Proper set-up and usage of Doctor Blades on the printing press ensures that you get longer life and excellent wiping action from the Doctor Blade.
Doctor Blade Mounting Tips
- The blade holders must be kept clean at all times – there should be no ink sedimentation between the blade and holder.
- At all times, ensure the blade fits firmly without undulations.
- Once the blade is mounted on the holder, the lamella should face upwards and be visible.
- Always tighten the screws from the middle outwards – the distance between the support blade tip and blade holder should be about 10-20 mm.
- The support blade should be clean and uniform, and mounted on top of the doctor blade.
- To allow flexibility and proper lubrication, the thickness of the support blade should be a minimum of 0.5 mm - 0.6 mm approximately.
- In order to provide more flexibility to the doctor blade at the cylinder ends, the edges of support blade should be tapered (as in fig.). This will help the blade from cutting at the cylinder ends and will enhance blade life as well as printing cylinder life.
Contact Angle & Pressure
- The doctor blade contact angle is one of the most important points, in order to achieve a brilliant and clean printing result. If the angle is set to 60-70 degrees, the contact area between the blade and the cylinder will be minimal. This will automatically allow the operator to use a minimum of doctor blade pressure. Lower pressure will allow for a longer doctor blade life as well as much less cylinder wear.
- Adjust the blade holder for a uniform setting and gently increase the pressure till a good wipe is obtained.
