"Star Peripherals from Heidelberg" Article Series, Part III
The new DryStar 3000 and DryStar 3000 UV dryer systems from
Heidelberg deliver maximum production speed thanks to innovative
drying technology
The Heidelberger Druckmaschinen AG (Heidelberg) Star System covers the whole system solution incorporating peripherals for Speedmaster presses. The key peripherals are connected to the press via the Prinect CP2000 Center control station by means of a CANopen data bus (CAN = Controller Area Network).
In the first two articles in the series devoted to innovations on the peripherals market, we presented the AirStar 3000 air supply, CoatingStar coating supply and InkLine 3000 ink supply system. The third part deals with the DryStar 3000 and DryStar 3000 UV drying systems from Heidelberg.
The Heidelberger Druckmaschinen AG (Heidelberg) Star System covers the whole system solution incorporating peripherals for Speedmaster presses. The key peripherals are connected to the press via the Prinect CP2000 Center control station by means of a CANopen data bus (CAN = Controller Area Network).
In the first two articles in the series devoted to innovations on the peripherals market, we presented the AirStar 3000 air supply, CoatingStar coating supply and InkLine 3000 ink supply system. The third part deals with the DryStar 3000 and DryStar 3000 UV drying systems from Heidelberg.
DryStar 3000 - the patented round-nozzle dryer
As production speeds increase, the time the sheet is retained under the dryer becomes shorter and shorter while air turbulence in the delivery increases. At speeds of 15,000 to 18,000 sheets per hour, an innovative drying system is required to dry dispersion coatings sufficiently. This is particularly true for high-gloss coatings, ultra-thick coatings and when printing on absorbent cardboard.
The key to efficient drying is air application. The more hot air is applied to the sheet and the greater the speed at which it is delivered, the better the drying result. The temperature of the hot air and the performance of the IR lamps play a minor role. However, because more air also means that the sheets contact or scratch more easily, particular attention must be paid to integrating drying and sheet travel.
With the DryStar 3000 Combination, Heidelberg is offering the perfect solution for drying dispersion coatings in the delivery. The core component of every DryStar 3000 Combination is its patented round nozzle technology. The air is heated to 100 °C and applied to the sheet via 57 round nozzles. The special shape of the nozzles accelerates the speed of the air to 33 meters per seconds - fast enough to penetrate the ambient air drawn along by the sheet (laminar layer) and drive the water out of the dispersion coating.
The design of the round nozzles ensures that the high air speed does not impair sheet travel. The nozzles are so small they can even be positioned between the infrared lamps. This extends the available drying section, up to 100 percent more hot air can be applied, and the even air application stabilizes sheet travel at the same time. Instead of delivering massive amounts of air through a few hot-air blades, the DryStar 3000 Combination provides more air than any other dryer and distributes it evenly. Hardly any air is blown under the rear edge of the sheet and the sheet is not smudged.
As production speeds increase, the time the sheet is retained under the dryer becomes shorter and shorter while air turbulence in the delivery increases. At speeds of 15,000 to 18,000 sheets per hour, an innovative drying system is required to dry dispersion coatings sufficiently. This is particularly true for high-gloss coatings, ultra-thick coatings and when printing on absorbent cardboard.
The key to efficient drying is air application. The more hot air is applied to the sheet and the greater the speed at which it is delivered, the better the drying result. The temperature of the hot air and the performance of the IR lamps play a minor role. However, because more air also means that the sheets contact or scratch more easily, particular attention must be paid to integrating drying and sheet travel.
With the DryStar 3000 Combination, Heidelberg is offering the perfect solution for drying dispersion coatings in the delivery. The core component of every DryStar 3000 Combination is its patented round nozzle technology. The air is heated to 100 °C and applied to the sheet via 57 round nozzles. The special shape of the nozzles accelerates the speed of the air to 33 meters per seconds - fast enough to penetrate the ambient air drawn along by the sheet (laminar layer) and drive the water out of the dispersion coating.
The design of the round nozzles ensures that the high air speed does not impair sheet travel. The nozzles are so small they can even be positioned between the infrared lamps. This extends the available drying section, up to 100 percent more hot air can be applied, and the even air application stabilizes sheet travel at the same time. Instead of delivering massive amounts of air through a few hot-air blades, the DryStar 3000 Combination provides more air than any other dryer and distributes it evenly. Hardly any air is blown under the rear edge of the sheet and the sheet is not smudged.
More air, shorter distances and perfect coordination
In addition to maximum air application - between 1,200 und 3,600 square meter per hour on a DryStar 3000 Combination - the distance between the dryer and the sheet is also crucial. With the DryStar 3000 Combination, the distance between dryer and sheet has been reduced to 80 millimeters. A reduction of a single centimeter increases drying performance by around 5 percent. This means a productivity increase of 25 percent with no increase in energy consumption.
Coordinating the dryer with the gripper bar is another important factor. When using the Preset Plus Delivery in conjunction with the DryStar 3000 Combination, this problem does not occur thanks to the round-nozzle technology of the dryer and the optimized, aerodynamic gripper-bar geometry.
The drying of the lateral sheet edge is also critical for many rival systems. In order to dry the maximum sheet format sufficiently, heat must be applied over the edge of the sheets. This means the heated area would have to be extended by 100 to 200 millimeters, but on most presses, the side wall does not allow this. Heidelberg offers a solution to this problem in the form of edge zone compensation. A special IR lamp is used to apply twice as much infrared radiation to the sheet edge than to the center of the sheet. This removes all obstacles to processing sheets printed almost right up to the edge.
Meik Drake of Drake & Huber in Bad Oeynhausen is impressed with the DryStar 3000: "With my new Speedmaster XL 105, production speeds of 18,000 sheets per hour are the everyday norm. That's almost 6,000 sheets per hour more than on all other presses. The DryStar 3000 ensures this is also the case for jobs requiring large quantities of coating and therefore represents a real increase in productivity," he adds.
In addition to maximum air application - between 1,200 und 3,600 square meter per hour on a DryStar 3000 Combination - the distance between the dryer and the sheet is also crucial. With the DryStar 3000 Combination, the distance between dryer and sheet has been reduced to 80 millimeters. A reduction of a single centimeter increases drying performance by around 5 percent. This means a productivity increase of 25 percent with no increase in energy consumption.
Coordinating the dryer with the gripper bar is another important factor. When using the Preset Plus Delivery in conjunction with the DryStar 3000 Combination, this problem does not occur thanks to the round-nozzle technology of the dryer and the optimized, aerodynamic gripper-bar geometry.
The drying of the lateral sheet edge is also critical for many rival systems. In order to dry the maximum sheet format sufficiently, heat must be applied over the edge of the sheets. This means the heated area would have to be extended by 100 to 200 millimeters, but on most presses, the side wall does not allow this. Heidelberg offers a solution to this problem in the form of edge zone compensation. A special IR lamp is used to apply twice as much infrared radiation to the sheet edge than to the center of the sheet. This removes all obstacles to processing sheets printed almost right up to the edge.
Meik Drake of Drake & Huber in Bad Oeynhausen is impressed with the DryStar 3000: "With my new Speedmaster XL 105, production speeds of 18,000 sheets per hour are the everyday norm. That's almost 6,000 sheets per hour more than on all other presses. The DryStar 3000 ensures this is also the case for jobs requiring large quantities of coating and therefore represents a real increase in productivity," he adds.
DryStar 3000 UV - the productivity boost for UV printing
The new DryStar 3000 UV does for UV printing what the DryStar 3000 does for conventional jobs. This is primarily thanks to the re-calculated lamp geometry and reflector coating. UV inks need a high energy peak in order to trigger cross-linking and hardening of the ink. The new dryers have therefore been designed so that the beam is focused with optimum precision onto the surface of the sheet. Because different geometries are used for interdeck and end-of-press dryers, there is no need to make compromises between the high energy peak, radiation applied to the blanket, and installation space. The result is an increase of up to 20 percent in production speed.
The new DryStar 3000 UV does for UV printing what the DryStar 3000 does for conventional jobs. This is primarily thanks to the re-calculated lamp geometry and reflector coating. UV inks need a high energy peak in order to trigger cross-linking and hardening of the ink. The new dryers have therefore been designed so that the beam is focused with optimum precision onto the surface of the sheet. Because different geometries are used for interdeck and end-of-press dryers, there is no need to make compromises between the high energy peak, radiation applied to the blanket, and installation space. The result is an increase of up to 20 percent in production speed.
Less heat transfer and better register
A special feature of the DryStar 3000 UV is its blue shimmering URS reflector (URS = UV Reflection System)*. The URS coating has over sixty layers that reflect the UV light, while the hot infrared portion is absorbed and dissipated via the water cooling system. The thermal load to which the substrate is subjected is much lower than with cheap aluminium reflectors. Post-baking of ink and dirt into the reflector surface is also prevented. With other systems, performance noticeably slackens off after just a few weeks, while the reflective properties of the DryStar 3000 UV remain constant over several years.
The DryStar 3000 UV also features tool-free lamp exchange (FLC = Fast Lamp Change). The cooled UV lamp can be exchanged in less than a minute (as opposed to around 20 minutes for other systems). The interdeck dryer can also be changed over quickly. The air supply, power and, in the case of the Speedmaster XL 105 UV, water contacts are connected via quick-release couplings. The printer can therefore change the dryer in a few minutes with no need for tools. Waiting times before and after washing are also a thing of the past with the DryStar 3000 UV and InstantStart option. The dryer switches to standby and washing can start immediately - the UV press behaves almost identically to a conventional offset press.
* URS = trademark of IST Metz GmbH
A special feature of the DryStar 3000 UV is its blue shimmering URS reflector (URS = UV Reflection System)*. The URS coating has over sixty layers that reflect the UV light, while the hot infrared portion is absorbed and dissipated via the water cooling system. The thermal load to which the substrate is subjected is much lower than with cheap aluminium reflectors. Post-baking of ink and dirt into the reflector surface is also prevented. With other systems, performance noticeably slackens off after just a few weeks, while the reflective properties of the DryStar 3000 UV remain constant over several years.
The DryStar 3000 UV also features tool-free lamp exchange (FLC = Fast Lamp Change). The cooled UV lamp can be exchanged in less than a minute (as opposed to around 20 minutes for other systems). The interdeck dryer can also be changed over quickly. The air supply, power and, in the case of the Speedmaster XL 105 UV, water contacts are connected via quick-release couplings. The printer can therefore change the dryer in a few minutes with no need for tools. Waiting times before and after washing are also a thing of the past with the DryStar 3000 UV and InstantStart option. The dryer switches to standby and washing can start immediately - the UV press behaves almost identically to a conventional offset press.
* URS = trademark of IST Metz GmbH
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