Adjustment method of plastic pellet cutter blade

The adjustment of the plastic pellet cutter blade is a key step in ensuring uniform particle size, improving production efficiency, and extending tool life. Improper adjustment can lead to uneven cutting, continuous cutting, long strips, or premature tool wear, affecting the overall quality of granulation.

Key points and steps of core adjustment

Adjust the gap between the cutting blade and the bottom blade (fixed blade)

The gap between the cutting blade (moving blade) and the bottom blade (fixed blade) should be controlled at around 0.1mm, which is the basis for ensuring sharp cutting and regular particle size.

Excessive gap: incomplete cutting, prone to long strips or continuous particles;

Too small gap: increases friction, leading to tool overheating, accelerated wear, and even blade breakage.

Adjustment method: Rotate the handwheel on the upper part of the machine, move the upper rolling cutter bearing seat, and fine tune the relative position of the upper and lower rolling cutters or swinging cutters with the bottom cutter.

Ensure the flatness and perpendicularity of the blade

The cutting edge of the blade must be kept perpendicular to the template granulation belt, otherwise it will cause uneven local stress, leading to tool cushioning, tool retraction, and even high torque shutdown.

Use a dial gauge for testing: Hold the testing tool on the spindle, rotate the disc, record the data deviation when each knife contacts the granulation belt, and adjust it to the minimum error.

If there are no grinding marks or uneven cutting on some blades, the perpendicularity between the spindle and the template needs to be recalibrated.

Control the feed pressure and tool pressure settings

The feed air pressure should be set according to the equipment model, with an empirical value of 0.24 MPa, used for initial feed during sharpening or normal cutting.

Low blade pressure: The cutting blade cannot adhere tightly to the template, resulting in incomplete cutting of particles;

Excessive knife pressure: Increasing the impact load can easily cause a chain stop of knife retraction.

It is recommended to use pneumatic balancing technology for the granulator to make the cutting blade more evenly stressed and improve operational stability.

Regularly inspect and maintain the condition of cutting tools

Visual inspection: Check for any gaps, curled edges, or material buildup on the moving and fixed blades, and promptly clean or replace them.

Preventive replacement: Equip each pellet cutter with a set of spare blades with pre adjusted clearances for quick replacement and reduced downtime.

Suggestion for grinding: Use full tooth grinding technology to maintain the original tooth angle and avoid reducing the outer diameter and lifespan caused by only grinding the back of the blade.

Matching process parameters to optimize cutting effect

Matching the cutter speed with the host speed: It is recommended that the cutter line speed be 10% -20% faster than the melt extrusion speed to avoid particle stretching deformation.

Cooling system coordination: The air-cooled or water-cooled system needs to operate stably, control the tool temperature within a reasonable range (recommended cooling water temperature is 10-25 ℃), and prevent overheating and sticking of materials.

Grinding operation process (taking standard underwater granulator as an example)

After confirming that the resin is clean, fill the template with resin for grinding;

Clean the surface of the template, apply silicone oil, close the mold and lock the trolley;

Cut the granulation water to a large cycle, start the motor to feed and sharpen the knife, with a grinding amount of about 0.15mm;

After grinding, drain the water and check if there are continuous grinding marks on each blade;

If the standard is not met, the equipment will be ground or recalibrated.