Why does my squeegee blade leave these marks on screen?

[bryanprints]

If I have my pressure high enough to clear a screen I normally get these marks.  Do I need to purchase a sharpener and round my edges off more?

I can sorta always see it, sometimes it effects the print and I have to work on it, but most times I can't see it. 

Press is about a year old, everything is setup the same as when the tech left.

[rmonks]

Looks as if your don't have enough angle and to much down force. Looks like it is catching and then jumps, a skipping motion.

[whitewater]

you know this happened to us..but it happens sporadically.. i have not figured it out yet...sometimes the blade was at an good angle..

[bryanprints]

I've been sitting this afternoon trying all different angles and pressures.  I normally run at 15 degree angle.

[Colin]

Servo heads or air?

Even with servo heads I see this on occasion.  But MOST often with air heads.

Print stroke can be to slow and the squeegee is digging into the emulsion then the pressure gets it to release - making it skip like that.

As stated the solution is to increase the angle and/or change your pressures.  Also, potentially go to a softer squeegee - but I dont know what you used.

[domineight]

I'd call it "chatter" you can see a couple of pressure changes in that image - Could be the lighting maybe, but top left shows quite a thin film then there's a bit of a step, then another step when the open area of mesh is quite large under the squeegee. As above, more noticeable with air printheads where there is a bit of stagger in getting the squeegee moving after the inversion.

Just guessing here - Do you have the squeegee depth bottomed out, and rely on adjusting the regulator on the printhead? If so try the other way - Give the squeegee more pressure on the reg and back the depth of the squeegee depth/inversion back off so you're printing, and just a touch more to see if there's any difference.

[Squeegie]

My first thought was not enough emulsion on the squeegee side of the mesh.  I see a lot of texture that on my screens would be smooth.

[bryanprints]

Coat 2/1. Could just be the lighting or picture. I think workhorse set ours so the print heads aren’t bottomed out and we have our pressures around 50-70.  Maybe I’ll play with some different combinations. I just left it because I assumed they knew best. Guess I also just need to dial it in more for me.

[mooseman]

I have absolutely no experience with an auto so please consider that fact...but from what I see it looks like ink drool off the back (trailing edge) of a squeegee.
You can get this manually to a much greater (sloppier) degree when there is too much ink on the back side of the squeegee blade after the flood stroke when push printing or there is too much ink reservoir on a pull stroke.
Again just my observation not  my experience I may have absolutely no concept of what the picture actually represents.
mooseman

[Prince Art]

After moosman's reply, it raises the question: Which lines are you talking about in the picture? The ones that go from top left to bottom right, or the ones that go from bottom left to top right?

Mooseman's comments seem correct for the latter. For the former, others above could be correct... though the uniformity/regularity of those "skips" seems strange. It's almost like there's a rhythmic pulse affecting squeegee travel or pressure. I've personally not seen anything like it. (But my auto experience is limited, and doesn't include workhorse.)

You could be on to something with the squeegee blade, if it's very new and very sharp. At least in manual printing, I've found fresh squeegees can "grab" (especially at the end corners) if pressure isn't right, and if any area where blade meets screen is dry. You could try rounding those corners just to remove a variable. (Sandpaper or a cement floor will work, no sharpener needed for that task.)

[im_mcguire]

What press is this on?  Cutlass or Sabre

[IntegrityShirts]

Is that waterbased ink? I get chatter sometimes when running the squeegee angle too vertical w/ waterbased inks.