What is Rotary-Screen Printing Machine?

by Engr. Kh. Mashiur Rahman | Apr 16, 2019 | Printing & Packaging

Rotary-Screen Printing Machine

Rotary-screen printing machine used for both carpet printing and textile printing but the main difference of the rotary screen printing machine depend on between the carpet and other textile printing according to the type of squeegee used. All carpet squeegees are considerably larger and wider opening end rings are used. The standard print width is usually 4 m, so considerable storages space is needed for many screens and design used by a typical carpet factory. The screens are made by Galvono Nickel of a fairly heavy gauge (0.3-0.5 mm thick) with a much coarser mesh(20-30).Lacquer screens are not used for carpet printing. Standerd rotary screens give a repeat pattern of 1 m but a larger screen can give repeat sizes up to 3 m printing of oriental carpet designs. Read about  Offset Printing Machine

Advantage of the Rotary- Screen Printing Machine:

• More productive than older flat screen machine.
• Print speed is 15-20 m/min.
• The machine occupies much less space.
• Labor costs are lower.
• With actuating mechanism it is possible to print repeat pattern 2-3 m for bordered oriental square designs.

Disadvantages of the Rotary- Screen Printing Machine:

• Uses higher cost of galvano nickel screens.
• Screen changing time longer.
• There is also a tendency for carpet to spoil during stoppages(Cause: the paste tends to flow fairly easily through the coarser mesh screen when it is stationary)
• The use of thickeners with short flow properties can help prevent leakage from the screens when stopped.

Minimizing dye paste use in rotary screen printers

A water-saving system on the washing machine for the barrels or screens not only reduces water consumption, but also results in a more concentrated waste load. In case the washing process takes place in three stages, in the first stage residual water from the second and third stages is used that was temporarily stored in a recirculation reservoir. The strongly contaminated wastewater resulting from the first stage is discharged to the water treatment system and then to the sewer. In the second stage of the washing process, both the water intake and the water outlet are connected to the recirculation reservoir. Finally, in the third stage of the wash cycle, the barrels or screens are washed with clean water. The residual water resulting from this last stage is then fed into the recirculation reservoir, which is thus replenished. In the recirculation reservoir and on the intake side of the water pumps, filters make sure that pollutants of all sizes are removed from the water, thus preventing blockage of the spraying system.
By implementing a water-saving system, the water consumption of a specific machine can be reduced by 80%.
A water-saving system is applicable for the cleaning of screens, squeegees and barrels.
A water-saving system can be installed on existing machines or a new system can be purchased with an integrated water-saving device. The additional costs compared to washing machines without water-saving is approximately EUR 10 000 for screen washers and EUR 3 000 for barrel washers.

In rotary screen printing, for every colour there is a screen, a supply system for the colour and a paint kitchen inventory. After every printed batch the system has to be cleaned thoroughly. As a result, considerable amounts of dye paste end up in the wastewater, because the volume of the machines is significant and a substantial quantity of dye paste stays behind in the system. Minimisation of the system volume on rotary screen printing machines has become a reality with the introduction of a new pump and squeegee system.

Environmental effect

Usually, the system volume of rotary screen printing machines varies from a few kilograms to maximum 10 kilograms, with an average of 5 kilograms. With the new pump- and squeegee system it has become possible to reduce the system volume per recipe by approximately 60% in comparison with a conventional squeegee system. This means a significant reduction of the use of dye paste. Furthermore the system allows to return a large part of the excess paste into the system. This way 1,5 kilograms of dye paste per pattern can be recycled.
A second option to reduce the excess paste and pollution from the rinse water is the use of a rubber ball in the squeegee. After printing, the ball (25 – 30 mm diameter) scrapes the squeegee clean and the excess paste is transported back to the dye kitchen.

Reduction of dye paste emissions and water consumption. The quantity of washed out sludge can be reduced by 5 – 35 % at the overall corporate level.
This measure is applicable as a replacement investment for rotary screen printers.

Conclusion

The additional costs are around EUR 50 000 (INR 2 500 000) Savings can be achieved on raw materials and auxiliary materials as well as wastewater charges. Because of the additional costs this measure is especially feasible when the rotary screen printers are being renewed. End of Rotary-Screen Printing Machine article

What is Industrial Inkjet Printing Machines?

by Engr. Kh. Mashiur Rahman | Apr 16, 2019 | Printing & Packaging

Industrial Inkjet Printing Machines

Industrial Inkjet Printing Machines is a stream of liquid in the form of a dye solution produced by a spray nozzle. It is an innovative method for the application of wonderful patterns to the textile materials whose small droplets of dye solution are ejected and applied to a precise location. It is mainly used to produce pattern on carpet. Average speed =625000 drops/ sec. Design produce by CAD. Read about Digital Inkjet Fabric Printing Machine

• Unlimited color is produced.
• 0 (zero) waste printing.

Types of Ink-jet Printing:

It is mainly two types.

1. Continuous Ink-jet Printing.

2. Drop-on-Demand (DOD) Ink-jet Printing.

In continuous ink-jet printing the link is forced at high pressure through a small nozzle of (10-100) micros in diameter. Thus a continuous stream of dye droplet is format which is directed onto a substrate. This is achieved at a frequency of 625 KHZ. The droplets are selectively charged with negative electric charge. There are two application methods.

1. Multilevel application:

Charged drops are used for printing and unchanged drops mare collected in a catcher. It is possible to control up to 30 different dot possible per nozzle. The ink is collected in a catcher and recirculated.

B. Binary Application:

The uncharged drops are used printing which the charged one are collected by the catcher. Only one dot position per nozzle is possible. The  ink is collected into catcher and recirculated.

1. DOD:

Here droplets of color produced by nozzles that open or closed quickly on command from a computer are fixed into the substrate passing beneath the nozzles. Here the dye liquor is jacketed by a suitable electromagnetic valvs.Located in dye liquor feed tube in a pre determined sequence determined by the pattern to be printed. It is also called chromo tonic process.

Ink formation recipe-

Pigment- 2-4%

Binder-10-15%

Additives-1-2%

Fixer-1-2%

Water is required.

Design is made by-

1. Scanning.

2. Create design in CAD. 3. Directly formatting to digital pattern on machine

Steam Fixation of Prints:

Very considerable energy would have to be expended to dry the carpet (having about 250 pick up of print paste) the steaming time is much reduced when the process is carried out on wet carpet. The first requirement of the steamer is that must be capable of transporting the material through its interior without affecting the quality of goods and without allowing unfixed dye to mark off on to other parts of the print. The second requirement is that the steam quality must be such that dyes are fixed as rapidly as possible, with out any tendency to being or any loss of clarity of print.

Advantage of Ink-jet Printing:

Digital pattern data from CAD system can be used immediately to drive the printer, hence allowing quick customer response.

There are no screens to handle and there is instantaneous change of pattern and hence much improve machine occupation making short runs economically viable for comparison  changing screens on an eight color rotary screen carpet printing machine takes about 1 hour.

No screen replacement or storage space is required.

No physical pressure is exerted on the carpet pile therefore optimum surface appearance results.

Large repeats are possible without resorting to special techniques.

Disadvantage of Ink-jet Printing:

Skill worker need.

Very expensive.

NEW FEATURES
• Higly configurable powerful Center Side QC module
• Completely new powerful recipe editor
• Manual match modification to adjust match results in the results table
• Textual and graphical lab recipe history
• Impressive and powerful 3-D dyestuff display in color space facilitates dyestuff selection for difficult matches
• Manual smartmatch housekeeping with computer aided grouping of similar points supported by exciting 3D graphics
• Green tile calibration for improved calibration reliablility
• Improved match input dialog allows to measure new substrates directly and simplifies selection of dyesets
• Save and restore match parameter settings
• Improved stock solution volume calculation reduces liquor amount if necessary

Conclusion

Usage of Industrial Inkjet Printing Machines for stock solution configurable per client. Restricted users can not delete or rename data, can not change important settings

What is Flat Screen-Printing Machine?

by Engr. Kh. Mashiur Rahman | Apr 16, 2019 | Printing & Packaging

Flat Screen-Printing Machine

Initially there were two types of types of flat screen-printing machine for carpets namely BDA machine (Manufactured for a time by Single Cobble) and that produced by peter Zimmer. Read about Rotary-Screen Printing Machine

The BDA machined in operation until 1990 but none is still in use. In this machine a reservoir of dye was confined between the blades of a double squeegee passed. To achieve this conventional rubber transport blanket was replaced by an endless belt of perforated metal platens which carried the carpet forward when the screens were lifted after each printing cycle. The screens are covered with (60-70) mesh polyester screen fabric. Despite the relatively low vacuum used (about 75 mm water gauge) it was possible to obtain good penetration on fairly long pile carpets. The maximum speed of the BDA machine is about 5 m/min.

Study on Carpet manufacturing (Machines &unlike dyeing process) technology first we thought its easy topics for our senior project work. But when we started our work that time understood what a hard project.

First we wanted to know where carpet is made. We searched the internet and got Bengal Carpet is the only carpet manufacturer in Bangladesh. First we went their corporate office in 37 Kamal Ataturk Aavenue, Banani-Dhaka-1213. Then our honorable course instructor gave us a forwarding letter to Bengal carpet for 10days thesis work. But after 15 days later there was no Bengal carpet office. That time we were disappointed about our project work. Then we told about Bengal carpet to our honorable Instructor . Then she tried to search about the Carpet manufacturing company in Bangladesh. Then she told us to go carpet show rooms at Elephant road in New market. Then we went new market and tried to search about Carpet manufacturers in Bangladesh. Then we understood Carpet were the only Carpet Importers in Bangladesh. They told us there is no Carpet manufacturer in Bangladesh. We also disappointed about our Project work.

Bengal carpet was one of the Carpet manufacturers in Bangladesh. is company produced different types pf Carpet & gives them different printing effect. In Millat camp and Society handicrafts also produced different types of carpet in Bangladesh.

But now a day’s carpet demand decreasing day by day.

Most of the people in our country live in under poverty level and they have no enough idea about carpet. Because 85% of them depends on agriculture and 15% of them depends on Job, business etc. In Bangladesh more than 50% people are supporting their live by hand to mouth system.. So in 15% people only 8% are very rich. So its easy to understand what would be the carpet market in Bangladesh.

So demand of the carpet for Bangladeshi people is not mandatory with their life. Few people in a city who are using carpet in hotels, show rooms and also using house for decorative purposes. On the other hand they wanted to use carpet in winter.

I f a country 10 people were consumer a product so what will be the demand & market of this product?