A Tank head spinning machine fits rotationally symmetrical vessel heads when its forming capacity matches the blank diameter, material grade, plate thickness, head profile, and production method. Machine selection must also account for thinning control, dimensional tolerances, and applicable vessel standards.
Pressure vessel heads are produced in several geometries. Each profile creates a different forming load and material-flow pattern, so machine capacity cannot be selected from diameter alone.
| Head type | Forming characteristic | Important machine requirement |
|---|---|---|
| Hemispherical | Deep profile and significant material movement | High rigidity and controlled multi-pass forming |
| Ellipsoidal | Smooth crown-to-knuckle transition | Accurate programmed roller path |
| Torispherical | Defined crown and tighter knuckle radius | Strong local forming control |
| Conical head | Straight taper with a transition area | Stable support and axial positioning |
| Flat or shallow head | Lower depth but potential edge distortion | Reliable blank clamping and sizing |
A Pressure Vessel Head Spinning Machine may use cold spinning, hot spinning, or a combined process. The appropriate method depends on material formability, head size, thickness, required mechanical properties, and qualified production procedures.
Large blanks generate substantial radial and axial loads during spinning. Insufficient machine rigidity can cause vibration, roller deflection, profile error, and unstable wall thickness. The spindle, bed, tailstock, roller carriage, and hydraulic system must work as one rigid structure.
The machine should provide enough forming force for the most demanding planned head without operating continuously at its maximum limit. Reserve capacity supports smoother forming and allows for reasonable variation between material batches.
Roller movement must also be progressive. Trying to force a deep contour in too few passes may create wrinkling at the edge or excessive thinning near the knuckle.
CNC systems can store roller paths, feed rates, spindle speeds, and multi-pass sequences. Once a forming program has been validated, these settings help reproduce the same geometry during later batches.
CNC control is particularly useful for managing:
Crown depth and overall head height
Knuckle radius and transition shape
Final outside diameter
Roller position during each forming pass
Feed reduction near high-strain areas
Automatic return and finishing movements
The program should remain linked to the approved blank size, material specification, tooling, and heating condition. Reusing one program for a different plate grade or thickness without trials may produce an unacceptable result.
Head production frequently includes more than spinning. Depending on the process, the line may require blank cutting, heating, temperature monitoring, edge trimming, sizing, polishing, and dimensional inspection.
Hot forming requires controlled and documented heating. Uneven temperature can cause inconsistent material flow and local dimensional differences. Cold forming avoids heating equipment but may demand higher force and can increase work hardening.
A suitable layout should provide safe loading for large blanks and formed heads. Overhead lifting, manipulators, guarding, and protected operator areas may be necessary for heavy components.
Inspection should cover overall diameter, head depth, roundness, profile deviation, edge condition, and minimum wall thickness. High-strain transition areas deserve particular attention because external dimensions alone cannot reveal excessive thinning.
Surface cracks, laps, wrinkles, and tool marks should be checked before trimming or polishing hides their origin. Material traceability and forming records may also be required according to the governing specification and purchaser’s quality plan.
A Vessel Head Machine Supplier needs head drawings, applicable standards, material grades, original and minimum finished thicknesses, blank diameters, production volumes, and expected tolerances. The buyer should also identify whether heating, trimming, or automated loading must be integrated.
Representative trials are essential for new profiles. A machine should be evaluated by the quality of the completed head and documented process stability, not simply by its nominal diameter or hydraulic power.
Previous: How To Spin Conical Parts?
