Posted by Srimay Basu (195.229.185.188) on September 06, 2007 at 04:12:18:
In Reply to: Quality problems on surface posted by Alex on September 03, 2007 at 15:39:17:
: We are using anodised aluminium extrusion parts as decorative elements on appliances. Parts are brushed and then anodized to get "stainless steel" like color (size is app. 30 x 90 cm). We noticed that after a few weeks of keeping products packaged in warehouse, we get "white" irregular areas on about 30% of the products. Microscope pictures show small bubbles just below the surface in anodised level (not in aluminium). We can not observe this marks - areas on fresh from production pieces. Any idea what might cause this problem?
Hi,
The description of the defect is not very clear. For this reason I may have to ask you to do the followings :
- Strip off the anodic film very carefully and then examine the surface again; whether, or not the metal surface carry any scurr marks on those areas!
- Check the sealing parameters; I presume you must be using hot seal, especially the temperature, time, water pH and conductivity.
- If you are using wrapping paper in your packing then check the paper quality, mainly the alkalinity level.
It would be better if you can post the photograph of the defect as well.
I'm sure this will lead us to a conclusion.
Thanks & regards,
S. Basu