Vacuum generation Improving injection quality with vacuumejet units
The new vacuumjet units developed by Cumsa are designed to create a vacuum by pulling the air out of the cavity before and during the injection process.
With a performance of up to -900 mbar, the new vacuumjet units from Cumsa are ideally suited for the creation of a vacuum in the injection cavity. The devices feature a 60 L per minute suction capacity, and eliminate moulding problems caused by gas stuck in the mould, the company claims. They also come up with the option to blow-off the injection gases through the same air channels which cleans the vents to prevent clogging, while helping to eject the parts after every cycle.
The vacuum created inside the cavity improves the overall quality of the part, including improved solidity, faster filling time and reducing flashing. The devices use much less energy than vacuum pumps, the company states. They can be combined with the LV (Laminar Gas Outlet) and VD (Double Valve) gas evacuation systems to increase and optimize the generation of vacuum and ensuing blowing of the plastic part.
Both units include a double inlet of pressurized air: Ø8 for the vacuum channel and Ø6 for the blowing channel. According to the company, the new VB-units are the only system on the market that features a single outlet through which the system pulls / blows the air. The units can be used as a stand-alone solution or in conjunction with other Cumsa vacuum devices, such as VG or VM to get more pulling force, or with the VJ or SV if vacuum valve can suit in the cavity.
The SV-model features a selector placed in the backside of the device, which permits the user to choose between four different vacuum levels, afterwards it will repeat for every cycle without continuous manipulation. It integrates electronics and a solenoid valve to manage the opening and closing of the Vacuum Valve (VV) automatically during the injection process.