Deflashing Machines

Parts are conveyed through the deflashing machine on a continuos stainless steelwire mesh belt, which has large enough mesh to allow the deflashing media to pass easily through it. Two turbine impeller wheels, one in the upper part of the deflashing chamber and one located below the conveyor belt, propell Nylon grit at high speed toward the parts, providing simultaneous media impact on flash located on both upper and lower surfaces; lateral impact is also achieved as a byeffect. The parts travel on the band at the desired speed from the loading area through the deflashing chamber and out to the discharge point.

Media velocity is controlled by vari-speed drives of the turbines. Media size is available from 0,5 to 2 mm in either cubic or cylindrical shape. The wire mesh conveyor belt has a vari-speed drive to provide the required deflashing residence time for parts passing through the chamber.

Residual dust and media left in recesses of the parts are removed by air-jets positioned above the belt, outside the deflashing chamber, near the exit point. If all the media cannot be removed by these air-jets, the mouldings can be down-loaded into an in-line rotating cleaning drum, provided that they will not be damaged in the process.

To minimize operational noise and keep media loss to pratically zero, retainer barriers have been built into the machine at both entry and exit ends; these two issues have been an ongoing problem with conveyor deflashing machines previously available to industry.

A negative pressure, self-cleaning dust collector removes dust from the deflashing chamber. The media that collects at the bottom is conveyed by an auger screws system and recycled back to the upper and lower turbines. Large pieces of flash are continuously separated from the media through an automatic sieve and discharged to the outside of the machine. To prevent the build-up of static charges on the media and on the parts, anti-static liquid is automatically metered into the grit as it is propelled through the turbines. Mouldings can be placed by hand or by robot onto the wire mesh conveyor belt at the “entrance” of the machine. After being deflashed, the parts are discharged through a covered slide-chute.

On the COMPACT the grit recovery compartment is fix at 90° with the deflashing drum. The COMPACT requires the minimum space and fits easily into a production unit together with moulding machines. This minimizes manpower and internal transports for the best economy.

The feeding conveyor has a ribbed belt that lifts the parts in bulk into the loading hopper. It is completely enclosed and its speed is continuously adjustable.

From the hopper the parts are transferred to the deflashing chamber by an adjustable linear vibrator that drives them into the rotating drum. This is cylindrical, made out of stainless steel net, and slopes forward in order to move slowly the parts ahead while rotating; their movement can be affected by rubber pegs that one can fix in the net on the base of empirical observations. While the parts roll and tumble in the drum, the grit stream from the impeller hits them on the whole surface. This method employs only 20-30% of the power required by a pneumatic system.

The drum can rotate continuously, at intermittence and even with reversal, setting the relevant timer controls on the electric cabinet. The grit and the large flashes gather at the chamber bottom. The small flashes and powders are sucked away through a rotating self cleaning stainless steel filter to the air filter with dust collector. The grit is depurated of the flash pieces and moved up again to the impeller by an auger system. The grit stream can be given different directions over the deflashing drum and the impeller speed can be adjusted continuously as the drive is a frequency converter.

A very tiny quantity of surfactant chemical in water solution is introduced at regular intervals in the impeller housing by an automatic dosing pump; this maintains the necessary humidity to avoid electrostatic charges and keep the granules from sticking to the parts surfaces. Parts get out perfectly clean from dust.

From the hopper the parts are transferred to the deflashing chamber by an adjustable linear vibrator that drives them into the rotating drum. This is cylindrical, made out of stainless steel net, and slopes forward in order to move slowly the parts ahead while rotating; their movement can be affected by rubber pegs that one can fix in the net on the base of empirical observations. While the parts roll and tumble in the drum, the grit stream from the impeller hits them on the whole surface. This method employs only 20-30% of the power required by a pneumatic system.

The drum can rotate continuously, at intermittence and even with reversal, setting the relevant timer controls on the electric cabinet. The grit and the large flashes gather at the chamber bottom. The small flashes and powders are sucked away through a rotating self cleaning stainless steel filter to the air filter with dust collector. The grit is depurated of the flash pieces and moved up again to the impeller by an auger system. The grit stream can be given different directions over the deflashing drum and the impeller speed can be adjusted continuously as the drive is a frequency converter.

A very tiny quantity of surfactant chemical in water solution is introduced at regular intervals in the impeller housing by an automatic dosing pump; this maintains the necessary humidity to avoid electrostatic charges and keep the granules from sticking to the parts surfaces. Parts get out perfectly clean from dust.

The grit removal compartment is also equipped with a stainless net rotary drum; the parts get reed of the grit granules and proceed to the exit, while the incoming air stream traps in the granules that fall down to be recycled.