The adjustable wrench body is the core load-bearing component of an adjustable wrench. It is responsible for clamping various fasteners (bolts, nuts) and directly affects the clamping accuracy and service life of the wrench.
Commonly used materials include 45# steel, chromium-vanadium steel (Cr-V), etc., which are required to have high strength and wear resistance. It features complex geometric characteristics, consisting of special-shaped structures such as three curved surfaces, open slots and a central large hole, with strict dimensional tolerance requirements for all parts (e.g., slot width tolerance of ±0.03mm, hole position tolerance of ±0.05mm).
Common risks in traditional machining processes include: dimensional deviations caused by multiple clamping operations (reject rate ≥ 10%), low efficiency due to multi-process transfer (20 units/hour), and high manual operation errors (e.g., the milled surface roughness Ra ≥ 3.2μm).
The traditional machining of adjustable wrench bodies requires four independent processes: large-hole drilling → rough jaw milling → finish jaw milling → slot milling. Each process demands separate clamping, which gives rise to three major pain points:
- Precision loss: Cumulative repeated clamping errors exceed 0.1 mm, with the reject rate reaching 12%.
- Labor redundancy: 8 workers are needed to operate one single machine, and labor costs account for 35% of the total production cost.
- Low efficiency: The output of one machine is only 20 units per hour, failing to meet the delivery requirements of large-volume orders.
These problems directly drive up production costs, delay order cycles and weaken the market competitiveness of enterprises.
Blank (forging/casting) → One-time clamping → Large-hole drilling → Rough jaw milling → Finish jaw milling → Slot milling → Inspection → Finished product
- Large-hole Drilling: A special carbide drill bit is adopted. The CNC program sets a rotational speed of 1000 rpm and a feed rate of 0.2 mm/r, with the hole position accuracy controlled within ±0.05 mm. Key equipment: the built-in high-precision spindle of the 8GX machine prevents drilling deviation.
- Rough Jaw Milling: A coated carbide milling cutter is used, with a rotational speed of 1500 rpm and a feed rate of 0.3 mm/r to quickly remove machining allowance. CAM tool path optimization (e.g., helical milling entry) prevents over-cutting and tool wear.
- Finish Jaw Milling: A diamond-coated milling cutter is adopted, with a rotational speed of 2000 rpm and a feed rate of 0.1 mm/r, ensuring the surface roughness Ra ≤ 1.6 μm. The on-line measurement module monitors dimensions in real time to guarantee the jaw surface parallelism ≤ 0.02 mm.
- Slot Milling: A special slotting cutter (made of tungsten steel) is used, with a rotational speed of 1200 rpm and a feed rate of 0.25 mm/r, and the slot width tolerance is controlled within ±0.03 mm. The automatic chip removal system clears chips in a timely manner to avoid precision loss caused by chip residues in the slot.
| Indicator |
8GX Composite Machine Tool |
Traditional Processing |
Improvement Degree |
| Production Cycle (12-inch body) |
120 units/hour |
20 units/hour |
500% increase |
| Scrap Rate |
<1% |
12% |
91.7% reduction |
| Labor Requirement (2 devices) |
1 person |
16 persons |
93.75% reduction |
| Single Unit Processing Cost |
0.8 CNY |
4 CNY |
80% reduction |
| Dimensional Tolerance |
±0.03mm |
±0.1mm |
70% improvement |
Case Study: A hardware tool factory in Zhejiang (with an annual production capacity of 1 million adjustable wrenches) introduced 2 units of the 8GX machine tool in 2023. The original staffing requirement of 8 workers per machine was reduced to 1 worker operating 2 machines, cutting labor costs by 75%. The reject rate dropped from 12% to 0.8%, and the monthly production capacity increased from 20,000 units to 120,000 units, enabling the factory to successfully fulfill large overseas orders.
Application Scenarios: Batch production of adjustable wrench bodies (10-18 inches) and customized machining of special-shaped wrench bodies for hardware tool manufacturing enterprises.
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