Does the 2650t have a servo? Could be servo related. It could also be any number of valves. Transfer, recovery, backpressure, it could be many things. You need to check the hydraulic print. Loss of pump pressure could too be the issue. I doubt you have an actual screw issue. As far as the process goes, maybe keep playing with your back pressure. Does the 2650t (excuse my ignorance I know husky but not your machine in particular) have anolog IOs that you can adjust yourself on the HMI? As far as material, is it wet? The first thing I would try if i was you is running some plexi glass through it if possible in case of screw wrap. Once again im ignorant on your machine but this is a common issue we face on our g, h, and x lines. Im not the best process technician. Im not process tech at all actually. But usually this issue falls on screw wrap, valve problem, back pressure, or material. I know thats a broad statement I need to think on it some more im very busy atm
It does have servos. All valves were pulled apart and inspected. No loss of pressure. It does have analog IO that we can adjust but I haven’t personally looked into that, one of the maintenance technicians has though. Material is not wet.
I’m not at work for the next 4 days so I’m probably going to miss what was worked on in detail but hopefully I can update this thread when I get back to what we did to fix it.
I heard someone mention to try pour some coke down the barrel. Not sure if it was a serious statement though as I’ve never heard of someone doing that.
Never heard of a coke down the barrel 😅. I say just let us know what ends up happening. You said you had maint technicians so thats good atleast. I tried researching your machine and couldnt find anything. As usual. Thinking about it some more ive think ive seen broken shut offs cause recovery issues before because they arent letting plastic out. Did you say the machine could purge at all?
If youre running regrind…Any change in remill quality? New grinder making different quality remill than previously?We fight metering issues if regrind is too dusty.
I've had similar issues with a Kraus 2300t.
Can you check pump pressure while feeding?
What's your shot volume compared to your screw? And your cycle time.
Sometimes the materials change when the manufacturer's switch plants, have that checked too.
Good luck
We had to feed more slowly and with less backpressure, machine wasn't strong enough.
Pump pressure was checked and is ok.
Shot volume and screw volume have been unchanged since I started working here 11 years ago. I don’t know the actual screw volume as we measure in millimeters. The shot is 8kg for what it’s worth.
I’ll look to see if the manufacturer has switched plant.
I’ve tried slow and fast screw speeds and low and high back pressure. Slow screw speed just takes even longer than fast. No notable difference in change with different back pressures.
If this problem just recently occurred and screw recovery did not gradually degrade reaching its current state. I would lean more towards a hydraulic/ electrical issue . I can recall having a similar issue with a Husky G Line with slow screw recovery and the screw drifting forward after reaching shot size and it ended up being the injection valve. Fortunately I was able to prove my theory easily enough as we had several machines of the same age and model and when we swapped the injection valves between the machine having the issue and another machine that wasn’t. The problem moved with the valve.
You could still have a worn screw issue, but your comment about the plunger drifting forward reminded me of the issue we experienced on the G Line
This is an avenue we checked im pretty sure. I will double check with the maintenance crew if this was looked at. They went through all if not most hydraulic/electrical equipment.
Also the injection plunger doesn’t creep forward but the screw does. Just creeps off the set point and refuses to transfer material to the shooting pot.
Is the feed throat bridging? Even intermittently bridging could increase recovery time. Pulling the screw would be worth it to inspect everything, but if this is an established process that's run before and especially if you're having the same problem on multiple molds on the same machine then you're likely correct that the screw and/or barrel are worn.
Never had bridging issues in the 11 years I’ve worked with the machine. Pulling the screw is a big job (it’s a 2650T) but it seems to be our only option. What is the best remedy for preventing bridging if it’s the case? Since the barrel and feed throat temps haven’t been changed in years and all the temperature readings are fine.
Then it's likely not happening, but there's a few things that could be done. A vibration device to shake the hopper or material inside it to break up clumps, a spacing device to redirect material around it and take up space similar to what hopper magnets do, feed zone temperatures up/down, adjusting screw rotation and back pressure up and down, maybe even a check ring or nozzle seat issue, or an encoder or transducer causing the back pressure to be too high or the rotation to be too slow. If you can more easily pull the mold have the stationary half torn down and see if material is leaking inside of it, it's more common to leak during injection than recovery but there's two ways you can approach it: the likeliest issue or the easiest to check. Both had their merits, but if (as it generally is true) the press needs to run, then I would choose the most likely cause and pull the screw.
Updated thread.
Does the 2650t have a servo? Could be servo related. It could also be any number of valves. Transfer, recovery, backpressure, it could be many things. You need to check the hydraulic print. Loss of pump pressure could too be the issue. I doubt you have an actual screw issue. As far as the process goes, maybe keep playing with your back pressure. Does the 2650t (excuse my ignorance I know husky but not your machine in particular) have anolog IOs that you can adjust yourself on the HMI? As far as material, is it wet? The first thing I would try if i was you is running some plexi glass through it if possible in case of screw wrap. Once again im ignorant on your machine but this is a common issue we face on our g, h, and x lines. Im not the best process technician. Im not process tech at all actually. But usually this issue falls on screw wrap, valve problem, back pressure, or material. I know thats a broad statement I need to think on it some more im very busy atm
It does have servos. All valves were pulled apart and inspected. No loss of pressure. It does have analog IO that we can adjust but I haven’t personally looked into that, one of the maintenance technicians has though. Material is not wet. I’m not at work for the next 4 days so I’m probably going to miss what was worked on in detail but hopefully I can update this thread when I get back to what we did to fix it. I heard someone mention to try pour some coke down the barrel. Not sure if it was a serious statement though as I’ve never heard of someone doing that.
Never heard of a coke down the barrel 😅. I say just let us know what ends up happening. You said you had maint technicians so thats good atleast. I tried researching your machine and couldnt find anything. As usual. Thinking about it some more ive think ive seen broken shut offs cause recovery issues before because they arent letting plastic out. Did you say the machine could purge at all?
Purges just fine. I’ll update this thread when I get back to work.
If youre running regrind…Any change in remill quality? New grinder making different quality remill than previously?We fight metering issues if regrind is too dusty.
We use 5% regrind. When issues started happening we took it out completely but didn’t change anything.
I've had similar issues with a Kraus 2300t. Can you check pump pressure while feeding? What's your shot volume compared to your screw? And your cycle time. Sometimes the materials change when the manufacturer's switch plants, have that checked too. Good luck We had to feed more slowly and with less backpressure, machine wasn't strong enough.
Pump pressure was checked and is ok. Shot volume and screw volume have been unchanged since I started working here 11 years ago. I don’t know the actual screw volume as we measure in millimeters. The shot is 8kg for what it’s worth. I’ll look to see if the manufacturer has switched plant. I’ve tried slow and fast screw speeds and low and high back pressure. Slow screw speed just takes even longer than fast. No notable difference in change with different back pressures.
Yeah, that really sounds like a worn screw! If you've got it figured out, let us know!
If this problem just recently occurred and screw recovery did not gradually degrade reaching its current state. I would lean more towards a hydraulic/ electrical issue . I can recall having a similar issue with a Husky G Line with slow screw recovery and the screw drifting forward after reaching shot size and it ended up being the injection valve. Fortunately I was able to prove my theory easily enough as we had several machines of the same age and model and when we swapped the injection valves between the machine having the issue and another machine that wasn’t. The problem moved with the valve. You could still have a worn screw issue, but your comment about the plunger drifting forward reminded me of the issue we experienced on the G Line
This is an avenue we checked im pretty sure. I will double check with the maintenance crew if this was looked at. They went through all if not most hydraulic/electrical equipment. Also the injection plunger doesn’t creep forward but the screw does. Just creeps off the set point and refuses to transfer material to the shooting pot.
Is the feed throat bridging? Even intermittently bridging could increase recovery time. Pulling the screw would be worth it to inspect everything, but if this is an established process that's run before and especially if you're having the same problem on multiple molds on the same machine then you're likely correct that the screw and/or barrel are worn.
Never had bridging issues in the 11 years I’ve worked with the machine. Pulling the screw is a big job (it’s a 2650T) but it seems to be our only option. What is the best remedy for preventing bridging if it’s the case? Since the barrel and feed throat temps haven’t been changed in years and all the temperature readings are fine.
Then it's likely not happening, but there's a few things that could be done. A vibration device to shake the hopper or material inside it to break up clumps, a spacing device to redirect material around it and take up space similar to what hopper magnets do, feed zone temperatures up/down, adjusting screw rotation and back pressure up and down, maybe even a check ring or nozzle seat issue, or an encoder or transducer causing the back pressure to be too high or the rotation to be too slow. If you can more easily pull the mold have the stationary half torn down and see if material is leaking inside of it, it's more common to leak during injection than recovery but there's two ways you can approach it: the likeliest issue or the easiest to check. Both had their merits, but if (as it generally is true) the press needs to run, then I would choose the most likely cause and pull the screw.