Hwashi MFDC Double-Head Spot Welder for Barrel Hoop Lock Clips | Dual-Point Precision Welding
Two Welds. One Cycle. Zero Asymmetry.
Introducing the Hwashi MFDC Double-Head Spot Welder for Barrel Hoop Lock Clips — a purpose-built medium-frequency inverter DC spot welding machine designed from the ground up for simultaneous dual-point welding of barrel hoop lock clips. Engineered for drum manufacturers who demand symmetrical weld quality, high throughput, and reliable performance on galvanized and coated steel hoops.
Product Description
A barrel hoop lock clip has two attachment points — one on each side of the latch mechanism. If either weld fails, the hoop loosens, the seal breaks, and the contents leak. The lock clip is the most critical joint on the entire barrel hoop assembly, and it's under constant mechanical stress every time the barrel is opened, closed, and transported.
The Hwashi MFDC Double-Head Spot Welder eliminates weld asymmetry by welding both attachment points simultaneously with independently controlled but perfectly synchronized current and pressure. Both heads fire in the same cycle, producing two welds with identical nugget size, identical penetration, and identical pull strength — every single time.
Powered by MFDC inverter technology operating at 1000Hz, this machine delivers fast, concentrated energy pulses that form solid nuggets before zinc coating can vaporize — making it ideal for galvanized steel hoops without spatter, burn marks, or coating damage. The pneumatic clamping system is specifically designed for the curved geometry of barrel hoops, ensuring full, even electrode contact on cylindrical surfaces.
With cycle times as low as 3–5 seconds per hoop (including loading and unloading) and 101 stored welding programs for instant changeover between specifications, a single operator can process hundreds of hoops per shift with consistent, certification-grade weld quality.
Product Details
Working Principle
The machine performs the entire lock clip welding process in a fully automatic cycle:
- Load — Operator places the barrel hoop and lock clip into the purpose-designed fixture
- Clamp — Pneumatic system secures the workpiece and positions both electrodes onto the lock clip attachment points
- Weld — Both MFDC welding heads fire simultaneously with synchronized current and pressure, forming two identical weld nuggets
- Hold — Electrodes maintain pressure during solidification to ensure full nugget formation
- Release — Electrodes retract, fixture opens for part removal
The PLC-controlled automatic cycle manages every step — no manual triggering, no timing judgment calls, no operator-dependent variation.
Key Features
| Feature | Benefit |
|---|
| Dual-head simultaneous welding | Both lock clip attachment points welded in one cycle with identical parameters — eliminates quality asymmetry between left and right joints |
| MFDC inverter technology (1000Hz) | Fast current rise, short welding duration — prevents zinc vaporization on galvanized hoops, eliminates spatter and burn marks, saves 30%+ energy vs. AC |
| ±1% current control precision | Consistent nugget quality across every weld cycle — meets UN packaging certification requirements for drum manufacturers |
| Curved-surface fixturing | Custom-shaped electrodes and locating blocks designed for barrel hoop geometry — ensures full, even contact on cylindrical surfaces regardless of hoop diameter |
| Fully automatic welding cycle | PLC-controlled sequence from clamping to release — removes human variability, new operators produce same quality as veterans |
| 101 stored welding programs | Instant recall for different hoop sizes, strip thicknesses, and buckle designs — changeover in minutes without test welds |
| 3–5 second cycle time | Hundreds of finished hoops per shift from a single operator — maximizes throughput |
| Pneumatic clamping & electrode actuation | Fast, repeatable, no manual adjustment between parts — consistent force application |
| Three-phase balanced input | No power factor correction needed — reduces grid load and eliminates reactive power penalties |
Technical Specifications
| Item | Specification |
|---|
| Machine Type | Vertical, double-head MFDC spot welding machine |
| Welding Heads | 2 (left and right, independently controlled, simultaneous) |
| Inverter Frequency | 1000 Hz |
| Input Voltage | Three-phase 380V ±10%, 50/60Hz |
| Rated Capacity | 63 / 100 / 150 KVA per head (selectable) |
| Max. Secondary Current | Up to 20,000 A per head |
| Duty Cycle | 50% |
| Current Control Precision | ±1% |
| Electrode Stroke | Upper 80 mm / Lower 30 mm |
| Electrode Force | 200–1500 N (pneumatic, adjustable) |
| Welding Time Range | 1–999 ms |
| Automatic Cycle Time | 3–5 s/pc (including load/unload) |
| Stored Programs | 101 |
| Operation Mode | Manual loading / automatic welding cycle |
| Pneumatic Supply | 0.4–0.6 MPa |
| Cooling | Water-cooled (closed loop, flow monitored) |
| Safety | Light curtains, interlocks, E-stop, overload protection, low-pressure alarm |
| CE Certification | Yes |
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