Miss feeds and Doubled Sheets are typically caused by inadequate sheet separation or static electricity.
Late model presses offer static eliminators that discharge the negative ions which dissapates the clinging effect of static build up in sheets and allows sheets to separate properly for high speed production.
If your press does not have a static eliminator you can add an aftermarket device or use spray-on type chemical de-ionizers.
If your press does not have back-air blowers, you can devise your own by tapping into the exhaust/blower hose of the press compressor and directing the air into the back edges of the pile.
If you do not have the necessary expertise to develope your own back-air blowers, PressSavers offers several models which are listed in the products under 'Kompac upgrades' by press manufacturers.
Back-air blowers introduce additional air into the back edges of the sheets helping to lift top sheets away from pile on a cushion of air to aid in the feeding of troublesome stocks at high production speeds.
Another unique and helpful feeder tool are 'telescoping' Bigfoot Sucker Tubes.
Bigfoot Sucker Tubes are powered by press vacuuum and automatically desend 1/3 of an inch lower/beyond the level of fixed sucker tubes allowing you to operate the feed table at a lower setting.
Operating feed table at lower setting allows air from the front and rear air-blowers to better work and separate top sheets more effectively.
Bigfeet telescoping sucker tubes are especially beneficial when feeding at top speeds as they do not pound-down onto the top of the sheets as do fixed sucker tubes.
With fixed tubes the top sheet is pressed down against the second sheet before lifting, developing suction 'between' the backside of top sheet and front side of second sheet causing them to feed as a unit.
Bigfoot telescoping sucker tubes stop desending upon enitial sheet contact, immediately sucking up the top sheet and retracting back to standard tube length before feeding sheets into press.
An ideal feeding upgrade/package for portrait feed presses is a set of Bigfoot telescoping sucker tubes and the back-air blower system.
With this combination you can run with the feed table 50% lower than normal, and the top sheets (especially with coated stocks) float up and away from seconds sheet on cushion of air for high speed production without miss-feeds or doubles.
