Machine Comparison
Mitsui Seiki J6CN vs Mitsui Seiki J7CN
Mitsui Seiki vs Mitsui Seiki · CNC Boring Machines
Summary
The Mitsui Seiki J6CN and Mitsui Seiki J7CN are both from Mitsui Seiki's cnc boring machines lineup, making this a common upgrade or lineup decision for shops already invested in the Mitsui Seiki ecosystem. The Mitsui Seiki J7CN leads in x travel (700 mm (27.6 in) vs 600 mm (23.6 in)). The Mitsui Seiki J7CN shows specification advantages in 6 categories, though the Mitsui Seiki J6CN may still be the better choice depending on your shop's specific needs and the type of work you run. Both machines are proven performers in production environments and represent solid investments for shops in the market for a cnc boring machine.
Specifications Comparison
| Specification | Mitsui Seiki J6CN | Mitsui Seiki J7CN |
|---|---|---|
| X-Axis Travel | 600 mm (23.6 in) | 700 mm (27.6 in) ▲ |
| Y-Axis Travel | 500 mm (19.7 in) | 600 mm (23.6 in) ▲ |
| Z-Axis Travel | 400 mm (15.7 in) | 450 mm (17.7 in) ▲ |
| Tool Capacity | 20 tools | 20 tools |
| Rapid Traverse | 10 m/min (394 ipm) | 10 m/min (394 ipm) |
| Table Size | 800 x 500 mm (31.5 x 19.7 in) | 1,000 x 600 mm (39.4 x 23.6 in) ▲ |
| Accuracy | +/-1.0 um | +/-1.0 um |
| Repeatability | +/-0.5 um | +/-0.5 um |
| Control | Fanuc 31i-B with high-resolution scales | Fanuc 31i-B with high-resolution scales |
| Max Table Load | 800 kg (1,764 lb) | 1,200 kg (2,646 lb) ▲ |
| Spindle Speed | 8,000 rpm | 8,000 rpm |
| Spindle Taper | BT40 | BT40 |
| Spindle Motor | 7.5 kW (10 HP) continuous | 11 kW (15 HP) continuous ▲ |
| Scale Resolution | 0.01 um (10 nanometers) | 0.01 um (10 nanometers) |
| Price Range | $400,000 - $550,000 ▲ | $500,000 - $650,000 |
Advantages
Mitsui Seiki J6CN
- More competitive pricing at $400,000 - $550,000 compared to $500,000 - $650,000
- Backed by Mitsui Seiki's dealer and service network for parts and support
- Gauge and master tooling manufacturers where hole location accuracy to +/-1.0 um is a contractual requirement
Mitsui Seiki J7CN
- Greater x travel of 700 mm (27.6 in) accommodates larger workpieces
- Greater y travel of 600 mm (23.6 in) accommodates larger workpieces
- Greater z travel of 450 mm (17.7 in) accommodates larger workpieces
- Superior table size at 1,000 x 600 mm (39.4 x 23.6 in) vs 800 x 500 mm (31.5 x 19.7 in)
- Superior max table load at 1,200 kg (2,646 lb) vs 800 kg (1,764 lb)
Verdict
The Mitsui Seiki J7CN edges ahead on specifications in this comparison, particularly in X Travel and Y Travel. However, the Mitsui Seiki J6CN remains competitive and may be the better choice depending on price, dealer support in your area, or specific workholding and tooling considerations. Both are capable machines — the best decision comes from running your actual parts and evaluating total cost of ownership including tooling, training, and service.