Make screen separation faster and easier with solutions from Vibra FinishJune 29, 2016 REDWIRE is news you can use from leading suppliers. Powered by FRASERS.
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There are several ways to reduce the time needed for degating and separating die-castings. Vibra Finish, a Mississauga, Ont.-based finishing equipment manufacturer, provides some information on its website on how to make the most of parts screening processes.
Modifying a horizontal barrel tumbler
One common degating method is to tumble in an open mouth oblique barrel before screen separating the parts. However, dealing with small pieces in a large barrel results in a densely packed load with poor flow properties, and too much time is spent moving and screening the parts. To solve this problem, a standard horizontal enclosed barrel tumbler can be altered by adding an extra large door opening with a screen instead of a solid door. This allows the parts to fall out as the barrel rotates, and leaves all the gates in the barrel. The parts are degated, deflashed and separated in one step.
Oblique tilting tumblers
Oblique tilting tumblers can be similarly modified to improve the parts screening process by using locks to clamp a screen door to the mouth of the barrel. While horizontal barrels are superior because they are faster and more thorough, this is a good solution for taking advantage of existing tilt tumblers.
There are a variety of machines designed for separation operations. For example, one type uses a set of counter-rotating, angled rollers with a gap for parts to fall through. These systems work great for small parts but cannot handle a large volume.
Another type of separation method requires the use of drop-off screens. Drop-off screens can be used to handle large parts in any volume. These vibrating screens allow scrap to fall through while they feed the parts to the far end where they drop off into catch pans. Drop-off screens are superior to batch screens because the parts will not cover the screen holes, and they are well suited for incorporating into an automated system.
Getting tough-to-reach spots
Sometimes self-tumbling or tumbling parts in media is not enough to remove flash from specific areas such as a tight crevice. In these situations, the parts can be run in a screen basket in a sandblaster using glass shot. This will remove flash from any area with no danger of crushing fragile parts.
Visit the Vibra Finish website for more information on screen separation solutions.