Precision parts machining process at Ohnoseiko Vietnam: from 5-axis CNC to grinding and CMM measurement

Technology & Services

Depending on the shape, material, tolerance, and drawing requirements, a precision machined part at Ohnoseiko Vietnam may undergo various processes such as CAD/CAM programming, CNC milling, CNC turning, 5-axis machining, Wire EDM, surface grinding or cylindrical grinding, CMM dimensional inspection, and laser marking.A notable feature of Ohnoseiko Vietnam's equipment system is its ability to combine multiple machining methods within a single process. Instead of only performing milling or turning, the company possesses a system ranging from machining centers, CNC milling machines, CNC turning machines, wire cutting machines, grinding machines, to 3D measuring equipment.Notably, in addition to the FANUC ROBODRILL 5-axis machining center, Ohnoseiko Vietnam has also added a Makino DA300 5-axis machining center, thereby enhancing its capability to process parts with multiple surfaces and complex geometries.

Drawing Analysis and Machining Program Preparation using CAD/CAM

The precision part machining process begins with reviewing the drawing and determining the appropriate machining method. At this step, it is necessary to clarify:

• part shape and dimensions;
• surfaces to be machined;
• location of holes, grooves, and inclined surfaces;
• accuracy requirements;
• processes to be performed;
• machining sequence;
• fixturing plan.

Ohnoseiko Vietnam utilizes CAD/CAM systems such as SOLIDWORKS, SolidCAM, Autodesk FeatureCAM to support design and machining programming.Preparing the program before loading it onto the machine helps determine tool paths, machining sequence, and the approach method for each surface of the part.For products with complex geometries, the programming step is even more crucial as it requires simultaneous consideration of tool accessibility, fixturing position, and the relationship between surfaces.

Workpiece Preparation Before Main Machining

After determining the machining plan, materials are prepared to appropriate dimensions before being loaded onto CNC machines.Ohnoseiko Vietnam has cutting equipment such as:

• AMADA;
• ANDOSAW;
• workpiece cutting equipment for material preparation.

Proper workpiece preparation helps minimize unnecessary material waste and facilitates subsequent machining steps.Depending on the product, the cut workpiece can be directly transferred to a machining center, CNC turning machine, or other machining equipment.

CNC Milling for Main Part Shaping

CNC milling is one of the important processes in Ohnoseiko Vietnam's machining system.The factory currently has numerous machining centers from brands such as: BROTHER; OKUMA; AKIRA; FANUC; MAKINO. Specifically, there are multiple machines of the BROTHER S500 series, allowing for flexible machining arrangements for suitable products.For conventional parts, a 3-axis CNC machine can handle many basic operations. However, when a product has multiple surfaces or difficult-to-access areas, the number of setups may increase. This is where 5-axis machining demonstrates its advantage.

5-Axis Machining for Multi-Surface and Complex Geometry Parts

Ohnoseiko Vietnam currently has a FANUC ROBODRILL α-D21LIB5 machine and has added a Makino DA300, enhancing its 5-axis CNC machining capabilities.Unlike 3-axis machines that only move along the X, Y, and Z axes, 5-axis machines add rotational movements of the table or workpiece, allowing the tool to access the product from more directions.This is particularly useful for:

• parts with multiple surfaces requiring machining;
• holes located in various orientations;
• inclined surfaces;
• complex contours;
• parts requiring control over the positional relationship between multiple surfaces.

Why is Reducing the Number of Setups Important?

When machining a part with multiple setups, each removal and re-fixturing requires re-establishing the product's position. If the product requires tight control over the relationship between multiple surfaces, reducing the number of setups can help limit deviations arising during re-establishment of datum.5-axis machining allows access to multiple surfaces of a part in a single setup or with fewer setups, depending on the specific geometry of the product.Therefore, the addition of the Makino DA300 is not merely about adding another CNC machine but also about expanding the range of machining methods for parts with complex structures.

CNC Turning for Rotational Parts

Not all parts are suitable for CNC milling. For products with cylindrical shapes, CNC turning is often a more suitable method.Ohnoseiko Vietnam owns several OKUMA CNC turning machines such as: LS250-S; LS250; GENOS L250-e; GENOS L250II-e. The recorded machining diameter range is approximately φ150–φ180 mm.CNC turning can be used to create features such as:

• outer diameters;
• inner diameters;
• shaft shoulders;
• end faces;
• grooves;
• other rotational shapes.

For some products, CNC turning can be combined with milling, grinding, or other processes to complete the part.

Wire EDM for Contours Difficult to Machine with Cutting Tools

After milling or turning, some parts may still require Wire EDM.Ohnoseiko Vietnam has several wire cutting machines from brands: MITSUBISHI; FANUC; CHMER; TAINATEC.Wire EDM uses an electrical discharge process to remove material instead of direct cutting with a tool.This method is particularly suitable for conductive parts with:

• contours difficult to access with cutting tools;
• narrow slots;
• complex shapes;
• requirements for machining mold components or tool parts.

In a precision machining process, CNC and Wire EDM do not necessarily replace each other but can complement each other.CNC milling handles the main shaping, while wire cutting can process areas that are difficult to access with conventional cutting methods.

Surface Grinding and Cylindrical Grinding for Machined Surface Finishing

Depending on the drawing requirements, after CNC milling or turning, some surfaces may continue to be finished by grinding. Ohnoseiko Vietnam has both surface grinding and cylindrical grinding machines, allowing for the selection of the appropriate finishing process based on the characteristics of each part.

Surface Grinding Machine

Equipment from NAGASE and NAGASHIMA is used for surface grinding operations.Surface grinding is suitable for surfaces such as:

• datum surfaces;
• contact surfaces;
• surfaces requiring finishing after milling.

Cylindrical Grinding Machine

Ohnoseiko Vietnam has cylindrical grinding machines from TOYODA and MARUEI.Cylindrical grinding can be applied to shaft-like parts or rotational surfaces after turning.Thanks to having both milling, turning, and grinding capabilities, Ohnoseiko can select the appropriate method for each stage instead of trying to complete the entire product with just one type of machine.

Dimensional Inspection using CMM (Coordinate Measuring Machine)

Precision machining not only depends on shaping capabilities but also requires a post-machining inspection step.Ohnoseiko Vietnam currently has two CMM systems:

• TOKYO SEIMITSU XYZAX AXCEL RDS 9/10/6;
• MITUTOYO Crysta-Apex V574.

Depending on the inspection content, the CMM can help confirm:

• dimensions;
• distances between features;
• hole locations;
• relationships between surfaces;
• product geometry.

In addition to CMMs, Ohnoseiko also has other inspection equipment such as:

• NIKON MM-400IT measuring microscope;
• MITUTOYO LH-600EG height gauge;
• MITUTOYO HR-320MS Rockwell hardness tester.

The arrangement of inspection equipment within the factory system helps connect the machining process with the product quality verification step.

Shot Blasting and Laser Marking After Machining

Depending on product requirements, after machining and inspection, parts may further be processed using auxiliary equipment.Ohnoseiko Vietnam has:

• shot blasting machine;
• MF20-E-A laser marking machine.

Laser marking can be used to create identification content on products such as:

• product codes;
• symbols;
• management numbers;
• traceability information.

Having laser marking equipment in the factory adds a post-machining finishing step when products require marking.

Multi-Process Equipment System is Ohnoseiko Vietnam's Advantage

One of Ohnoseiko Vietnam's outstanding features is its equipment system, which is not focused on a single process.The factory currently has equipment capabilities ranging from:CAD/CAM↓Workpiece Preparation↓CNC Milling / CNC Turning↓5-Axis CNC Machining↓Wire EDM↓Surface Grinding / Cylindrical Grinding↓CMM Inspection↓Shot Blasting / Laser MarkingThe combination of various types of equipment helps Ohnoseiko develop suitable machining plans for parts with different shape and process requirements.Notably, the addition of the Makino DA300 alongside the existing machining center system indicates that Ohnoseiko continues to invest in its capabilities for 5-axis machining and complex part processing.

Ohnoseiko Vietnam – Precision Machining Capabilities from CNC to Inspection

With a system of BROTHER, OKUMA, FANUC, and MAKINO machining centers, OKUMA CNC turning machines, MITSUBISHI/FANUC wire cutting machines, TOYODA/NAGASE grinding equipment, and TOKYO SEIMITSU and MITUTOYO CMMs, Ohnoseiko Vietnam meets many essential requirements for precision mechanical part machining processes.Instead of focusing solely on a single technology, Ohnoseiko can review drawings and combine methods such as milling, turning, 5-axis machining, wire cutting, grinding, and inspection depending on the requirements of each product.Businesses seeking a machining partner in Vietnam for precision mechanical parts, multi-surface parts, complex-shaped parts, or products requiring a combination of multiple machining processes can send their drawings and technical requirements to Ohnoseiko Vietnam for consideration of a suitable production plan.