unwinding/winding machine

[g***@hotmail.com]

I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.

I am planning to make this machine.

Unwinding the paper roll is not a problem as the scanner can pull the
paper in.

When comes to winding, I have the following problems:
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling

Conditions:
The paper width can be from 10 - 30 cm
The paper length can be from 10m - 100m
The paper quality can vary
The scanning speed can be 10cm per sec (max)

As it is quiet difficult to synchronise the scanner with the motor
connected to the winding part, I decided to let the paper coming out
the scanner to drop and a sensor will detect the paper lag and activate
the winding motor.

A simple ASCI diagram is as below:
1 = unwinding section
2 = scanner
3 = tension rollers
4 = winding section
5 = gap in the table for paper to drop

@ o @
| _____________ o |
| |____________| | |
---+-------------------------- -+-----+--
1 2 5 3 4

Any ideas, suggestions are welcome. You can contact me @
***@hot......com

Thank you in advance.

Regards
Giji George

[Terry Harper]

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.

The textile industry has been dealing with this sort of problem for
years. You might find a fabric inspection table second hand that would
meet your needs.

[Uncle Al]

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.
I am planning to make this machine.

[snip]

The major problem is that escalating tension on the take-up reel is
amazing destructive. Take-up tension must be controlled to be
constant.

Vacuum metallization of (Mylar, polypropylene) film has this down to a
pretty, especially the rewind. Sound and video tape recorders are
pretty good at it, too. Maybe Kodak will sell you some of their
obsolete photographic film manufacture takeup reels and equipment.

1943, England, Colossus. Handled paper punch tape at about 30 mph
(Tommy Flowers got it up to 60 mph, but that was a rapid mistake).

[Jonathan Barnes]

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.
I am planning to make this machine.
Unwinding the paper roll is not a problem as the scanner can pull the
paper in.
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling
The paper width can be from 10 - 30 cm
The paper length can be from 10m - 100m
The paper quality can vary
The scanning speed can be 10cm per sec (max)
As it is quiet difficult to synchronise the scanner with the motor
connected to the winding part, I decided to let the paper coming out
the scanner to drop and a sensor will detect the paper lag and activate
the winding motor.
1 = unwinding section
2 = scanner
3 = tension rollers
4 = winding section
5 = gap in the table for paper to drop
@ o @
| _____________ o |
| |____________| | |
---+-------------------------- -+-----+--
1 2 5 3 4
Thank you in advance.
Regards
Giji George

Normal practice ( in the labeling industry ) is to run a spindle continuosly
and use a friction clutch to provide a set tension from the take up roll.

[Bill Jeffrey]

Big old instrumentation tape recorders used to leave a long loop of tape
hanging down just in front of the take-up reel. The loop was as much as
4 or 5 feet long. A small rolling weight was hung at the bottom of the
loop. (In reality it was more complex than that, but that's what it
amounted to). The weight, being constant, maintained more-or-less
constant tension in the loop as it moved.

Then there were 3 or 4 sensors (optical would do nicely) that determined
the length of the loop - how much tape was hanging down. If the loop
got too long, the motor on the take-up reel was activated. If the loop
got too short, the take-up reel was slowed down and stopped. For
intermediate loop lengths, the motor was run at intermediate speeds.
The effect was that, as the supply reel and capstan started and stopped,
the loop on the take-up side would lengthen to as much as 5 feet or
shorten to as little as 2 feet, but usually oscillated between 3 and 4
feet. The only requirement was that the take-up reel had to capable of
taking up tape faster than the max speed at which the capstan could spew
it out, to ensure that the capstan could never get ahead of the takeup.

Regarding the "little rolling weight" I mentioned. I have seen it done
as a small polished steel cylinder on the short leg of a long L-shaped
rod. The top of the long leg was fixed and pivoted on the machine's
front panel. As the weight went up and down and the rod pivoted, they
tripped microswitches to control the takeup motor. More modern tape
machines actually housed the loop in a vacuum column - the vacuum pulled
the tape loop down without mechanically contacting the tape.

In the case described by the OP, where the material to be rolled is not
as fragile as magnetic tape and the capstan speeds are nowhere near 1000
inches per second, I would think that a polished hardwood dowel simply
riding in the bottom of the loop might even be sufficient. The dowel
could have flanges screwed or machined on the ends, to keep it from
working its way endwise out of the loop as it rolled.

Bill Jeffrey
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Post by Jonathan Barnes

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.
I am planning to make this machine.
Unwinding the paper roll is not a problem as the scanner can pull the
paper in.
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling
The paper width can be from 10 - 30 cm
The paper length can be from 10m - 100m
The paper quality can vary
The scanning speed can be 10cm per sec (max)
As it is quiet difficult to synchronise the scanner with the motor
connected to the winding part, I decided to let the paper coming out
the scanner to drop and a sensor will detect the paper lag and activate
the winding motor.
1 = unwinding section
2 = scanner
3 = tension rollers
4 = winding section
5 = gap in the table for paper to drop
@ o @
| _____________ o |
| |____________| | |
---+-------------------------- -+-----+--
1 2 5 3 4
Thank you in advance.
Regards
Giji George

Normal practice ( in the labeling industry ) is to run a spindle continuosly
and use a friction clutch to provide a set tension from the take up roll.

[Brian Whatcott]

On Tue, 14 Mar 2006 17:43:10 -0700, Bill Jeffrey

Post by Bill Jeffrey
Big old instrumentation tape recorders used to leave a long loop of tape
hanging down just in front of the take-up reel. The loop was as much as
4 or 5 feet long.
Bill Jeffrey

Ah, those were the days! Before there were disk drives
there were high speed tape drives. IBM, Honeywell, Decca.
With two loop chambers.

The loop was sucked down. The position was sensed either
photoelectrically, or with pneumatic sensors

The capstan had slots for suction traction. The spool hub
motors could pull tape twice as fast as the capstan.

Let's see. The tapes were typically 2400 ft long. The tape density
started out at 200 bits/inch, then went up to the amazing density of
556 bits /in, then up to several thousand bpi.

Taking 556 bpi X 2400 ft X 12 in/ft to give a mighty 16 MBytes or
so of storage. (for an 8 track tape....)

Brian Whatcott Altus OK

[Mark Thorson]

Post by Brian Whatcott
Taking 556 bpi X 2400 ft X 12 in/ft to give a mighty 16 MBytes
or so of storage. (for an 8 track tape....)

Tapes of that era were either 7- or 9-track.
That's either a 6-bit character plus parity,
or an 8-bit byte plus parity.

[Brian Whatcott]

Post by Mark Thorson

Post by Brian Whatcott
Taking 556 bpi X 2400 ft X 12 in/ft to give a mighty 16 MBytes
or so of storage. (for an 8 track tape....)

Tapes of that era were either 7- or 9-track.
That's either a 6-bit character plus parity,
or an 8-bit byte plus parity.

Quite so... The term 'byte' was an introduction from (I think) IBM
though before that point they were using a 6 bit encoding with two
formatting bits and a parity bit (In the 1401 series for example.)
This gave the machine the interesting capability of adding or
multiplying numbers of arbitrary length as marked by the field marks,
up to a large fraction of the avaiable memory - which wasn't all that
much its true.


Brian Whatcott Altus OK

[g***@hotmail.com]

Thank you each of you who reply to my post.

Most of the reply advises of a roller that is hung on the media, I am
sure that this will work (except that it pulls the paper out of the
scanner); however, I am trying to use a solution that can create
tension just before the winding part (section 4).

My initial plan was to use a idling roller with a damper to sit on top
the winding roll, I dropped this as it does not work when the width of
the paper can vary. The second method was to feed the paper through two
rollers pressing each other. It pretty much provides the tension I
require, but occasionally shifts the paper to side and cause crumbling
of paper. Now I am lost!

As for detecting the paper slack, I plan to use a sensor near (section
4) to detect the paper. Once the paper is wound and the slack is no
more, the paper will not touch the sensor, hence the motor will stop.

However, the following problem remains unsolved!
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling

Regards
Giji George

[Jamie]

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.
I am planning to make this machine.
Unwinding the paper roll is not a problem as the scanner can pull the
paper in.
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling
The paper width can be from 10 - 30 cm
The paper length can be from 10m - 100m
The paper quality can vary
The scanning speed can be 10cm per sec (max)
As it is quiet difficult to synchronise the scanner with the motor
connected to the winding part, I decided to let the paper coming out
the scanner to drop and a sensor will detect the paper lag and activate
the winding motor.
1 = unwinding section
2 = scanner
3 = tension rollers
4 = winding section
5 = gap in the table for paper to drop
@ o @
| _____________ o |
| |____________| | |
---+-------------------------- -+-----+--
1 2 5 3 4
Thank you in advance.
Regards
Giji George

make your self a load cell roller arm.
this will output tension and you can regulate
the take up motor.
or !, use a roller arm that is connected to a
pivot point that has a potentiometer on it that
can be used as dancer control. just adding weight
the roller will govern your tension.
in most cases they call this a catenary arm, and
the arm simply rest at the lowest gravity point on
the material, the pintle end will have a device that
monitor position.

[Smitty Two]

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.
I am planning to make this machine.
Unwinding the paper roll is not a problem as the scanner can pull the
paper in.
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling
The paper width can be from 10 - 30 cm
The paper length can be from 10m - 100m
The paper quality can vary
The scanning speed can be 10cm per sec (max)
As it is quiet difficult to synchronise the scanner with the motor
connected to the winding part, I decided to let the paper coming out
the scanner to drop and a sensor will detect the paper lag and activate
the winding motor.
1 = unwinding section
2 = scanner
3 = tension rollers
4 = winding section
5 = gap in the table for paper to drop
@ o @
| _____________ o |
| |____________| | |
---+-------------------------- -+-----+--
1 2 5 3 4
Thank you in advance.
Regards
Giji George

Tension -- a spring loaded idler at the bottom of the loop at station 5.

Take-up speed control -- A dancer arm controls a pot that controls the
take-up motor speed. (as per another respondent)

Core holder -- a flexible wire frame like a paint roller.

[Ian Macmillan]

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.
I am planning to make this machine.
Unwinding the paper roll is not a problem as the scanner can pull the
paper in.
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling
The paper width can be from 10 - 30 cm
The paper length can be from 10m - 100m
The paper quality can vary
The scanning speed can be 10cm per sec (max)
As it is quiet difficult to synchronise the scanner with the motor
connected to the winding part, I decided to let the paper coming out
the scanner to drop and a sensor will detect the paper lag and activate
the winding motor.
1 = unwinding section
2 = scanner
3 = tension rollers
4 = winding section
5 = gap in the table for paper to drop
@ o @
| _____________ o |
| |____________| | |
---+-------------------------- -+-----+--
1 2 5 3 4
Thank you in advance.
Regards
Giji George

The best simple constant tension rewinder uses a Zero-max variable speed
drive (see Google) in which the speed control lever is connected to a dancer
roller so that as the dancer rises the drive slows. The output drives the
rewind spindle. The tension is half the weight of the dancer. I've used this
type of winder for many years for rewinding very thin film and they work
very well and reliably.

All the best
Ian Macmillan

[Anthony]

Post by g***@hotmail.com
I require a unwinding/winding machine. This machine will release paper
from a roll and it will go through a special scanner and have to wind
the paper back into a roll.
I am planning to make this machine.
Unwinding the paper roll is not a problem as the scanner can pull the
paper in.
A simple mechanism to hold the 15mm paper core (eg. Axial chuck)
A simple mechanism to provide tension to the paper that is wound
A simple mechanism to keep the paper aligned, prevent crumbling
The paper width can be from 10 - 30 cm
The paper length can be from 10m - 100m
The paper quality can vary
The scanning speed can be 10cm per sec (max)
As it is quiet difficult to synchronise the scanner with the motor
connected to the winding part, I decided to let the paper coming out
the scanner to drop and a sensor will detect the paper lag and activate
the winding motor.
1 = unwinding section
2 = scanner
3 = tension rollers
4 = winding section
5 = gap in the table for paper to drop
@ o @
| _____________ o |
| |____________| | |
---+-------------------------- -+-----+--
1 2 5 3 4
Thank you in advance.
Regards
Giji George

Having several years of experience in the printing industry, having slack
anywhere in the system is an absolute no-no. Tension must be critically
controlled throughout the system.
Tension is normally controlled via a 'dancer roller' and tension drive
stand between the unwind roll and the printing (scanning, in your case)
feeder. The same mechanism is used between the scanning device and your
take-up reel.

A dancer roller works by having a roller on an offset pivot. The roller
would be approximately 8-10" from the pivot point, and in operation,
would reside at a horizontal position. This dancer roller is attached to
an encoder, which feeds information to either the brake control mechanism
or drive, or to the take-up drive. The dancer roller is pre-tensioned,
typically via pneumatic cylinders, to determine your web tension. Using
the feedback from the dancer rollers, the drive or brake attempts to
maintain a horizontal position of the roller, thus creating a constant
tension on the web.

This type of thing is down to a science, and plenty of machinery exists
to do this. Do a search for 'paper rewinders' or 'paper rewinding
inspection machines'. Bobst-Champlain is but one of many manufacturers of
this type equipment, provided they are still in business.