Lets talk squeegee blade's

[3Deep]

Ok here is my problem, printing halftone's and keeping them nice and clean from the first shirt printed to the last without dot gain.  I fight this problem all the time changing to higher mesh ct squeegee angle pressure bigger halftones smaller halftones and printing halftones over a base id wicked crazy at times.  I think my major problem though is my squeegee not being as sharp edge as they should be, I really don't know what brand I use anymore being I have not bought any for some time but I know they are 70/90/70 and 70 duro.  How often do any of you sharpen your blade's or know when to toss out blades and replace with new rubber, right now it feels like I'm trying to cut steak with a butter knife.  I've thought hard about buying a sharpener, but I don't think they get the edge as good as buying new blades and the old using sand paper and block of wood tried it and made a mess with blade so bad I had to toss it or used it to spank my wife with it    So who makes the best blade that holds up it's edge for bad printer's like me?

[tonypep]

My side of the coin is new blade..........others will disagree.

[Homer]

I bought a sharpener a year or so ago, once a week we run them through. takes less than a minute. We noticed a huge difference in detail.  We replace them after a year or so, you can only sharpen them so much before you start to change their properties. I'll sharpen some for you if you want to try it out.

[alan802]

I'm not going to say that it's impossible to not have dot gain, but if you're going to print thousands of halftones on top of an underbase, then step on those halftones with other screens while wet then you'll have dot gain to a fairly high degree.  The things that you can do to lessen the gain is to print subsequent colors on top of wet halftones with high speed, very little pressure, proper off contact, and SHARP squeegee blades.  The longer that mesh is in contact with the halftone the more it's going to gain.  The harder the mesh is pressing against that halftone dot the more it's going to gain.  The more dull that squeegee edge is the more gain you'll have.  If the mesh doesn't release as quickly as possible from on top of the wet ink the more gain you'll have.  Those aren't the only things to look for, but it's a good start.

But having said that, it takes such little action to destroy that halftone that at times I think it's impossible to keep it from happening at all. Even if you were printing with virtually zero pressure felt on the pallet it's still probably enough to smash that tiny halftone dot.

I know there has been more talk about squeegee blades the last year or so but I still think it's the most overlooked tool of the trade and I'd venture to guess that some 90+% of shops print with crap squeegees.  I have a sharpener and use it, but mainly because I use Joe's blades and I don't have to sharpen a specific blade very often.  His blades will retain their edge FAR longer than any other blade I've used.  And even if they provided nothing else in terms of performance over a traditional blade, the longevity is a large enough selling point for me.  But we're able to get the blades to perform much better than any triple, double or traditional blade and add the longevity into the equation and it makes no sense to use any other blade.  But that's our shop, I won't ignore the fact that many have tried them and didn't like them and I don't want to downplay those results, but we've used them for so long and I've had many opportunities to try other blades and Joe's design when used properly will run circles around the average blade.  If you're a shop that throws a few blades to your head printer and say "try these out" and you walk away, you'll probably get bad results.  If you're a shop that doesn't want to experiment or try to print a little differently and you're happy with what you're doing then you won't like a high performance blade.  They really do have to be pushed beyond the average print parameter to find out how good they are.  If you only use it as if it's just another squeegee blade then it will perform just like another squeegee blade, or perhaps even worse in some scenarios. 

So how often do you need to sharpen or replace?  Who the hell knows?  If you print a few jobs per day, smaller quantities, maybe you can get 6 months out of a 75 duro blade made from quality materials.  I'd have to take a wild guess but the average shop like ours, one auto, a few hundred thousand shirts printed per year, a few months, 2-4 would be about all the average blade would last.  If you use excessive pressure, 35-50psi, which most shops do, that edge will die much quicker than if you are printing ink with 20-25psi.  I'm getting 8-10 months out of Joe's double beveled blades and they are seeing at least hundreds, but averaging closer to a thousand imprints per day on underbase screens.  But we're printing at 15-30"/sec with 20-25psi.  I don't have any real numbers to back my next statement up, but I bet you couldn't get 3-4 months out of the same double beveled blade if you printed at 4-6"/sec at 40psi.

If you like the traditional blade, and don't plan on pushing the limits on speed and pressure while printing, I'd buy a couple dozen feet of triple duro from a high quality manufacturer and start paying a lot more attention to your squeegee edge.  I hold mine up to the light and look at the edge and then I'll run my thumb across the edge to test for sharpness.  I don't have much feeling in my thumbs and my fingerprints are always in bad shape so looking at the edge is the best way for me to tell how sharp the edge is.  If you have a blade and have no new blades to compare it to, take the blade out of the holder and look at the side that hasn't been used and that will show you how sharp the blade was when new.  It will give you perspective and something to shoot for if you try to sharpen. 

[3Deep]

Good read Alan, yeah your about right, in the pass the squeegee blade was something I took for granite, working from a manual press I really didn't care, but working from an auto is another deal all together.  I guess it's like owning a chain saw if the blade ain't sharp you'll burn out the motor quicker.

[Colin]

A Quality squeegee is number one.  Knowing how to use it like Alan said is number 2.

Knowing what kind of dot gain to expect is the other half of your battle.  You will have different dot gain when printing directly onto fabric than you will on top of another ink (usually a base plate).

Compensating in your art program for dot gain - making your halftones smaller with the expectation that they will "gain" on press - is necessary.

Also knowing what kind of physical dot gain you get with different lpi is important.  The dot/droplet of ink will always spread out essentially the same (for this example we will be talking about a fixed volume of ink/mesh count.  Different mesh counts will deposit a thicker or thinner drop.)  Seeing the physical difference between a 35 lpi 50% dot and a 55 lpi 50% dot will tell you how much you will need adjust.

This is kinda disjointed sorry.  In a rush here.....

There are a lot of really good articles on the web about adjusting for dot gain. 

[RICK STEFANICK]

OHHH, The basics of screen printing. gotta love it

[jsheridan]

dull blades suck period

be it my 8" henkle kitchen knife or 4" sleeve blade.. always sharp

[Printficient]

Uh.......double bevel.  Physics will always win out.

[Lizard]

Give 85 duro a try. I think you will be pleasantly surprised. We use the stuff from M&R.   I-image on top, film on the bottom.

[GaryG]

That there is some might fine shadows. Nice~
What mesh counts?

[Lizard]

230 on base and whites. 305 on colors.  55 line.