Bobbin thread peeking up thru design

[Laughing Palm]

I know some folks out there have probably come across this problem before, so I'm hoping there's some magical solution to this issue that's been happening for the last few months:

Machine is an original 2003 Red Amaya (with new rollers).

Lately, the bobbin thread has been visible in a design every now and then - sometimes more than others. This didn't used to happen, so I know something has changed. Interestingly, this has also coincided with the appearance of "loops" in satin stitches now and then.

Here's what I've already tried in order to remedy the issue:

Checked bobbin tension - seems fine - any changes to bobbin tension doesn't fix the problem.
Checked bobbin cases for damage - nope.
Checked presser foot height - doesn't seem to matter.
Checked Acti-Feed/Material Thickness settings - manual or auto doesn't fix the problem. (Values in Thread Feed setting in Amaya OS are...Column Feed: 40; Run/Fill Feed: 95; MT: 3 - all unchanged for years)
Replaced bobbin cases - no effect.
Used different bobbin threads - no effect - happens to both white & black bobbins. (Bobbins are same Coats bobbins we have been using for years. Even happens with new Magna-Glide bobbins.)
Completely cleaned/reinstalled/adjusted rotary hook/hook timing - problem unaffected.
Checked thread paths & rollers - all are fine - no change; happens with any colors/positions.
Changed sewing speeds - no effect.
Various backing materials does not seem to have an effect unless the combination of backing & garment material is very thick.
Tried both Poly & Rayon threads - no difference.
All lubrication to machine is OK - done regularly.
Used brand new needles - no change.
Inspected needle plate - it's just fine.
Checked the entire system for bent/broken/marred/damaged elements - didn't find any.
Checked hooping - garments hooped properly - same as always.
Backing materials are the same we have used for years, so no change there.
Problem occurs with any designs - in other words, it's not design specific.
Also, it doesn't seem to occur with any particular stitch density.
This occurs with pique knits, jersey knits, wovens, etc...again, not particular with any specific type of material - even caps!

Anything sound familiar to anyone?? I'm out of things to try...HELP!

[SkyLinePrints]

whoa! Sounds like you have checked everything.

If bobbin is coming through that is a sign of running "tight" on your upper threads. Well, it is in the non-Amaya world.

since you said you ran in auto and manual mode with no difference, I am going to suggest actually changing the bobbin casing to a new one. I know you said you checked it but I have found in years past that when I have a tension problem with bobbin and all else fails, changing the bobbin casing has resolved it. The new case will have tighter tension retention than the older one. When you pull the bobbin casing out and do the drop test, the old could look fine but when the actual run load is on the bobbin, the spring is weaker than a new therefore allowing the bobbin to run loose.

Just a thought

[signman]

I bet many of us will be watching to see the 'cure' for this one...as I read your complaints, I mentally listed off everything I've done for the same thing...and you hit all of them! Sometimes...it just happens. To fix it, grab the color fabric pen that matches (bought a bag of them at Jo-Ann fabrics for $10 or something-handy to have) and for the loops, if you can pull the thread back down from behind, hit it with fray check-that will glue it down.
I think it may just be the little pixy that hides in the machine coming out to play...

[The Embroidery Authority - OLD]

Please describe for us how you go about setting your bbbbin tension. Let's not assume anything at this point.

Ed Orantes
Melco Tech & Trainer
504-258-6260

[Wishes]

Last week we were having a similar problem and did lots of what you have described. The thread on all but four needles was making a triangle pattern on the front and back of column stitches. After two calls to Melco, we had a tech come. He saw our samples and immediately decided it was the thread feed drive gear.
If you look in the amaya maintenance procedures for 10,000,000 stitches (I have an xt)it tell you to remove the drive covers. After taking those off there is a white plastic gear that matches up with the gears for each needle. The single gear had a crack in it so when stitching it would not keep good tension and made very uneven stitches. If that piece is cracked that might be your probem. Just a thought and hope it helps.
Margaret

[Laughing Palm]

Thanks for those who posted replies. I'm just now getting back to addressing this issue after being gone on vacation!

I had already tried new bobbin cases, and they don't seem to have an effect on the problem.

Ed...I test bobbin tensions with a TOWA bobbin tension gauge. I've tried setting the bobbin tension tighter, and even looser - all to no avail. I also checked the bobbin cases for trapped lint, etc...no problems there.

I'm intrigued by Margaret's reference to a cracked gear, so I'll have to check that out - but I would think that it would also mess up my regular stitching if that were the case - however it's something to check out!

Interestingly enough, I had a tech come out only a few months ago and do a thorough checkout of the machine - it's the process that techs supposedly do before they cover your machine for the extended warranty - and although I'm not very confident that he did such a great job of it (he was only at it for about an hour), he didn't indicate that there was anything that needed to be repaired on the machine. And I was having this issue before he came out, so nothing changed.

The good news is that it doesn't happen ALL the time - just enough to be bothersome! -sigh-

[Sewfly]

When there are problems with the bobbin thread, then it is 99% of the time, the culprit is in the top tension.

I noticed that you have done everything and then some. One thing that I didn't remember seeing was a software item in the OS.

Open up OS, turn on machine(s), go to settings on toolbar of OS. Click on "Thread Feed" tab. First item is column feed. Could it be that your column feed setting here is off? I have mine set at 50 (I normally keep it here). Sometimes I have mangaed to change it and have problems. I know that I have seen this particular diagram (next to to the 50) somewhere else, but can't think of where that is right off of the top of my head. I want to say it is in the DS software. And I think I changed it there in the "machine settings" to go with the design.

Anyway, hope this isn't a repeat of something you have already tried.

Susan

[Laughing Palm]

I haven't changed the column feed setting (ever), so it's still set at 40. Just as an aside, I wonder what other folks have it set at?? Is a setting of 50 better for overall stitching than 40? What's the repercussion of changing it? Is there a time when changing this setting is beneficial for certain types of jobs? Maybe one of the techs can answer this...

[Laughing Palm]

It just occurred to me that I haven't really mentioned something specific about WHERE the bobbin thread shows up in the stitching, as it might give a clue about the problem.

It's pretty much isolated to the EDGES of a design and not so much in the middle of a fill area. For example, if I had a big filled circle, the bobbin thread would only show up around the outside edges where the thread goes back into the design. If I have a large letter "O" stitched, then bobbin thread might appear at the inside and outside edges of the "O".

Oh yeah...it also seems to occur whether it's a satin stitched section or a filled tatami area. And stitch lengths don't seem to affect it - could happen with a short 2mm stitch length or a longer 5mm stitch length.

Does this help narrow down the problem? Are we having fun yet?? [img]tongue.gif[/img]

[Shuffletown Embroidery]

Interesting. It sounds like the problem is occuring when the stitch direction is reversed. Acti-feed issues????
Are you using an edge run underlay? Also, how much pull compensation? Is is possible that too little of one and too much of the other could be doing this?
Oh, yes, we're having fun now!
Mary

[Laughing Palm]

Well, the reason for me scratching my head is that it didn't use to do this before (for years!), and I'm fairly certain that I'm not doing anything different.

The peeking seems to happen in a variety of situations. For example: edge run or no edge run; pull comp on or off; curved areas or straight areas. Again, it doesn't happen all the time, just every now and then. Because of this issue, I'm having to be very aware of the color of the bobbin thread in use so that it doesn't show so distinctly (like having a black bobbin while white thread is being stitched).

[Shuffletown Embroidery]

Hmmm. Have you changed bobbin or thread types? Or are you using metal bobbins without the brake spring? This sounds like a very pesky problem. What a nuisance to have to be so fussy with the sew out.
I'd call technical support to see it there is a known solution.
Mary

[Rod or Sharon]

Jim,
The old home embroidery guideline of 1/3rd top thread 1/3rd bobbin, 1/3rd top thread when you look at the reverse side of your embroidry is still not a bad way to judge what is happening with your bobbin column. It dsoesn't mean that it covers all situations tho.....

The 40 column column feed that you are referring to, is the default setting and 100 is the default setting for the run/fill. You can watch the little graphic diagrams to the right side of the display to get a visual of what is happening when you increase or decrease the numbers. When you make the bobbin column narrower, then it will pull the top thread tighter toward the middle of the column. Auto activ-feed IF it is working properly will then compensate for this exta tightness and feed out more top thread and keep the bobbin thread from being pulled to the top.

Increasing the run/fill will allow more thread to be added to each stitch length, but will not change the length of the individual stitch, thereby allowing the thread to sit on top of the garment rather than being pulled too tightly down into the fabric.

Now, there are certain things that will GREATLY affect these tools to function properly. One is the auto activ-feed system. IF it is not functioning properly, then thread tension, which is based on CORRECT take-up lever throw travel, which is also dependent on the CORRECT gear mesh setting of the main threadfeed drive gear and the takeup levers, will not be tight enough for the acti-feed system to read properly, to control the proper amount of thread at the right time. Now, having said all of that, another machine part that is heavily involved in determining the proper takeup lever travel is the takeup lever cam disk. IF it is worn, than nothing else will work properly either.

There are other things to be aware of, like proper tension on the X-axis cable and the age of the machine, the wear on it based on lubrication practices and many of the other items already mentioned in the above posts.

Sorry to make it sound like it is a complicated problem but I see it as a tech should see it..."everything" must be "right", for everything to work right!!

The only real clue to what you are saying is that as you put it-----"
Well, the reason for me scratching my head is that it didn't use to do this before (for years!), and I'm fairly certain that I'm not doing anything different." For years? This tells me that there could be considerable wear on certain parts of the machine and this is where the problem lies....for a tech to properly check out ALL of the critical functions of the machine, takes approximately 5 hours, give or take, depending on what is found in the process.

Rod Springer
Amaya Tech & Trainer

[Laughing Palm]

Thanks, Rod. It may very well be an "aging" issue. This machine is an original Amaya I purchased 5 years ago, although for the age of the machine, I don't believe it has all that many stitches on it - and I've been very meticulous about keeping the lubrication/maintenance up-to-date.

I spoke with another tech that also made some suggestions concerning specific things to check out, so I'm going to go over those and see if any of them affect my output.

I did have a Melco-recommended technician come out and give the machine what was supposed to be an entire going over not too long ago, but it only took about an hour or so, so I have to conclude that it wasn't that exhaustive an inspection!

Is there any way I can determine for myself if the takeup lever cam disk is worn?

[Rod or Sharon]

Jim,

I suppose the easy way to determine this is to measure the take-up lever throw at the high point and then at the low point. We hang a 12 gram weight on a piece of thread attached to the take up lever. Attach a metric ruler to the base casting and rotate the Z axis by hand. Take note of the high and low measurements. They should be between 48 to 51mm high and low. Any thing out side of this box will indicate wear on the disk. If the cam disk is worn, then the take-up lever cannot go to it's maximum required travel on the upstroke and will not pull the thread up tightly around the thread break sensor, which will then cause the auto activ-feed to not function properly....etc...

Replacement of this disk means needle case assembly, thread feed roller assembly, presser foot assembly, and reciprocator assembly removal. It is not a task one without specialized training should attempt.....

Rod Springer