Processes
5-Axis Machining Processes in Vietnam, From Machine Layout to Toolpath
"5-axis" on a quote can mean five different machine layouts and two different ways of cutting. This page sets out what each one is, what it suits, and what we ask a Vietnamese shop before its name goes on your short list.
5-axis simultaneous moves all axes while cutting. 3+2 indexed tilts, locks, then cuts with three.
Your part has to fit with the table or head tilted, which is smaller than the brochure travels.
Faces and holes on several sides rarely need simultaneous motion. We say so when that is the case.
Machine layouts you will meet in Vietnamese shops
Where the two rotary axes sit decides how big the part can be and how the machine reaches it. When a shop tells us it has a 5-axis machine, the layout and model are the first thing we write down.
| Layout | Axes | Envelope | Typical work and motion |
|---|---|---|---|
| Trunnion table (table-table) | Two rotary axes in the table, usually A and C or B and C. The spindle stays vertical. | Part size and weight limited by the trunnion. The usable envelope with the table tilted is well below the table diameter. | Small to mid-size housings, impellers, medical and electronics parts. Runs both simultaneous and 3+2 indexed. |
| Swivel head and rotary table (head-table) | One rotary axis in the head (B), one in the table (C). | Heavier and taller parts than a trunnion, because the table only turns. | Larger housings, mould inserts, structural parts. Both motions, depending on control and CAM. |
| Head-head (gantry or ram) | Both rotary axes in the head. The table does not move in rotation. | Large, long or heavy parts. Less common in Vietnamese job shops. | Big frames, moulds and structural parts. Often used mainly for 3+2 indexed work. |
| Mill-turn with B-axis head | Turning spindle(s) plus a milling head that tilts. Some add a lower turret. | Bar or chuck work, round parts with milled features. | Shafts with angled holes, valve bodies, turned parts that would otherwise go to a second machine. |
| Tilting rotary table on a 3-axis machine | A bolt-on two-axis table added to a vertical machining centre. | Small parts only, low table load. | Usually 3+2 indexed. Simultaneous only if the control and post processor support it, which must be checked. |
Toolpath strategies, and which motion each one needs
The machine is only half the process. The CAM strategy decides whether the part needs 5-axis simultaneous or can be cut 3+2 indexed. A good shop mixes both on one part.
3+2 positional milling
3+2 indexed. The part is tilted to a fixed angle per face. Pockets, bores and flats on many sides in one clamping.
Angled holes and ports
3+2 indexed in most cases. The spindle is aligned with each hole axis, so standard drills and taps work.
Short tool, tilted
3+2 or simultaneous. Tilting lets a short, stiff tool reach a deep floor instead of a long one that chatters.
Swarf milling
5-axis simultaneous. The side of the cutter follows a ruled surface such as a blade wall or a tapered rib.
Multi-axis contouring
5-axis simultaneous. Ball, barrel or lens shaped tools follow a freeform surface with the tool kept normal to it.
Edge breaking and chamfers
Often 5-axis simultaneous on complex edges, to replace hand deburring along an intersection curve.
What has to be in place for simultaneous work
Every item below is something a shop can show, and each one is separate from owning the machine. Background on the kinematics is in the multiaxis machining overview.
- Tool centre point control. TCPC or RTCP on the control, so the tool tip stays on the programmed path while the rotary axes move. Without it simultaneous toolpaths are impractical.
- A post processor for that machine. Built for the exact kinematics and control, not a generic 5-axis post edited by hand.
- Machine simulation. The full toolpath checked against a model of the machine, holder and fixture before the first cut, because collisions on a tilting machine are expensive.
- Kinematic calibration. The rotary axis centres measured and corrected on a schedule, usually with a spindle probe and a reference sphere. Drift here shows up as mismatch between faces.
- Probing for setup. Part location measured on the machine so the program follows the real part, which matters most on one-off and small batch work.
- Thermal warm-up. A warm-up routine before precision work, because spindle growth moves the tool tip.
Processes around the 5-axis machine
Few parts leave the 5-axis machine finished. The operations around it decide lead time, and they are where we ask most of our questions.
| Operation | Where it usually happens | What we ask the shop |
|---|---|---|
| CMM inspection | Owned by some 5-axis shops, subcontracted by others. | Which machine, its measuring volume, and a sample report on a similar part. |
| 3D scanning | Used for freeform surfaces where a CMM touch probe is slow. | Point spacing and how deviation is reported against your model. |
| Wire and sinker EDM | Common in shops that also make moulds. | Whether it is in house, because sharp internal corners and narrow slots depend on it. |
| Heat treatment | Usually done by a specialist heat treater outside the shop. | Whether finishing happens after heat treatment, and who owns distortion. |
| Anodising, plating, passivation | Almost always outside finishers. | Coating thickness allowance on fits and threads, and masking. |
| Grinding | In house at precision shops, otherwise subcontracted. | Which features are ground, and how they are measured afterwards. |
A general tolerance block such as ISO 2768-m covers non-critical features. Mark the features that really need tighter limits, and say which inspection report you expect. That, more than the axis count, decides which shop fits.
Related pages
- Materials. How aluminium, stainless, titanium and plastics behave on a 5-axis machine.
- Parts. Which part families need simultaneous motion and which are 3+2 indexed work.
- Guides. Basics, shop checks, cost and origin, parts and materials.
- How matching works. What we check before a shop sees your drawing.
Questions about 5-axis processes
Is 3+2 indexed machining real 5-axis?
It uses a 5-axis machine, but only three axes move during the cut. The two rotary axes position the part, lock, and the cut runs like 3-axis. It is the right process for most parts with features on several faces, and often the cheaper one. What matters is that the quote says which process you are buying.
What tells me a shop can run simultaneous 5-axis?
A machine model whose control supports tool centre point control, a CAM system with multi-axis toolpaths and a post processor built for that exact machine, and a sample of similar geometry. A rotary table bolted on a 3-axis machine does not prove it.
Does 5-axis hold tighter tolerances than 3-axis?
Not by itself. It holds feature-to-feature positions better because the part is machined in fewer clampings. The tolerance on an individual feature depends on the machine, the tool, the temperature and the measurement, the same as on 3-axis.
When is mill-turn better than a 5-axis mill?
When the part is mostly round: shafts, valve bodies and fittings with angled holes or flats. A mill-turn machine finishes them from bar in one cycle, where a 5-axis mill would need a turned blank from another machine first.
Not sure which process your part needs?
Send the drawing. We tell you whether it needs 5-axis simultaneous, 3+2 indexed or neither, and match it to up to3 shops that run that process. We reply within 24 business hours.