White lines on aluminum profiles and their causes 

                                                                         -----------aluminium extrusion press maintenance tips

In aluminum profile extrusion production process, some time there are some white lines on the aluminium profile surface, it will affect the beauty of aluminium extrusion profiles. How to avoid this problem? What is the cause? How to miantain the aluminum extrusion machine? The method is following:

There are two kinds of white line: transverse lines and vertical lines
1. Transverse lines, if the lines (the lines are deep) show on four faces of profiles, check the plunger pump (ram pump) displacement, the press pressure may be not stable. If the ram pump is all right, then check the prefill valve.  Other aluminum extrusion factory said, the dummy block may cause this problem, but we have not met this problem at our client’s factories.
If the white line (the lines are light) is on the bottom side of aluminium profile, that may cause by the handing table system. When the run-out saw cut the aluminium profile, the table may shake and aluminum profiles may lightly hit the handing table. So adjust the balance of handing table system.

2. Vertical white lines, check the billet temperature, then the die temperture and surface quality, and then aluminium billet quality.

Hope it can help you to fix your aluminium extrusion machine .

This is original article, edited by Judy Wei. Please indicate the source if you reprint.