ENGEL gasmelt/watermelt

The alternative solution for thick-section parts and good surface finishes

Shapes that lie comfortably in your hand, absolute dimensional precision, surface finishes that leave absolutely nothing o be desired – these are the qualities that decisively influence  the success of a new product. Being able to combine design and function without having to pay heed to the limits imposed by the material has a twofold advantage: new materials can be utilized and, by the same token, new products can be developed – for the ultimate benefit of the  user. Technologies for achieving optimum surface quality of the moulded part by applying, with either a fluid, a constant internal pressure during the critical holding and cooling phases considerably broaden the scope of possible applications for plastic parts. The technologies developed by ENGEL to this end are called gasmelt and watermelt.

The process

The gasmelt and watermelt processes offered by ENGEL permit the moulding of parts with thicker walls and sections than normally permitted by the material used. With both processes, a separate medium is injected into the mould during the mould filling operation. This medium generates pressure inside the part so as to ensure that the shrinkage of the material which normally occurs during the cooling phase cannot pull the surfaces of the parts away from the walls of the mould cavity and cause sink marks and other surface blemishes.

The pressure medium used is either nitrogen or water. Nitrogen   is used in cases where chemical inertness is a prime consideration; water is used in cases where cycle time, heat transfer and long melt flow-pathes take priority. These pressure media do not just serve to compensate shrinkage but also, and equally importantly, to reduce wall thickness by producing hollow areas inside the parts. Reducing wall thickness also reduces the amount of material used, and this in turn means a reduction in cooling time. 

>> For detailed information on  ENGEL watermelt and ENGEL gasmelt please click here (pdf)