In-house flexo plate prepress – cost or investment?

In-house flexo plate prepress – cost or investment?

urządzenie do obróbki płyt fleksograficznych

Virtually every day we hear about multi-million investments made by printers, but most of them go to the print department. They are buying increasingly modern printing machines, with more colours, with additional sections and technical innovations. Owners of printing businesses believe that it is the printing machines that bring profits. But in the end, printing is not only printers and their machines. It is becoming more and more important for efficiency, flexibility and higher competitiveness to own an in-house, independent prepress.

For many companies, printing plate preparation is an outside service provided by a company that delivers ready-made printing matrices.  Many people think it is convenient. The printing facility sends over the project and provides printing parameters. The next day, at the earliest, it gets the ready-made printing plates. Well, that’s it – the next day!

What happens when a very important client is waiting to accept the printout and it turns out that you need to urgently replace the plate?

Do you know the exact costs of effective cm2 of a flexographic matrix purchased from an outside prepress provider?

How do you price the time you need to wait to get a new plate? How do you price convenience and security? Is it even possible?

Will having an in-house prepress allow us to reduce costs, reduce the preparation time of polymer plates and increase efficiency?

It helps to imagine a situation when after receiving a new order we can provide the printing department with ready-made matrices within an hour.  Even if something needs to replaced, we will be able to react immediately.  No outside prepress will provide us with such convenience and flexibility. Only setting up in-house prepress makes it possible to fully control the preparation process provided that you choose wisely…

It is hard to persuade printers to adopt any technology, but it is a good idea to encourage them – before they take a decision – to learn about experiences and observations coming from years of practice and work with water-wash flexo plates we have done here at Print Systems.

The first piece of equipment necessary for prepress is the UVA plate setter, which some still call the copy frame.  Many years ago as we started our adventure with flexography everybody was excited about oxygen inhibition. It was supposed to make small dots pointed, lower than screens, which allowed more delicate printing with a smaller minimal dot and smaller dot gain.  Today everybody is excited about Flat Top technology – a flat top dot allowing 1:1 reproduction. In the quest for the highest quality printers were buying strong copy frames, with high energy exposure. Now we know that this wasn’t a bad road but at some point, it exposed printers to problems related to heightened temperature during exposure.

Long exposure to strong light makes the temperature at the exposure table rise to more than 50 degrees C. Lamps warm up to only slightly lower temperatures. In this situation, the Japanese manufacturer of TOYOBO plates and other flexo plates manufacturers say that polymer continues to polymerize, but increased inhibition of oxygen begins to slowly damage the finest elements of our matrix. Badly or incompletely formed dot tops are produced, with pitting and damage that make printing poor quality and unstable.

Naświetlanie UV_Print_Systems

To prevent this, the temperature of the table and the lamps is controlled in many machines. In the event of an increase above the programmed temperature, it is automatically reduced using cooling systems. Individual solutions are used in the processors depending on the customer’s expectations. Radiators for distributing temperature are used or strong ventilators for high-quality heat exchangers are installed outside the copy frame. Interestingly, many of our clients have experience with this type of device and confirm that with a stabilized polymer exposure environment you can reduce exposure time with a better quality result, which is getting smaller, more stable and flat dot – FLAT TOP.

The next important element of prepress is the thermal processor with the developer and washing unit. Modern machines of this type use a range of solutions and conveniences that make their operation very simple, and applied technology has a beneficial influence on the final quality of the matrix.

What merits special attention is the system of adjusting the silicone plate relative to the brushes in the washout unit. In contrast to old-generation machines in which the operator had to adjust the brushes by raising or lowering them, which often caused problems in everyday use, adjustment and cleaning the processor.

Szczotki_Print_Systems

 The old way of adjusting the brushes

The system of adjusting the silicone plate is installed in new-generation machines. It is controlled with a touch panel that can save up to ten different settings for different plate thicknesses.

Wymywarka_Panel_Print_Systems

WO63 panel photo

Apart from a very easy, intuitive machine operation, this solution makes it possible to set optimal washout parameters for each medium to obtain the highest quality.

All new processors offered by Print Systems are equipped with a membrane filtration system. Years of experience allow me to conclude that this is the only and the most effective method of filtering the solvent together with the remains of the water-wash flexo polymer.

Filtration makes it possible to provide clean water to the washout process every single time. As a result, each plate is washed out in optimally the cleanest solution with unchanged parameters, which is very important for maintaining high-quality standards of matrices.

An additional advantage is that all processors can be made entirely from acid-proof sheet metal, which significantly extends their life and makes handling, cleaning, and maintenance very easy for the operator.

It is also worth mentioning the economic aspect. Often the processors for solvent-washed plates are much more expensive than systems for water-wash plates. You must also take into account toughening regulations relating to CO2 emissions and limiting the impact of other factors that threaten the environment. Solvent-based processors come hand in hand with investment in advanced ventilation systems, thermal oxidizers, etc.

In the case of the water-wash plates by the Japanese company TOYOBO, the solution resulting from the solvent – water, detergent, and polymer can be mostly drained off to the sewage system, and the rules governing this are specified by the local sewage operator. Small amounts of detergents used in this process have a similar composition to chemicals used in automatic dishwashers and are 100% ecological.

Therefore, the costs of the cleaner/detergent are disproportionately lower than the costs of the solvents normally used to wash out flexographic matrices that have to be then distilled and disposed of.

These are only selected issues that merit attention when facing a choice of technology and equipment to start an in-house, independent prepress for photopolymer matrices.

It’s good to remember that in the scale of the whole operation the cost of polymer, the raw material, is not crucial. What often hides behind this expense is several benefits that may prove very important in the long-term cooperation with the supplier: service, safety, convenience, quality, process standardization, time, and as a result … savings.

Author:

Jarosław Chudziński_Print_SystemsJarosław Chudziński

Expert, experienced photopolymer plate processing and flexographic printing practitioner. Vice President and co-owner of the company Print Systems. Responsible for the implementation and maintenance of technology based on water-wash plates by the Japanese company Toyobo. He advises and cooperates with all the major labels and packaging printers in Poland, in Italy and the Balkans.