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Our last post was about garment related causes for print registration problems. A stable substrate is

always the first thing to check when registration is an issue, and then one moves on to checking the press.

Before checking the press itself, one needs to check the screens and platens (pallets) on the press.

Check the easy things first, before getting into the more difficult to diagnose problems. The platens must be stable, and first just check and see that they are secured to the press firmly. Are all the locking mechanisms tight? On our MHM presses the platens are always tightly on the machine, but the brackets on the platens themselves can come loose and  you need to check those.

Just grab every platen and see if physically you can move it, you shouldn’t be able to.

Next check the screens and their holders, make sure that each screen is securely in the press and isn’t moving. Clamp issues, loose corners on the screens, bad air pressure, grease that could cause slippage, bad locking pins, etc all can contribute to a screen not locking firmly in place.

On our MHM presses, the most common problem would be an obstruction keeping

the pins on the screens from setting into screen holders on the machine firmly.

Next check the mesh in the screens. If you have poor tension the image will move and you won’t keep registration. If you have very poor tension on the mesh almost always you will have registration issues.

This is compounded if you are using the wrong mesh. If you use too high of a mesh count then  you will need excessive pressure to get the ink through the screen and the squeegee under high pressure will “drag” the mesh and move it out of registration.

Even a screen at a reasonable tension if you put too much downward pressure you can stretch the mesh and cause poor registration, or on some presses too much squeegee pressure can even physically move the screens out of position.

The screens also should have the proper off contact distance and if the screen is right on the substrate or too high off the substrate you can get registration problems. Also check that you don’t have a warped screen or some problem with your press that is causing an uneven off contact distance.

Next check your platens for being level, flat and parallel. This is a good idea in general for printing well.

Platens are the most common source of mechanically related  registration problems. A telltale sign is when only some of your prints are out of registration. You c an put test shirts on the press

and number the platens and print a couple of rounds to see which platens are off.

Only when you cannot figure out what is going on, should you go to checking on more serious mechanical press problems. We have test films that consist of two parallel lines that are meant to print just a hair apart.  We get two screens and put a line  on each screen and then on to the press and print them. The lines should register so that there is a nice even gaps between the line. Anything less than perfectly aligned on all platens, is a sign that something is out of whack on the press. Usually the two screens will reveal the problem. On the rare occasions that

the problem is still not apparent, then keep one screen in place and move the screen with the other line to each of the other print heads and register it and print all platens.

If you cannot determine the issue yourself at this point, at least you have some good evidence to give to your press tech, and they should be able to narrow it down more easily than if

they were starting from scratch.