Backpressure & Decompression in Molding
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- čas přidán 5. 08. 2024
- This video goes over what is backpressure & how we use it in molding.
Also we go over what is decompression before screw rotates & after screw rotates. The settings that we are talking about are machine controlled setting that the process techs or maintenance would set.
Relevant information
Thank you so much sir
I am a new set-up technician at a factory and this videos very helpful. 😀
Thanks for watching I do appreciate it. Glad to help
You in fl?
Thanks for watching & the support to the channel I greatly appreciate it.
Currently an apprenticeship through berry Global, these videos helped a lot early on
Thanks for watching them I appreciate it very much.
@@injectionmoldingskillsmore1064 keep it up!!
Subscribed. I'm a mold setter and desire to move into process technician and appreciate this info on learning about the presses.
I hope I can help you out to become a Technician. Thanks for watching
I’m currently running a valve gate mold, I’m having issues with the screw not rotating after each shot it just decompresses, do you think it might be the back pressure not being adjusted correctly?
If you are bottoming out with no cushion this may cause the screw not rotating. I would check to make sure you have a cushion then take all the back pressure to zero. This should let the screw go back, to much back pressure with make the screw slip. If you don't have a cushion then make sure it is about a half of an inch or higher. Let me know if this helps. Thanks
@@injectionmoldingskillsmore1064
Let me rephrase that, it is not rotating every other shot. One shot the screw rotates and the other just decompresses. I currently do have a cushion.
@@gerardooseguera9885 Let me think about this, due to I haven't had this issue before.
@@injectionmoldingskillsmore1064 I don’t know how familiar you are with material but I am running (Isoplast 2510 ETPU) very tough material to process.
very much appreciated sir, would you mind sharing the reference book you use? I found it hard to find one that is a good reference. Thank You!
I will see what i can do sir.
All i have is something i put together for troubleshooting issues. It gives you some ideas on how to fix flash, shot shots, burn, voids, bubbles, jetting, & so on. This is all i have & the years of working in the field doing the troubleshooting on the presses my self. I hope this helps
sir. just some question... what is the different between INJECTION SPEED and INJECTION PRESSURE
Injection speed is a setting of how fast you want to inject material, & Injection pressure is a setting of how much pressure you want to use.
@@buffalo417694 Can injection speed have an effect on injection pressure? Also, the check ring is open upon retraction of the screw, correct? If this is the case, why doesn't plastic drool from the nozzle tip or cause excess pressure on the valve gates? The company I work for uses decomp post injection, and I'm confused as to how plastic does not flow into the manifold and put pressure on the valve gates.
@@xxTAARGUS I will show something in the next couple of videos ok sir.
1)if backpressure is action and reaction process, than it means backpressure is directly proportional to injection pressure, if we increase injection pressure than backpressure also increase simultaneously , is it correct ? .
2) if it is correct, than how there is seperate control given in machine for back pressure as it is depended on injection pressure.?
1) The back pressure should always stay at the set you want no matter how high of injection pressure you have.
2) Both injection pressure & back pressure, can both be controlled by the press settings.
I hope this helps, Let me know if I can still help.
@@buffalo417694..firstly thank you for replying ....
1. what is the direction of back pressure , is it towards mold side or opposite to mold side i.e. hydraulic cylinder side ?
2. how does back pressure decide shot size ?
@@usmanpadaya6027 Back pressure is away from mold side always. The more back pressure the more material you can put into the shot size as well. NO back pressure the material is what is forcing it back. So lets say you have a shot size of 3 inches & you have 100 psi back pressure it will stay at 3 inches. Now we take the back pressure up to 200 psi now your shot size may very to 3.25 inches. I hope this helps
@@injectionmoldingskillsmore1064 .....very well explained....thank you so much...
Sir please send trouble settings alll problem solution
What are you needing a troubleshooting guide to go over issues?
Good voice. Repeat this voice in your next videos!
Thanks for watching & the support to the channel I greatly appreciate it.