3+2 CNC Milling · Aluminum
Holding 0.02 mm Position in EN AW-6082 Aluminum with 3+2 CNC Machining
A real EN AW-6082 aluminum case using datum-led dovetail fixturing and 3+2 indexed machining to control a drawing-specified ⌀0.02 mm position requirement across multiple faces.
At a Glance
- Material
- EN AW-6082 aluminum
- Process
- 3+2 indexed milling — not simultaneous 5-axis
- Datum scheme
- A · B · C established from one dovetail setup
- Drawing requirement
- ⌀0.02 mm position to A | B | C
- Final machining step
- Temporary clamp removal on a conventional mill
From the Production Drawing
The Requirement, in the Engineer's Own Notes
The redacted production drawing identifies the A/B/C datum structure and the ⌀0.02 mm positional requirement that drove the setup strategy. Customer information, QR code, order data, drawing number, and personnel details have been removed.
01
The Challenge
The part combines bores, threaded holes, curved internal geometry, and precision features distributed across several faces. The drawing ties a ⌀0.02 mm positional requirement to datums A, B, and C. Re-clamping the part face by face would repeatedly transfer those datums and add setup variation exactly where the related features needed to stay aligned.
02
OUJI's Approach
OUJI planned the multi-face work around a temporary dovetail clamping feature. The datum system was established and maintained from that setup while the five-axis machining center indexed the part into a series of fixed cutting orientations. This was 3+2 indexed machining: the rotary axes positioned the part, stopped, and the cut was then made from that fixed orientation. After the related faces were complete, the temporary dovetail portion remained available for workholding and was removed in a separate operation on a conventional vertical mill.
03
The Result
The related multi-face features were completed with fewer re-clamping steps and without repeatedly rebuilding the A/B/C relationship. According to the production confirmation provided for this case, the critical dimensions, including the drawing-specified ⌀0.02 mm position requirement, were OK. This case does not publish inspection footage, measured values, cycle time, surface-roughness data, yield, or the material temper, so none of those details are inferred here.
Production Sequence
From Aluminum Blank to the Machined Part
The photographed route follows the physical part through one datum-led 3+2 setup, the retained temporary clamp, and its final removal on a conventional mill.
3+2 indexed machining means the rotary axes position the part and stop; cutting then takes place from that fixed orientation. It is not simultaneous 5-axis motion.
01 · Blank
Start with the EN AW-6082 blank
The rectangular aluminum blank provides enough stock for the multi-face geometry and the temporary workholding feature. The exact material temper is not published in this case.
02 · Dovetail setup
Establish the workholding and datum relationship once
A dovetail-style clamping feature holds the blank while the A/B/C relationship is established for the multi-face route. Keeping that setup intact reduces repeated datum transfer between faces.
03 · Fixed orientation
Index the part, then cut from a fixed position
The rotary axes place the part at the required orientation and stop before cutting begins. That distinction makes the operation 3+2 indexed machining rather than simultaneous five-axis machining.
04 · Multi-face machining
Reach related features from additional indexed faces
Further fixed orientations expose the bores, curved profiles, and side features while the original dovetail setup continues to carry the datum relationship.
05 · Intermediate state
Keep the temporary dovetail portion until indexing is complete
The main geometry is visible at this stage, but the temporary clamping portion remains attached so the part can stay controlled through the indexed operations.
06 · Clamp removal
Remove the temporary feature on a conventional mill
After the 3+2 work is complete, the part is held for a separate conventional milling operation that removes the remaining temporary clamping material.
07 · Machined state
Review the part after clamp removal
The resulting bare-aluminum part shows the connected multi-face features after the temporary workholding portion has been removed. No unverified finishing or inspection claim is attached to this image.
Sources & technical references
- ASME Y14.5 — Dimensioning and Tolerancing — ASME (American Society of Mechanical Engineers)
Defines the datum reference frame (A|B|C) and true-position tolerancing terminology referenced in this case's drawing callouts.
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