Seeds Problem in Glass

Sounds like it might be getting too hot....

http://www.sha.org/bottle/body.htm#Bubbles%20in%20the%20glass

Are the both lines being ran from the same batch? If not are the batches being mixed by the same equipment? At the posted volume I would think not. So I would first check the equipment that is mixing the batch. The agent added to the glass to produce the amber color could also cause the problem.

Dear sir

Yes, all three lines are running with the same batch.we have only one furnace. This line is not to hot.Running temperatures are almost same.we are using red iron oxide with sodium sulphate and carbon.mixing unit is from Zippie and system is PLC controlled.This problem is coming only on one line and on that line glass flow is less.Heavy glass flow is on other two production lines.what else information is required, I will forward.Thanks

Best regards

Basharat

Sounds like an obstruction.

Since it is the line with the lower flow is it possible that you are not getting the proper mixing action in the glass stream due to the lesser volume of glass or the time or distance allowed for the mixing to take place?

Dear sir

Glass is melting in furnace and refined glass is going in distributor and flow of glass is 42 tons on defective line.Two other production lines are on other hand and 77 tons glass is flowing on their side.Glass level and volume in the fore hearths is steady all the time.Same furnace same distributor and same melted glass but problem is only on one line.we have checked all these possibilities ,you mentioned but the problem is still invisible.Thanks for the concern.

Best regards

Basharat

If there is any place after the furnace where heat is being applied to maintain the flow characteristics. You may be getting reboil which can cause seeding. Since the lower flow of the one line it has longer to heat up as it maintains contact with these heat surfaces longer. Solution maybe just lowering the heat input at these points. It could also be that there is a calibration issue.

The product being injection molded? Are all three machines making the same product? The machine your having problems with the product larger or smaller then the others?

Also each of these machines will have some heating capabilities to maintain the temperature of the glass until it's ejected. There maybe a problem in the heating unit calibration. Or it could be that the slow flow allows the glass to get too hot.

I'm not from glass industry, but maybe the fact of lower pull from one side means longer "residence" time for material at that side of the furnace.

Maybe also, the higher pull from the other side is making an eddy of contaminant in the material of the low flow side.

Maybe the depth of the out-take is different and you're getting contaminant from lower/higher in the melt. (Or maybe there is slight tilt in the furnace giving the same effect.)

Please describe for me "What are seeds?" Are they air/gas entrapment or voids or solid inclusions?

Might be higher viscosity (cooler transfer to moulds) causing tearing of the material matrix.

Maybe it's shrinkage of the material against the mould surface creating internal voids.

Look at the shape of the seeds. This might tell you whether they are from dynamic action (Flow, tearing etc) or some static effect (Like shrinkage.).

I'm just trying to relate this to injection moulding where I have some experience.