Is there somebody who has experience with injection of Bayblend T45 PG? We have problem that we have to clean mold frequently to avoid mold surface damage and welding lines.

Hi,Jiri
Bayblend T45 PC/ABS material must be with good steel and hardness, if you have to clean mold frequently could be the steel problem, you have to using SS steel and with Nickel inside.such as S136 Steel with hardness, or 1.2344 hardness.
Also the mold temperature very important, normally need 80-120 degree according to the thinkness of parts wall. if the temperaute too lower will cause the welding lines.

Hi Steven, thank you very much for quick reaction. Your answer is very interesting. Unfortunately I cannot see all your comment. May be there is something wrong w/ my web broser. I can see and read only till "...or 1.2344 hardness."
May I ask you kindly to copy paste remaininmg part of comment to new comment. Thank you for help and understanding. Have a nice day.

Hi Jiri,What kind of steel the mold is? Bayblend T45 PG PC/ABC is a common material which shouldn't damage mold surface. Low volume of production, P20 HRC28~32 is enough, from the weld line issue, I think the venting of the mold is not good,please check and improve the venting.

For weld lines,can try higher mold temperature on cavity/core side to improve.For high volume mass production,you can use harden steel (HRC48~52). How the damage of mold surface look like? Usually, just POM or Glass Fillet will have damage problem on mold surface. For safety, pls sure you're using the actual Bayblend T45 PG PC/ABS.

Steven Lei • Hi,Jiri
Bayblend T45 PC/ABS material must be with good steel and hardness, if you have to clean mold frequently could be the steel problem, you have to using SS steel and with Nickel inside.such as S136 Steel with hardness, or 1.2344 hardness.
Also the mold temperature very important, normally need 80-120 degree according to the thinkness of parts wall. if the temperaute too lower will cause the welding lines.

Hi Steven, I am trying to get info regarding steel used for the mold. Anyhow, I will remember your recommendation regarding steel. Normally should be used steel recommended by you 1.2344 but we never know what kind of steel is really used by mold maker. :-( Regarding mold temperature, if we use higher temperature than 75°C than we have problem w/ sink marks. If the temperature is lower (about 60°C) than sink marks disappeared but very small welding lines are visible. Anyhow, thank you very much for your recommendations. Have a nice day.

Hi Aaron, I have checked the material and I can confirme that it is T45 PG. Surface damage is in area of air ventilation channel. It is probably caused by material oxidation due to high tempertaure and pressure. Now I am checking info about steel used for the mold. I will keep you informed.

Hi Jiri
Check moisture after drying it should be less than .02%. Check dew point of the deccicant dryer. As material is PC/ABS it is very sensitive hydrolysis inturn degradation. Check gate size it may be too small inturn shear induced degradation. Increase size of the vents specially at weld line area. My estimation is that material is degrading (depolymerization) & significant gas formation which comes together at weld line area. You can can call me if you need further assistance +1-248-821-5478.
Boney Mathew

Hi Boney, thnk you very much for your comments. I will check drying conditions. I was explined that it is OK, but finally it would be better to check it more in detail. There is fan gate 5 x 3 mm but I will try to increase it for sure. All experiences we got so far show us that your theory it correct. We have already improved cavity polishing ans slightly changed injection speed (very slow filling) and now it looks quite better. I will keep you informed about result once we improve ir vent and increase gate. Thank you very much again for our ideas for improvement and wih you nice day.

Jiri dostal: Its not clear as to what sort of marks/residues you have in the mold to clean frequently and also to protect the parting lines. If you have very small fibers gathering in the mold after a few shots which stick to the cavity/core, then the problem could be that compounding of the 2 materials is improper, or the heats are too low which make the 2 materials not binding together properly. As for improper steel, the argument may not be quite relevant since after you clean the mold the shots become all right. If the mold steel was not proper you may after some time have permanent damage of the parting lines, or you may have excessive compression of mating area.
If you could specifically pin point the problem, maybe a better understanding would be possible.

Dear Haideruddin, I am very sorry for late reaction. I was traveling a lot last few weeks and take personal holiday for few days. Thank you very much for your interesting and valuable comments. Our experience so far is that we have to clean cavity surface at least once per shift. If not, than some material (high probably some oxygen from resin burning) is sticking on cavity surface and in two days running it makes surface matt. Due to that start problems w/ surface of the part (not enough glossy, something which looks like welding line, small dots,...). All these defects are even more visible after chrome plating. As the next step we will try to apply some surface treatment of the cavity side. It seems that oxygens coming from burning of this resin are very aggressive and we hope that surface treatment can help us also to increase mold life time. Thank you very much again and wish you nice day.