Author Topic: Pressure : Depth on M&R Choppers  (Read 4074 times)

Offline ZooCity

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Pressure : Depth on M&R Choppers
« on: February 23, 2015, 09:15:41 PM »
I'm going to ask this to those with the more current M&R machines because these figures will vary wildly from press to press and won't be relevant between brands/models/major revisions.

What depth is your squeegee chopper set to and what pressure do you run for a typical plastisol, wb/dc or HSA print?

I had to run a job today (3 out sick/bereavement and we had to ship it out today, helloooo monday) that one of my ops setup and could not believe how high the pressure was on the heads- around 40-50psi.  The tech who installed this press set our choppers at 1.5 and I think he said he did something to lock them there and instructed us not to touch them, to use the pressure regs only, which we have done.   But the pressure we're running at seems crazy high.  Sure enough though, I backed one head in particular off and it didn't clear clean with 10 psi less.  My crew says this is ball park for nearly all the inks we use which vary wildly in rheology and print needs.  So there's my answer...

1.5 depth 40-50psi

....where's everyone else at?  I need a frame of reference here.  I know the plasti prints are mostly single stroked, not being driven in and are laying on top just fine because I check that periodically throughout each day.   Those pressure numbers feel high compared to what I've seen posted around here for plastisol prints, seems about right for dc/wb maybe.  Our heads also flex up like crazy during the strokes so it really got me thinking of ways to reduce that because I freaking hate it.

Just for background on my scenario- we just got a blade sharpener and we're using the qwik clamp system now so blades are about as perfect as they're going to get, all triple duros 70-90-70 and 55-90-55.  Our mesh is all thin thread.  All roller frames that get checked for tension every cycle and checked for level when re-tensioned. One of my ops parallels the presses every week, more in the busy times.  I feel like with all that we should somehow be printing with much lighter pressure.  I do encourage them to play with blade angle and speed during every setup to print at the lightest possible pressure but they say this is it. 
« Last Edit: February 23, 2015, 09:17:50 PM by ZooCity »


Offline jvanick

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Re: Pressure : Depth on M&R Choppers
« Reply #1 on: February 23, 2015, 09:25:24 PM »
on our 2014 Sportsman:

depth = maxed out...  why would you want to screw around with depth when you have psi control? (other than on the flood bar)
also, I haven't noticed any crazy amount of flexing anywhere...

plastisol:
typical print is 50psi for underbase/non-underbase print 70/90/70 triple duro
top colors... 40-45psi 70/90/70 triple duro

FWIW:
the tech that installed our press says that's the recommended pressures, and yes I experienced the same thing when backing off pressure.. we've been too damn busy lately tho to do any deep experimentation.

wb/dc:
65psi, typically double stroke to get that nice deep penetration
70/90/70

on my old javelin with the chopper heads, I was running at around 30 psi and was getting nearly the same result for plastisol prints, however, it's possible that I was running with lower off-contact... I haven't really checked into that with the new press as it hasn't been a major issue for us.

My theory, not sure if it's true or not -- maybe Rich could chime in?

the bore size in the chopper cylinders are different, and that causes different psi to equate to different pressure on the squeegee.

Offline ericheartsu

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Re: Pressure : Depth on M&R Choppers
« Reply #2 on: February 23, 2015, 09:28:50 PM »
our plastisol PSI is usually around 40-50. If we are using Smesh we can get it to around 35.

I think we keep our floods at zero, but i'll have to check
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Offline Binkspot

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Re: Pressure : Depth on M&R Choppers
« Reply #3 on: February 23, 2015, 09:36:31 PM »
Obsiouly my press is supireior to all others but never more then 40 usually in the 20-30 range, chopper stops all the way up.

Squeegee angle may play a larger part, I have found between about 3-5 degrees works well. Anything beyond that needs more pressure.

Offline patfinn

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Re: Pressure : Depth on M&R Choppers
« Reply #4 on: February 23, 2015, 09:45:24 PM »
You are right to have the chopper cylinders all the way up.. I usually recommend starting low and working your way up and only using enough to clear the screen. But 40-50 is not bad.
If you feel like you are using excessive pressure there are other things to consider. Tension, mesh selection, off contact etc.

Feel free to call us in the screen dept. anytime for printing/press questions.

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« Last Edit: February 23, 2015, 09:47:32 PM by patfinn »
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Offline ZooCity

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Re: Pressure : Depth on M&R Choppers
« Reply #5 on: February 23, 2015, 11:04:20 PM »
Patrick I'm going to call tomorrow if at all possible,  thank you!  I do think we have the mesh and off contact covered but screen printing is a never ending road so I'm really looking forward to speaking with you.

Jvanick, our tech set the depth at 1.5, I haven't had the chance to mess with setting it anywhere else.  I'll have to try then at max depth but I need to make those changes soon as we've already accumulated a good grip of press sheets with pressure info, resetting depth changes all that.    Your print heads don't flex up when stroking? I have been very impressed with the lack of deflection on the pallet arms but the deflection up top is noticeable,  it actually alarmed us a little at first. 

Also I really appreciate the responses this is immensely helpful to me.

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« Last Edit: February 23, 2015, 11:06:25 PM by ZooCity »

Offline alan802

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Re: Pressure : Depth on M&R Choppers
« Reply #6 on: February 24, 2015, 09:27:03 AM »
I've been wondering about this very subject for a few years now but more so how it pertains to different brand machines.  I know there will be a slight difference in press brand as far as if we are at 25psi another brand press should be within about 5psi...I would think, but it sure doesn't seem like it seeing all the M&R guys using 40-50psi for plastisol.  There is a way you can test manually by putting the blade in the down position and then trying to lift the chopper assembly up by hand.  When our pressure is set to 20psi you can lift it fairly easily and at 15psi there isn't enough air pressure in the chopper to lift and lower.  I can still lift it when it's at 40 but I have to put some muscle into it.  When I print with 50psi our heads begin to flex too much for my liking but I can't remember the last time we printed with 50, I don't think ever other than me messing around.

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Offline screenprintguy

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Re: Pressure : Depth on M&R Choppers
« Reply #7 on: February 24, 2015, 09:59:38 AM »
We were told right here in the shop, and then again at M&R back in December by Rich himself, make sure your squeegee choppers are always wide open and set wide open, control them with the air regulator. So then obviously like already mentioned, tensions, off contact, squeegee durometer and angle make all the difference, but our have been set wide open since first told and a lot of adjusting and little issues we were having in the first year were eliminated there. Since going with S-Mesh, I notice our pressure back off by at least 20 psi. This is on a DB, but like I said, even a demo on a 2014 Gauntlet 3 he said the same thing, leave the squeegee choppers wide open and control with air pressure.
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Offline GaryG

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Re: Pressure : Depth on M&R Choppers
« Reply #8 on: February 24, 2015, 10:23:04 AM »
Yeah for the first year I was always fidgeting with the squeegee pressure.
Then after talking to a M&R rep for our Sportsman, he said open all the way up
and adjust with air regulator only. Never looked back. Saved tons of time and uncertainty.

Offline 244

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Re: Pressure : Depth on M&R Choppers
« Reply #9 on: February 24, 2015, 10:27:52 AM »
We were told right here in the shop, and then again at M&R back in December by Rich himself, make sure your squeegee choppers are always wide open and set wide open, control them with the air regulator. So then obviously like already mentioned, tensions, off contact, squeegee durometer and angle make all the difference, but our have been set wide open since first told and a lot of adjusting and little issues we were having in the first year were eliminated there. Since going with S-Mesh, I notice our pressure back off by at least 20 psi. This is on a DB, but like I said, even a demo on a 2014 Gauntlet 3 he said the same thing, leave the squeegee choppers wide open and control with air pressure.
this is correct. Printing pressures should vary between 30 to 50 PSI. If you are having to go past 55PSI there is something wrong. That something could be a 100 defferent issues. Mesh, tension, EOM, angle, off contact, ink are just a few.
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Offline prozyan

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Re: Pressure : Depth on M&R Choppers
« Reply #10 on: February 24, 2015, 10:29:07 AM »
Same here on my Diamondback - controlled with air pressure only.  We print between 35 and 45psi, depending on the ink and other variables. 
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Offline Underbase37

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Re: Pressure : Depth on M&R Choppers
« Reply #11 on: February 24, 2015, 10:33:24 AM »
On our M&R presses. The target number is 40psi ( depending on mesh ) for colors directly on garment, & 20-30psi for top colors. 50-60psi for DC. The angle, mesh, & duro.............all play a big roll but, it sounds like you have that all in check.

One thing I did key in on is, you said you have a squeegee sharpener. Not that taking a little bit off at a time should so much but, at some point after grinding or slicing little bits off the squeegee, I would imagine this would start to effect the psi as well.

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Offline Gilligan

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Re: Pressure : Depth on M&R Choppers
« Reply #12 on: February 24, 2015, 10:50:57 AM »
Hey Chris,

If your barrels aren't bottoming out to that 1.5 setting, then all of your press sheets are still valid.  It's only a physical stop, it doesn't change the pressure vs wide open, as long as it doesn't bottom out.

Now if it bottoms out then that's a different story, but you may have been lucky and have "accidentally" been running "wide open" all this time.

Offline ZooCity

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Re: Pressure : Depth on M&R Choppers
« Reply #13 on: February 24, 2015, 01:00:33 PM »
To clarify, our choppers are set to the 1.5 in the up position, when chopped down they "bottom out" so that appears to be all tight and alright according to everyone who posted here.

It sounds like we're more/less in line with the norm regarding pressure but it just seems high for S mesh, kept at near perfect tension on M3 rollers, always printed with sharp, perfectly loaded triple duro blades, right?   In the end I guess the proof is in the print and we are certainly not driving plastisol inks through the shirts at these pressures but I'm always on the never ending quest to improve and would like to see all our machines printing at the bare minimum pressures needed.

Off contact here is a pretty rigid matter for all standard prints: 5/32" or 0.156" off the platen top to the bottom of the screen for plastisol on Ts.  Double that off the platen to 10/32" or 0.313" for fleece.   It could be messed around with again but it's an amount that seems optimal with our mesh and we have ran at these o.c.'s for quite some time on multiple machines.

Like others, the time just hasn't been available to goof around with a bunch of different angles but I have been encouraging everyone here to do this.  Angle : stroke speed adjustments may be our last little puzzle piece here. 

I started this thread because with this machine I have not had the press time on it, I'm only on the machine to fix any problems typically so I wanted to be sure I wasn't out there telling my crew to drop pressure if that was inappropriate.  I think it's already turned into a great thread thanks to everyone's input, hopefully it serves as a good reference for others. 

Offline chubsetc

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Re: Pressure : Depth on M&R Choppers
« Reply #14 on: February 24, 2015, 01:56:23 PM »

If your barrels aren't bottoming out to that 1.5 setting, then all of your press sheets are still valid.  It's only a physical stop, it doesn't change the pressure vs wide open, as long as it doesn't bottom out.

Now if it bottoms out then that's a different story, but you may have been lucky and have "accidentally" been running "wide open" all this time.

I just want to clarify that this is correct or not.  I already run my DB choppers so they do not bottom out, but if there is a reason to adjust them to fully open I will make sure I crank them all the way.