Mitsui Seiki HV4A
Key Specifications
X Travel
Y Travel
Z Travel
Spindle Taper
Tool Capacity
Rapid Traverse
Overview
The Mitsui Seiki HV4A is a vertical-spindle horizontal machining center with a 400 mm pallet, combining the high-accuracy DNA of Mitsui Seiki's horizontal platform with a vertical spindle orientation suited to precision prismatic parts requiring gravity-assisted chip evacuation and deep bore machining. The HV designation reflects the vertical spindle configuration on a horizontal platform — the column moves horizontally while the spindle points down, which is favorable for hydraulic manifolds, pump bodies, gearbox housings, and precision fluid control components.
The HV4A is built on the same Meehanite cast iron, box way, full thermal compensation architecture as the HS series. Positioning accuracy is ±0.001 mm full stroke with ±0.0005 mm repeatability, and linear scale feedback on all axes ensures closed-loop accuracy throughout the part cycle. The 400 mm pallet handles workpieces up to 600 mm diameter and 800 mm height, suitable for complex small-to-medium prismatic parts.
Spindle options include a 12,000 RPM, 18.5 kW (25 hp) inline spindle in No. 40 taper (CAT40/BT40/HSK-A63) for general precision work, or a 20,000 RPM high-speed option for aluminum and non-ferrous materials. A 40-tool ATC and 2-station APC are standard. The FANUC 31i-B5 control provides high-precision contouring and thermal compensation cycles native to Mitsui Seiki's accuracy philosophy.
The HV4A fills a specific niche: it is not the fastest machine in its pallet class, but for shops producing fluid power components, precision instrument housings, and hydraulic valve bodies where bore-to-bore positional accuracy is audited on every part, the HV4A's guaranteed accuracy spec is the reason it gets specified on the machine list.
Full Specifications
| Parameter | Value |
|---|---|
| Pallet Size | 400 mm x 400 mm (15.7 x 15.7 in) |
| X-Axis Travel | 760 mm (29.9 in) |
| Y-Axis Travel | 660 mm (26.0 in) |
| Z-Axis Travel | 760 mm (29.9 in) |
| Spindle Orientation | Vertical (column-type horizontal machine) |
| Max Workpiece Diameter | 600 mm (23.6 in) |
| Max Workpiece Height | 800 mm (31.5 in) |
| Max Workpiece Weight | 800 kg (1,764 lb) |
| Spindle Taper | CAT 50 |
| Spindle Speed | 12,000 RPM (standard) / 20,000 RPM (high-speed option) |
| Spindle Motor Power | 18.5 kW (25 hp) continuous / 22 kW (30 hp) 30-min |
| Rapid Traverse Rate | 36 m/min (1,417 ipm) all axes |
| Feed Rate | 1–15,000 mm/min |
| Positioning Accuracy | ±0.001 mm (±0.00004 in) full stroke |
| Repeatability | ±0.0005 mm (±0.00002 in) |
| Feedback | Full-closed loop, linear scales all axes |
| Thermal Compensation | Spindle oil cooling, ballscrew cooling, temperature compensation |
| Tool Capacity | 40 (standard) / 60 (optional) |
| Tool Change Time | 4.0 sec (chip-to-chip) |
| Pallet Changer | 2-station APC (standard) |
| Way Type | Box ways, induction hardened and precision ground |
| Base Material | Meehanite cast iron |
| CNC Control | FANUC 31i-B5 |
| Machine Weight | 12,000 kg (26,455 lb) |
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| Japan | Mitsui & Co., Ltd. (Head Office) |
| North America | Mitsui & Co. (U.S.A.), Inc.Mitsui & Co. (Canada) Ltd. |
| Central America And South America | Mitsui de Mexico, S. de R.L. de C.V.Mitsui & Co. (Chile) Ltda.Mitsui & Co. (Brasil) S.A. |
| Europe The Middle East And Africa | Mitsui & Co. Europe LtdMitsui & Co. Deutschland GmbHMitsui & Co. Benelux S. A./N. V.Mitsui & Co. Italia S. p. A. |
| Cis | Mitsui & Co. Moscow LLC |
| Oceania | Mitsui & Co. (Australia) Ltd. |
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| Manufacturer | Mitsui Seiki |
| Model | Vertex 550-5X |
Specifications sourced from machinio.com — verified 2026-03-28
Strengths & Limitations
Strengths
- Vertical spindle on horizontal platform provides excellent chip evacuation by gravity — critical for deep bore work in hydraulic manifolds and gearbox housings
- ±0.001 mm full-stroke positioning accuracy with laser-verified certification matches the HS series — rare at this pallet size
- Box way construction combined with full thermal compensation delivers long-term accuracy stability across shifts and seasonal temperature changes
- No. 40 taper at 12,000 RPM covers the majority of precision steel, aluminum, and titanium work in the 400 mm pallet class
- Compact footprint relative to 500–630 mm pallet HMCs makes the HV4A viable in shops with floor space constraints
- FANUC 31i-B5 control is universally familiar to precision machinists and supports advanced compensation and probing cycles
Limitations
- Vertical spindle configuration limits access to some five-sided machining strategies compared to conventional horizontal spindle HMCs
- 36 m/min rapids are slower than linear-guide competitors — the HV4A is not optimized for high-speed aluminum production
- Price premium versus standard 400 mm pallet HMCs is significant; ROI depends on work requiring certified micron-level accuracy
- 40-tool ATC is adequate but constrains complex multi-setup jobs — 60-tool option adds cost and footprint
- Mitsui Seiki's U.S. and European dealer networks are thinner than Fanuc-integrated competitors like Okuma or Mazak
Best For
Frequently Asked Questions
01
In the HV4A, the spindle points vertically downward (like a vertical machining center) but the machine architecture is horizontal — the pallet is mounted vertically on a rotary table and the column traverses horizontally. This combines gravity-assisted chip fall with horizontal machine rigidity and pallet-change capability. It is particularly effective for deep bore and manifold work where chip packing in blind holes is a problem on conventional VMCs.
02
The Matsuura H.Plus-400 is a linear-guide, high-speed HMC with a 12,000 RPM horizontal spindle optimized for prismatic production. The Mitsui Seiki HV4A has a vertical spindle, box ways, and a guaranteed ±0.001 mm accuracy spec. The Matsuura is faster and more production-oriented; the HV4A is more accurate and better suited to complex bore geometry. Price difference reflects this: the HV4A typically runs $200–400K more.
03
The HV4A is a 4-axis machine (X, Y, Z plus B-axis rotary table). It is not a 5-axis machine with simultaneous tilting — for 5-axis work, Mitsui Seiki's GR504 is the appropriate choice. However, the HV4A's 4-axis capability is sufficient for most prismatic part applications involving index-and-machine strategies with multiple setups on tombstone fixtures.
04
The primary buyers are aerospace hydraulic system suppliers, defense equipment manufacturers, fluid power component producers, and precision medical device companies. The vertical spindle configuration is particularly valued in the hydraulic manifold segment, where deep intersecting bore accuracy must be documented and audited.
Community Discussions
Pricing and buying discussion — Need Help! Mitsui Seiki HS4A Parameters - CNCzone
Options and configuration advice — Thread: Please help... need mitsui seiki parameters
Troubleshooting and problem-solving — Problem tool change issue - CNCzone
Troubleshooting and problem-solving — Need Help! Mitsui Seiki with Fanuc OM control - CNCzone
Links to community discussions. Summaries are editorial — visit the original thread for full context.
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