Slitter Man

Web guiding is a term describing the method used to correct badly wound rolls or material and is used on slitters and salvage winders .  A sensor looks at material (web) running through a machine and sends a signal to a device that moves parts of the machine to correct the badly wound roll.  Putting it at its most basic web guiding systems allow you to load a roll with a bad edge profile (I.E. not flat) onto a machine rewind it so that it has a flat edge profile. Guider eyes (sensors) read the edge of the web, a line on the web or a 'broken' line printed on a roll of material.  If the web guiding system 'sees' the web move left it will move the web to the right so that as it winds up on the rewind end of the slitter / doctor machine the edge of the final roll will be flat. Many older web guiders move the winding web using hydraulic or pneumatic (air) methods, but hydraulics can leak oil onto the web and pneumatics tend to have slow response times unsuitable to f...

Sometimes when cutting cores in a core cutter odd lengths are left over, they are too short to be useful so they are either discarded as waste or taped to other waste cores in an attempt to join several bits of scrap together to create a single usable core.  Taping several lengths of core together can create potentially dangerous problems that I won't go into, needless to say it's not a great idea! But I can see why companies wish to minimise scrap core waste, so here's a potentially better way of doing so: Save money and minimise core wastage without using tape to join together scrap bits of core Several of our customers buy in parent cores at multiple lengths and then use the most appropriate cores for each job.  We have designed our Core Cutter to accurately measure the parent core as it is loaded, the machine then works out how much trim to cut off meaning that each subsequent cut creates a usable core. One of our customers had an aggressively low target for reducin...

When you get right down to the gritty details of cardboard cores you'll find that no two core suppliers are quite the same, and when bought in bulk no two parent / master cores are quite the same length.  As your freshly purchased cores come off the transport and into your life you'll find the lengths in the batch are very similar, but they are infrequently all  exactly the same size. The variations in core lengths will often be very small, but when you're as focussed on minimising waste when cutting cores as you are focussed on cutting accurate core lengths then knowing exactly how long your parent cores are is crucial.  You could have your operator measure every core as it comes off the pallet, but that would be time consuming, and with the best will in the world it would probably also be inaccurate. Core cutter auto-trim Our CCA Automatic Core Cutters solves the problem of irregular sized parent cores by having a switch-able 'auto-trim' function. ...

A trim fan attached to a slitter. As discussed previously on this blog the process of slitting (at its most basic) can be reduced to the one-line description of ' a big roll is loaded on one side of the slitter rewinder, and smaller rolls are loaded off the other side'  and that's fine... most of the time. Here comes the example! If a 1000mm wide roll is loaded onto a rewinder and is slit down into rolls that are 212mm wide then four rolls would be produced.  If your mental maths is up to scratch you might have noticed that 4x212 does not equal 1000, and that means that from the original / master / jumbo roll there will be roughly 117mm left over.    Sometimes this happens because the edges of jumbo rolls are discarded due to damage, print reasons or simply because the material being slit isn't coated all the way to the edges of the roll. So what happens to this waste material? Waste material can be wound onto cores in the same way 'correct' rolls are, ...

Closed Loop Tension Control  describes of the systems we use to accurately control the tension of materials running through slitting and winding machines ; the simplest description of the process that I can come up with for the purposes of this blog post is thus: When we utilise Closed Loop Tension Control on a machine load cell (sensors) are installed on key parts of the machine, these load cells measure the actual tension of the materials being wound as it passes through the machine.  The information fed back from the load cells is then used by the control system to make precise adjustments to the machine to attain perfect tension throughout the slitting or rewinding process. Now I'll be the first to admit that the above paragraph is hardly a snappy explanation of a process that is essential to controlling substrate tension, so I'm going to try and simplify even further by explaining why you might want closed loop tension control rather than explaining how it works (...

Trim / waste disposal is a subject that is integral to efficient winding, but conceptually it can be a bit difficult to explain to customers who aren't familiar with managing waste. A lot of companies go to great lengths to try and minimise the amount of waste they generate, which makes sense as far as economics and environmental awareness, but sometimes waste cannot be avoided. The video below shows a trim winder that was a part of a l arge slitter we recently built for a regular customer of ours.  This slitter rewinder was designed to convert large rolls of metallized polyester, which is supplied on rolls that are not coated the full width of the web, so a trim needs to be cut off during the winding / slitting process.  Some customers wind trim waste material onto cores on the rewind shafts, and some let narrow trims fall to the floor, but while both options are workable both can be problematic for operators and potentially damaging to materials. Trim winders l...

A (used) 6" differential ball chuck designed to fit a 60mm rewind shaft (once the 3" chucks have been removed!) I sometimes use this personal blog of mine to talk about the basics of slitting and rewinding, with the content partly led by thinking back to the questions I had when I first started working in the converting machinery industry.  One of the first questions I had was 'how on earth can slitter rewinders with 3" rewind shafts be used for winding onto 6" cores?' A lot of converters and labellers / packaging companies regularly switch between winding onto 3" (76mm) and 6" (152mm) cores, which is one of the reasons we designed our Automatic Core Cutter to change between core sizes in under thirty seconds.  But what do companies who predominantly wind onto 3" cores do when they need to wind onto 6" cores?  The answer is actually quite simple - they remove the 3" ball chucks and slide on 6" core chucks!  There are of...