Cylindrical Grinding Machine specifications: what the numbers mean
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, food processing is used as the example: surfaces that clean down between production runs.
What the numbers mean
A data sheet for Cylindrical Grinding Machine is only useful if the numbers are read against the job. The usual entries, and what they tell you, are these.
- Centre height – 150 to 250 mm.
- Grinding length – up to 1,000 mm.
- Wheel size – 400 x 50 mm.
- Roundness achievable – 0.002 mm.
- Surface finish – Ra 0.1 to 0.4 µm.
- Workhead speed – variable, 20 to 400 rpm.
Comparing offers
Two suppliers can quote the same centre height and mean different things, because the figures are often quoted under the most favourable conditions. Ask what the value is measured over, what the material was, and whether it is a typical or a guaranteed figure.
| Specification | Typical value |
|---|---|
| Centre height | 150 to 250 mm |
| Grinding length | up to 1,000 mm |
| Wheel size | 400 x 50 mm |
| Roundness achievable | 0.002 mm |
| Surface finish | Ra 0.1 to 0.4 µm |
| Workhead speed | variable, 20 to 400 rpm |
What to check before specifying
Make sure the value you need is the value you have called up. Specify roundness and cylindricity, not just a diameter tolerance, on sealing journals, and the difference between a typical and a worst case figure is where most disputes start.
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: Horizontal Machining Centre, 5-Axis Machining Centre, Deburring. Reading them together gives a fuller picture of how the process, the material and the measurement affect each other.
