What a pre-shrinking machine does
The cloth is moistened and steamed so that the fibers relax. It is then pressed against a thick rubber blanket that has been stretched over a roller. As the blanket returns to its normal length, it carries the cloth with it, and the cloth is forced to shrink in the warp direction.
After this, a garment cut from the cloth shrinks little when washed. Residual shrinkage after washing is normally required to be 1% or less, and it is checked by a wash test.
Pre-shrinking compared with a stenter
A stenter fixes the width by stretching the cloth sideways. A pre-shrinking machine shortens the cloth lengthwise by compression. The two do different jobs and are often used on the same fabric: set the width first, then pre-shrink.
Typical process data
| Item | Typical range | Note |
|---|---|---|
| Moisture before shrinking | About 15% | Cloth is moistened by water or steam |
| Heated shoe or cylinder | About 180 °C | Older blanket-type machines |
| Pre-shrinking capacity | Up to about 10% | Depends on fabric and blanket |
| Residual shrinkage target | 1% or less | Checked by wash test |
| Fabrics | Woven cotton, denim, canvas, cotton blends | Knit fabric uses different equipment |
| Working width | Per order | Matches your widest fabric |
Typical process values from published technical sources, not machine ratings. Ratings are given in the quotation.
How to choose
State the residual shrinkage you must reach, in warp and weft. It sets the compression capacity.
State the fabric: type, weight in GSM, and widest width. Heavy denim and light shirting need different blanket settings.
Ask what is in the blanket supply and how long it lasts. The rubber blanket is the wear part.
Check the line around it. Many mills run a dryer or a stenter before the machine and a batcher after it.
Frequently asked questions
Is pre-shrinking the same as sanforizing?
The process is similar. Sanforizing is a trade name associated with one company, so we use the plain terms pre-shrinking and compressive shrinkage.
Does it work on knit fabric?
Not on this machine. Knit fabric is relaxed and shrunk in a relax dryer or a compactor.
What do I send for a quote?
Fabric type and weight, widest fabric, target shrinkage, speed or daily meters, and destination country.