|Troubleshooting blanket wash systems for web|
First of all, you must understand how an automatic blanket washing system works. Quite simply, it is designed to spray solvent and water onto the blanket and have it cleaned off by a brush or cloth. The devices are simple in design but have nuances that must be monitored closely. To start, here is a problem that is common to most systems and manufacturers still need to find a way to effectively deal with.
Dripping On The Web
Sometimes the upper lines that evacuate the solvent will get plugged. When this happens, you simply have to clean out the lines. Some will take a wet-vac and suck it out the end. Since it is basically a sludge that forms from the blanket piling, you can count on the hoses getting plugged from time to time. This is something that manufacturers of these devices have yet to perfect.
The following problems relate directly to the blanket not cleaning up properly.
Wrong Setting On The Brush Or Cloth
Just as the rollers inside the printing unit need to be set properly, so too the the brush of the blanket washing system needs to be set. For many printers this can be around 1/4" or more. You need to consult your manual to find this number.
Spray Bar Is Plugged
This could be for multiple reasons, but here are a few possibilities. First of all, the water source must not be one that could cause any kind of scaling or residue left in the lines. You may want to consider the quality of the solvent you use as well.
Many solvents are made to work as an emulsion and so if you find sludge grease like material inside the spray bar, you likely have the paper backtracking into the system and building up in your lines. Ensure that there is a proper mix of both to keep this under control.
This can last as long as 5 years, but once the hairs of the brush start laying down, it's time to replace your brush.
From time to time the automatic blanket washing system should be removed and cleaned. Sometimes it is not properly installed again. Ensure that all locks are in place and that it is secure. This could greatly effect the setting against the blanket.
Pump Not Functioning Properly
After checking the spray bar for any buildup or plugged holes, ensure that your solvent and water pump is working properly.
Use An Approved Wash
Some solvents work better than others. Some have a higher volatile organic compound rate than others or a higher flash point. Whatever the case, the approved solvent you choose will determine the settings that the automatic blanket cleaning system manufacturer can use. He can apply more solvent if the settings are right. Consult your manufacturer website for this information. Finally, I highly recommend an online troubleshooting guide. Or another source I have referred to hundreds of times when troubleshooting on an offset printing press and it should be in every press room library. It's the Guide To Troubleshooting For The Web Offset Press. It lists in detail causes and solutions and has saved my butt many times!
Web Press Troubleshooting Guide