Plastic Film Slitter Rewinder Machine

As a type of packaging machinery frequently applied in pre-press and post-press production, plastic film slitter rewinder machine can divide the film materials into strands whose widths are determined by requirements. Pre-press slitter is mainly used to cut raw film materials to meet the demands of packaging manufacturers. The post-press slitting machines is the most widely used after printing and compounding process, the printed composite film materials with fixed width and multiple patterns are cut into finished rolls for the use of following automatic packaging and bag-making procedure.

Main parts of plastic film slitting machine

In figure 1, a conventional plastic slitter rewinder consists of several sections including unwinding roller, rewinding roller, traction roller, position roller, tension roller, knife slitting system, braking system, hydraulic drive system, etc.

In winding process , web tension will be variable due to many factors including changes in roll diameter, vibration, inertia, etc. Unwinding mechanism adopts magnetic powder brake for unreeling tension system, cooperate with pressure probe and the automatic tension control device to form a closed-loop control system, and realize tension detection and control via changing unwinding speed automatically.

When the strain is applied to the plastic material, it deforms elastically proportional to the force applied. In the elastic range, it will return back to its original shape when the load is removed. However, once beyond the elastic region, the plastic film can no longer take the strain and it will be destroyed. Therefore, we must setup different tension ranges for each material to ensure smooth running and easy for slitting.

Razor cutting method employs razor blades slit in a grooved roll driven by a servo motor, blades are held in position and keep stationary while a sheet of plastic material is drawn over the slitter blade. Paper cores should be fixed on the rewind roller before slitting, to prevent movement or dislocation during the cutting process.

Rewinding station is the use of the double roll surface rewinding, also called contact rewinding or friction rewinding. The rewind rollers are pressed on the tracking roller via hydraulic control. The web material is transported onto the reel by the surface contact force between the drive roller and double drum rollers. The plastic film which has been divided into desired width is perfectly wound on the winding roll utill the slitting process is done.

High performance plastic material slitter rewinder

In flexible packaging industry, each plastic material has its own specific properties such as barrier, transparency, etc. Due to high requests on the surface quality of these plastic films, the performance level of slitting machines becomes especially important. On the other hand, automatic packaging equipments are more and more used in packaging industry, digital automation control system make it easy for operation and troubleshooting, and the machines can be linked together to create a production line, greatly reduce labor cost or mechanical handling.

High performance cutting machine should consider both characteristics of materials and machine parameter, in order to gain the best cutting results. The efficiency of plastic slitting machine is not only related to slitting speed, but also related to yield, downtime, stability, etc. Low yield will cause not only low working efficiency of the whole machinery but also also rise in cost of production. Downtime is any period of time when a slitter rewinder is not in production such as blade positioning, cutter changing, web material connecting, roll alternation, etc. If the downtime is too long, it’s meaningless to simply increase the speed of slitting machines. Therefore, the efficiency of plastic slitter is a comprehensive concept, LEAP has engineeres with over 10 years of experience, and we can design and manufacture quality plastic slitter rewinder machine with high efficiency and slitting accuracy.