The untimed bottom feed on your flamesealer relies on the friction of the rubber folder/gluer feed belts to draw and propel the carton blanks into the folder/gluer. Under the ever changing feed pile height, these feed belts expand or compress. As blanks are fed off the bottom of the pile, the weight on the feed belt decreases and the belts expand. This decreases the gap between the feed belts and the feed gate which causes skips to occur. Conversely, when the attendant places too many blanks in the folder/gluer feed hopper, the feed belts compress, increasing the gap between the feed belts and the feed gate, which causes doubles to be fed.

These skips and doubles can twist and jam in the flamesealer causing scrap, machine stoppages and other productivity delays. If a double makes it through to the folder/gluer it will most likely upset the flow of blanks into the stacker.

Typically straight-line cartons are run at very high production rates and stoppages can be dramatic. Jams tend to be worse because of the rate at which the cartons are passing through the flamesealer.
A high speed jam will usually take a longer time to clear and may even cause physical damage to the machine. Scrap rates tend to be higher and delays to productivity longer.

A prefeeder delivers separated blanks to the flamesealer feed hopper. There is no need for them to manually precondition or fan the blanks prior to their insertion into the feed box. The operator simply sets a pile height sensor in the flamesealer feed at the optimum height. The drive and stack height sensor is infinitely variable and therefore incrementally speed up or slow down to maintain a precise pile height in the gluer feed. A prefeeder delivers cartons to the flamesealer feed hopper in a continuous, uninterrupted, shingled stream while maintaining the proper pile height to within fractions of an inch. Change the speed of the gluer and the prefeeder responds accordingly, either speeding up or slowing down to maintain that critical pile depth.