Publish Time: 2026-10-26 Origin: Site
A double jersey frame is bought once a decade, and the specification signed then fixes the structures a mill can sell for years. Most sourcing mistakes are not mechanical. They start when gauge and diameter are copied from another mill's list, with no fabric specification behind them.
Choosing a double jersey circular knitting machine means fixing five decisions in order: fabric structure and target weight, then gauge, diameter and frame type, then feeder density and speed, then cam tracks and patterning, and finally the cost comparison and sample trial that prove the specification. Each decision narrows the next, and the specification is settled only when a finished sample meets it repeatedly.
The sections below follow that order.
The fabric decides the machine. Interlock, rib, pique, ponte and jacquard double jersey need different needle selection, feeder counts and cam setouts, so the fabric specification has to exist before any machine is compared.
A usable specification states structure, fibre, yarn count, finished weight, open width, shrinkage, spirality and end use, and without those numbers a machine comparison becomes a comparison of prices. A double jersey circular knitting machine at 2.8 feeders per inch with a 4+2 cam setout holds a different structure range from the same 30 inch E24 cylinder run at 2.1.
Single jersey uses one needle bed, so the cloth has a technical face, a purl reverse, curling cut edges and 30 to 60 percent widthwise stretch. A double jersey frame adds a dial: two usable faces, an edge that does not curl, 5 to 15 percent widthwise stretch and more weight per square metre, at the cost of 20 to 30 percent fewer courses per minute. Buying double jersey for cloth that needs one face pays for capability the fabric never uses.
Fabric family | Structure, weight, gauge and use |
Interlock | Two 1x1 ribs interlocked; 180 to 280 gsm; E24 to E32; polos, leggings |
Rib, 1x1 to 2x2 | Wales alternate on both beds; 200 to 350 gsm; E14 to E24; cuffs, collars |
Pique and double pique | Tuck stitches form a cellular surface; 190 to 260 gsm; E20 to E28; knit shirts |
Ponte roma and scuba | Compact double knit, often with elastane; 250 to 400 gsm; E20 to E28; dresses |
Jacquard double jersey | Selective needle control; 180 to 320 gsm; E18 to E28; patterned sportswear |
Ottoman and blister | Floats and tuck groups form cords; 220 to 380 gsm; E14 to E24; structured tops |
Stitch length, yarn count and finishing contraction also move the weight, so the band is a starting point.
A double jersey frame carries a vertical cylinder and a horizontal dial, so needles on both beds hold loops at the same feed. That produces the two-faced structure, the stable cut edge, the low widthwise stretch and the need for two feeders per interlock course.
At each feeder, cylinder needles clear, take yarn and form loops while dial needles hold theirs between cylinder needles, and the roles reverse at the next feeder. Because the two sets are gated diagonally, loops of one bed sit between those of the other, which is what gives double knit its firmness and resistance to running.
Every needle reaches each feeder as knit, tuck or miss. Cylinder selection builds the face, dial selection the back. Tuck against knit builds pique, and miss creates floats for colour jacquard, limited to about four or five needles before a float snags. A double knit circular knitting machine charges for the dial in cam complexity and finer clearances.
Gauge is needles per inch of cylinder circumference, written E. Double jersey work runs from about E14 to E32, and the right value holds the target weight with a yarn the mill can buy consistently.
A 30 inch cylinder at E24 carries about 2,260 needles against 1,696 at E18, which separates a frame making 180 gsm interlock from one making 300 gsm ottoman. Gauge is fixed in the cylinder, dial and cam box and cannot be changed later. The English gauge on circular machines is not the GG notation of flat machines, and a supplier quoting 24 should confirm the system in writing.
Gauge band | Working yarns, weight and end use |
E14 to E18 | Ne 10 to Ne 20 cotton or 300D to 600D filament; 260 to 400 gsm; heavy interlock |
E20 to E24 | Ne 20 to Ne 32 cotton or 150D to 300D polyester; 200 to 300 gsm; polo, ponte |
E24 to E28 | Ne 28 to Ne 40 cotton; 160 to 240 gsm; leggings, T-shirt weight interlock |
E28 to E32 | Ne 40 to Ne 60 cotton or 75D to 150D filament; 120 to 200 gsm; fine underwear |
Coarse gauge is forgiving and cheap to run, because heavy yarn costs less per kilogram. Fine gauge buys surface quality and light weight, and pays in yarn price, lower speed and maintenance: a needle shaft at E40 is roughly 0.4 mm across against 0.65 mm at E24.
Diameter sets how many needles work and how wide the cloth finishes, while frame type decides whether that width reaches finishing as a flat panel or a creased rope. Both affect final cost more than the price gap between frame options.
Frames are commonly built from 14 to 44 inches, with 30 and 34 inch cylinders covering most apparel demand. Tubular cloth at 30 inch flattens to about 47 inches and opens to roughly 2.4 m before contraction, so allow 5 to 10 percent width loss in dyeing and stentering, more with elastane. Work backwards from finished width, because a frame one step too small cannot be widened later.
Frame type | What it changes and where it fits |
Tubular | Taken down as a flattened tube, dyed in rope or slit later; lowest cost, highest crease risk |
Open width | Slit and spread in line; fewer creases, better stentering, more floor space |
High leg | Taller frame, larger batches, fewer doffs per shift |
Small frame | Compact 14 to 22 inch build for trim and short runs |
Jumbo industrial | Large roll capacity and heavy take-down for upholstery |
A 14 to 22 inch machine is a factory frame for trim, not a home knitting machine. Domestic machines use plastic beds and craft yarns and cannot hold interlock tension at production speed.
Feeder density, quoted in feeders per inch of diameter, is the largest lever on output and the largest risk to yarn quality. Frames are offered at 1.6, 2.1, 2.4, 2.8 and 3.2 feeders per inch, and the right choice is the highest density the yarn can support at a stable speed.
Output rises almost in proportion to feeder count, but each feeder shortens the dwell time for loop formation, raises tension variation and lengthens the creel. A 3.2 feeder frame on fine combed cotton shows more needle lines than the same frame at 2.8. Speed follows diameter and gauge: a 30 inch frame runs 22 to 32 rpm, a 34 inch frame 20 to 28 rpm, and finer gauge sits at the lower end.
A course is one crosswise row of loops, and interlock needs two feeders to complete one, so courses per minute equals rpm multiplied by feeders divided by two.
Calculation step | Worked example |
Cylinder, gauge, needles | 30 inch, E24, about 2,260 needles |
Feeders | 84, which is 2.8 per inch |
Courses per revolution | 42, two feeders per interlock course |
Speed | 25 rpm, giving 1,050 courses per minute |
Weight and width | 260 gsm at 2.2 m open width, 0.57 kg per metre |
Linear output | 58 cm per minute at 18 courses per cm |
Output at 80 percent efficiency | about 16 kg per hour, 385 kg per 24 hours |
Run the same calculation for every fabric in the range, because a frame that looks strong on interlock may be weak on 350 gsm ponte.
Track setout, written as cylinder plus dial, defines which stitches the machine can select at each feeder. A 2+2 frame covers rib and simple interlock, 2+4 adds knit, tuck and miss combinations, and 4+4 is what patterned double jersey requires.
Track setout | Stitches and fabrics available |
1+1 | Plain rib and simple interlock, minimal patterning, lowest cost |
2+2 | 1x1 and 2x2 rib, basic pique, simple striping; general purpose trim |
2+4 | Eightlock, Ottoman, blister, twill and crepe from four cylinder positions |
4+4 | Full jacquard double jersey, complex blister and spacer work |
A jacquard circular knitting machine adds electronic needle selection to the track setout, with pattern storage and quick changeover. The premium is significant and so is the skill requirement, because pattern files and repeats become daily production work. Specify an elastane attachment with the feeder layout rather than adding it later.
Two frames with identical specification sheets can differ by several points of efficiency, and the difference sits in frame rigidity, cam quality, needle standard, feed control and stop motions. Those items are inspected physically, not compared on paper.
Cams cut from alloy steel, hardened and ground to a consistent profile hold stitch length across the width and over the years, while soft cams wear into a shape no adjustment recovers. Ask for material and hardness, and ask to see a machine that has run three shifts for two years. Two cam systems also amplify vibration, so a frame that deflects produces needle lines that move with speed.
Measure cylinder and dial runout with a dial gauge.
Check cam material, hardness and track profile on a used machine.
Confirm needle and sinker availability locally.
Count storage feeders and confirm positive feed at every position.
Test yarn, needle and fabric fault stops.
Inspect take-down and check a full roll for creases.
Confirm diagnostics and pattern transfer method.
The invoice price is roughly a third of the five year cost. Build the rest from yarn consumption per good kilogram, energy, needles, downtime and changeover labour. Energy is smaller than most buyers expect: a 5.5 to 7.5 kW knitting motor plus fans and take-down sits in the low teens of kilowatts, a minor share at 16 kg per hour. Downtime is the underestimated line, and a cheap frame losing two hours a week to tuning costs more than the price gap within a year. Comparing circular knitting machine suppliers therefore means running one model with each supplier's numbers, with service response time counted as a cost.
A specification is a hypothesis until a finished sample confirms it. The trial must use the yarn the mill will buy, run at the intended speed, and be measured after dyeing and finishing, because greige results mislead on weight, width and spirality.
Send a complete trial brief: structure, composition, yarn count, target greige and finished weight, open width, shrinkage and spirality limits, and end use. State the running speed and feeder density, because a slow trial on selected yarn proves nothing. Repeat the trial on a second machine or shift, since repeatability is what a mill buys when it orders more than one.
Measurement | Practical acceptance criterion |
Finished weight | Within plus or minus 3 percent, at three positions across the roll |
Finished open width | Within plus or minus 2 percent, allowance stated separately |
Shrinkage after washing | Within agreed limits after three cycles |
Spirality | Under 5 percent after washing, on a squared-off panel |
Courses and wales per cm | Within plus or minus 1 per cm along a roll |
Surface quality | No needle lines, drop stitches, oil marks or barré |
There is no best circular knitting machine in general, only the best fit for a defined output. The same budget buys a fast commodity interlock frame or a slower patterned frame, and the answer depends on order size, fabric mix and the price the cloth earns.
A mill running long repeats of one interlock quality should buy feeder density and speed and accept a narrow structure range. A mill selling seasonal patterns should buy tracks, jacquard capability and fast changeover. A vertical mill that dyes in house should weight the choice toward open width, because creases cost more in finishing than they save in knitting.
Machine type | Role in a knitting mill |
Single jersey | One needle bed; plain, pique and mesh at the highest output |
Rib | Two beds; cuffs, collars and full rib garments |
Interlock and double jersey | Two beds with interlocked loops; stable two-faced cloth |
Jacquard | Electronic needle selection for colour and float patterns |
Fleece and terry | Sinker or loop wheel systems that build a raised back |
Seamless | Small diameter frames that knit shaped panels |
Production profile | Configuration to request |
300 to 600 kg per day of polo and legging fabric | 30 inch, E24, 2.8 feeders per inch, 2+4 tracks, open width |
1 to 3 tonnes per day of commodity interlock | 34 inch, E24 to E28, 3.2 feeders per inch, 4+2 tracks, high leg |
Trim, collars and cuffs in short runs | 14 to 22 inch, E14 to E18, 2.1 to 2.4 feeders per inch, 2+2 tracks |
Patterned fashion knits with frequent changes | 30 inch, E20 to E24, 4+4 tracks, electronic jacquard |
Heavy structure such as ottoman or upholstery | 30 to 34 inch, E14 to E18, 2.4 feeders per inch, heavy take-down |
Conversion, changeover time and site services decide whether a chosen frame still fits the mill two years later, and each belongs in the negotiation rather than after delivery.
Open width conversion is practical and usually sold as a kit, because it adds a slitting and spreading unit and a different take-down path. Changing diameter requires a new cylinder, dial, cam box and needle set, at a cost approaching that of a second machine.
A change within the same cam setout takes under an hour and involves stitch length, yarn and take-down adjustment. Moving from interlock to rib needs a cam and needle arrangement change, which runs four to eight hours plus a trial roll. Electronic jacquard patterns change in minutes, but the repeat still has to be validated.
Plan for a 5.5 to 7.5 kW knitting motor on a 30 to 34 inch frame, with total load higher once fans and take-down are counted. Compressed air at around 6 bar is needed for cleaning and pneumatics. Allow floor space for the creel, which can extend two to three metres, and confirm the floor is rated for the machine plus a full batch.
WELLKNIT was founded in Taiwan since 1987, and in 1995, we set up the production base in Quanzhou, Fujian, is the first Taiwan-funded weft knitting machine manufacturer to take root in Quanzhou.