Material preparation
6061 aluminum is the standard material. 7075 is available when specified by the customer. Cut round billets are prepared for stator-housing machining.
Manufacturing & Quality
Manufacturing & Quality for Pneumatic Rotary Unions
Function-led surface treatment for aluminum rotary-union components, documented with production photographs and a recorded coating-thickness measurement.
Production inspection
View Production Leak Testing →
100% passage-by-passage leak testing
See how every finished pneumatic rotary union and every individual passage is checked with compressed air after final assembly, including the PASS/NG decision and quarantine process.
Function-led surface treatment
Hard-anodized rotor and color-anodized stator housing
This construction assigns a different finish to each component according to its role. The rotating aluminum rotor is hard anodized, while the stationary stator housing uses color anodizing.
Hard anodizing increases surface hardness and supports wear and corrosion protection of the aluminum running surface. In a low-speed O-ring sealing structure, it helps reduce the risk of scratching and groove wear where the O-ring moves relative to the rotor.
Actual sealing and wear behavior also depends on final surface roughness, O-ring material, lubrication, pressure, speed, alignment, temperature and contamination. Surface treatment is one design control, not a service-life guarantee.
Rotor surfaceHard anodizing for the aluminum O-ring running interface.
Stator housingColor anodizing for appearance, identification and surface protection.
Design contextLow-speed rotary unions using dynamic O-ring sealing.
Stator manufacturing process
From Aluminum Billet to Color-Anodized Stator Housing
Begapunk's standard stator-housing workflow uses two setups on a 4-axis turn-mill machine. Machined dimensions are sample-inspected before the parts leave for external color anodizing.
Two machining setups
The first setup machines the initial features. The part is then reversed and clamped for a second setup to complete the remaining required features.
Dimensional sampling
After machining, finished stator housings are sample-inspected against the drawing before surface treatment.
External anodizing and return inspection
Parts are sent to an external anodizing supplier. Available colors are agreed by sample. The stator color-anodizing thickness is approximately 5 µm. The supplier checks coating thickness before return shipment, and Begapunk performs incoming sample inspection. Specified product tolerances accommodate the expected coating growth.
After final assembly, every finished rotary union and every individual passage enters the existing 100% leak-testing process.
View 100% Leak Testing →Photo note: These photographs document different stages of stator production. Final material, dimensions, color and inspection requirements are confirmed by the order drawing and agreed inspection plan.
Project color options
Color anodizing for machine styling and identification
The stator housing can be specified in a technically available anodized color to support equipment styling, brand recognition or circuit identification.
The final color is confirmed against an approved physical sample before series production, with an agreed shade tolerance that accounts for alloy, surface preparation, part geometry and processing lot.
Production coating measurement
Hard-anodized coating thickness
The production photograph shows the following coating-thickness measurement on a hard-anodized rotor:
51.7μm
production coating measurement
Coating thickness: The photographed part shows a hard-anodized coating thickness of 51.7 μm. Hard anodizing is controlled by production batch to maintain consistent coating thickness across the lot. The required thickness range can be specified for each order.
Production state
From treated components to assembled rotary unions
The assembly photograph shows an assembled pneumatic rotary union with multiple visible air fittings. The batch photograph shows multiple assembled units prepared for packaging.
Engineering controls
What should be confirmed before production
A useful coating specification connects the surface treatment to dimensions, sealing conditions and an agreed inspection method.
Component and alloy
Identify the exact rotor and stator material before selecting the anodizing process.
Coating requirement
Define coating type, target or allowable range, masking and any color sample.
Post-coating dimensions
Allow for coating build-up at fits, ports, grooves and mounting interfaces.
Running-surface finish
Confirm the required final roughness where the O-ring moves on the rotor.
Seal and lubrication
Specify O-ring compound, lubricant and compatibility with the transferred medium.
Operating conditions
Review pressure, continuous and peak speed, duty cycle, temperature, alignment and contamination.
Inspection and records
Agree measurement method, sampling locations, acceptance criteria and required records.
Color approval
Approve a physical sample and realistic shade tolerance before series manufacture.
Specify Your Surface Treatment
Send the component drawing, alloy, coating requirement, seal material, operating conditions, color preference, and any inspection records needed with the order.
Send Coating Requirements →