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(Aco Mold Co., Ltd - a good reputation company in China for custom plastic injection mold manufacturing.)
07-27-2014 05:14 上午
#1
How to get rid of warpage for PBT material?
07-27-2014 07:55 上午
Top #2
You have to know why the warpage happens,because different thickness(cause of stress) or eject issue?You can do moldflow analysis.Change the gate`s location/type and optimize injection parameter,etc.
07-27-2014 10:16 上午
Top #3
you have to preheat the material at 110 c for three hour then try .
07-27-2014 12:22 下午
Top #4
Please, explain about preheat material. Do you mean dry the material in a resin dryer?
07-27-2014 02:55 下午
Top #5
Here's a good read on warp. http://www.ides.com/articles/processing/2007/hatch_02.asp
Pressure drop in cavity due to long flow can create warp. Temperature issues, to short a cooling time can do the same. It may be a solution in nailing the process window.
Depending on size of part, running A side 10 to 20 f difference to B side might help. Molded stress from sharp corners, differential shrink and gate methods may be an opportunity to correct.
Pressure drop in cavity due to long flow can create warp. Temperature issues, to short a cooling time can do the same. It may be a solution in nailing the process window.
Depending on size of part, running A side 10 to 20 f difference to B side might help. Molded stress from sharp corners, differential shrink and gate methods may be an opportunity to correct.
07-27-2014 05:30 下午
Top #6
Why not post some more information so we can clearly see where the problem lies.
In most of the cases, warpage is caused due to faulty part design and wrong placement of gates. So no matter how much you try to change the other conditions, these 2 problems will not let you achieve a part with acceptable warp. Looking forward for more info. Lets solve it together.
In most of the cases, warpage is caused due to faulty part design and wrong placement of gates. So no matter how much you try to change the other conditions, these 2 problems will not let you achieve a part with acceptable warp. Looking forward for more info. Lets solve it together.
07-27-2014 07:33 下午
Top #7
Unsuitable mold temperatures and unfavorable switch over point from injection to holding pressure may be causes of warped molding of PBT either filled or unfilled grades.
heat the mold halves to different temperatures for resolve this problem.
heat the mold halves to different temperatures for resolve this problem.
07-27-2014 09:03 下午
Top #8
Thanks a lot for the all of your comment, let me sum up some more info,we have been facing this problem for the last 9 months, we have tried out all the possible way like mold flow analysis, but in the mold flow it self we get the part warped, the change temperature of both halves still no positive result, we tried out by different gate position and different types of gate , that too could not solve this, we played with the process like high packing, increase cooling time reducing cooling , injection pressure what ever can be done to our knowledge we have applied still no positive result,
we do secondary process ie: jigging but , at the time of jigging we get it with in 0.3 with in two days we go back to 0.8 and above , is there any jigging method that can resolve this, as we came to know that tooling and process cant help us,
if you all think there is any other remedy or solution kindly share, and if any body know any jigging process that can reduce the warp kindly advice. now after jigging with in 2~3 day it again warp.
The resin we use is 30%glass filled.
we do secondary process ie: jigging but , at the time of jigging we get it with in 0.3 with in two days we go back to 0.8 and above , is there any jigging method that can resolve this, as we came to know that tooling and process cant help us,
if you all think there is any other remedy or solution kindly share, and if any body know any jigging process that can reduce the warp kindly advice. now after jigging with in 2~3 day it again warp.
The resin we use is 30%glass filled.
07-27-2014 10:15 下午
Top #9
Cold runner? Hot runner? Gate methods tried? Dimensions of the part? Units of measure is mm? Ribs? Thin to thick sections, hard transition? Ribs, bosses or inserts? How is the mold cooled? Water lines as close as possible to cavity? Fill time?
Sounds like part is not designed for "moldability"?
Sounds like part is not designed for "moldability"?
07-27-2014 10:49 下午
Top #10
The PBT with glass is difficult to control the warpage in molding. It couldn't eliminate the warpage in molding completely. But may get better improvement by molding as below:
1> Increase the mold temperature, But mold temperature below 100 degree.
2> Add some rib, Use the molding pressure to make the warpage tend to the rib side.
3> Use outside tool, as fixture to hold the sample. Use heater sourcing to back of warpage to keep the side temperature after the sample is taken out from machine.
1> Increase the mold temperature, But mold temperature below 100 degree.
2> Add some rib, Use the molding pressure to make the warpage tend to the rib side.
3> Use outside tool, as fixture to hold the sample. Use heater sourcing to back of warpage to keep the side temperature after the sample is taken out from machine.
07-27-2014 11:58 下午
Top #11
I have made the fog lamp housing for the Porsche Cayenne. Well I learned a lot by making a good flow and warpage analyses. From that moment I was convinced that a good flow analyze is a trend setter for your mould construction and later process. The main problem is that only a few are capable of making a goof flow analyze. If you find somebody with product design skills, mould developed skill and process determination skills then you get a very good trend setting flow analyses. I have made may fog lamp housing afterwards and the optimization cost and lead time reduced to the minimum.
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