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Course: Press Work -
Web
Code: 506 |
Teaching Scheme
hrs/week |
Examination Scheme |
Theory |
Practical |
Theory
Marks |
Duration |
UT Marks |
Pr. Marks |
TW Marks |
3 |
2 |
80 |
3 hrs. |
20 |
-- |
20 |
Rationale:
Web machine operation is required to be learnt in order
to understand efficient working procedures. There is plenty of
scope for skillful personnel in this branch of printing. This
course imparts extensive knowledge about all the elements of web
machines used in all the printing processes such as offset, flexography,
gravure, as well as quality control procedures & auxiliary
operations.
| Lesson
No 1: Introduction
Theory.
|
Marks |
Hours |
1.1 |
Construction & Design – Common impression cylinder
(Satellite), Blanket to blanket, Inline, Stack, I, Y,
H, N configurations, paper path and colour combinations,
S wrap
|
4 |
3 |
1.2 |
Comparison with sheetfed machines
|
2 |
1 |
| Lesson
No 2: Infeed
Theory.
|
Marks |
Hours |
2.1 |
Reel stands- Single, Multiple, revolving; locations such
as inline, perpendicular, basement; Expanding shaft, tilt
lock, chuck systems
|
6 |
3 |
2.2 |
Automatic Splicers- Need and types
a. Zero speed- festoon
b. Flying splicer (match speed)
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6 |
4 |
2.3 |
Web tension – Dancer roller & its types, Infeed
metering rollers;
Brakes – Core brakes, Straps, Reel motors, Running
bands, tensionometer, Transducers, surface speed –
unwind and rewind
Angle bar, Turner bar, Web guide rollers, web cleaning
brushes, surface treatments, static charge elimination.
|
9 |
6 |
| Lesson
No 3: Dryers
Theory.
|
Marks |
Hours |
3.1 |
Need, operations and types-
Open flame, High velocity hot air, Oven, radiation, combination
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8 |
6 |
| Lesson
No 4: Chill rollers
Theory.
|
Marks |
Hours |
4.1 |
Need, operations and types-
Baffle plates, Jacketed (Embedded); Silicone application
|
6 |
3 |
| Lesson
No 5: Folders & related ancillary equipments
Theory.
|
Marks |
Hours |
5.1 |
Need, operations, maintenance, types, -
Former & its types, Jaw, Chopper, Combination; cut-off
and
different products, collect cylinders, conveyor mechanisms,
types of folds.
|
8 |
6 |
| Lesson
No 6: Image and web control
Theory.
|
Marks |
Hours |
6.1 |
Box tilt, Compensators, Cut-off, Controlling fan out,
mechanical and electrical color register, Web to web register,
viscosity control – ink mixing (gravure and flexo).
|
8 |
5 |
6.2 |
Register control devices: Differential gears, Displacing
units, Stroboscopes, Oscillating mirrors, Video viewers.
|
5 |
4 |
| Lesson
No 7: Ancillary operations
Theory.
|
Marks |
Hours |
7.1 |
Slitting and trimming – Blades, slot type, rotary
scissors, hard on hard slitters, perforators, sprocket
punching.
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6 |
4 |
7.2 |
Web reconditioners, water-cooled ink oscillators, Blanket
washers, Web break detectors, imprinters, side lay sensors,
Cut-off control, anti static devices, remoisturisers.
|
8 |
6 |
| Lesson
No 8: Trouble Shooting for Web Machines
Theory.
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Marks |
Hours |
8.1 |
Paper troubles – Out of round rolls, telescopic
rolls, picking or splitting, de-laminating, web-wrinkles,
web-breaks.
Delivery – sagging of web in folder, wrinkling on
former, poor folding, smudging and scuffing in folder,
set-off on chill rolls / folders, un-even drying, blistering,
ink tacky after chill rolls.
Print quality – mis-register in running direction,
fan-out, printing lacks sharpness, side to side mis-register,
ghost images in solids/half-tones.
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4 |
3 |
Reference books:
1) Web press operating- GATF
2) Web control- Durant
3) Handbook of Print media- Heidelberg
4) Solving Web-fed press troubles - GATF
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