// Why Dust Removal?... because Dust reduces Quality and Productivity
Dust and loose particles are a big problem in the printing industry:
- Dust adheres to the printing plates, so the ink won’t lay down properly creating hickeys and other print defects in these areas
- The dust mixes with the ink, adhering to the printing plate and or the Anilox, eventually re-depositing on the board leading to spots and defects on the printed image spoiling the finished print quality.
// Frequent machine stoppages, required to clean the print plates, result in signiﬁcant non-productive press downtime.
//So how CAN you remove that dust...?
In the corrugator
By cleaning, early in the process, the web/sheets in the corrugator; plastic, metal, dust particles, and paper strips and angel-hairs will be removed. The total amount of dust pollution in the plant will be reduced.
This will create a positive effect on all printing machines in the entire plant and will have a significant, favorable effect on the overall plant health and safety goals.al part of your health & safety objectives.
And / Or just prior to the print process
Dust and particle removal is highly recommended for printing machines with a high volume of HQ printing. Therefore cleaning the sheets before the first print unit is judicious. Dust adheres to the board the surface by a robust static charge. Even one dust spot will spoil the quality of the printing potentially leading to a press stoppage and expensive downtime.
// How does our Ionization System work?
- A vacuum chamber is located beneath the fixed brushes and electrodes.
- The first set of brushes detach angel-hair and/or larger paper particles and these larger particles are then drawn away from the board by the vacuum chamber.
- The electrodes electronically ionize the Oxygen (0₂) and Nitrogen (N) atoms found in the air above, and are designed for press speeds up to 1000 ft. /min.
- While creating an ionic field above the electrodes, the polarity of the electrodes alternates at a frequency of 50 Hz, creating positive and negative ions, which neutralize the static charge of the dust particles.
- As the board passes through the ionization field, the no-longer statically charged dust particles can be loosened, detached by the second brush and drawn away by the vacuum chamber.
// How efficient is the system?
Efficiency of the system will depend on the process; plant cleanliness, the precision of the edge trimming and considering the type of boards being used. Nevertheless, a reasonable goal of 4000-5000 sheets/h, without stoppages caused by dust-related issues, is easily attained. The Return On Investment of our system would be between 18 – 24 months.
// What additional options are available?
- Depending on the machine in question, an automatic board thickness adjustment option is available
- For severe angel-hair problems, the addition of a front rotating brush is available.
- When a dust collecting system is not available, our Centrifugal Dust Collector can be installed
// On what machines can this system be installed?
This system can be installed on nearly every type of printer like Bobst, Bobst DRO, Bobst FFG, Gopfert, BGM, Emba, Celmacch, MHI, LMC and many more!
// How does a Corona System work?
- This system has upper and lower electrodes.
- Both electrodes have a voltage of 15 000 volts and alternate between positive and negative, 7000 times per second
- A corona field between the electrodes is created, ensuring that all particles on the board surface between the electrodes are polarized
- Since the corona field exists only at maximum energy, during the interim periods the dust now with a static charge will move toward one of the two electrodes.
- The detached dust particles from both of the surfaces and will be collected at the electrodes, and vacuum exhausted away.
- Both sides of the board is cleaned.
This design is especially made for fine paper dust. Additionally to remove metallic particles and/or angel-hairs the system has two fixed brushes at the board infeed side.
// How efficient is our system?
Again, the efficiency of the system will depend on the process; plant cleanliness, the precision of the edge trim-ming process and the type of boards in use. Nevertheless, a reasonable goal of 4000-5000 sheets/hour, without stoppages caused by dust-related issues, is easily attained. The Return On Investment of our system is between 18 – 24 months.
// What additional options are available?
- Depending on the machine, an automatic board thickness adjustment option is available
- In plants with severe angel-hair problems, adding a rotating brush in front is possible
- Where a dust collecting system is not available, our Centrifugal Dust Collector can be installed.
// This board cleaning system can only be installed on these machines!
The system can be installed only on Bobst Flexo, Bobst Flexo Vision, Bobst Dynaflex, Bobst Masterflex A, L & HD.
// The dust removal system consists of:
- 2 ionization bars
- 2 vacuum chambers
- 4 brushes
- 2 infeed plates
- 4 pneumatic cylinders to move/adjust the system
- 2 vacuum pumps
- Complete piping
- And an electrical cabinet
The system is integrated in the machine control. At job changes or machine jams, the upper part is raised rapidly to avoid damage to the system or cause machine stoppages. The vacuum levels are set though pump frequency converters based on the board and web thickness.
Our Centrifugal Dust Collector can be added to collect the dust particles
// Depending the available space on the corrugator, the system can be either installed after the slitter or cross-cutter
// How effective is the system?
- Our experience and customer feed-back shows that jobs with full surface printing; the time between press-stoppages for dust-related issues has been extended by two or three-fold or a decrease in down time of 50 - 67 %
- Overall print quality will be increased, leading to a reduction in customer complaints, increased customer satisfaction, and significant lower job costs.
- With less dust floating around, a significant and favorable effect on the overall plant health and safety goals is achieved
// Centrifugal Dust Collector (Cyclone)
Our Centrifugal Dust Collector, sometimes called a cyclone, a cyclone separator, cyclone filter or cyclone dust collector, can be used on printing machines for the removal of paper and dust particulates from the airstream coming from different components of the machine.
A centrifugal dust separator essentially consists of four parts: the in-feed cylinder (above), cone (middle), the particle collection container (below) and the dip tube which is centrally mounted in the in-feed cylinder.
A high speed rotating air flow is established within the conical container called the cyclone. The air flows in a helical pattern, beginning at the top (wide end) of the cyclone and ending at the bottom (narrow) end before exiting the cyclone in a straight stream up through the center of the cyclone and out the top. This tapering of the cone causes the rotational speed of the air to increase to such an extent that most of the contained paper and dust particles are thrown by centrifugal force against the cone walls. As they decelerate, they separate from the airflow and trickle down into the collection container.
The main advantage of a centrifugal dust separator, since filter cartridges or filter mats are not used, is that maintenance becomes a non-issue while ensuring that its performance is always optimal. The sizing of a centrifugal dust separator is determined by the air volume to be treated. Higher air volumes result in greater separation or lower cut-points (ie lower particle size).
Duo-Technik engineers Centrifugal Dust Collectors for different air volumes to maximize efficiency with low particle cut-points.