Open Width vs. Tubular Circular Knitting Machines: Which Is Better?

Fabric mills buying circular knitting capacity usually settle cylinder diameter, gauge and feeder count first and leave the take-down system for the end. That detail decides how every greige roll leaves the machine, and therefore how the fabric is inspected, dyed, slit, compacted and cut for the next decade. Get the knitting head right but the fabric presentation wrong, and the mill carries a permanent tax in handling labour, crease rejects and duplicated process steps.

Neither system is better in absolute terms. Open width is the stronger choice when the fabric is sensitive to a permanent centre crease, or when the downstream route runs flat rolls through dyeing, printing, stentering, inspection and cutting, because opening the fabric at the knitting machine removes a separate slitting operation and the handling attached to it. A tubular system remains the better choice when the finishing line is built for tube-form processing, when the product is used as a tube, or when floor space, operator skill and capital budget cannot absorb the extra slitting, spreading and edge-guiding hardware. The correct decision is the configuration that removes the most cost and risk from the mill's complete production route.

The comparison below separates the mechanical differences from the commercial ones, so the choice rests on process evidence rather than brochure language.

What Actually Differs Between Open Width and Tubular Knitting?

The loop-forming process is identical. Both machines knit a tube on a circular needle bed, and the difference appears only below the knitting point, where the take-down either flattens and winds the tube as two compressed layers or slits it, spreads it and winds it as a single flat layer.

In a weft-knitting circular knitting machine, needles around a cylinder take yarn from rotating feeders and form a continuous tube of interlooped courses, which the take-down rollers pull away at a diameter set by the cylinder. Everything after that point is a handling decision, not a knitting decision, and that decision carries width, crease risk, edge condition and finishing compatibility.

How a Tubular Take-Down Forms the Tube

The tube is flattened between rollers and wound onto a beam as a double layer, with the fold staying in the same position for the whole roll. There are no cut edges, so there is no edge curl, no trimming lint and no blade to maintain, and the compact roll suits dyehouses built around tube form.

The limitation is the fold. A fold line held under pressure for days and then wet-processed can set into the loop structure, and in fine-gauge, lightweight or elastane-rich fabrics it may survive dyeing and show in the garment. If flat fabric is needed later, the tube must be slit on separate equipment, adding a handling step and another chance to distort it. For background on tube formation at the needle bed, the standard reference on circular knitting is useful: https://en.wikipedia.org/wiki/Circular_knitting

How an Open Width Take-Down Opens the Fabric

An open-width configuration adds four functions below the knitting point: slitting, spreading, edge guiding and synchronized winding. The tube is cut at a defined position, opened into a single layer, held flat across its width and wound under controlled tension.

Each function depends on the others. A clean cut is worthless if the spreader pulls the course line out of square, and a well-spread fabric will telescope on the beam if winding tension drifts. A representative build is the open-width double circular knitting machine, where slitting and spreading are integrated with the frame.

Open Width vs. Tubular: A Side-by-Side Comparison

On fabric quality the two systems are close when both are set up correctly, and the gap opens only with crease-sensitive fabrics. On process cost, open width usually wins when the mill would otherwise slit as a separate operation, and tubular wins when no slitting is needed at all.

The comparison is often framed as a quality question, but in most mills it is a routing question: which route delivers an acceptable roll at the lowest total cost, including everything after knitting.

Fabric Width, Cylinder Diameter and Yield

Width is the most frequently miscalculated part of the decision. A tube knitted on a given cylinder has a circumference close to the cylinder circumference, adjusted by stitch take-up and relaxation, so its flattened width is roughly half that figure, while the slit and opened width returns to roughly the full circumference less slit allowance and edge trim.

These are starting points, not specifications, because delivered width also depends on structure, yarn count, stitch length, elastane content and finishing shrinkage. A larger cylinder is not automatically better: if the finished width is fixed by the cutting plan, an oversized cylinder produces fabric that must be trimmed, and the trimmed edge is waste.

When Open Width Is the Better Choice

Open width is justified when it solves a named problem: a crease that survives finishing, a downstream process that cannot accept a tube, or an inspection requirement that a folded roll cannot satisfy. If none of those conditions exists, the additional hardware is hard to defend.

Crease-Sensitive Fabrics

Fine-gauge single jersey, lightweight interlock, smooth-faced fabrics and structures containing elastane are the classic candidates. The risk is not that a fold appears, but that it becomes permanent. Online slitting removes the cause rather than treating the symptom, because the fabric is never wound as a folded tube. It does not remove every possible mark, since spreader pressure, edge contact and winding tension leave their own traces, so a trial should confirm the absence of both fold marks and tension marks on the actual fabric.

The Next Process Needs Flat Fabric

If dyeing, printing, stentering, compacting, inspection or automated cutting expects an open-width roll, opening the fabric at the knitting machine removes one complete operation and one internal transport movement. The saving is easy to underestimate, because it appears as avoided labour and waiting rather than as a line item on a quotation. Map the route from knitting to cutting table, note which steps exist only because the fabric arrived as a tube, and those are the steps the open-width option deletes.

A flat roll also allows full-surface inspection without opening a tube first. Some buyers specify open rolls, so a mill that cannot present fabric that way either declines the order or pays for a separate slitting step.

When a Tubular Machine Is Still the Better Choice

A tubular system is the better choice when the fabric never needs to be flat before it reaches the customer or the cutting table, when the finishing line is designed around tube form, or when the investment in slitting hardware cannot be recovered from the order mix.

Open width is not a mark of progress. It is one configuration among several, and buying it for its image rather than for a process requirement is an expensive mistake.

The Finishing Line Is Built for Tubes

Many dyehouses run overflow or jet machines loaded with rope or tube-form fabric, followed by tubular compacting and tubular stentering. In that environment an open-width machine delivers a flat roll that must be re-assembled into a tube or routed to a different line, so the mill gains a slitting step it did not need and loses the handling advantages of a compact roll.

The Product Stays in Tube Form

Seamless garments, tubular knitwear, some sock and accessory constructions and certain industrial fabrics are used as tubes. Slitting such fabric creates two edges that must later be joined or finished, which is work that adds no value to the product.

Simplicity, Space and Capital Cost

A tubular take-down has fewer moving parts, fewer settings and a smaller footprint. Where floor space is tight, where operators are stretched across several machines, or where the order mix is dominated by plain greige sold in tube form, a single circular knitting machine with a conventional take-down will usually deliver a better return than a complex frame with capacity the mill cannot use.

Single Jersey and Double Jersey: Different Risks

Single jersey is the harder fabric to open, because cut edges curl and thin fabric distorts easily. Double jersey, rib and interlock are more stable but heavier, so synchronized cutting, spreading and winding become the critical points instead.

Single Jersey

Single jersey curls at cut edges because face and reverse stitches pull in opposite directions, so the slit line, the spreader and the winding tension must control that curl without stretching the fabric or pulling the course out of square. Background on how loop structure drives these properties is available in the standard reference on knitted fabric: https://en.wikipedia.org/wiki/Knitted_fabric

Fine-gauge versions are the most demanding, which is why the circular knitting machine gauge should be settled with the take-down specification rather than separately. A demonstration on a heavy, easy-running fabric proves little, because lightweight and elastane-plated single jersey shows tension variation across the width. A meaningful trial confirms stable cutting, uniform tension from selvedge to selvedge, edge control without stretching or curling, smooth winding, and acceptable appearance at the target weight and yarn count.

Double Jersey, Rib and Interlock

Interlock, rib and other double knits are more stable and curl far less, but they are heavier, so the take-down must move more mass per metre without creating tension differences between the two needle beds. Two checks matter: whether the frame supports the required cylinder and dial arrangement, feeder count, gauge, width and take-down range as a single offered build, and how long a changeover takes when structures are switched. Fine-gauge versions remain sensitive to uneven tension, and a slow, heavy demonstration fabric hides exactly the problem the mill needs to see.

The Real Cost Comparison Goes Beyond Machine Price

Machine price is the smallest part of the comparison. The decision belongs on total process cost, which includes the slitting operation that may disappear, the labour and transport that go with it, losses from crease rejects, edge waste, blade and sensor maintenance, changeover time and floor space.

The arithmetic is not automatically favourable. A mill selling plain greige in tube form to a customer whose dyehouse processes tubes gains nothing from open width, while a mill running fine-gauge elastane single jersey into a flat finishing line usually repays the hardware within the machine's service life.

How to Specify and Test Before You Buy

The specification should be written from the fabric backwards, not from the machine forwards. A supplier can only configure the correct frame, slit position and winding package if it receives the fabric, the finishing route and the roll requirement together.

Supply the fabric sample or structure, yarn composition and count, greige and finished weight, finished usable width, dyeing route, printing or stentering requirements, elastane details, expected roll diameter, available floor space and target daily output. State the acceptance criteria in the purchase terms: edge condition, width stability across the roll, winding quality and the absence of a permanent centre crease after the mill's own finishing route.

FAQ

Can an open-width take-down be retrofitted to an existing circular knitting machine?

Sometimes, but it is rarely simple. The frame, slitting unit, spreader, edge guidance and winding drive must be matched to the machine's diameter, speed range and fabric path. Retrofitting is most feasible when the original machine was designed to accept an open-width frame; otherwise the cost, and the risk of compromised fabric control, usually favour a complete configuration.

Does open-width knitting create more fabric waste?

It creates a different kind of waste rather than automatically more. Slitting produces a narrow trim allowance and two cut edges that must be controlled, but open width removes the losses caused by crease rejects and by re-slicing fabric damaged in tube form. For crease-sensitive fabrics the net effect is usually a reduction; for heavy, stable fabric sold as a tube, slitting adds loss with no compensating gain.

Which system suits a small mill with limited floor space?

A tubular system is usually the more practical starting point, because it needs less floor area, fewer settings and a lower capital commitment, and it keeps the process path short for mills selling greige in tube form. A small mill should move to open width only when a specific customer requirement or fabric problem justifies it, such as a flat-roll inspection requirement or a fine-gauge fabric that cannot tolerate a centre crease.