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Barred blanket production

Service to Printers

A Conversion Manual

Quality Printing Blankets

Blanket Format Geometry ought to be kept within the Strictest Coherency with the Blanket Thickness Tolerance.

It is just commonsense that as from batch manufacture and especially throughout the Barred Blanket Production process, storage, cylinder dressing and the entire printing life cycle the squareness and the thickness tolerances (including those of the blanket layers) must constitute the closest possible match to the overall blanket thickness tolerance specified by the blanket designer.

IberoWIN Conversion System is a custom developed Business Management Application that covers to the very least detail Blanket Converter’s activities, from model specifications and raw material purchases to the delivery of ready-to-use formats according to the most stringent printer needs and preferences.

IberoWIN Conversion Manual

The Production Menu of IberoWIN Conversion Manual sets an exhaustive range of “standard Executions” defining not only Blanket Format cutting Dimensions and shape but also Bar model and execution details. Except for this core segment, executions are interactively “personalised” according to the particular press model and unit specifications. Personalisation takes also into consideration the needs, preferences, storage requirements and logistic details of each particular printing operation.

Copies of this Application, which sets New Standards of Blanket Conversion Professionalism and Offset Printing Efficiency are obtainable from Deltatec – Tecnologias de Sistemas, Lda.      Read more

The Instructions contained in this Manual translate the unique know-how acquired during 30 years of close contact with the shop floor both at the printers and blanket conversion operation, duly supported by persistent Laboratory testing and research.

We are simply extending to the Sheet Fed Users Community the best available procedures that make it possible for successful web printers to dress their blanket cylinders very seldom.

Some of the internal tensions built-in during the production process will be released during Blankets’ lifetime.

With blankets, a straight line cut will produce two distorted format edges. This becomes particularly critical for Barred Blanket Production at the gripper egdes, where the bars are to be fitted.
How much the format edges become distorted, depends on the technologies adopted not only by the fabric factory but also by the blanket manufacturer.
Distortion is easily measurable on the edges that define the format length.

Each blanket model has its distortions determined experimentally.

Unless corrective provisions are taken, bars will be fitted to slightly convex gripper edges.
Barred Blanket Production becomes thus particularly hazardous and the resulting printing results are certainly not only imprecise but also unpredictable.
Web printing performance is particularly sensitive to format squareness and bar parallelism.
But there is no valid reason why Sheet Fed Performance should be immune to poor format geometry.

A Cutting Table Designed from scratch for Reinforced Rubber Composites.
Our cutting equipment includes a set of provisions to minimise format distortion:

The permanent cutting blade moves always on the same track, with a format cutting capacity of up to 2300 mm.

It is electronically assisted to warrant minimum blanket reaction.

Blanket area adjacent to the cutting operation is duly confined, thus effectively reducing blanket movement and distortion.
The position of the full width movable stop is precision driven on both sides of the cutting table. A laser beam controls its exact parallelism to the cutting track.
Very efficient laser cutting was tested but discarded due to environmental reasons.

Different blanket manufacturing technologies led to the development of three distinct cutting methods.
After the typical blanket model distortion pattern is determined the respective figures are included in its specifications sheet.
At the operators’ choice, those values may be automatically considered, thus enabling to obtain the exact dimensions of each format.

Available origin cutting options are readily available.

A handy preview of format cutting arrangement is available for each cutting option including the respective amount of waste area.

Area usage diagrams and respective data will reflect material distortion options.

Prior to bar fitting, each Web format is obtained in two stages:
In the first stage two simple cuts define format gross dimensions.
At a later stage, four additional trimming cuts are made to the final format dimensions.

The following images and written instructions illustrate the Barred blanket Production process.
Printing Blanket cutting procedure

Procedure to correct the lack of linearity and squareness of the roll feeding edge.

Checking printing blanket squareness

Checking if sequential edges form a perfect right angle.

Printing Blanket strippable area

Precision depth cut Operation in preparation of a stripped area.

QC check of Printing Blanket Squareness

In-line quality control of cut-format squareness, before corners trimming and bar application.
When all the parameters are optimised, diagonal values may fall within a tolerance as little as 0,3 mm.

Printing Blanket Feed identification

When the lead and the trail edges use the same bar model, web blanket formats have the lead edge duly identified.
Metal decoration multinationals are already joining the acquaintance process to cleaner prints.

printing Blanket corner trimming

Corner trimming data and cutting sequence.

Printing Blanket Stripping procedure

After solid glue application, time comes to strip out unwanted surface area.

Printing Blanket Squareness Inspection

Final squareness check prior to initiating the packing procedure.

Printing Blanket Bending Line

A guide line is drawn to define the exact bending distance into a narrow channel web press.

Printing Blanket Surface Protection from Bar Edges

Photo illustrates the standard conditioning instruction for sheet fed blankets.
Written notes remind the operator about extra recommendations.

  • Detailed instructions are contained in PCKOUT – the standard for web blankets.
  • At the present instance it is further applicable the particular procedure illustrated in PKOUT1.
Barred Blanket Production relies on the in-house custom designed IBEROWIN BAR SYSTEM.

The daily use of solid glue provides further practical evidence of the importance of the oscillatory blanket behaviour and how each blanket manufacturer sets his production tolerances standard.
The innovative gluing method used will promptly denounce any significant blanket batch variation, requiring software setting adjustments.
Ease of bar fitting for added geometry precision together with Shock-Proof Glue Efficiency provide an innovative barring solution that exceeds by far recommended safety factors.

Glue Application on Printing Blanket
Printing Blanket Bar pressing

Bar pressing is effected on a custom built hydraulic press.

The best set of parameters is determined for each bar model and blanket gauge.
Printing Blanket Glue Activation