6061-T6 Aluminum Robot Cylindrical Mounting Bracket with 0.008mm Flange Flatness and Turn-Mill One Setup

This is the fixed half of a robot joint interface: a machined round flange that bolts to the arm, a cylindrical seat that carries a bearing, a reducer spigot or a sensor housing, and a set of ribs that hold the two together without adding mass at the wrong end. The flange is what transfers load into the arm, so its flatness decides how evenly the bolts clamp; the bore is what positions the joint, so its concentricity to the flange decides whether the axis runs true.

We turn the flange and bore in one clamping on a turn-mill centre, drill and ream the dowel holes with live tooling in the same setup, then mill the ribs. The result is a bracket with 0.008 mm flange flatness and 0.01 mm bore-to-flange concentricity, without relying on a second operation to line things up.

1. Drawing and interface review. We check flange diameter and bolt circle, dowel pattern, bore fit, seat depth and rib layout, and confirm the section can carry the joint load, then quote within one working day.
2. Material verification. 6061-T6 bar or plate is checked against the mill certificate for grade and temper, and for soundness where the flange is cut from plate.
3. Rough turning. The flange OD, seat and bore are roughed with 0.4 mm of stock, which keeps the finishing pass cool on a part where the bore wall is only a few millimetres thick.
4. Stress relief between operations. Where the flange removes a large volume of material from a plate blank, the part is stress relieved before finishing so the flange does not dish after the last cut.
5. Finish turning. The flange face and bore are finished in one clamping, giving 0.008 mm flatness and 0.01 mm concentricity, with the bore held to H7 and 0.008 mm roundness.
6. Live-tool drilling. Bolt holes and dowel holes are drilled, bored and reamed with live tooling in the same setup, so the dowel pattern is positioned to the bore rather than to a re-chucked surface.
7. Rib milling. Ribs and lightening pockets are milled to leave 4 mm minimum section, then edges are broken and the part is deburred at every bore entry.
8. Anodizing and inspection. Black anodizing with the flange face and bore masked, then CMM for flatness, concentricity and dowel position, a bore gauge check, and a first article report with the batch.

A flange measured on the bench is measured free. On the robot it is pulled down by four or six bolts, and if the flange is thin or the bolt circle is close to the bore, the face deforms and the joint preload becomes uneven. That is why flange thickness matters as much as flatness, and why we check flatness on three support points rather than on a full surface plate, which can average away a dish.

Coating plays a part too. Anodizing on the flange face adds a layer that is not perfectly uniform, so the face is masked where the joint preload is calculated from metal-to-metal contact. The coating record and the flatness reading travel together in the inspection report, so the customer knows which surface was measured.

Flange diameter, bolt circle, dowel pattern, bore and seat depth, rib layout, material grade and coating are all built to your drawing. One piece is a normal order with no tooling charge and no setup fee, and the prototype follows the same inspection plan as production. If a rib layout leaves a section below 4 mm at the flange root, our engineer raises it before machining.

• NDA before files. Mutual non-disclosure is signed before drawings or samples are released.
• No public reference. Confidential brackets never appear in samples, catalogues, website photos or trade fairs.
• Separated cell. Sensitive work runs with named operators and project-coded programmes.
• Partner control. Anodizing suppliers receive process specifications only.

Dongguan Changxinda Precision Technology Co., Ltd has produced custom machined parts since 2008, with four-axis and five-axis machining centres, turn-mill lathes, CNC lathes and milling machines on site. The company employs 90 to 102 people, holds ISO 9001:2015 certification, serves more than 200 customers, exports 50 to 60 percent of output and records annual sales of USD 10 to 20 million.

• Confirmed dates. Prototypes 4 to 7 working days, batch orders 14 to 22 working days after drawing approval.
• Repeat orders skip setup. Programmes, fixtures and gauge sets stay on file.
• Reserved machine time. Blanket orders are scheduled into fixed monthly slots.
• Early warning. If material, anodizing or capacity threatens the date, you hear it before it is missed.
• Dispatch evidence. Photos, inspection report and packing list before shipment.

• Consumer Electronics
• Automation & Industrial Equipment
• Semiconductor & Vacuum Equipment
• Medical Devices
• Automotive
• Aerospace & UAV
• Optics & Photonics
• Communications
• Robotics
• Instrumentation

Each bracket is bagged with desiccant, seated in a foam tray so the flange face and bore cannot be bruised, then sealed in a moisture barrier bag. Trays fit a five-layer export carton marked with part number, quantity and batch code. Sea freight ships on fumigation-free plywood pallets; neutral cartons are available.