Need Help Summa S3 creating a rough cut

[DeathByStickers]

Hi folks, in need of some help. One of our cutters has developed a nasty habit of creating a really rough cut after a bit of cutting. It’s a summa S3, tangential head, using the standard blade on laminated vinyl. 100 stickers before these cut just fine, but towards the end of the page these cuts start to show up. Have done all calibrations and everything else works perfectly, just seems like the blade is not turning perfectly towards the end of a sheet. Any help would be appreciated.

 

[Smoke_Jaguar]

Try squeaking your blade up a full rotation in the holder, might be going too deep and bumping the cutting strip. Also, make sure the cut line looks nice and smooth, can get jagged if following a pixelated line and give a nasty sawtooth cut.

 

[Saturn]

My first thought is that it wasn't securely seated in the holder and came loose. But could something else like a really bad chip or some other mechanical gremlin.

This type of bad cut looks like the Origin is not centered right.

 

[Smoke_Jaguar]

Tangential blades tend to hold up well, but yeah, could be chipped.

 

[DeathByStickers]

Sorry I should have prefaced this by saying we have seven of these cutters that run almost 24 hours a day. I regularly change the blades, cutting strips and make sure the latest firmware is updated. Regularly run calibrations and blade depth is set so that pressure is at 400gr and two passes cuts through our vinyl.

This particular cutter I replaced everything on it in an effort to stop this problem. So it has a new blade, new blade holder, new cutting strips, and a new nosepiece. It’s not happening consistently, it will cut an entire 100” long sheet fine, then once it hits 90% done or so, it begins cutting this way, almost like the head is getting “tired”.

I’m stumped at this point.

 

[DeathByStickers]

Try squeaking your blade up a full rotation in the holder, might be going too deep and bumping the cutting strip. Also, make sure the cut line looks nice and smooth, can get jagged if following a pixelated line and give a nasty sawtooth cut.

I try to keep the pressure at 400 and the blade length set accordingly so that two passes will cut through the vinyl. I could back the blade off and up the pressure, but we use similar settings on our other cutters without any real issue. And the cutline is not the problem, this design I posted was basically a circl so I knew the cutline wasn’t the issue.

 

[DeathByStickers]

My first thought is that it wasn't securely seated in the holder and came loose. But could something else like a really bad chip or some other mechanical gremlin.

This type of bad cut looks like the Origin is not centered right.

So I did replace the blade thinking it was a blade issue, and I use the blade replacement tool to set it well. Also to note it’s not consistently cutting this way, it can cut a whole sheet fine, and slowly begin cutting this way towards the end.

I too believe it’s an issue with the head not rotating the blade perfectly but I’m just not sure how to calibrate that back to normal.

 

[DeathByStickers]

Tangential blades tend to hold up well, but yeah, could be chipped.

Yeah that was my first thought but I have replaced this blade.

 

[Smoke_Jaguar]

400 is pretty high pressure in my experience, I tend to do around 250 for a thru-cut and 270 if going through ink as well (UV ink is a mofo to cut). But things like backers and material thickness tend to be a real wild card, so your mileage may vary. Maybe do a light cut on first pass and just see how it goes. Something like 180-220gr and see what the cut looks like and go from there. High pressure tends to kill accuracy in my experience. However, I am on an older S120T, but they share the same toolhead parts.

 

[Saturn]

400 might be a little high, but not outrageous for a worn in blade. I usually go from 250+ to 300+ pretty quick on a blade for GF-201 laminated with Substance 3150.

If you're running 7 cutters, I'd guess you've got a pretty good feel for things. If it's not something really obvious, it's probably something wrong with the head. X/Y motors I think would just cause drifting, and you'd probably hear them going bad.

I'd blast air down the holder hole, and maybe try and get a real good peek that everything is clear too. You can also (if you haven't already) take the shell off the head and just eyeball that everything looks normal.

They do wear out eventually, especially at the rate you're going. How old is this one?

 

[jerry369]

Try using a 45° knife

 

[cornholio]

I'm installing and servicing Summas since they first came out.
I never had such an issue. If the tangetial motor can't reach the correct angle, it should show an error imo.
But given your experience and from what you tell, i would replace the cutting head to troubleshoot.

 

[DeathByStickers]

I'm installing and servicing Summas since they first came out.
I never had such an issue. If the tangetial motor can't reach the correct angle, it should show an error imo.
But given your experience and from what you tell, i would replace the cutting head to troubleshoot.

In your experience, how can the axis of the head be adjusted? My fear is the band inside the cutting head that twists the blade housing has somehow gotten loose and now isn’t “straight”.

 

[DeathByStickers]

400 is pretty high pressure in my experience, I tend to do around 250 for a thru-cut and 270 if going through ink as well (UV ink is a mofo to cut). But things like backers and material thickness tend to be a real wild card, so your mileage may vary. Maybe do a light cut on first pass and just see how it goes. Something like 180-220gr and see what the cut looks like and go from there. High pressure tends to kill accuracy in my experience. However, I am on an older S120T, but they share the same toolhead parts.

So we set our cutters to 400 because otherwise the blade winds up sticking out a bit too far for my liking. We are cutting a thicker laminated vinyl so it may be justified. I have tried backing off the pressure and increasing the blade depth and the same ripple cutting happens.

 

[FrankW]

Regularly, as the knife is set correctly, this happens if the knife origin is deviated (knife doesn´t home in cutting direction). That should be visible if cutting an rectangle. It is adjustable in the knife calibration.

Could be too specially with thick media, if the knife landing is not correctly adjusted. But this is a function in the service mode with the S3, should be guided by a technician.

Be sure that the knife is set to a low depth.

 

[cornholio]

In your experience, how can the axis of the head be adjusted? My fear is the band inside the cutting head that twists the blade housing has somehow gotten loose and now isn’t “straight”.

The timing belt in the cutting head needs to be somewhat loose. (remove the cover of one of your other machines, it should be similar)
As long as it doesn't jump teeth, you are ok.(I don't think it does, since you say the cut is fine in the beginning, then at some point gets bad and is good again when you start a new job)
I think, i just found the possible cause of your problem. It must be the encoder in the tangetial motor, or the cabling, or the counting electronic circuit.
During initialization, the blade turns and stops at the "home" signal of the encoder. Then the offset is added, so the blade looks in the correct direction. During cutting, the mainboard only looks at the AB signals to keep the angle correct. If there is a problem with these signals, the blade angle gets wrong and you get your cutting results.
Now the problem could be everywhere from the encoder on the motor, the cable to the head board, the head board, the flat cable going all the way to the mainboard and the mainboard itself. Id reseat all these cables first.(You don't need parts for that)
My next step, test it with a known working head.(highest likelyness)
Then the flat cable from the head to the mainboard could have a defect. (Happens in heavily used cutters, but rarely)
Then the mainboard.( rather unlikely, but possible)