Pallet Deflection

[chubsetc]

I see this problem on my diamondback once in a while,  I could never figure out what it was, it is always in the center of the first 2 inches of the design typically when laying down a large area of ink. When it happens I typically just have to put way more pressure on that head than I'd like.  It gets the job done but I don't like it. From what I've read I would agree it's not an Anatol problem but the air heads as John stated.

[CSPGarrett]

I will take a video if I can today and get it up, maybe we can figure it out.  The big issue with it is that we get our shear just perfect and after the initial sample from warming the pallet it doesn't happen, then as the first run comes around we see it.

A few options we have found.

1. Pressure, crank it down a few clicks and increase speed (not great, since it is usually mostly seen on white screens). Speed has to go up so the squeegees don't get stuck.
2. Reduce off contact (a bit better than pressure since it is uniform).
3. Increase angle and a little more pressure (usually works but totally changes our original shear).
4. Slower Speed, but this usually doesn't really solve too much of the issue.

Step one today is checking the distance, I really hope it is it. 

[Inkworks]

Can you adjust the pallets so the outside edge is a little higher? effectively giving you more squeegee pressure out where you're having problems? I know it's not ideal, but maybe a millimeter there would compensate for the deflection and treat the symptom if it doesn't solve the problem.

[Parker 1]

I had the problem on some older presses that also had air and it was from the stroke starting before the chopper's had a chance to fully pressurize and push the screen down. Essentially it's a timing issue where the head needs to wait an extra .5 second before the stoke activates.



We have the same problem on our Stratus, and its all electric.  We increased the dwell time too .8 sec. and it helped.  We get deflection and the pressure on the choppers are inconsistent.  We double stroke with decreased pressure when needed and make sure our inks our mixed well and up to a workable temp.  Also check your off contact, we decreased ours to less than 1/8" off the shirt.  All of our screens are 30-35Nm.  We also increased our flood bar angle to 15-20 degrease to insure the top of the image gets a good flood.  Hope some of this helps.

Chris 

[Parker 1]

Also check the upper cushion on our lift cylinder and insure the table is all the way up before the print stroke begins.  Watch the bearing going into the catch fork while cycling the machine with all heads firing and at full stroke.

[CSPGarrett]

Also check the upper cushion on our lift cylinder and insure the table is all the way up before the print stroke begins.  Watch the bearing going into the catch fork while cycling the machine with all heads firing and at full stroke.

I will double check this tomorrow but pretty sure it is correct since it was serviced Sunday to perfection and we have a delay on the stroke (but this theory makes sense).

I am understanding that this issue isn't related to just our machine so we will be going through a series of variables to find the solution for myself and others.

1st we will be using a triple squeegee tomorrow on head #1 with a regular angle (this way to see if we can overcome an increase in pressure to get the right angle and blah blah).  I have used triple duro since I started printing and have used the single euro that came with Anatol since I got it, so going back may work.

I will report back on the "changes" that happen when doing so. 

Please note that I do take attention on press to my variables so can tell when they are changing but I have a lot to learn (40+ more years) so the more theories the better.

I must say, the further I get into quality control standards of correct screen printing, the easier my DTG company sounds compared.

[ol man]

Also check the upper cushion on our lift cylinder and insure the table is all the way up before the print stroke begins.  Watch the bearing going into the catch fork while cycling the machine with all heads firing and at full stroke.

How would one fix this issue , i have definitely noticed it on one of our machines.....thank you

[GaryG]

...stroke starting before the chopper's had a chance to fully pressurize and push the screen down…..
and slow down the print speed a tad to let the pressure build up.

That's my take
Along with a sharp squeegee

[Binkspot]

Add a 30 second delay before the print to rule out the choppers not fully charged. Have it table up but not print for an extended amount of time to give everything a chance to settle in.
Could be a kinked air line restricting the flow.

Do all the heads do this or just the first? Maybe move the screen to another head and try.

[ZooCity]

We have yet to have a press in the shop that does not deflect to some degree somewhere on either the platen/arms or print heads.  It seems that when you engineer the deflection out of one area it gets transferred to another.  Case in point, our old '92 Gauntlet deflects both at the arm and on the head, like an alligator opening it's jaws up evenly.  Our '13 Sportsman has near zero deflection at the platen/arm but the heads flex up.   When we were looking at both MHM and S.roque we saw that the MHM (excepting the 4000) may have deflection on the platen/arm, as posted in other threads by MHM owners here.  The S.roque appears to have none at the platen/arm but may have deflection on the print head from what I hear. 

So I would agree that the issue could well be traced back to the fact that "it's an Anatol" but hey, you already knew that.  I still wanted to chime in to say that there may not be a carousel press that truly has zero head and arm deflection, that force has to go somewhere and containing it within the bounds of design requirements for a carousel machine that you can thread t shirts and various garments onto and easily walk around to load/unload screens is a very tall order to fill.  To get a truly "zero deflection" press could mean giving up a lot of the things we really need on textile machines.  Would we rather have no deflection at the cost of reduced access to load screens and setup or at the cost of not being able to effectively load long sleeves and smaller items that need threaded onto the platen? 

Deflection at any point will cause the issue of variance in your print parameters at that point.  The solution for us is to adjust for it, as many are suggesting here.  What I really hate about deflection is that, if you have too much of it on your machine, it demands that you print in a way that is not best for the art/ink but to accommodate the machine and that can be annoying.   

Off the cuff I would say you have a combination of natural deflection and maybe chopper cycling that's messing with you.  Do as binkspot says to rule in or out the choppers not having enough time to load up with air as the issue and go from there.  On the Anatol manual we have the arms and platen mounts are very strong and have little deflection there.  I've never ran an automatic red press so I can't speak to the print head deflection but I could ask one of our printers who has. 

However, don't rule out the blade and the angle/pressure/speed it is set at.  Squeegees need x amount of time to "recover" after hitting the platen or going over collars, seams, etc. and this can force you to slow down the stroke and adjust durometer/angle/pressure to accommodate.

[Parker 1]

Also check the upper cushion on our lift cylinder and insure the table is all the way up before the print stroke begins.  Watch the bearing going into the catch fork while cycling the machine with all heads firing and at full stroke.

How would one fix this issue , i have definitely noticed it on one of our machines.....thank you

There is an adjustment screw at both the top and bottom of the Lift cylinder on our Stratus. I do not know about other presses. 

[Binkspot]

Here's the deal, just occurred to me. The only way to control your squeegee pressure is by using the chopper knobs, you can not adjust the chopper pressure. As its printing the pressure is good through most of the stroke over a sturdy part of the pallet and pallet arm. But at the end of the pallet is no way to compensate for any deflection. Plus you have the quick style pallets not the slide. The quick have no support other then 1/4" PL where the slide type generaly the slide bracket runs almost the entire length of the pallet giving needed support.

I run like many others rely on pressure, chopper knobs never make contact. Because the squeegee floats but always maintains constant pressure of what ever is set, let's say 30psi it can make up for any deflection.

If this is the case adding regulators so you could run strictly on pressure would be an easy fix costing about $60 per head in parts. You could just rig one up real quick by adding a regulator at the valve body under the hood and test out the theory.

[Screen Dan]

I used to experience this on the 2002 Gauntlet2 I ran forever...a long time ago.  Pneumatic heads.  I would put dimes at the front corners of the pallet and nickels at the rear corners and level it so the leveled flood bar would just barely make it over all of them evenly.  It solved the problem so well that I started advocating others do that...but in my time here I've only ever come across one other person who actually cared about learning about and maintaining the presses.

First thing though I would be sure to rule out deflection at the arm.  Not too sure what you could do about that...but my press days are long behind me now.

EDIT: removed confusing opposite information.

[GaryG]

I was thinking to rule out deflection of a particular arm-
Cut a piece of wood 2X4" just the right height under arm bar to the floor, so -No deflection occurs,
print that head, and see if the same thing happens early in the print stroke.

Stable arm with zero deflection, watch the print carriage for raise and notice what happens
early in the stroke.

[CSPGarrett]

So we did start to solve it.  We lowered our off contact to just about nothing and increased our squeegee pressure on the white head a bit with a 10 degree angle.

This allowed us to run without the great miss-shearing.  By this I mean if you looked at the prints it would literally be spotty.  Also, we increased the angle on the white flood bar to really help push ink into the stencil.  This may have played a part in the issue.  To test I sent the head forward and noticed where the flood bar stopped in the design.  The only way to adjust for this at this point in time is to run the design way down the pallet, so can't really do that without putting the collar on.

The prints looked great today once the settings had bee found, bright vivid whit (

Yes, when you watch the run you can see the pallet deflect ever so slightly down but I don't really think this is too much of the issue since I can see it making contact.

A few other thoughts we have on it.  We are placing our registration 7-8 inches down from the outside of the frame, and the design starts .5-1 inch down from there (depending on design size giving 2.5-3 inch distance).

We thought that maybe the design his just a tad bit too close to the frame top not allowing it to make proper smooth contact (makes sense why just about no off contact works).  By no off contact I mean 6-7 clicks down from 0.

It is still a LITTLE spotty but a double hit seems to take care of it to about 98-99%.  Actually looked good enough we didn't need a highlight white.  Just I can't risk having even 1 miss print per 300-500 shirts.

We have some brand new 180 screens that just arrived that I need to quote tomorrow to test.

We did delay the head and everything is working properly has far as indexing correct, smooth stroke, and such.  We turned our air up to 90 PSI from 75-80 to make sure we are keeping enough pressure as we run more heads or multiple strokes.

One major change we are now working with is not looking at the "clicks" so much other then setting it the first time.  So we are more changing the settings by feel and look on how it is shearing.

I don't think we have the issue related to one particular arm since the issue can be found on all arms when it is happening.