Unit 2: Drop-box and jet looms & design execution
Advance Weaving notes · PTU syllabus (BSTD 310-20)
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Unit summary
This unit covers drop-box and jet looms, punching and the design process from theme to documented woven swatches.
After this unit you can
- Explain a drop-box loom and when it is used
- Compare air-jet and water-jet looms
- Follow a systematic design methodology for a woven collection
PTU syllabus topics
- Drop box looms
- punching and the technology of air jet and water jet looms
- systematic design methodology (theme, colour story, product, market, cost, material)
- executing a design collection from concept through to woven swatches with full documentation
Air jet
Jet of compressed air
Fast, light-to-medium cotton and blends
Water jet
Jet of water
Synthetic filament yarns only
Rapier
Rigid or flexible rapier arms
Wide variety, fancy yarns
Projectile
Small gripper projectile
Wide-width fabrics
Topic 1
Drop-box and jet looms
A drop-box loom has boxes holding several shuttles of different colours; the boxes rise or drop so that the required weft colour is picked in the sequence needed for checks and stripes in the weft.
| Loom | Weft carrier | Strengths | Limits |
|---|---|---|---|
| Air-jet | Compressed air | Very high speed; fine yarns; low cost per metre | High energy use; hairy yarns problematic |
| Water-jet | Water jet | Fast; low noise; filament synthetics | Not for water-absorbent fibres; fabric must be dried |
Punching means making cards or electronic files that carry the lifting information for dobby and jacquard looms.
Topic 2
Design methodology and execution
- 1
Theme
- 2
Colour story
- 3
Product
- 4
Market
- 5
Cost
- 6
Material
- 7
Weave swatches
- 8
Documentation
| Stage | Output |
|---|---|
| Theme and colour story | Mood board and palette |
| Product and market | Target customer, season, price point |
| Cost and material | Yarn choices, estimate per metre |
| Swatches | Woven samples labelled with draft, lifting plan, EPI, PPI |
| Documentation | Folder with sketches, plans, photographs and reflections |
Warping and weaving usually take most of the time, so preparation and planning save effort
Key terms
- Drop-box loom
- Loom changing weft colours automatically
- Air-jet loom
- Loom inserting weft by compressed air
- Water-jet loom
- Loom inserting weft by water
- Punching
- Preparing lifting information on cards
- Colour story
- Planned set of colours for a collection
Quick revision
- Drop-box = several wefts; jet looms = shuttleless, fast.
- Methodology: theme → colour → product → market → cost → material → swatches → documentation.
- Document every swatch with its plans.
Important exam questions
Practice questions written to the PTU exam pattern for this unit's syllabus: short answers (Section A style) and long answers (Sections B and C style).
Short-answer questions
- Q1.What does a drop box do?
- Q2.Why is a water-jet loom not suited to cotton?
- Q3.What is punching?
- Q4.What is a colour story?
- Q5.Name two items in design documentation.
Long-answer questions
- Q1.Compare air-jet and water-jet looms.
- Q2.Explain a systematic design methodology for a woven collection.
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