If you’ve ever wondered how the flexographic printing process works, image carrier services are an important component. Flexographic printing plates or cylinders are created after an image has been provided and edited for the printing process.
Every image carrier that leaves a company, is a meticulously engineered manufacturing process. This process is outlined below to take you on a virtual tour of what happens behind the scenes and to demonstrate how quality and precision are maintained throughout the production journey.
Flexographic Image Carrier Elastomer Sleeve Production in 13 Steps:
The process varies depending on customer requirements such as elastomer selection, adhesive requirements, dimensional considerations, and others — however, for the vast majority, the process is as follows:
- Receiving / Incoming Inspection
All new and used sleeves, integral shafts, demounts, and narrow web units are thoroughly inspected to ensure that the specifications on bearing journals, bores, gears, and so on are within tolerance. Units that pass inspection are then placed in the production steam. Any specification that is found to be out of tolerance is presented to the customer as a repair or replacement option.
- Base Preparation
The bases are then meticulously cleaned and prepared for the next step.
- Rubber Wrap
Special elastomer strips are fed into a machine where they are heated and extruded through multiple strainer screens to ensure there are no contaminants in the finished product. The units are then carefully primed and adhered to while adhering to controlled thickness specifications. Depending on the material used, there could be one to three applications.
- Autoclave / Vulcanization
The wrapped image carrier is cured in a dry-heat Autoclave. During this process, all seams on the sleeve’s surface are removed. Dry heat is used to prevent moisture from deteriorating the cylinders. Most rubbers must cure for 24 hours before the next steps can be taken.
- Rough Grind
When the curing process is finished, the rollers are cooled to room temperature. After removing the vulcanizing tape, the rollers are rough ground or thermo-cut to a specified amount larger than the final finish diameter.
This is determined by the elastomer and stock removal method used. At this point in the process, the hardness of the rubber is initially verified to be within specification.
This step’s goal is to remove any excess rubber from the image carrier.
- Finish Grind
Before the final grinding, the rubber is stabilized for 24 to 48 hours. Temperature control is given special attention during the finish grinding process to ensure dimensional stability.
To precisely grind off the same journal, bearing, or bore that the rollers run off of on the press, a variety of precision tooling and specialized hardware are used. This aids in maintaining as much concentric rubber surface-to-impression roller contact as possible.
Once the roller has reached the desired finish diameter, the surface is micro-polished to ensure a smooth, consistent finish, roller after roller. The company’s QC department monitors RA polisher recording on all jobs to ensure that the rubber surface finishes are consistent time after time.
- Laser Engraving
There are three digital direct laser engraving systems. These make use of both CO2 and YAG laser technology, which can work independently or simultaneously during the engraving process.
This provides the full range of ITR engraving options. The digital engraving files can be supplied by the customer or created by in-house graphics technicians in collaboration with the end user.
- Print Proof
An inspection process begins after the image has been engraved into the roller and cleaned. The first step is to create a physical image proof of the roller.
This step ensures that the ground surface is concentric, that the roller is free of low spots or surface defects, and that all engraved elements are printed and provide a sharp transfer. Once the proof has been approved, the roller is thoroughly inspected to ensure that all internal and customer-specific specifications are within tolerance.
- Final Clean-up
The roller is cleaned up completely. This removes any non-printing rubber that may have remained on the roller after engraving. After that, the roller is thoroughly cleaned and wrapped in UV-resistant paper before being removed from the machine and delivered to the customer.
- Step 12: Final Inspection
During this phase, design, width, depth, and other flexo printing flaws are all checked for.
- Step 13: Shipping
The roller must be shipped with extreme caution. A variety of protective wraps, end shock protection, corrugated tubes, boxes, and wooden and steel crates are used.
A Company’s Contribution to Flexographic Image Carrier Production:
Every step of the flexographic image carrier manufacturing process is completed with one goal in mind: producing a final product that will please customers and assist them in meeting their printing objectives.