Mitsui Seiki J6CN
Key Specifications
X Travel
Y Travel
Z Travel
Spindle Taper
Tool Capacity
Table Size
How much does the Mitsui Seiki J6CN cost?
Estimated price range
Our best estimate for a cnc boring machine in this class — not a quote from Mitsui Seiki. Configuration moves it a long way.
Overview
The Mitsui Seiki J6CN is a CNC boring machine with 1,020 x 760 mm (40.15 x 29.92 in) of X and Y travel, a quill spindle and a listed positioning accuracy of ± 0.001 mm (0.00004 in). Mitsui Seiki's figures describe a machine for locating and finishing bores, with spindle speed and power kept low.
The spindle works between two columns set 1,120 mm (44.09 in) apart, over a 1,280 x 960 mm (50.39 x 37.79 in) table rated for 1,200 kg (2,645 lbs). Vertical movement is split between two axes: Z travel is 300 mm (11.81 in) and a W axis adds 750 mm (29.5 in). The maximum distance from table top to spindle nose is 950 mm (37.5 in), with 1,150 mm and 1,300 mm listed as options. W rapid is only 560 mm/min (22 ipm), so it is an axis that is set for the part height and then left alone.
The quill is 125 mm (5 in) in diameter, 145 mm (5.7 in) at the nose, around a 75 mm (3 in) spindle. Speed runs from 40 to 3,200 RPM and power is listed as AC 10 kW (7 hp). The taper is ISO no. 45 NT, with Cat 45 and a 50 taper as options. Those numbers place the machine in boring, reaming and light finish milling; high-speed small-tool work and heavy stock removal are both outside it.
Rapid traverse is 5,080 mm/min (200 ipm) in X and Y and 3050 mm/min (120 ipm) in Z, with fine feeds from 0.1 to 2,000 mm/min. Repeatability is ± 0.0005 mm (0.00002 in).
No tool changer is part of the base figures: the ATC is an option, listed as 20ATC or 60ATC. The work handling row reads manual 0-point and robot loader. The machine measures 5,800 x 5,180 mm (228 x 204 in) without guarding, ATC or coolant system and weighs 9,000 kg (19,800 lbs). The J7CN is the larger sibling, with 1,530 mm (60.23 in) of X travel, a 2,000 kg (4,400 lbs) table load and a weight of 14,000 kg (30,800 lb).
Full Specifications
| Parameter | Value |
|---|---|
| X-Axis Travel | 1,020 mm (40.15") |
| Y-Axis Travel | 760 mm (29.92") |
| Z-Axis Travel | 300 mm (11.81") |
| Travel W | 750 mm (29.5") |
| Distance Between Columns | 1,120 mm (44.09") |
| Max Distance Table Top to Spindle Nose | 950 mm (37.5") (opt. 1150, 1300mm) |
| Table Size | 1,280 X 960 mm (50.39" x 37.79") |
| Max Table Load | 1,200 kg (2,645 lbs) |
| Quill Diameter | 125 mm - 5" ,(145 mm - 5.7" at nose) |
| Spindle Diameter | 75 mm (3") |
| Spindle Speed | 40~ 3200 RPM |
| Spindle Taper | ISO no. 45 NT (Cat 45 -opt) (opt. 50 Taper) |
| Spindle Motor Power | AC 10 kW (7 hp) |
| Rapid Traverse Xy | 5,080 mm/min. (200 ipm) |
| Rapid Traverse W | 560 mm/min. (22 ipm) |
| Rapid Traverse Z | 3050 mm/min (120 ipm) |
| Fine Feed Xy | 0.1 - 2000 mm/min (0.0039 – 78.7 IPM) |
| Fine Feed Z | 0.1 - 2,000 mm/min. (0.004 ~ 80 ipm) |
| Positioning Accuracy | ± 0.001 mm (0.00004") |
| Repeatability | ± 0.0005 mm (0.00002") |
| Tool Capacity | Option: 20ATC; 60ATC |
| Work Handling | Manual 0-point; Robot Loader |
| Machine Length | 5,800 mm (228") (w/o guarding, ATC or coolant system) |
| Machine Width | 5,180 mm (204") (w/o guarding, ATC or coolant system) |
| Machine Weight | 9,000 kgs (19,800 lbs) |
| CNC Control | Fanuc 30iM-B |
Specifications sourced from mitsuiseiki.com — verified 2026-10-03
Strengths & Limitations
Strengths
- Positioning accuracy of ± 0.001 mm (0.00004 in) and repeatability of ± 0.0005 mm (0.00002 in)
- 1,280 x 960 mm (50.39 x 37.79 in) table carrying 1,200 kg (2,645 lbs)
- W axis of 750 mm (29.5 in) in addition to 300 mm (11.81 in) of Z, with optional 1,150 mm or 1,300 mm table-to-nose distance
- Fine feed from 0.1 to 2,000 mm/min in X, Y and Z
- 125 mm (5 in) quill, 145 mm (5.7 in) at the nose, for a stiff boring spindle
Limitations
- Spindle speed tops out at 3,200 RPM, which limits small-diameter tools
- The automatic tool changer is an option (20ATC or 60ATC), not standard
- Spindle power is listed as AC 10 kW (7 hp), which rules out heavy roughing
- W-axis rapid is 560 mm/min (22 ipm), so large height changes are slow
- Takes 5,800 x 5,180 mm (228 x 204 in) of floor before guarding, ATC or coolant system are added
Best For
Frequently Asked Questions
01
Mitsui Seiki lists positioning accuracy of ± 0.001 mm (0.00004 in) and repeatability of ± 0.0005 mm (0.00002 in). Fine feed is adjustable from 0.1 mm/min, which supports the slow, controlled approach that finish boring needs.
02
Size. The J6CN has 1,020 mm (40.15 in) of X and 760 mm (29.92 in) of Y travel, a 1,200 kg (2,645 lbs) table load and weighs 9,000 kg (19,800 lbs). The J7CN has 1,530 mm (60.23 in) of X and 1,020 mm (40.15 in) of Y, carries 2,000 kg (4,400 lbs) and weighs 14,000 kg (30,800 lb). Both have 300 mm (11.81 in) of Z and the same AC 10 kW (7 hp) spindle power.
03
Only as an option. The tool capacity row lists the ATC as an option in two sizes, 20ATC and 60ATC. The machine dimensions of 5,800 x 5,180 mm (228 x 204 in) are given without guarding, ATC or coolant system, so an ATC adds to the floor space.
04
A quill spindle: the quill is 125 mm (5 in) in diameter and 145 mm (5.7 in) at the nose, with a 75 mm (3 in) spindle. Speed range is 40 to 3,200 RPM and power is listed as AC 10 kW (7 hp). The taper is ISO no. 45 NT, with Cat 45 or a 50 taper as options.
05
The maximum distance from table top to spindle nose is 950 mm (37.5 in), with 1,150 mm and 1,300 mm listed as options. Vertical travel is 300 mm (11.81 in) in Z plus 750 mm (29.5 in) on the W axis. The distance between columns is 1,120 mm (44.09 in), which limits part width in that direction.
Videos
CT-MACHINERY-SYSTEMS / CT-DEFENSE-DYNAMICS
CT-MACHINERY-SYSTEMS / CT-DEFENSE-DYNAMICS
CT-MACHINERY-SYSTEMS / CT-DEFENSE-DYNAMICS
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