BIZOMAT MAKEOS · Manufacturing
Centerless Grinding Through-Feed Rate
How fast do parts pass through this centerless grinder, and how many per minute?
Axial through-feed rate of a centerless grinder from the regulating wheel diameter, speed and inclination angle, with work rotation speed and parts per minute.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Regulating wheel diameter | mm | Current regulating wheel diameter. |
| Regulating wheel speed | rpm | Regulating wheel speed. |
| Regulating wheel inclination | ° | Inclination of the regulating wheel axis (typically 1–6° for through-feed). |
| Work diameter | mm | Diameter of the part being ground. |
| Part length | mm | Length of each part. |
| Gap between parts | mm | Gap between parts as they feed through (0 for end-to-end feeding). |
| Feed efficiency (slip allowance) | % | Allowance for slip between wheel and work (about 90–98%). |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Regulating wheel diameter
- What it is
- The present diameter of the regulating wheel, the rubber-bonded wheel that controls the work’s rotation and axial feed.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 5000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 250 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Through-feed rate rises in proportion to the wheel diameter.
- Get it right
- Measure the current diameter; it reduces as the wheel is dressed.
What this means: Regulating wheel speed
- What it is
- The rotational speed of the regulating wheel, not of the grinding wheel.
- Units and format
- Enter a number in rpm: revolutions per minute. The form accepts 0.000001 rpm to 10000 rpm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 40 rpm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Through-feed rate rises in proportion to the regulating wheel speed.
- Get it right
- Do not enter the grinding wheel speed; the regulating wheel turns much more slowly.
What this means: Regulating wheel inclination
- What it is
- The angle the regulating wheel axis is tilted from the grinding wheel axis, which turns part of the wheel speed into axial feed.
- Units and format
- Enter a number in °: degrees of angle. The form accepts 0.1° to 10°. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 3° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Through-feed rises with the sine of the angle, so a larger tilt feeds faster.
- Get it right
- Read it from the machine’s inclination scale for the current setup.
What this means: Work diameter
- What it is
- The diameter of the part being ground, used to work out how fast the part spins.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 1000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 20 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Work rotation speed falls in inverse proportion to the work diameter; through-feed does not change.
What this means: Part length
- What it is
- The length of each part along its axis as it passes through the grinder, used with the gap to count parts per minute.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 80 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
What this means: Gap between parts
- What it is
- The space between the end of one part and the start of the next as they feed through; zero for parts fed end to end.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0 mm to 10000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 5 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A larger gap lowers the parts per minute at the same through-feed rate.
What this means: Feed efficiency (slip allowance)
- What it is
- An allowance for the work moving slower than the theoretical feed because it slips against the regulating wheel, expressed as the share of theoretical feed achieved.
- Units and format
- Enter a number in %: percent: the number is read as a percentage, so type 8 for 8 %. The form accepts 1% to 100%. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 95% as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Through-feed and parts per minute rise in direct proportion.
- Get it right
- Type the percentage (95 for 95 %). Calibrate it from measured output on your machine.
Method and formulas
- Through-feed f = π Dr nr sin(α) × efficiency.
- Work speed ≈ Dr nr cos(α) ÷ dw.
- Parts per minute = f ÷ (part length + gap).
- Example: a 250 mm wheel at 40 rpm and 3° feeds 1,562 mm/min, about 18.376 parts/min.
Limitations
- Slip depends on wheel condition, work rest and coolant; measure actual output to refine the efficiency.
- Stock removal per pass and number of passes are not considered.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Set regulating wheel speed and angle for a production rate
- Estimate output of a through-feed job
- Check work speed
Who it is for
- Grinding machinists
- Manufacturing engineers
What you get
- Through-feed rate
- Work rotation speed
- Parts per minute
Interpreting the result
- Increase the angle for faster feed; reduce it for finer finish and better roundness.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1259–1261. Topic reference; no source tables or recommended settings are reproduced.
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