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screen printing => Screen Making => Topic started by: Parker 1 on March 21, 2014, 07:43:25 PM
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I am dabbling with the idea of switching over to Murakami Smart mesh. The pics below show a run of the mil 1 color white print on Royal PFP. Using Shur-loc's panels 125/70 stretched to 32NM, 1 stroke with medium pressure, using smiling jack squeegees. I can Increase pressure and it will clear or double stroke, I would like to avoid doing this.
Chris
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I use shurloc panels as well. I've been slowly switching to Murakami Smart mesh. I'm able to get 1 stroke and clear wilflex epic white using a 150/48. I still print flash print but it will clear with one stroke as opposed to using a 156/64. I could probably get a 1 hit white if I would increase the eom. I'm really digging the smart mesh. Everytime I use a 156/64 until it's no good any longer I replace it with the 150/48. Also, I'm able to hold successfully a 50 lpi halftone with a 150 as well. I'm adding 180/48's to the mix as well.
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I have been printing white with a 225s recently and it is clearing in one pull on my manual. I am coating 2/1 and it has good eom and holds amazing detail. Some shops would probably sell it as a one hit white, but I p/f/p still because I want true 100% opacity.
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S mesh will more than likely fix that BUT eom and ink temp/viscosity can also produce the same symptoms. S mesh just makes everything pass through the mesh easier.
150/48 really is the most versatile mesh I have used. Been stretching more 200/48 as well and they perform great too.
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EOM is good, coated 2/1, ink mixed and the pic was taken at 200 impressions. My biggest concern with useing S mesh is how delicate it is. My guys really do not understand "handle with care"
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Parker - last week we were using 310 s mesh for a base with open area larger than the buffalo picture you posted above. It was clearing entirely with 1 stroke after the pallets heated up (about 15-20 shirts in). Eventually got it up to 10-12" per second stroke speed - and that was with Miami ink's superior with a 75/95/75. The feel is quite good on it. I'd def recommend murakami's s mesh in 135 and 150 meshes as standard great under base screens but know, like others have mentioned, that you should be able to clear the ink with higher mesh counts too in the s and lx mesh.
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EOM is good, coated 2/1, ink mixed and the pic was taken at 200 impressions. My biggest concern with useing S mesh is how delicate it is. My guys really do not understand "handle with care"
You are so correct about delicate but as long as you treat them with tender loving care you'll be fine. Having said that I've never had one pop on press probably because they don't stretch to a extremely high tension. If I'm not mistaken when they are first stretched they are somewhere in the neighborhood of 28 newtons and settle at around 22.
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YES
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i keep hearing people talk about how delicate it is, but I treat mine the same way I treat all my screens and the only one I've had pop was the result of a glass shard flying through it when my exposure unit shattered.
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Using S thread will definitely bring to light any poor screen handling by your guys, but I believe they'll last forever if taken care of properly.
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My guys really do not understand "handle with care"
Then it's time to get them ready for it. I think most shop staff will lay waste to thin thread mesh without a sea change in how screens are handled. We have it down here and screens pretty much only pop from being at the end of their natural life, but we also only have 3-4 people ever handling screens. Main thing is to make a mesh safe spot for screens at every step of the process and make it crystal clear that screens cannot be elsewhere, like on the floor, etc. Also, say goodbye to laying blades and floods on the screen.
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Outside of the 310/30 mesh, I haven't noticed any of my S meshes being particularly delicate. The 310/30 seems to rip if you sneeze at it, but my 225, 150, and 330 I haven't noticed a great difference.
Then again, it is possible we just handled mesh more carefully than I previously thought.
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135/48 is pretty darn fragile. It was hard getting it up to 25N without popping and it settles down a lot lower after a few reclaims. 150/48 aren't that bad once you get used to handling them, but the 135/48's are a little skiddish!
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Thanks everyone for your great comments and tips.
Here are a few for those moving over to S Mesh:
1. In the beginning a customer of mine marked the frames by spraying the end with red paint, red tape would work as well. This communicates to workers that this is S mesh. Handle like a 300 and the prints will improve a lot. Rolling racks help, dropping them to the floor doesn't help!
2. No tools on the screen during set up as mentioned.
3. Avoid scratchy pads that can nick fine meshes that latter can pop when drying after degreasing.
4. Where possible put only one frame at a time in a reclaiming tank. Or make sure they are separated by bars. Corners of Newmans and static stretch and glue frames can be dragged across screens still in the tank. Also avoid sharp cornered dry wall spatulas to remove ink.
5. Round off squeegee ends. Square cut corners on an automatic will be abrasive to the mesh. A rounded corner allows the mesh to slide over rather than having a sharp squeegee corner carving away at the mesh.
6. Tensions Murakami 150S mesh: 22-24n 28n is possible but this puts it right at maximum tension.
Murakami 180S mesh: 28-30 newtons
Murakami 225S mesh: 24-26 newtons
One other S that is excellent for High Soids Acrylics is 135S stretch to 22n. This mesh can also hold a 50 line halftone at 61 degrees. The extra bit of open area helps with inks that are prone to drying in or need more color.
WB and Discharge: 65/95/65 squeegee
Plastisol 70 duro, 65/95/65 or 75/95/75
You can also play around with a little more angle since the ink cleans very well from the mesh and allows a little more pop to the opacity.
For those who want to see what we are talking about here is a video, posted before, but seeing is believing. Watch it past the credits at the end if you want to see why people move to Socal.
https://www.youtube.com/watch?v=WFShG5cWeGY&feature=plcp (https://www.youtube.com/watch?v=WFShG5cWeGY&feature=plcp)
We also have pre-stretched screens available here at the main office in LA that you can buy through your Murakami Dealer or we also have select stretchers in the US to help.
Al
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This mesh can also hold a 50 line halftone at 61 degrees.
Hey Alan, I know this is possible to image but how can one get the emulsion durable enough to hold up over a longer run? We hit a wall with this where the emulsions we are using can do the fine lines and halftones on very open mesh counts like 135/48 and 150/48 but cannot bridge over a long wb/dc run without failure. It seems like the emulsion must need to have some special, extra strong bridging properties to get this done without the additional threads there to support the stencil.
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Part of the key to obtaining the highest tension possible is to have a very clean stretcher with no glue drips on any bars or insertion bars on a bar stretcher. Sand these down (metal) w/ 600 weight wet and dry sand paper, or carefully remove glue drops from rubber capture bars before attempting S mesh.
On Newmans you need to make sure you have adequate corner softening to avoid the sharp metal corner where the roller meets the end of the roller. On some Newmans this is an extremely sharp little square corner. The inside of the channel that the mesh rests on is always problematic since Newmans last a long time and small nicks in the edge are enough to cut fine mesh. There also shouldn't be any dried emulsion bumps, major dents, or dried inks in the channel or on the roller where it rests. Again 600 wet and dry keeps them very polished and smooth. First time out you might want a lower grit followed by the 600 wet and dry.
The inside edge of a Newman is quite sharp. You can fold S mesh under to capture a double layer of mesh. This helps the tensioned mesh rest on mesh instead of being stretched tightly around the sharp inner edge. Another trick is to put a flat, bump free layer of masking tape and wrap it around this sharp inside edge of the channel. Both act like a shock absorber.
To avoid moire run a pencil line along a mesh thread in the long direction of the piece to be stretched so that on the first capture the pencil line is parallel to the channel. This makes for consistent mesh capture and predictable non moire results. For Shurloc panels the mesh is captured well to avoid this. In fact from my time studies, the Shurlocs cost no more if you have a stretch table or a manual op. The time it takes to capture the mesh on a newman costs more in labor than the price of the Shurloc process. (4 captures, 4 softenings all done instantly with 4 clicks of the Shurloc strips. (One other note on Newmans: Always make sure all rollers turn outward the same amount. Older tables and sticky rollers can cause one roller to do all the stretching while the other barely moves. Opposite rollers should always turn the same amount outward. Keep a rubber mallet handy to assist the table, or bump the pulling clamps with the heel of the hand to help the stretcher out. Sometimes the manifold can malfunction as well and not send equal air to the cylinders. When one roller moves outward much more than the other it will curve the thread instead of keeping it straight and this will put a lot of strain on the threads and mesh knuckles.)
One other key point. Too often we get in the habit on Newman stretch tables of just flipping the air switch and allowing the last stretch settings to make the stretching faster. Avoid this with S mesh. Back the air off 1/3 of the way at least so it goes to 6-9 newtons, then bring up the tension on the warp and weft to desired tensions, just takes a few turns but this helps the mesh stretch a little. You can also preserve S mesh by dropping the narrow direction of the frame 1-2 newtons from the long direction. The reason for this is the main print forces are along the long direction, while the narrow width only gets pulled as the squeegee passes. We textile printers use squeegees within 1.5 inches of the inside of the frame. Dropping the narrow direction 1-2 newtons helps prevent momentarily high tension that occurs from the squeegee corner to the inside of the frame as it prints. Eliminates a lot of popping issues on press, especially if you don't round off the corners of your squeegees.
One final trick: You can stretch this mesh on the bias for specialty halftone techniques like square halftones that run vertically. (This is a Photoshop bitmap technique). Stretch mesh at 22.5 or 61 degree angle. Affliction uses this technique a lot. Draw a line along the long direction of the mesh piece, then with a protractor find 22.5 or 61, mark a dot at 22.5 or 61 and on the center mark of the protractor. Draw another line connecting these dots, this will be a 22.5 or 61 degree angle biased stretched screen.
A newsletter we did for this: http://murakamiscreen.com/stretching-s-and-lx-mesh/ (http://murakamiscreen.com/stretching-s-and-lx-mesh/)
OK one more, sorry, I'm gone for a week so I'm putting it all out there now:
We carry another mesh with S designations: LX Mesh
The main difference is less mesh knuckle, the threads look like they go through one another rather than over and under. This creates a much smoother surface for the squeegee and also produces a slightly brighter base plate. The softer outer core of this mesh gives a little to allow better transfer of plastisol. It was originally designed for water base and discharge.
Al
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Hello Chris,
Thanks for the reply.
I know we tested some emulsion awhile back but I think we need to look at a few things there again.
1. Degreasing, use a commercial degreaser. We have DGR-801 for standard work, for ultra fine details MS-Cleanser will degrease even better. Avoid using dishwashing liquids, most contain lanolin or other chemistry that can leave a residue.
2. Next is exposure time. Assuming we have well dried screens, should be real dry where you are, and I remember you had humidity controlled, so I'll assume dry screens. Then exposure time would be my next area to check. What emulsion, what time now?
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Hey Alan, it's not a degreasing or exposure issue I'm referring to, but one of the emulsion's bridging strength + water resistance.
The issue is that we have not found an emulsion that will bridge a mesh with this much open area and hold up to a waterbased print run. You wind up with dots having very little thread contact and they will wipe right off on press. Mark Gervais mentions the same technique you did for printing HSA inks and I agree, it's a great notion and the stencil can definitely resolve the detail but we cannot get it to hold up without delaminating.
I see Mark was using a Murakami pure diazo for this, the AC I think? Is a pure diazo the solution for that bridging strength or is his choice to use pure diazo more related to supply costs for a large production outfit? I understand that some of this may be proprietary info if you cannot share no worries.
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I switched over to static S-Thread frames and even those are a huge difference. I'd like to switch to retensionables at some point in my printing career, but for now, printing manually, these frames are amazing. 150-S is my go to mesh. Holds excellent detail and clears extremely easy which my hands are thankful for.
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Hello Chris,
Maybe we should try Aquasol TS. This is a lower viscosity emulsion designed for fine detailed wb/dc printing. Not meant for low mesh counts. 150 on up. It is the toughest wb/dc emulsion we sell for fine details and halftones. Add 8g of diazo per gallon, burn screen for as long as it can stand before it overexposes, post expose in sun or 2X on the exposure unit again, harden with A&B hardener. Like I mentioned in another post you may want to try some micro grit to texture the mesh for better emulsion bonding. On our mesh, all meshes above 280 come pre treated. Give Kevin a call at Forward Printing in Oakland CA, he is really into fine meshes and printing discharge with lots of tones. He did a 4/C process discharge/WB on 420S for us of 'Trapper Walt' (our salesman) that was excellent.
Al