Burr is a common problem encountered in TPU injection products. A burr (also known as a “flash”) is an unwanted raised edge or small piece of TPU material left in a part after a injection manufacturing process. Burrs not only disfeature the appearance of plastic parts but also affect it’s properties.

How to analysis and solve the burrs problem during TPU injection process. Burrs of a TPU injection part can occur for several reasons-from raw material problems, injection molding machine problems, improper set-up of injection molding machine to the mould. Improper handling in the process and material all can cause the flash in the TPU injection parts. so recognizing the cause of burrs when it is occurring can point you in the right direction. It is necessary to proceed from obvious and easy to unconspicuous and difficult when estimate the cause of burrs. Below four sequential steps for your reference.

1.Check the material: check whether the raw materials are thoroughly dried, whether they are mixed with impurities, whether different types of raw materials are mixed, and if the viscosity of the raw materials is affected;

2.Check the pressure and injection speed of the machine: Correctly adjust the pressure control system of the injection molding machine and the injection speed to match the clamping force;

3.Check the mould and vent,runner of the injection machine: Whether the mould are worn, whether the vent is blocked, and whether the runner design is reasonable;

4.Check the parts of the injection machine: whether there is deviation in the parallelism between the injection molding machine templates, whether the force distribution of the template tie rods is uniform, whether the screw check ring and the melt barrel are worn out.