Birdnesting under garment

[That_Spidey_Dude]

Notice on the gold stitching it birdnests up and doesn't show any bobbin at all, and the center the black top thread was pulled far under and looped. Any ideas on what the problem is? I am sewing on to the front of some backpacks. Bobbin casing is clean, just changed my needles to troubleshoot the problem, thread is ran properly, no dust clogging the channels.

[mooseman]

hard to call from a distance but bird nesting results from two primary elements.
The first is tensions.
Your top tension is too low or weak. The top thread is being pulled to a greater degree by the bobbin tension. Additionally you may be sewing too loose overall . this means that you general tensions even if in balance may be too light for the fabric you are sewing on.
Digitize up a simple column stitch about 1/4 inch wide and about 3/4 to one inch long. Use this each time to test your tension on any given needle.
I am guessing you are up to speed on the 1/3 - 1/3- 1/3 tension test???/

Second factor is the hooping of the garment or fabric. Backpacks are not polo shirts they are hard to hoop and looking at your photo I am again guessing you are not getting the nylon fabric tight and even in the hoop. Use the smallest hoop you can and keep things tight.
It is very hard to hold nylon backpacks in the hoop. They are heavy bulky and can just be an overall pain to maintain taught.
Looking at the waviness of the nylon I am guessing you getting some flagging (bouncing and uneven sewing due to the hooped condition.
Next slow down the machine going fast or too fast adds to the flagging issue also raises the temp of the needle as it works through the nylon. You are actually getting some areas where your tension is good on the gold thread but it gets lost in other areas.
Lastly ....digitizing is an issue always. Looks like you main problem is in the inner sections of the gold pattern where the design is making corners. Look at the stitches you may have to move or remove some in the turns as things are definitely bunching up there.

Hope this helps, BTW you do not need tear away backing on nylon backpacks, you actually do not need any on the heavy fabric.
mooseman.

[lrsbranding]

Agree with Mooseman. Tension is most likely the problem. We sew the logo on vinyl seatbacks for a flight trainer manufacturer and their vinyl will always do that on 3 heads out of 6. I do a sewout on different vinyl and it works great. Their vinyl, not so great. I don't know what the difference is, they feel the same.  Anyway, If I crank up the upper tension as high as I can without thread breakage it goes away. Of course this is assuming that all other factors are ok. Like your hooping properly, the product isn't flagging, rotary hook timing is correct, needles, digitizing, position of the moon to mars, etc. Try sewing it on different material and see how it does. I just got a new upper thread tension gauge and it will show around 15-20 less than the old one.  That explains why I always went tighter than what the gauge recommended to get a good sewout.