# finished stitching without bobin



## haory (Feb 11, 2008)

Hello all,

I need help with some embroidery machine problems I've been having. I have three 2-5 year old Tajima machines and the problems have just recently started. The problem is that the machine will stitch without the bobbin sometimes. When that happens, the embroidery loops on the top and the machine doesn't stop embroidering usually. This happens on all machines.

I've attached a picture to describe my problem.

The top picture is an example of a stitching that stitched without the bobbin and looks okay on top, so I didn't notice that happened until we were trimming the back of the embroidery design. 

In the middle picture, I was doing some tension testing and when there was a thread break, the top line was what it looked like on the back. 

The third picture, after the design had finished on a cap, the embroidery had looping on one letter and when I looked at the back the one letter had black thread bunched up without bobbin thread and it looked like a birds nest. 

Do you have any ideas on what the problem might be? 

I also have an additional question--for the bobbin, when you put the bobbin in the case, is it okay to leave the thread hanging without going around the pigtail or do I have to hook the thread through the pigtail? Can you also tell me what the pigtail is for? Because the embroidery machine embroiders without me hooking it through just fine. I ask because I'm wondering if the pigtail might be the cause of the problem.

Thanks


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## portoman (Jun 18, 2012)

Google is your friend.
"Thread clumping, otherwise known as "bird-nesting," is when the thread clumps or balls up under the embroidery and/or under the throat plate. Thread clumping often happens when the needle thread tension is set too loose, or an incorrect needle is installed, or when the thread comes out of the thread path. 

The most prevalent cause of bird-nesting is the thread coming out of the take-up lever. If you experience bird nesting or clumping, check to make sure that the needle thread is passing through all the thread guides."


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## tfalk (Apr 3, 2008)

2 things come to mind...

Have you run H or FOX tests to verify that your upper and lower thread tensions are set correctly?

The machine should detect that the bobbin has run out - sounds like something is wrong with the sensor or the machine setting for how many stitches the machine should run before stopping - do you know what the machine is currently set to?


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## haory (Feb 11, 2008)

Thanks for reply. Yes, I ran the H test and all the needle tension looks fine. I clean all thread pass and all bobbin case(It took three hours for three machines) to make sure there's no debris left. What i don't understand is when its out of bobbin in the bobbin case or thread breaks machine stop but top picture shows it finished embroider without stopping and there was more than half of bobbin inside bobbin case. Note that first picture happened 3 times out of 16 shirts. I think sensor is ok because machine stops when its out of bobbin or thread break. Did anyone had this problem?


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## beanie357 (Mar 27, 2011)

Must go through pigtail.
We leave 2 inch tail


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## zoom_monster (Sep 20, 2006)

If you run the machine and purposfully cut the top thread, How long does it take to react. Also, does this happen on all thread colors the same?

Did you upgarde the software recently?


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## haory (Feb 11, 2008)

If you run the machine and purposfully cut the top thread, How long does it take to react. Also, does this happen on all thread colors the same?

Did you upgarde the software recently?


It takes about 4 stitches to react. I'm not sure if it does happen to all needles but at least it happened on three different machines.
I'm suspecting bobbin or bobbin case causing the problem. I've been stitching three days with bobbin without going through the pig tail and no problem so far. I can't say my problem is solved because it usually happened about once a week before.
I'm sure everybody had a birds nest problem before. How did you guys fix it ? or you just stitching without knowing what exactly causing it ?


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## haory (Feb 11, 2008)

Yes, I tried to upgrade software for the machine whenever I get chance and I did the last upgrade about three month ago. It's 4.7 ver for Tajima.


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## haory (Feb 11, 2008)

still having problem... can anyone advice?


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## embroiderycrd (Apr 14, 2011)

We also have this happen on occasion, and just fix and go on. You might try new bobbin cases, they are pretty cheap and can get scratches that would cause bobbin to break or get hung up. Also a different brand of bobbin may help, we go midrange price but do still have an issue sometimes. We have tried magna-glide bobbins and they run really well, about perfect actually, but also the most expensive. Good luck, keep us informed if you figure it out!


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## philipfirth83 (Aug 17, 2012)

Does you machine have a bobbin sensor?

Have you checked that it is working properly?


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## inobu (Dec 29, 2010)

The bobbin case has an arm that grabs the top thread and wraps the bobbin thread around it. If the rotation of the bobbin arm misses the thread, the needle backs out and the thread is left hanging creating the nest after a few stitches. . 










The bobbin tension is associated with the rotation of the arm. If the two are not balanced the thread will break or the stitch will indicate a bobbin empty because there is no tension on the needles thread on the up stroke. 

If the weave in the fabric and backing is tight enough it will hold the thread just enough for the needle to pull out and not triggering a bobbin thread "error". The bird nest is the fabric and backing holding the needles thread instead of the stitch being locked in by the bobbin thread. 

If the machines are working off an on the only variable is the bobbin tension being out of balance with the top needle tension. The intermittent problem may be based on thread consumption. Either good on newly loaded bobbin or gets better as the thread is used up. 

You may need to dial in the bobbin tension as it is out of tolerance with the top tension. 

Inobu


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## inobu (Dec 29, 2010)

Haory,

I have been on a steeeeep learning curve but the questions posed really helps in understanding the dynamics of the machine.
Because there are so many moving parts on a machine isolating the problem can be difficult. In order to find your problem you have to identify the common denominators and eliminate them one by one. 

To simplify things I'll uses an analogy that's easy to visualize. 
*
Role play *

The bobbin is you and the needle is your friend on the other side of a wall. He is going to bore a hole in the wall and hand you a green loop. You are going to grab the loop and stick a blue rope through the loop. This will prevent the green rope from pulling back through the hole. 

Once the blue rope is in the loop your friend will pull the green rope taught. As your friend pulls back on the green rope you will start moving to the next hole and repeat the process. Your blue rope is the bobbin thread. (If your movements/slack is right you will see 1/3 green, 1/3 blue and 1/3 green.)

You and Your friend take one step forward, make another hole, hand the green loop through the hole and you loop it again. This will be your straight stitch. 

Now, On a satin stitch........He tells you that he is going to bore the holes 2 feet apart up and down 3 inches apart (stitch setting). This means that you will look down, see the green rope coming through the wall, place the blue rope through the green loop and move quickly to the next location. You must do two things. Keep the blue rope taught so he knows that it is locked in and follow him to the next point. Your tension is an indicator to him. It lets him know things are ok and locked in. 

If he tugs on the green rope and does not feel any tension he thinks that your blue rope is broken. He will call "bobbin break" and stops. If he pays no attention (auto bobbin detect off) to the tension he will just keep on stuffing the green rope in the holes. You will see a bunch of loops with no blue rope holding them in place (birds nest). 

With this analogy you can understand the roles of each component and their cause and effects. The tension you place on the blue rope will dictate how tight the green rope is against the wall. How much of the green rope he placed through the wall and how much tension you have on it will dictate how wide your blue "bobbin" line will be. 

The needle is handing the thread through the fabric. The bobbin thread is locking the stitch in place. The amount of thread feed is dictated by the thickness of the material plus backing and the column width. 

The wall analogy helps in understanding what is happening. 

With all that said...........your problem can also be associated with maintenance/lubrication. If your needle rods are dragging just a little bit it could throw off your needle and bobbin timing. The bobbin arm swings by before the thread loop is low enough or the thread feed rate is off causing the miss between the thread loop and bobbin cycle. 

Your intermittent trouble on multiple machines really makes it hard to narrow down. if you can pull a report on which needle are failing and use only the good one it should point you in the right direction. 

In any case I learned a lot from your question. 

Hopefully my input can give you a few leads. 

Inobu


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## binki (Jul 16, 2006)

did the problem start after you upgraded your software? if so, contact tajima. this would sound like a switch is turned off for detecting a bobbin thread break.


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## haory (Feb 11, 2008)

Thank you so much for all of your advise. Inobu, thank you extra for that detailed explanation. Im sure it took a good chunk of your busy schedule. I really do appreciate it. Would anyone happen to know if the new Tajima machines have a bobbin sensor? and if it does, could you explain how i could change the setting on the bobbin sensor? also has anyone had this problem with the bobbin sensors? 

One other thing that really confuses me is that every single time i do get a bird's nest, there seems to always be *one single thread* wrapped around the middle of the picker. You can see it in the picture attached to this post. You guys think that might be a key factor into getting bird's nest? would anyone know how in the world it gets wrapped around there int he first place? I could understand the huge clump of thread in the back but i dont get why there is one single thread always wrapped around the picker when a bird nest forms. Thank you so much in advanced.


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