How Are Shock Absorber Tubes Closed? End Closing, Center Holes and Machine Choice
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Shock absorber, damper and hydraulic cylinder tubes need one end closed to hold internal pressure, while the other end takes the rod, guide and seal. How the closed end is made affects pressure resistance, appearance and production cost.
Common closing methods
| Method | Description |
|---|---|
| Welded end cap | A separate cap is machined and welded on, then leak-tested and ground |
| Spin closing | A closing machine spins the tube itself closed – one piece, no weld seam |
End shapes and holes
- Round end: even stress distribution, common on shock absorber outer tubes and gas spring cylinders.
- Flat end: a flat face that makes it easy to weld on eyes or fittings.
- Center hole: left open for later welding, fastening or other processes.
Quality points
- No cracks at the closure – the tube must be ductile enough, and any weld seam must be sound.
- Consistent end shape and length for trouble-free assembly.
- Large cylinders need a rigid machine, ideally with an adjustable closing path.
TONG DA shock absorber tube closing machines
| Model | Features |
|---|---|
| TD-31050 shock absorber tube closing machine | Two-station round-end closing, with or without a hole |
| TD-382 NC closing machine (large cylinders) | Servo-controlled closing path for large cylinders and hydraulic tubes, flat ends and holes |
Why TONG DA
- TONG DA has designed and built tube processing machines since 1989 and runs contract processing on its own machines.
- Tooling is designed to your tube and drawing; sample trials available.
- CE certified; machines sold to the USA, Germany, Turkey, the UK, India, China and more.
FAQ
Can eyes or fittings be welded on after closing?
Yes – flat ends and ends with a hole are easy to weld.
Can I send samples for a trial?
Yes, please send the tube OD, wall, material and closed-end drawing.
How do I request a quotation?
Send your tube specification, closed-end drawing and requirements to sales@tdco.com.tw and we will reply promptly.