Fully Automatic Piston Groove Cutting Machine

Ningbo XIAYI Electromechanical Technology developed the Fully Automatic Piston Groove Cutting Machine XYGC-(N) for precision machining of damping oil grooves and sealing grooves on powder metallurgy shock absorber pistons. The equipment combines automatic feeding, workpiece detection, pneumatic clamping, optional piston flipping, CNC groove cutting, and automatic unloading in one production unit.

Using a Dafeng DF21-TDc CNC control system and servo drive technology, the machine achieves machining accuracy of 0.01 mm and repeat positioning accuracy of 0.01 mm. With spindle speeds adjustable from 0–3000 rpm, automatic lubrication, circulating cutting fluid cooling, and replaceable piston fixtures, it is designed for continuous production of different piston specifications.

Groove Machining Requirements

Damping Oil Grooves

Damping oil grooves provide designated flow paths for hydraulic oil within the shock absorber piston assembly. Their dimensional consistency is important when manufacturers require repeatable piston performance across a production batch.

The CNC machining system allows the groove cutting path and machining parameters to be defined through the programmed process. This provides controlled movement of the cutting tool along the required groove geometry.

Sealing Grooves

The equipment can also be configured for sealing groove machining on powder metallurgy pistons. The positioning fixture and cutting tool are selected according to the piston structure and required groove dimensions.

For different piston designs, dedicated tooling can be supplied to maintain the correct relationship between the workpiece reference position and the cutting path.

CNC Machining Accuracy

0.01 mm Accuracy

The Fully Automatic Piston Groove Cutting Machine uses a Dafeng DF21-TDc CNC control system with servo-driven motion. The specified machining accuracy reaches 0.01 mm, while repeat positioning accuracy is also 0.01 mm.

This level of positioning control helps maintain consistency in groove dimensions and circumferential location during repeated machining cycles.

Servo Drive Movement

Servo-driven feed modules control the movement of the machining axes. X/Z-axis ball screws and linear guides provide the mechanical transmission required for controlled tool movement.

The combination of CNC programming, servo drive control, ball screw transmission, and dedicated positioning fixtures creates a consistent machining reference for each piston.

Spindle Speed Adjustment

The spindle speed can be adjusted from 0–3000 rpm according to the machining requirement. The 3.7 kW spindle servo motor and matching servo drivers provide the drive capacity for the groove cutting operation.

Actual spindle speed and cutting parameters can be selected according to piston material, groove geometry, cutter specifications, and production requirements.

Workpiece Positioning

Piston Reference Position

Accurate groove machining depends on maintaining a stable relationship between the piston and the cutting tool. The machine uses a dedicated positioning chuck and locating mandrel according to the piston design.

During automatic loading, sensors detect the workpiece position before the pneumatic chuck clamps the piston for machining.

Pneumatic Clamping

The pneumatic clamping system secures the piston during the CNC cutting operation. AIRTAC pneumatic components are used for the relevant clamping and movement functions.

Stable workpiece holding helps prevent unwanted movement during cutting and supports repeatable groove positioning.

Piston Flipping

For piston designs requiring machining on different sides, an optional pneumatic flipping mechanism can change the piston orientation automatically.

This allows the same automated production cycle to accommodate double-sided grooving requirements without requiring operators to manually reposition every workpiece.

Cutting Tool Management

Dedicated Grooving Cutters

Different piston designs may require different groove dimensions and cutting geometries. The machine therefore uses dedicated grooving cutters selected according to piston dimensions and groove requirements.

The tooling configuration can be changed when the production model changes, allowing the cutting system to adapt to different piston specifications.

Tool Retract Position

After the programmed groove machining operation is completed, the cutting assembly retracts to its home position before the finished piston is unloaded.

This programmed movement provides a defined sequence between machining completion and workpiece transfer, reducing interference between the cutter and the unloading mechanism.

Cutting Fluid Control

The machine includes a circulating cutting fluid cooling system. Cutting fluid is supplied during machining to assist with heat management and chip removal around the cutting area.

The circulating system includes a dedicated cooling water tank and filtration arrangement. Regular inspection and cleaning of the cutting fluid system are required to maintain stable machining conditions.

CNC Program Management

Programmed Groove Geometry

The CNC system executes pre-programmed machining codes for the required damping oil groove or sealing groove. Groove dimensions and tool movement are determined according to the production program and tooling configuration.

This approach allows manufacturers to establish repeatable machining conditions for different piston models.

Parameter Adjustment

When changing piston specifications, operators can modify the corresponding CNC parameters after installing the correct positioning fixture and cutting tool.

The ability to combine dedicated tooling with adjustable CNC programs allows one machine configuration to support multiple compatible piston models.

Machining Data Storage

The CNC control system supports machining data storage, providing a reference for production setup and process management. Stored programs can help operators reproduce established machining conditions when returning to an existing piston model.

Automatic Part Handling

Tray Feeding

Powder metallurgy shock absorber pistons are placed on the feeding tray and transported automatically toward the machining area.

The feeding mechanism reduces the need for manual loading of individual pistons and supports continuous machining cycles.

Detection and Clamping

Sensors identify the incoming workpiece and confirm its position before pneumatic clamping. This allows the machine to establish the required machining position before the CNC program starts.

Automatic Unloading

Once groove machining is complete, the cutting unit returns to its home position and the unloading mechanism transfers the finished piston to the output area.

The machine then returns to the next machining cycle, allowing continuous automated production.

Machine Configuration

CNC Control Unit

The control system uses a Dafeng DF21-TDc CNC system with a 3.7 kW spindle servo motor and matching servo drivers.

Transmission System

Servo feed modules, X/Z-axis ball screws, linear guides, and the turret cutting assembly form the primary machining transmission structure.

Pneumatic Components

The pneumatic system includes AIRTAC cylinders, solenoid valves, and an air filter regulator unit. Omron proximity switches, magnetic sensors, and safety door micro switches are used for position and safety monitoring.

Auxiliary Equipment

The machine includes an automatic guide rail lubrication system, circulating cutting fluid cooling tank, feeding tray, outlet conveyor belt, and rotary unloading table.

Main Technical Specifications

Production Applications

Automotive Shock Absorber Pistons

The Fully Automatic Piston Groove Cutting Machine is designed for powder metallurgy pistons used in automotive hydraulic shock absorbers. It can perform damping oil groove and sealing groove machining according to the required piston design.

Motorcycle Shock Absorber Pistons

The equipment can also be applied to motorcycle hydraulic shock absorber piston production where consistent groove dimensions and automated material handling are required.

OEM and Component Manufacturing

The machine is suitable for shock absorber component manufacturers and piston OEM subcontractors that need automated CNC groove machining for repeated production.

For manufacturers using multiple piston production processes, the grooving equipment can also be connected with XIAYI's fully automatic PTFE piston banding equipment to create a more complete automated piston manufacturing workflow.

Production Line Integration

Grooving Before PTFE Banding

For piston designs requiring both groove machining and PTFE banding, groove cutting can be arranged as an upstream machining operation before the PTFE banding process.

The Fully Automatic Piston Groove Cutting Machine can therefore be combined with XIAYI's fully automatic piston banding machine to create a connected production solution covering groove machining and PTFE banding.

Automated Material Transfer

The automatic feeding and unloading mechanisms provide defined input and output points, making it easier to connect the machine with upstream feeding systems, downstream inspection equipment, or additional piston processing equipment.

Multi-Process Manufacturing

For manufacturers producing powder metallurgy shock absorber pistons in volume, combining several dedicated machines can reduce repeated manual transfers between processes and create a more structured production sequence.

Maintenance Requirements

Daily Checks

Before each production shift, operators should inspect safety guards and machine feet, check the lubricant tank and cutting fluid level, verify air pressure, and test the emergency stop and electrical control functions.

After the production shift, chips and oil contamination should be removed. High-pressure air should not be directed toward encoders or servo motors. Precision components should receive appropriate anti-rust treatment when required.

Weekly and Monthly Service

Guide rails and ball screws should be cleaned and lubricated regularly. The spindle and chuck should be inspected, while the electric cabinet heat dissipation filter and pipe joints should also be checked.

Monthly maintenance includes spindle, turret, and tailstock inspection, cleaning of the cooling water tank, validation of limit safety switches, and tightening of electrical terminals.

Periodic Inspection

Quarterly or semi-annual maintenance may include lubricant replacement, spindle radial runout inspection, pneumatic component servicing, and machine level calibration.

Annual overhaul can include replacement of oil, seals, and other wear parts, together with positioning accuracy compensation and a no-load running acceptance test.

The machine should never be operated without the required lubricant or cooling liquid. Operators should also avoid tool collisions, prevent the mixing of different lubricant types, and avoid using high-pressure air on encoders or servo motors.

Installation and Support

Machine Commissioning

XIAYI provides on-site installation and commissioning support after delivery to help establish the machine according to the customer's production requirements.

Operator Training

Training can cover machine operation, CNC programming, parameter modification, fault diagnosis, tooling changes, and the complete maintenance procedure.

Warranty Service

The equipment includes a 12-month warranty from the acceptance date. XIAYI provides lifelong spare parts supply together with remote and on-site technical consultation support.

XIAYI's quality management system is established in accordance with IATF 16949:2016, supporting its manufacturing and quality management processes for equipment serving automotive-related production applications.

Frequently Asked Questions

What is this machine used for?

The machine is designed for CNC machining of damping oil grooves and sealing grooves on powder metallurgy pistons used in automotive and motorcycle hydraulic shock absorbers.

What machining accuracy can it achieve?

The specified machining accuracy is 0.01 mm, with repeat positioning accuracy of 0.01 mm. Actual machining results can depend on workpiece material, tooling condition, machine setup, and process parameters.

Is the piston grooving process automatic?

Yes. The machine integrates automatic feeding, workpiece detection, pneumatic clamping, optional piston flipping, CNC groove machining, and automatic unloading into a continuous production cycle.

Can different piston sizes be machined?

Yes. Replaceable positioning fixtures, locating mandrels, and dedicated grooving cutters can be configured according to different piston specifications. The corresponding CNC parameters can also be adjusted for different production models.

What CNC system does the machine use?

The machine uses a Dafeng DF21-TDc CNC control system with a servo-driven spindle. The spindle speed range is 0–3000 rpm.

What air pressure is required?

The specified working air pressure is 0.5–1 MPa, with 0.5–0.7 MPa recommended for normal operation. The machine uses a Φ10 air inlet pipe.