Thread

[GaryG]

Hey,

Our Tajima 6 head is really a nice machine, but every now and again, it doesn't stop for quite awhile, see pic.

Why would it sometimes stop right away and sometimes go for this long?

Thanks,

[mooseman]

We have a little embroidery experience but the image provided leaves me completely confused as to
what i am looking at.
some more detail or a short video might help generate an answer.
mooseman

[GaryG]

It is of thread fray. Where the needle abrades thread, but doesn't break it.
It just continues to stitch with partial thread making weak density.

[Admiral]

The sensors only tell when the thread actually breaks.

That could have happened from a rotary hook with burrs on it.  See the condition of the hook and if you have those you can smooth them away.

[Pangea]

As long as the thread sensor keeps moving it won't yell at you to check it. Possibly a burr somewhere like Admiral said, check your thread path.

[mooseman]

First change the needle....the eye of the needle may have been damaged by the hook or other condition. Additionally the needle should be rotated very slightly towed the side the thread approaches the needle. This twist or turn offers the thread slightly better access to the needle eye.
Lastly is this happening on all needles on the same head or just one needle ? If one needle then most likely the needle change will solve the problem. If several needles you should focus on the hook timing and condition.
You can get all kinds of details from you tube vids.
mooseman

[GaryG]

Thanks Guys,

I always thought the sensor was sensitive enough to stop on a fray, but yes, most likely a burr.

[mooseman]

The thread sensor is simply a photo cell and as long as the sensor wheel is even moving intermittently it will not stop the process. You can test this by taking the thread off the sensor completely and simply twist the sensor wheel back and forth with your thumb and index finger.
The light passing through the sensor will be sufficiently interrupted and allow the head to continuing to stitch.
mooseman

[dsh]

For what it's worth,  frayed thread will cause my Tajima to stop.  When I see the tread isn't broken, the next thing I check is for frayed thread.