TD-627 Servo Damping Groove Machine | 1, 2 or 3 Inner Grooves at Different Depths for Tailgate Struts & Gas Springs
Gas spring damping groove (inner grooving): layouts, groove types and opening speed
The damping groove sets how the strut opens
Where the piston passes a grooved section, oil or gas flows around it through the groove and the strut moves fast; where there is no groove the motion is damped and slow. The length, depth, number and position of the grooves are therefore the speed setting of a tailgate strut or gas spring: constant speed, slowing down before the end of the stroke, or a fast–fast–slow profile. Because damping comes from the groove in the cylinder wall and not from an orifice in the piston, it works in any mounting position, horizontal or rod up.
Grooves the TD-627 can make
| Layout | Description |
|---|---|
| Single groove | One lengthwise groove, the most common |
| Two grooves at 180° | Two grooves opposite each other |
| Three grooves at 120° | Three grooves evenly spaced |
| Different depths | Up to three grooves, each with its own depth, for progressive damping |
| Segments on one line | One to three segments on the same line |
| Groove start and end | Type A square in and out, Type B taper in and square out, Type C taper in and out, Type D segmented |
Groove length, depth, width and position are set from the drawing on the touch screen and stored; a product change is a parameter recall.
Machine highlights
- Cylinder OD 15–28 mm, tube length up to 600 mm.
- Servo X and Y axes: groove length and depth come from the program, so every cylinder is the same.
- Servo drive is not affected by oil temperature, so groove depth stays stable.
- Available with automatic or manual loading and unloading. The automatic version can have servo rotation for automatic indexing of 180° and 120° grooves.
- Low noise, no oil leaks, few consumables, low vibration and longer tool life.
Servo vs hydraulic inner grooving
| Item | TD-627 servo | TD-61530 hydraulic |
|---|---|---|
| Cylinder OD | 15–28 mm | 15–28 mm |
| Tube length | Up to 600 mm | Up to 450 mm |
| Grooves and depth | Up to 3, different depths | Up to 2, same depth |
| 180° / 120° grooves | Optional servo rotation on the automatic version | Tube turned by hand |
| Stability | Servo drive, not affected by oil temperature | Cylinder speed changes with oil temperature |
| Best for | Many sizes, frequent changeover, tight depth consistency | One fixed product in high volume |
Related videos
 Servo Inner Grooving – 3 Grooves at 3 Depths |  Servo CNC Gas Spring Damping Groove (Inner Grooving) Machine |  Damping Groove Test – PTFE Piston Passes Smoothly |
More machine videos on our YouTube channel: youtube.com/@closingmachine
FAQ
Can three grooves have three depths?
Yes. The TD-627 makes up to three grooves and each depth is set separately (see the video).
Can the groove taper in and out?
Yes. Square, taper-in, taper-in-and-out and segmented grooves are all set from the drawing.
What changes with the cylinder size?
Each cylinder ID needs its own grooving tool set; a change of groove length needs no tooling change.
Can you run our samples?
Yes. Send cylinder OD × wall × material × length and the groove drawing (length, depth, number, position) to sales@tdco.com.tw.
