Dough Sheeter

In the process of cracker manufacturing, The dough is fed into several sets of rolls to form a sheet. The feeder itself consists of 2 to 4 rolls which draw the dough from a hopper and forms a thick sheet that is then fed to other rolls. The feeder shown above has 3 rolls. The purpose of the 3rd roll (and 4th roll if there is one) is to pressurize the dough within the rolls which helps maintain dough uniformity. Here we can see the high pressure region (in orange and red) within the 3 rolls. If there is variation in the pressure or in the dough thickness or speed, the entire process is affected, yielding poor uniformity in the final product.

In this study, it was desired to control the pressure within the rolls while also controlling the speed and thickness of the dough sheet. All of these parameters are strongly interrelated ("coupled"). Using the developed model, we were able to determine the roll speed and gap settings needed to "uncouple" these parameters, thus enabling tighter control of the whole process.

One aspect of the design of this feeder that was not known prior to the development of the simulation model was that there were recirculation zones that develop within the feed hopper. In these recirculation zones, the dough tends to simply go around and around. The dough in these regions will generally stay there for a very long time (some is always leaving and some entering due to normal variation).

Dough is a very dynamic material. There are chemical and physical changes that are taking place due to enzymes, yeast, leavening, etc., that change the properties of the dough, and thus the properties of the product. These changes, if not controlled, will lead to off-color or off-flavor product, poor texture, inadequate rising and a host of other problems. In this case, a redesign of the hopper is needed to help ensure that the product is always what the manufacture wants it to be.