Why plastic belt of unequal thickness would happen?

Why plastic belt of unequal thickness would happen? A high thickness. That is, a raw material melting state not average, resulting in the density and hardness is not the same, in the process of extrusion is prone to the status of the uneven thickness; To avoid this kind of situation, to do well in the process of raw materials processing time and temperature control, ensure the melting of the raw materials are exactly the same. Another is the problem of machine, film extrusion machine production pressure can't keep stable or feed port and discharging port is the presence of foreign body, will result in a high thickness uneven problems. In this case, must complete the film extrusion machine cleaning and maintenance work, ensure the constant pressure, the working area clean, not affect the quality of the product.