What causes fluting?
There are many factors that can cause this problem. The main causes are often connected to the heat intensity, ink coverage, layout and web tension. Other things to consider are the basis weight of the paper and the different moisture retention properties of the printed and unprinted areas of the printed product.
What can I do to solve the problem?
There are a number of things you can adjust if you get issues with fluting. Here are some common solutions that you can try straight away:
- Try to reduce the ink film thickness if you can.
- Remoisten the web after printing, and if you are using silicone, we recommend you to reduce the ratio of silicone to water.
- Where possible, ensure that the gutters in non-image areas have ink coverage. This will help to stabilise the sheet.
- Reduce the web tension. An excessive web tension can cause a ‘shower curtain effect’ in the web.
- Check the humidity and run water levels as low as possible.
- If you are running a dual zone drier, set the first zone up to 10⁰C higher than the second one, to reduce the shock when the paper hits the chill rollers.
- Set the chill rollers so that the paper exit temperature is between 22⁰C to 24⁰C. This is also to reduce the temperature shock on the paper.
If you have completed your print run and notice that you have issues with fluting, don't give up! The waves can diminish after the sections have been trimmed and acclimated to the ambient conditions.
For more specific troubleshooting and help with reducing fluting issues, please contact our technical services.