TD-31040 Heat Pipe & Heat Exchanger Tube End Closing Machine | Stainless & Copper Tube Sealing
What a heat exchanger tube end needs
After closing, heat pipes and heat exchanger tubes see internal pressure and repeated thermal cycling. The closure must have no weld porosity and no plug gap. TD-31040 cold roll-spins the tube end into a seamless one-piece dome; the wall thickens at the closure, which suits thermal cycling better than a welded cap.
Tube range
| Item | Spec |
|---|---|
| Tube OD | Ø10–40 mm |
| Wall thickness | 0.8–2.0 mm standard; heavy-wall stainless evaluated per size |
| Materials | Stainless steel (304, 316), copper, carbon steel, aluminum. Good ductility required; welded tube needs a sound seam |
| Closed-end type | Fully closed dome, or dome with center hole set by tooling |
Production examples
| Material | Size | Customer |
|---|---|---|
| Stainless steel | Ø12.7 × 1.7 mm | Thailand |
| Stainless steel | Ø26.67 × 2.9 mm | — |
| Stainless steel | Ø33.4 × 3.4 mm | USA |
| Copper heat pipe | Small-diameter flat closing | On TD-21025 flat-type machine |
Dome end or flat end
TD-31040 makes a dome-shaped closed end, the strongest form for pressure and the right choice for stainless and heavy-wall tube. For a flat closed end on small copper heat pipes (where the end face mates to a heat sink), TONG DA offers the TD-21025 flat-type closing machine. Both can be trial-closed for comparison.
Machine features
- Three stations cycling in turn; one operator.
- Cold forming: no heat-affected zone, no discoloration or annealing of stainless.
- Quick changeover by jaw and collet set.
- PLC + touch screen, proximity-switch positioning for consistent closure length and hole size.
- Forced air cooling; 220–415 V, 3 phase.
FAQ
Will stainless crack?
Not with normal-ductility 304/316 seamless tube or welded tube with a sound seam. For wall thickness beyond the standard range, send samples first; we trial-close and report.
Is any welding needed after closing?
No. The dome is one piece. Leak testing is to the customer’s own specification; trial samples are supplied for testing.
Copper?
Yes. Copper is among the easiest materials to close; for small copper heat pipes consider TD-21025 flat type as well.
How to send samples?
Tube OD × wall × material × length and the closed-end drawing; we trial-close and return samples.
Sealing machine to process tube require: ＊Sealing machine to process tube hardness have to less HRB55 and need enough ductility. ＊Because it is a cold forming process, the tolerance will be unstable due to the factors of the pipe, and the tolerance of the incoming material will affect the overall tolerance. The tolerance of the incoming material must be as small as possible. ＊Sealing machine to process tube weld bead have to firm, when sealed weld bead will not dehiscence. ＊Outside dia less than 20mm, within length 1000mm can to install tube holder keep tube don't shake (need extra purchase). ＊Stainless steel tube hardness is softer the better and good ductility, tube material weld bead have to firm. ＊Tube outside dia and thickness have to collocation each other. Especially outside dia more than 25mm tube.
＊TONG DA reserves the right to modify technical data, design, end of delivery, color, materials, specifications and models. | ||||||||||||||||||||||||
| Three Station-Tube Sealing Machine | Specification |
|---|
Patent Information:
Safety certification:
CE MARK
Partner company:
Sold to Germany gas spring factory , European, USA company, China, Thailand, Japanese car companies
