Single Jersey Circular Knitting Machine

The fabric target comes first

Single jersey is often selected for T-shirts, underwear, sportswear and other lightweight apparel because the structure combines a clean face with useful stretch and breathability. The archived Kunyuan record describes a machine with an 18–38 inch diameter range, 7G–50G gauge range, 54F–114F feeder range, and a reference speed of 20–35 RPM. It also notes optional multi-feed work and conversion possibilities, but those options should be tied to a written fabric brief rather than treated as standard on every machine.

The buying question is not simply “how fast can it run?” It is whether the chosen needle, feeder and yarn combination can hold the required weight and width without barre, needle lines, holes or edge instability. A high gauge may suit a fine fabric, while a coarse gauge may be the right starting point for a heavier hand; the sample decides.

What the circular path controls

The cylinder carries the needles that form the single-jersey loops as the yarn feeders pass. Small changes in yarn tension, stitch length, take-down or needle condition appear quickly on the face of the fabric. If the mill plans several colors, ask for the exact multi-feed arrangement and the changeover method. If the order will later move to fleece or terry, list the designated accessories and the conversion boundary in the quotation; a generic “convertible” claim is not enough.

Use the recorded 18–38 inch and 7G–50G ranges to narrow the discussion. Then give the supplier the yarn composition/count, target greige and finished weight, finished width, stretch requirement, dyeing/finishing route and planned shift pattern. The machine should be compared against that brief, not against a catalogue RPM alone.

Selection table for a single-jersey line

Trial checks that catch expensive surprises

Run the buyer’s yarn at a stable setting long enough to expose gradual drift. Take samples from the beginning, middle and end of the run. Record speed, stitch length, take-down, stop causes and any manual intervention. Inspect the face under consistent light for horizontal barre, vertical needle lines, holes, oil marks and repeating feeder defects. Measure width, weight and skew at agreed points, then repeat after the actual finishing route.

If the mill expects stretch or elastane, test extension and recovery in the same direction used in the garment. If the fabric will be converted to another structure, run the proposed accessory set separately and label it. Approval should attach the fabric result to the exact configuration, not to the product family name.

Daily operating discipline

Operators should look at the yarn path and stop motions before raising speed. A single repeated line usually deserves a needle, sinker or feeder-location check; random holes call for yarn handling and tension checks as well. Keep lubrication and cleaning records, and isolate the machine before changing needles or entering the knitting zone. Store the accepted settings with the program version so a second shift can reproduce the same fabric.

The archived record lists 20–35 RPM as a reference speed. Treat that as a starting range only: yarn, gauge, stitch length, environment and finishing determine the usable window. Ask for the test conditions behind any output number quoted in a proposal.