced to a minimum and great importance has been attached to ease of main­tenance, so that wear parts can usually be replaced by the machine operator without the need for a service intervention. 

GKV 6000-4 Ultraschall Netzmaschine für Netzverpackungen ohne Metallclip
Ultra­sonic Net Sealing — A Gekupack® Invention

Global market leader in the area of net sealing machines

With the imple­ment­ation of ultra­sonic welding tech­nology in a new gen­er­ation of net pack­aging machines, we at Gekupack® suc­ceeded as early as 1994 in taking a step towards species-pure pack­aging that has received much attention from the industry. The ultra­sonic net sealing machines not only elim­inate the use of metal as sealing material (clip, clip wire) when sealing the PE net bags (other materials such as PLA are also com­patible), but also seal the packages com­pletely and reliably without any addi­tional foreign material. The single-species net pack­aging pro­duced in this way is thus more sus­tainable than con­ven­tional pack­aging in many respects and also offers sig­ni­ficant eco­nomic advantages.

  • Netting is way more resource-saving than film material.
  • The species-pure packings exhibit a sig­ni­fic­antly higher recyc­lab­ility than the cor­res­ponding bags with wire clips.
  • Our machines feature minimal wear and tear, as the number of wearing parts com­pared to con­ven­tional net clipping machines is drastically reduced to only 3 real wear parts in total.
  • The wear com­ponents (e.g. the net cutting knife) are easy to replace due to a speacial pull out gath­ering unit without the need of a service call.

Seit der Erfindung der Net­z­sch­weiß­technik auf Basis der Ultras­chall­tech­no­logie haben wir unsere Maschinen kontinu­ierlich weit­er­entwickelt – auch unter enger Ein­bindung unserer Kunden. Inzwischen sind die Net­z­sch­weißmaschinen nicht nur wesentlich eff­iz­ienter als dies zu Beginn der Fall war, was mitunter auch auf anderen tech­no­lo­gischen Erfolgen und einge­setzten Kom­pon­enten beruht, sie sind auch kom­patibel mit diversen nach­haltigen Net­zma­ter­i­alien (z. B. kom­posti­erbarem Netz). Here you can learn more about pos­sible pack­aging types and materials.

This tech­nique is used in pack­aging chunky goods such as garlic, con­fec­tionery, cheese snacks, peanuts, fat balls, lemons, garlic or onions, potatoes, as well as hardware and toys, such as LEGO bricks, foot­balls, golf balls, etc.. 

he high per­formance and reli­ab­ility of our ultra­sonic net sealing machines, com­bined with the com­petence and decades of exper­ience in engin­eering and man­u­fac­turing not only the sealing machines them­selves, but also all the necessary addi­tional com­ponents to com­plete entire pack­aging systems, have led to the out­standing repu­tation of Gekupack® and have made GK Indus­tries the global market leader in this field. Our value pro­pos­ition is rounded off by an excellent spare parts avail­ab­ility and supply worldwide.

Func­tion­ality and the­or­etical background 

How does ultra­sonic net sealing work?

Ultra­sonic sealing has become a popular method in the pack­aging industry for pro­ducing repro­du­cible packs from securely and effi­ciently welded netting. Ultra­sonic sealing is a welding process based on the use of ultra­sonic waves and, according to DIN 8580, is one of the main group 4 joining tech­niques. In this process, the molecules or atoms con­tained in the materials to be sealed are set in vibration by means of high-fre­quency oscil­la­tions in the ultra­sonic range (>20 kHz). The res­ulting friction effect gen­erates heat, which causes the materials to fuse together and creates a strong bond.


An ultra­sonic gen­erator ini­tially gen­erates elec­trical oscil­la­tions (elec­trical energy) in the high-fre­quency range. Via a hf-cable these ini­tially still elec­trical vibra­tions are applied to the con­verter (also: ultra­sonic head), where the elec­trical energy is con­verted into mech­anical vibra­tions using the piezo­electric effect. The con­verter con­tains special PZT ceramics that change in length when a voltage is applied. Thus, the applied high-fre­quency AC voltage causes the ceramics to altern­ately elongate and shorten, which results in oscil­la­tions. The amp­litude of the mech­anical oscil­lation is then trans­mitted to an ultra­sonic booster, which is screwed to the con­verter, and gets amp­lified or reduced. The amp­li­fic­ation factor here depends on the mesh to be welded (such as the amount/volume of netting and the material or the spe­cific energy absorption of the netting). The oscil­lation movement thus obtained is trans­mitted via the booster to the ultra­sonic sono­trode , which then gets pressed against a coun­terpart anvil with the netting between both parts. Under pressure of up to 0.7 MPa, the mech­anical oscil­la­tions are thus trans­mitted to the work­piece (the netting). For reliable welding to function properly, it is essential that the entire oscil­lating system is in res­onance and that the fre­quency and amp­litude are adapted to the packing material to be welded.

Working prin­ciple of the GKV 6000

Highest output rates at a low price

The products to be packaged are fed to the ultra­sonic net sealing machine from above via a ver­tically running plastic net tube on which the extruded netting is loaded. The GKV 6000’s net take-off is pneu­mat­ically operated with pressed-on brush pro­files that are adapted to the respective outer tube diameter.


Before the welding begins, the mesh is gathered together by an 8‑finger gath­ering system. Sub­sequently, the ultra­sonic process (see Func­tional and the­or­etical back­ground) is triggered. The sealing energy used and the sealing tem­per­atures occurring are mon­itored during the entire process and can get adjusted auto­mat­ically.This is a decisive advantage, espe­cially in the case of changes during the start-up phase of a pro­duction shift or in the case of changing, non-con­stant ambient tem­per­atures. After a short holding time to cure the weld, the fin­ished pack is seperated from the net tube end (the start of the next pack) via a inde­pend­ently con­trolled pneu­matic net knife. After cutting in the middle of the welds, the shirring unit then opens and releases the fin­ished pack, which usually passes via an exit chute onto a dis­charge con­veyor. While the shirring system is still closed and the sealing process is active, the next fat ball is fed to the net pack­aging machine.


As soon as the net on the active filling tubes is used up, a auto­matic tube change is per­formed. A machine operator can then fill the empty net tube with new net without this res­ulting in machine downtime. The par­tic­u­larly eco­nomical net tubes also allow a large stock of filled net tubes to be prepared.