What Is Gas Spring Press-Fit and Edge Folding? Pressing Guides and Seals, Folding the Tube Mouth
After a gas spring (gas strut, tailgate strut, gas lift) cylinder has been closed, grooved and filled with oil, the open end still has to be sealed. Press-fit and edge folding means pressing the piston rod assembly, rod guide and oil seal into the tube in order, then folding the tube mouth inward so it locks the parts in place and closes the cylinder before gas charging. This step decides whether the gas spring will leak gas or oil.
Where it sits in the production line
- Tube processing: cutting, grooving, end closing, inner grooving
- Oil filling
- Press-fit: rod assembly, guide and seal pressed into the tube
- Edge folding: tube mouth folded inward over the parts
- Gas charging, force and speed testing
What matters in press-fitting
- Correct depth: too shallow and parts work loose, too deep and the seal is damaged.
- Concentric pressing, so the seal lip is not scratched or rolled over.
- Clean tube bore and parts – debris causes leaks.
What matters in edge folding
- An even fold all the way round, so the guide and seal stay held for the product's life.
- No cracks or wrinkles at the tube mouth, and a clean appearance.
- Fold position matched to the cylinder groove and part design.
Common defects and likely causes
| Defect | Likely cause |
|---|---|
| Gas or oil leakage | Seal pressed in at an angle or scratched, uneven fold, debris |
| Loose parts, noise | Insufficient press depth, fold not tight |
| Cracks or wrinkles at the mouth | Low tube ductility, wrong folding tool or over-forming |
| Inconsistent quality | Manual variation, unstable fixture location |
TONG DA press-fit and edge folding machines
| Model | Description |
|---|---|
| TD-AT155 press-fit and edge folding machine | Presses gas spring components and folds the tube mouth closed |
| TD-724 four-station press-fit and edge folding machine | Press-fit and folding split across four stations |
TD-AT155 and TD-724 are the same machine type with different station layouts. Oil filling before this step can be handled by the TD-YL506 automatic oil filling machine, and TONG DA also builds the closing, inner grooving and roll grooving machines for the cylinder – buy one machine to fill a gap, or plan a full line.
Why TONG DA
- TONG DA designs and builds gas spring cylinder machines and also runs cylinder contract production on its own machines.
- Press and folding tooling is designed to the customer's tube and part drawings.
- CE certified; machines sold to the USA, Germany, Turkey, the UK, India, China and more.
FAQ
Can one machine handle different gas spring sizes?
Yes, by changing the tooling and fixtures for each tube size.
TD-AT155 or TD-724?
It depends on your product and line layout – send your drawings and we will recommend a model.
How do I ask for a quotation or a sample trial?
Send your gas spring drawing, tube specification and requirements to sales@tdco.com.tw and we will reply promptly.