Cylindrical Grinding Machine and CNC Milling: how the two fit together
Cylindrical Grinding Machine is a machine that finishes external and internal diameters with a rotating wheel and a rotating workpiece. It is used for holding diameter tolerance and roundness on shafts, pins and bores after heat treatment. This entry explains what it is, what the numbers on a data sheet mean, and what to put on a drawing.
It is written from the point of view of the buyer and the drawing office: the values that are realistic in production, the ones that cost money, and the way the result is verified. Where an industry sets the requirement, aerospace is used as the example: traceability and a first article before anything enters the batch.
How the two fit together
Cylindrical Grinding Machine and CNC Milling are specified together more often than separately. Cylindrical Grinding Machine is a machine that finishes external and internal diameters with a rotating wheel and a rotating workpiece, while CNC Milling is a cutting process where a rotating multi tooth tool removes material from a stationary workpiece; one produces the result and the other controls or finishes it.
Sequence
The order matters. Work is done with Cylindrical Grinding Machine, and then CNC Milling is applied to it; reversing the order is the usual cause of a part that measures correctly but does not work.
What to specify
| Specification | Typical value |
|---|---|
| Aspect | Note |
| This entry | Cylindrical Grinding Machine – ±0.002 mm |
| Related entry | CNC Milling – ±0.02 mm |
| Material | 52100 bearing steel |
| Finish | Ra 0.2 µm standard |
| Documentation | in-house approval with dimensional reports |
A combined note for the drawing
Where both apply, state the result and let the route follow: the tolerance, the finish and the verification. Specify roundness and cylindricity, not just a diameter tolerance, on sealing journals
Applications
Cylindrical Grinding Machine is used for holding diameter tolerance and roundness on shafts, pins and bores after heat treatment, and in practice it appears most often in hardened shafts, bearing journals, hydraulic rods, gauge pins.
How it fits into a machining route
Cylindrical Grinding Machine is one station in a route rather than the whole of it. The part arrives with the previous operation finished and leaves with the features it is responsible for completed, so the datum and the clamping method are agreed before the first part rather than discovered on it.The route is fixed before the first part is cut, and it is the route rather than the individual setting that holds the result: stock allowance and the number of diameter changes. Where a drawing calls for something the route cannot hold economically, that is raised at quotation rather than after the parts are made.
Standards, documentation and what is issued
The documentation requirement is in-house approval with dimensional reports. Material is supplied against a certificate where the application calls for it, inspection results are recorded with the job, and the records are kept so that a repeat order can be compared with the first instead of being measured from scratch.
Roundness tester and air gauge, plus a roughness check is the verification step. Where a customer format or a standard report is required, it is agreed before the batch starts, because a report written after the event is a report nobody can use.
Frequently asked questions
What tolerance should be specified for Cylindrical Grinding Machine?
±0.002 mm is realistic in production. Tightening it beyond the functional requirement increases cost without improving the part.
Which material is usually used?
52100 bearing steel is the usual choice, supplied against in-house approval with dimensional reports.
How is the result verified?
Roundness tester and air gauge, plus a roughness check, with the results recorded so a repeat order can be compared with the first.
What is the most common mistake?
A dressing interval that is too long, which burns the shoulder on hard steel.
How long does it take and what does it cost?
A realistic cycle is 20 to 90 minutes per shaft, and the cost driver is stock allowance and the number of diameter changes.
Related capability
If you are specifying Cylindrical Grinding Machine on a drawing and want a second opinion on the route, send the model and the quantity. The first response is a manufacturability review with the likely risk points and a quotation, so the decision can be made on facts rather than on a price alone.
Machining, inspection and documentation are handled in one place, which is why the dimensional report and the material certificate arrive with the parts rather than after them.
Related entries
These entries sit next to Cylindrical Grinding Machine in the encyclopedia: Coordinate Measuring Machine, CNC Drilling Machine, Deep Hole Drilling. Reading them together gives a fuller picture of how the process, the material and the measurement affect each other.
