winding a paper core - making a centre on which to wind it

[JerryNotts]

I want to be able to wind some 'cardboard' cores on which to wind some paper.

Those members with roll-fed labelling machines or who have worked in the paper and board industry will know immediately what I mean. Most tiolet rolls have a core.

I imagine a bar (brass or steel?) between centres on the lathe with a number of sectors fixed ( but adjustable diameter ) to the outer diameter but I am really lost on this!

The sizes I want to make are between 20 and 50 mm ID and up to 100 mm long.

I can make an anilx roller to apply the glue and cones on the take up roller.

Any guidance please.

Jerry

[BillTodd]

you'll probably need a collapsible mandrel - three or four segments on a tapered core  if you can arrange the control of the core with a collet closer lever it could be single sided

while a lthe will work , you might want better control over speed , especially if hand feeding the paper.

I've built specialist winders for copper coils ( 100mm wide 1.5mm thick) and found the best way to tension was with pinch rollers , although 6ou may get away with one roller with card or paper.

[JerryNotts]

I've now spent some time looking at the potential difficulties in this task. Perhaps I should have done this before posing the original question.

I have looked at both the main products of the paper core business, square paper tubes and spiral wound tubes, taking some account of the facilities I have, especially space.

On the face of it square paper tubes are the simplest when small scale maual methods are considered, since a frame using two rollers with nip adjustment and an operator who can acquire the skill to apply an adhesive controllably are all that is needed.

Making spiral cores, except on an ad hoc basis, requires much more thought but, in conversations with ex-colleagues with who have experience can yield consistent results and if needed high production rates.

A problem which the uninitiated often apparently expereince is the diffficulty of removing the wound core from the mandrel. On occasion when making square cores it has been necessary to destroy the core in order to recover the mandrel. This is less of a problem in industrial  scale production as the paper tension or the nip pressure on the machine can be controlled as can the condition of the mandrel. The simplicity of a manual technique appeals to me because of its simplicity. Do I have the concentration to make about 50 cores without making mistakes?
As Bill Todd mentioned in his reply I haveexamined the idea of a collapsible mandrel.  I am told this should not be necessary (I'm looking forward to proving this). It seems that with the correct adhesive, tension, nip pressure and attention to the condition of the mandrel that a core can be wound which needs minimal force to remove. First picture from the tube gives an idea and in the actual video he manages to remove the mandrel without brute force.

Making a spiral winding machine is much more challenging. I intend to spend some time drawing out how this might be done. Watch this space but don't hold your breath.  See the second attached picture from UT for the drive mechanism of this sort of machine. The mandrel in these machines does not rotate but the constant polishing of the paper against the steel keeps it in good slippery condition. Industrial machines need some considerable power to drive the belt rolls, typiccally 40-50 HP depending on the number of plies being combined,

[BillTodd]

I've just finished a spiral winder , on a somewhat different scale to the one in your picture , I had to deal with +/-1um tolerances and one dimension spec'd at 3.2um . Amazingly, there are parts of the above paper coil winder that are strangely familiar 

[JerryNotts]

i''m sorry Bill I am not sure which parts you mean, or which winder.

Jerry

[AdeV]

I've just finished a spiral winder , on a somewhat different scale to the one in your picture , I had to deal with +/-1um tolerances and one dimension spec'd at 3.2um .

 

What on earth are you winding - DNA???

[BillTodd]

i''m sorry Bill I am not sure which parts you mean, or which winder.

Jerry

i was just amused by the similarity of the machine to wind paper and what I made to wind tungsten tape

[BillTodd]

Are you winding a few or looking to go in production?

Taking a close look at a bog roll core , I see it is made of a couple (maybe more)  of layers of card offset to cover the join. My guess it that they are spiral wound to enable continuous production i.e. the tube spirals off the end of a mandrel in a long length and is cut to length my a second operation (just like spiral ducting etc.)

should have search youtube first ;-)

Bill

[JerryNotts]

Sorry I didn't reply to your last post Bill.

I'm hoping to make about 50 individual cores initially.

At one time I was closely involved with companies using these things, but although I often wondered how they were made I never had an opportunity to watch the process. Now I have spoken to some who worked on these specific machines.

As you say the winding is a continuous process, the some of the power of the drive to the belt is consumed  in the effort required to push the freshly wound spiral along the mandrel. That's one of the reasons to keep the mandrel as smooth and slippery as possible. Formulation of the glue is also important: it must set-up quickly. The cores are cut to length as they come to the end of the mandrel; Usually using rotary knives working against each other on opposing sides and moving horizontally with the wound spiral as the cut is made. If you do a search on the manufacturers, often Indian or Chinese, you will see they make a big thing of their ability to hold core length to size.

' kraft paper' is usually used for cones (German: kraft = strength,strong) (sorry if I am teaching my grandmother) and the winding angle  25 -30degrees imparts crush resistance. Crush and bending resistance is important especially when there is a roll of paper wound on to it which might weigh around 20 tonnes.

I am currently trying to draw out  a model of a spiral care winder and have only just begun to think about all this so take whatever I say with a large bag of salt.

Jerry

[JerryNotts]

After a lot of cogitation and even more guesswork I've made a start on the drawings.

I have started on the most important part of the winder, the winding uinit itself. The components are shewn in the second picture and the proposed assembly iin the first. The relationship of the mandrel to the winding belt (not figured out how to draw this twisted thing in Inventor yet) is in any case and the first picture represents the view along the centre line of the two drive rollers and the end of the mandrel

This drawing is based on a mandrel diameter of 10mm for ease of doing the sums.

[ddmckee54]

Silly question, but have you sourced your roll stock yet, and how much are you going to be using?

I work in a plant that rolls tubes like this on an industrial scale and I'm having trouble imagining a supplier selling the small quantities that a home hobbyist would use.  Although, now that I think about it there is probably a cottage industry somewhere that is doing something similar.

Don

[JerryNotts]

I already have a supply and stock of kraft sufficient for a few hundred small cores such as these. In any case there are several alternative ways of supplying the paper; buy wide rolls of kraft from ebay  and run through my Titan slitter to bring to size or as a last resort use till roles, most of these seem to be about 2" wide. On this scale cost is not significant.

Your location is not shewn on your posting but I imagine you are not in the UK. Before I retired we used to use about 300 per day of cores a little over a metre wide to fit 4" cones and found it OK to buy them in India.

Jerry