Voids & Bubble In Molding

Voids & Bubbles in Injection Molding parts.
How to fix them with 3 different variables,
Machine, Material, & Mold

[@rafaelmarquez5198]

Thanks for your videos, they are very helpful to improve our molding techniques, greetings from Tijuana

[@injectionmoldingskillsmore1064]

Thanks for the support

[@gareththomas2265]

Topman. I've Been molding for 25 years and agree with what you suggest. P and R Alpla Hellermann Tyton and Aquapurge I've helped to use these practices during the process

[@injectionmoldingskillsmore1064]

That is awesome!

[@joseplara5396]

Thanks David. We faced air bubbles in a new mold and the only solution to reduce them but not remove at all was reduce the mass temperature in the barrel and in the manifold.

[@injectionmoldingskillsmore1064]

Cool, thanks so much for the support to the channel.

[@geoffcrumblin7505]

Many moulders run low temperature settings and fats cycle times to improve output, with little regard to part quality. Injection moulding is a thermodynamic process, where heat in must equal heat out. I recommend raising the mould temperature, and gradually increasing the pack pressure. If you get an increase in part weight, then keep increasing the pack time. This part of the scientific moulding method. You will also notice an increase in part dimension, and that is the key to achieving uniform parts.

[@kuharajmuniyandi2608]

Thank you very much

[@injectionmoldingskillsmore1064]

Thanks for watching

[@johntrocchi9322]

Love that shirt !!

[@injectionmoldingskillsmore1064]

Thanks a lot

[@johntrocchi9322]

@@injectionmoldingskillsmore1064 bye the way great video, I just happen to work for Synventive, thought you were spot on. Keep them coming!!

[@injectionmoldingskillsmore1064]

@@johntrocchi9322 Thanks for the support

[@donghuixing246]

Vielen Dank and thinks

[@injectionmoldingskillsmore1064]

Thanks for watching

[@helpinghands.904]

Hello Sir. Recently we are doing molding of PBT 30 for a 40gm product. Currently the cooling time is 30 sec and MTC is 80 Deg C and machine type is horizontal. We are planning to go for 20 sec cooling time to increase the productivity. Is it required to reduce the mold temp from 80 Deg C to 60 or 70 Deg C? As per material data sheet range of mold temp is 80 Deg C to 100 Deg C. Also, please let us know what risks are possible in reducing the cooling time. Thanks for your help!

[@injectionmoldingskillsmore1064]

That sounds ok, What I would watch for is the part shrinking or the dement ion are out due to running a faster cycle. I would check the parts at run then after 8 hours then after 24 hours. If no change you should be great on running faster. Thanks for your support to the channel.

[@helpinghands.904]

@@injectionmoldingskillsmore1064 Thank you sir!!

[@stejokelec5224]

Hello David, we are injecting a product but we always get a whole in the thinnest part (zero complete prodcts in 4 days of work). we tried everything we could think of and asked many people but to no avail... perhaps you have an idea that we didn't think of? I am really desperate...

[@injectionmoldingskillsmore1064]

Are you filling the part fast or slow? Is there vents to help the gas & air escape the mold? What are your heats on the mold temp & barrel heats? Some times if you fill to fast it will create a air or gas area in the mold that cant get out fast enough. Heat also has a lot to do with it as well to hot is not good!! Let me know the type of material as well & I will see if I can help.

[@stejokelec5224]

@@injectionmoldingskillsmore1064 We are using ABS. And we did them all (fast slow hot cold.....) we even tried different kind of plastic, even recycled plastic. But still the same problem. It used to work perfectly.

[@injectionmoldingskillsmore1064]

@@stejokelec5224 If it use to run perfectly, Then something has changed in the process. Maybe it could be material related or something outside of the process. Is the mold watered the same as last time, Is the fill time close to where it was the last run. There are so many variables to look into, I am just crisping straws due to I don't know the part & the process. I wish I could help more, but I would try process of lamination. Try to only run a fill shot at 95% to 98% & see what the part looks like. You might have to change several things & see what changes & document the changes. Let me know if you figure it out I would love to know what you find. Thanks for the support to the channel.

[@plasticman3952]

@@stejokelec5224 Immerse part in 200-degree water to prevent a void from forming and check your screw tip condition. Does your screw drift forward on hold?

[@PeckhamHall]

Hi there, just read about your problem, at a guess I would advise you to check the water circuits and make sure part of the mould as not got block inside, the flow still might look good but a baffle or something could have come dislodged or something. Also a air leaking from a valve gate if in use. Also a blocked or restricted gate or hot runner gate. Also a floating core due to flashing up the tool at some point that now makes the core move and reduce wall thickness, Also the mould location ring diameter and depth more the moving half ring depth isn't too deep and bottoming out. Machine: blocked nozzle or check ring failure. So check nozzle and check ring double check material velocity is correct to spec and if the 3 are o.k I'd remove the tool and investigate it, also check the hotrunner out if in use like for a down heater band or damaged thermocouple. Good luck and hope you've already fixed it. Jim🏴󠁧󠁢󠁥󠁮󠁧󠁿🇬🇧🧐