ONA Diamond P400

$140,000 – $260,000 Updated 2026-03-17

Key Specifications

X Travel

450 mm (17.7 in)

Y Travel

350 mm (13.8 in)

Z Travel

400 mm (15.7 in)

Accuracy

2 um

Repeatability

1 um

work tank dimensions

900 x 650 x 550 mm (35.4 x 25.6 x 21.7 in)

Overview

The ONA Diamond P400 is a high-performance production sinker EDM from ONA Electroerosion, a Spanish EDM manufacturer with over 70 years of history in electrical discharge machining. The Diamond series represents ONA's premium sinker EDM line, and the P400 delivers 450 x 350 x 400 mm of X/Y/Z travel in a C-frame architecture engineered for the most demanding mold, die, and aerospace component applications. The P400 targets shops where surface finish quality, positioning accuracy, and unattended production reliability are non-negotiable.

The heart of the Diamond P400 is ONA's G2 generator with ONA-adapted Power Control technology. The G2 generator samples gap conditions continuously and responds at microsecond resolution to maintain optimal discharge conditions. Its adaptive arc prevention system virtually eliminates surface damage from uncontrolled arcing — a critical advantage when machining high-value aerospace or medical components where surface integrity cannot be compromised. On graphite, roughing rates reach 400 mm3/min; on finishing, the generator drives to VDI 4 (Ra 0.2 um) and with mirror-polishing electrode strategies, VDI 2 (Ra 0.1 um) is achievable on steel.

ONA built the Diamond P400 on a monoblock cast iron base with three-point leveling and thermal stabilization. The guideways are hardened and precision-ground, with roller bearing carriages providing both low friction and high rigidity. The Z-axis uses a high-resolution digital encoder for precise electrode position feedback, enabling the micro-step movements required in fine and mirror-finish EDM. The work tank accommodates workpieces up to 2,500 kg, appropriate for the P400's travel class.

The ONA DIAX4 CNC control is the operator interface, featuring a large touchscreen display, graphical orbit programming, and ONA's integrated Expert System that automates discharge condition selection based on material and surface finish targets. The control supports full 4-axis simultaneous orbiting and includes ONA's proprietary electrode wear compensation algorithm. An optional 16-position ATC enables full multi-electrode unattended programs. ONA's remote diagnostics system connects to factory support in Spain for rapid issue resolution, a significant benefit for European and Latin American customers where ONA's service network is strongest.

Full Specifications

Parameter	Value
Work Tank Dimensions	900 x 650 x 550 mm (35.4 x 25.6 x 21.7 in)
X-Axis Travel	450 mm (17.7 in)
Y-Axis Travel	350 mm (13.8 in)
Z-Axis Travel	400 mm (15.7 in)
Max Workpiece Weight	2,500 kg (5,511 lb)
Dielectric System	Petroleum-based with temperature-controlled filtration
Surface Finish	VDI 2 (Ra 0.1 um) achievable with mirror strategy
Control System	ONA DIAX4 CNC with Expert System (touchscreen)
Generator Power	ONA G2 generator with Power Control, up to 60 A peak current
Machine Weight	5,800 kg (12,787 lb)
Positioning Accuracy	2 um
Repeatability	1 um
Metal Removal Rate	400 mm3/min (graphite roughing)
Electrode Weight Max	150 kg (331 lb)

Strengths & Limitations

Strengths

G2 generator's adaptive arc prevention system provides superior surface integrity on high-value components where arc damage is unacceptable
ONA's 70+ year EDM heritage and Diamond series premium position deliver proven reliability on demanding mold and aerospace applications
DIAX4 Expert System automates discharge condition selection, reducing setup time and operator dependence on EDM process knowledge
2,500 kg workpiece capacity in a compact C-frame footprint maximizes the usable weight-to-travel ratio
Optional 16-position ATC enables fully unattended multi-step roughing-to-mirror programs
Competitive pricing against GF Machining Solutions and Makino in the mid-size premium sinker EDM segment

Limitations

ONA's service presence in North America and Asia is limited compared to Makino, Sodick, or GF — European customers have much better support access
400 mm3/min graphite roughing rate is lower than Makino's HyperI or Sodick's LN2 generator at equivalent current levels
DIAX4 control and ONA's programming methods have a limited user community in North America, making operator training and knowledge transfer harder
Diamond series pricing, while competitive against premium Japanese/Swiss machines, is significantly above CHMER and other Taiwanese value-tier options
Resale value in North America is lower than equivalent Makino or Sodick machines due to lower brand recognition

Best For

European mold and die shops seeking premium sinker EDM performance with strong local ONA service and support Aerospace and defense suppliers requiring guaranteed arc-free surfaces on titanium and nickel superalloy components Medical device toolmakers where surface integrity documentation and process repeatability are regulatory requirements Precision toolrooms running complex multi-electrode programs that benefit from the DIAX4 Expert System's automated setup

Frequently Asked Questions

01 What does the ONA Diamond P400 cost?

New Diamond P400 machines typically range from $140,000 to $260,000 depending on generator configuration, ATC, and options. In North America, pricing tends toward the higher end due to import and distribution costs. ONA's European pricing is more competitive. Used Diamond series machines are uncommon in the secondary market.

02 How does the Diamond P400 compare to the ONA QX6?

The Diamond P400 is ONA's premium tier, using the G2 generator and DIAX4 control with advanced Expert System capabilities. The QX6 is the mid-range model with similar travel but a less advanced generator. The Diamond series costs approximately 20-30% more than the equivalent QX model and targets higher-precision and higher-value applications.

03 What makes ONA's arc prevention system different?

ONA's G2 generator uses real-time gap monitoring to detect pre-arc conditions — the voltage and current signatures that precede an uncontrolled arc discharge — and immediately adjusts discharge parameters to prevent the arc from completing. Conventional generators react to arcs after they occur; the G2 system prevents them. This is particularly valuable in deep cavities or with complex electrode geometries where flushing is imperfect.

04 Is the Diamond P400 suitable for large workpieces?

The P400's 2,500 kg workpiece capacity covers the vast majority of mold inserts, die components, and aerospace fixtures in its travel class. The 450 x 350 mm X/Y travel is the practical limitation — the machine handles any workpiece that fits within that footprint, regardless of hardness.

05 Where is ONA manufactured and what is their history?

ONA Electroerosion is a Spanish company founded in 1954, headquartered in Durango, Basque Country. ONA is one of the oldest EDM manufacturers in the world and exports to over 80 countries. Their primary engineering strength is in sinker EDM generator technology and the DIAX control platform.