CNC Machined Parts 6061 Aluminum Anodized Optical Lens Barrel 0.01mm Concentricity

In an optical assembly, the barrel is the reference every element is aligned to. If the stepped bores are not concentric, no amount of lens adjustment recovers the image. We machine lens barrels as a combined turning and 5-axis job: the outer diameter is turned as the master datum, all internal bores and threads are cut from that same datum, and concentricity is held to 0.01mm and verified on a mandrel with a dial indicator before the barrel is anodized.

• One datum, one setup family: the outer diameter is turned first and becomes the master datum; every bore, seat and thread is referenced to it, so errors cannot stack between operations.
• Finish boring instead of drilling and reaming: stepped bores are single point bored with a rigid boring bar, which corrects any deflection left by the drill and produces a true cylinder.
• Thin-wall support: a machined support sleeve backs the wall during finishing, and radial depth of cut is kept low so the barrel does not spring back into an oval after unclamping.
• Thermal stability: finishing is done after the part reaches shop temperature, and the measuring room is kept at controlled temperature so the 0.01mm reading is real rather than a thermal artefact.
• Thread concentricity: threads are milled rather than tapped on thin walls, keeping the thread axis aligned with the bore axis.

1. Drawing and optical stack review: element seats, retaining thread positions and clear aperture are checked against machining capability.
2. Aluminum bar sawed, faced and centre drilled.
3. Rough turning of outer profile and bores, with stress relief pause for thin sections.
4. Semi-finishing of datum outer diameter.
5. Finish turning and boring of all seats, steps and the retaining thread in one clamping.
6. 5-axis milling of flange slots, flats, focus scale marks and mounting holes.
7. Deburring, ultrasonic cleaning and inspection of concentricity on a mandrel.
8. Anodizing with thread protection, then final check of bore size and thread gauge.
9. Individual wrapping with lens-safe foam and export carton.

Machine vision lenses, LiDAR and distance sensor optics, laser collimator and beam expander tubes, microscope and endoscope optics, industrial camera modules, spectrometer housings, photoelectric sensor barrels and custom imaging assemblies. Typical add-ons include focus and zoom grooves, retaining ring threads, dowel pin holes for element alignment and anti-reflection baffle steps.

Each batch is released with a dimensional report covering bore diameters, concentricity on a mandrel, thread gauge results and surface roughness, plus the anodizing thickness record. For optical customers we can also provide a first article inspection report and a process capability summary for the critical bore features.

Dongguan Changxinda Precision Technology Co., Ltd has machined custom parts since 2008 and now serves more than 200 customers in optics, medical, robotics, automation, automotive, aerospace, telecom and instrument industries, exporting 50–60% of output. The workshop combines 4-axis and 5-axis CNC machining centers with turn-mill compound lathes and CNC lathes, run in two shifts by about 100 staff. Prototype barrels are delivered in 7–10 days, repeat batches in 15–25 days, and capacity for repeat programs is reserved in advance so the delivery date confirmed at order intake is the date the shipment leaves the plant.