Fitting the wrong Doctor Blades in your Flexographic Process will cost your business
Doctor Blades play a key role in the flexographic print process. Fitted along the length of the ink chamber system, the Doctor Blade runs against the anilox surface to remove excess ink and deliver a precise amount of Ink to the printing plate.
It is essential to your print quality and productivity that the appropriate Doctor Blades are chosen to suit your print requirements and fitted correctly.
To deliver the precise metered amount of ink to the printing plate, the Doctor Blade pressure setting is critical. This shouldn’t be more than 1Bar, approx. 14.5psi.
The consequence of incorrectly fitted Doctor Blades
The Doctor Blade manages the ink transferred to the anilox roller, whilst the retainer blade captures any excess ink and forms a seal within the ink chamber.
If the Doctor Blade is too thin, this can lead to too much ink delivered to the anilox roller, due to the Doctor Blade distorting. Excess ink will result in ink being delivered into places it shouldn’t be applied to.
Applying too much ink will cause colour inconsistency and print issues such as graphics or letters in your print bleeding together.
Incorrect action to compensate for incorrect set-up
When too much ink is transferred to the anilox roller, the action often taken by operators is to increase the pressure.
Thinking that increased pressure will reduce the ink flow, only leads to other issues.
This action will close the gap between the Doctor Blade, chamber and anilox roller face. The distortion of the Doctor blade will invariably lead to the anilox rollers becoming damaged.
Either outcome is an expensive error to correct.
Incorrectly fitted or the wrong Doctor Blades can lead to print issues, including:-
- Too thin Doctor Blades can distort.
- Distorted blades will allow surplus ink to transfer to the printing plate.
- Excess ink delivery can lead to increasing the pressure, to counteract ink problem.
- Too much pressure will cause incorrect ink distribution.
- Increased pressure of Doctor Blades will escalate wear and tear.
- Increased pressure can lead to damaged and scored anilox rollers.
- Damaged or scored anilox will lead to print defects in your final printed product.
- Scored or damaged anilox rollers will result in a costly refurbishment.
Simple mistakes are a costly exercise
The needs to select and fit Doctor Blades correctly is an essential aspect to gaining high-quality print and pro-longing the life of Doctor Blades, ink chambers and anilox rollers.
Incorrect actions, such as increasing the Doctor Blade pressure, will result in unnecessary waste of materials and additional cost to your business.
Once an anilox roller is damaged or scored it will not deliver premium print. This would mean either a full refurbishment or replacing the anilox roller. Either option is a costly and time-consuming process.
Refurbishing an anilox roller involves
- Sending the anilox repair, which takes approx. 4 weeks.
- This will impact your production schedule.
- Cause possible issues with your customers, due to delays in production.
Understanding the correct setting and requirements of the Doctor Blades is essential to the flexographic print process operating at its optimum level, to deliver high-quality print and productivity.
- NB: setting of 1Bar is a guideline. The correct pressure depends upon the type of print job, the press and substrate being printed on, as well as the condition of your anilox roller.
If you are experiencing any print issues or concerned about any aspects raised above, then talk to our team. Our technical support provides site assessments, and anilox audits, to check on the condition of your anilox rollers and discuss any print issues you are experiencing.
We here to support you maintain consistent high-quality print and reduce unnecessary production downtime.
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