HITBOT Welding Cell
Solo project · pilot for Hindustan Metals · in sales talks
Hindustan Metals showed me the parts they wanted welded without a person holding the torch. I built a cell where you show a HITBOT arm the weld once, by hand, and it repeats it as many times as you need.
I took their parts back to the XP Robotics office and ran the pilot there, and it worked. The piece in these videos is one they gave me. Then I went to Hindustan Metals to sell them the cell, and those talks are ongoing. I did this one on my own, from the software to the pilot to the pitch.
The torch tracing the seam on the Hindustan Metals part during the pilot.
show it once
- Free drive. The arm switches to manual mode with drag teaching on, so it goes slack and an operator can guide the torch along the seam by hand.
- Teach. At each corner of the seam the operator presses Teach and the arm records its tool pose as a waypoint, P1 to P4.
- Dry run. The arm traces the full path with the arc off, to check the waypoints safely.
- Weld. It moves to the start with the arc off, strikes the arc, starts weaving if it's set, welds P1 → P2 → P3 → P4 → P1 in straight moves, then stops weaving and puts out the arc.
- Repeat. The taught path stays in memory, so the same weld runs again on the next part.
Close up: the torch on the arm's flange, approaching the joint.
the software
I wrote the control software: a FastAPI server with a dashboard in the browser. It talks to the HITBOT S922's controller (a Fairino FR-series) directly over XML-RPC on port 20003 instead of through the vendor SDK, because the SDK expects a state port this firmware doesn't serve. Each call has a bounded timeout, motion calls get a longer one, and an emergency stop halts the arm and disables it.
Weave amplitude and frequency, travel speed and the home pose are all set from the dashboard. With no robot attached it runs in a simulated mode, which is how I tested the weld sequence before the arm ever moved.
| Robot | HITBOT S922, Fairino FR-series controller |
|---|---|
| Link | XML-RPC over wired Ethernet |
| Teaching | Drag teach, four waypoints, linear moves |
| Welding | Arc start and end, optional weave |
| Stack | Python, FastAPI, a browser dashboard, pytest |
The pilot cell with the MIG welder behind it.
what it means for the plant
At Hindustan Metals I walked them through the time, labour and money the cell saves on each part compared with welding it by hand.