Robot Actuator Cylinder Housing 7075-T6 Aluminum Honed Bore Hard Anodized 0

What the Bore Has to Do

In an actuator cylinder the bore is the working surface. A piston seal that runs in an out-of-round bore leaks at the high point, wears at the low point, and the actuator loses force and repeats poorly. This housing is therefore machined around the bore: turned and bored in one clamping so the ends are square to the axis, honed to Ra 0.2 with roundness held at 0.005 mm, then hard anodized inside and lightly re-honed so the coating is a wear surface rather than a rough skin.

The outside carries mounting bosses, a cable window with radiused corners, threaded ports and an O-ring groove at each end. Those features are cut after the bore work, in a sequence that does not disturb the alignment you paid for.

Production Sequence

Honing after coating is the step most shops skip, and it is the reason a coated bore can still seal consistently.

Precision Capability

Custom Actuator Shells

Shells are cut to your drawing, including the seal and port arrangement. The range below is what the lathes and 5-axis machines actually handle.

• Outer diameter 30-400 mm, bore 15-350 mm, length 30-500 mm
• Materials: 7075-T6, 6061-T6, 6082-T6, 2024-T351, 304/316L stainless, 4140 steel on request
• Internal features: seal grooves, wear bands, retaining shoulders, circlip grooves, oil channels, honed or lapped bores
• External features: cable windows, sensor pockets, mounting bosses, threaded ports, keyways, flats
• End configurations: open, closed end, threaded end, flange end, mixed ends
• Coatings: hard anodize inside, hard anodize all over, chromate, black oxide, masking on seal surfaces
• Input formats: STEP, IGES, X_T, STL, DXF, 2D drawing with GD&T, or a sample for scanning and rebuild

Confidentiality

The Plant

Dongguan Changxinda Precision Technology Co., Ltd has machined custom parts since 2008. Equipment includes 4-axis and 5-axis machining centres, turn-mill combination lathes, CNC lathes and milling machines, plus honing and pressure test stations, backed by an ISO 9001:2015 quality system and an in-house CMM room. Over 200 customers in medical equipment, robotics, automotive, aerospace, automation, laser, LED, lithium battery and precision instruments are supplied from this site, and 50-60% of output is exported. Thin-wall turning, honed bores and coating-then-rehone work are routine here.

Delivery

• Capacity around 10,000 pieces per month for this shell family
• Repeat orders keep the same programme, hone parameters and coating spec, so seal fit stays predictable
• Each part number allocated across two machining centres to protect your date
• Express, air and sea freight; EXW, FOB or CIF terms; bores plugged and VCI protected
• Rush capacity for line-down situations, quoted with a date we can hold

Key Features

• 7075-T6 aluminum for wall stiffness in a pressurised shell
• Bore and faces finished in one clamping before honing
• 0.005 mm roundness and Ra 0.2 after honing
• Hard anodize 50 µm inside, then re-honed to final seal fit
• O-ring grooves cut with the bore, not after it
• Pressure tested to 0.6 MPa with results per serial
• Ports and windows cut on 5-axis with internal deburr verified
• NDA-protected handling and project-code documentation

Typical Applications

• Robot linear and rotary actuator housings
• Servo and motor cylinder enclosures
• Pneumatic and hydraulic actuator bodies
• Gripper and end effector cylinders
• Semiconductor handling actuator shells
• Medical and laboratory actuator housings
• Test rig and endurance bench cylinders
• Automation drive and damper housings

FAQ

Q: Why re-hone after hard anodizing?
A: Coating grows into the bore and changes seal fit. Re-honing after coating restores the diameter and gives a smooth wear surface, so the piston seal behaves the same on part 1 and part 500.

Q: Can you hold 0.005 mm roundness on a thin wall?
A: Yes, with stress-relieved stock, light clamping, separated roughing and finishing, and honing for the final geometry. If the wall in your drawing cannot support it, we say so before quoting.

Q: Do you pressure test every part?
A: Every shell is tested and the result is recorded against its serial. Higher pressures are quoted separately after a wall-thickness review.

Q: Will you sign an NDA before we send the actuator drawing?
A: A mutual NDA is signed first, covering drawings, models, scans and samples, including seal and pressure details.

Q: What is the minimum order?
A: One piece, with no tooling charge and no programming fee, so a single shell for a prototype actuator is a normal order.

Q: Can you supply matched pistons or seals?
A: We machine to your seal and piston specification and can supply matched pistons, or work with parts you already stock. Seal fit is verified against the honed diameter.

Q: What do you need to quote?
A: 2D drawing with tolerances, 3D model, quantity, material, coating spec, test pressure and target date. Quote and DFM comments return within 24 hours.

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