BIZOMAT MAKEOS · Manufacturing
Radial Chip-Thinning Feed
How does reduced radial engagement change feed per tooth?
Calculate a geometric chip-thinning correction for a 90° peripheral cutter and supplied maximum chip thickness.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Cutter diameter | mm | Effective diameter of a cylindrical cutter with a 90° entering angle. |
| Radial width of cut | mm | Actual radial engagement on a straight peripheral pass, greater than zero and no greater than the diameter. |
| Specified maximum chip thickness | mm | Validated target maximum chip thickness from supplier data or an approved process. |
| Spindle speed | rpm | Proposed speed checked against machine, cutter and workholding limits. |
| Effective cutting teeth | teeth | Effective cutting teeth used in the feed calculation. |
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: Cutter diameter
- What it is
- The cutting diameter of the end mill or side cutter with a square (90°) entering angle.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 10 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- For a fixed width of cut, a larger diameter lowers the engagement ratio and, below half engagement, raises the feed multiplier.
- Get it right
- Use the actual cutting diameter, not the shank diameter, for reduced-neck or undersize tools.
What this means: Radial width of cut
- What it is
- How far the cutter engages into the side of the material, measured across the cutter at right angles to the feed direction (often called ae or stepover).
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Below half the diameter, a smaller width gives a thinner chip and so a higher feed multiplier.
- Get it right
- Do not confuse with axial depth of cut along the cutter; it must not exceed the cutter diameter.
What this means: Specified maximum chip thickness
- What it is
- The maximum chip thickness you want each tooth to cut, taken from the tool supplier’s data or a proven process.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 0.05 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Feed per tooth and table feed are directly proportional to this value.
- Get it right
- Do not enter the catalogue feed per tooth for full slotting unless the supplier states it as the chip thickness.
What this means: Spindle speed
- What it is
- The rotational speed of the spindle and cutter you plan to run.
- Units and format
- Enter a number in rpm: revolutions per minute. The form accepts 0.001 rpm to 1000000 rpm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 2000 rpm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Table feed is directly proportional to spindle speed.
- Get it right
- Check it against the machine, tool and workholding limits before using the feed.
What this means: Effective cutting teeth
- What it is
- The number of cutting edges on the cutter that actually cut in each revolution.
- Units and format
- Enter a number in teeth: a whole number of teeth. The form accepts 1 teeth to 1000 teeth. Use a whole number. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 4 teeth as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Table feed is directly proportional to the number of teeth.
- Get it right
- Count only effective edges; some cutters have unequal or non-cutting flutes.
Method and formulas
- Let r = width/diameter. Below r = 0.5, factor = 2√[r(1 − r)]; at or above 0.5, factor = 1.
- Feed per tooth = maximum chip thickness/factor. Table feed = feed per tooth × teeth × RPM.
- Example: 1 mm engagement on a 10 mm cutter gives factor 0.6. A 0.05 mm chip requires 0.083333 mm/tooth, giving 666.667 mm/min with 4 teeth at 2000 rpm.
Limitations
- Straight peripheral milling with a 90° entering angle only. Ball-nose, round-insert, high-feed and changing-engagement paths need other models.
- Very small engagement can request very high feed. Machine dynamics and tool limits still govern.
- No suitable chip thickness is selected and no machine program is issued.
- Default values are worked examples, not recommended settings or material properties.
Typical uses
- radial engagement
- chip thinning
- feed per tooth
Who it is for
- CNC programmers
- Manufacturing engineers
What you get
- Chip-thickness factor
- Corrected feed per tooth
- Calculated table feed
Interpreting the result
- Check corners, entry and increased engagement across the whole path.
- Compare the calculation with supplier limits, then validate the process.
References
- Sandvik Coromant: Milling formulas and definitions — https://www.sandvik.coromant.com/en-gb/knowledge/machining-formulas-definitions/milling-formulas-definitions
- Harvey Performance: How to combat chip thinning — https://www.harveyperformance.com/in-the-loupe/combat-chip-thinning/
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