旋盤の回転とフライス加工のための表面フィート/分 (SFM) 、RPM、または切断速度を計算します。任意の2つの値を入力します-すぐに3番目を取得します。
回転、フライス加工、および掘削作業用。インペリアル (SFM) またはメトリック (m/min)。
A medical device manufacturer was turning 17-4 PH stainless steel on a CNC lathe with a carbide insert. They were running at 1,200 RPM with a 12mm diameter workpiece — giving a surface speed of approximately 45 m/min. Inserts were failing after 80 parts, with edge chipping and built-up edge formation. Using this calculator, they determined the correct surface speed should be 120 m/min for that material. By adjusting RPM to 3,200 (and verifying with our 切削速度・送り計算ツール), tool life increased to over 350 parts per edge — a 4× improvement. The annual savings on insert costs alone exceeded $12,000.
Surface speed — measured in SFM (Surface Feet per Minute, imperial) or Vc (meters per minute, metric) — is the linear velocity at which the cutting edge passes through the material. It is the single most important parameter in machining because it directly determines cutting temperature, tool wear rate, and surface integrity.
Imperial (SFM): SFM = (π × D × RPM) ÷ 12
Metric (Vc): Vc (m/min) = (π × D × RPM) ÷ 1000
カーバイド工具の推奨表面速度
材料
| ターニング (SFM) | フライス加工 (SFM) | 掘削 (SFM) | アルミニウム6061 |
|---|---|---|---|
| ステンレス钢304 | 800-1,500 | 800-1,200 | 400-600 |
| チタングレード5 | 400-600 | 250-400 | 150-250 |
| 硬化スチール (45-55 HRC) | 200-350 | 150-250 | 80-150 |
| マイルドスチール1018 | 250-400 | 150-250 | 80-120 |
| インコネル718 | 600-900 | 400-700 | 250-400 |
| 鋳鉄 (グレー) | 100-200 | 80-150 | 40-80 |
| チップ負荷が最適な表面速度に影響を与える理由 | 500-800 | 400-700 | 200-350 |
The relationship between SFM and 表面粗さ is often misunderstood. At higher surface speeds, the chip load per tooth must be maintained within the recommended range — otherwise the tool rubs instead of shearing, generating excessive heat regardless of SFM. This is why a proper speeds-and-feeds calculation requires both surface speed AND chip load optimization. Use the チップ負荷計算ツール after setting your SFM to verify the feed per tooth is adequate.
小径 (6mmエンドミル):800 SFM → 〜12,000 RPM
あなたの表面速度が間違っていることを示します
Too fast: Rapid flank wear, plastic deformation of the cutting edge, built-up edge, chatter, discolored chips (blue/purple), poor surface finish.
Too slow: BUE formation, high cutting forces, poor chip control, chatter, smearing on the workpiece surface, reduced productivity.
When in doubt, consult the 切削速度・送り計算ツール which incorporates material-specific SFM ranges for carbide end mills.
What is SFM in machining? SFM (Surface Feet per Minute) is the linear speed at which a cutting tool edge travels through the workpiece material. It determines cutting temperature, tool life, and surface finish.
How do I calculate SFM from RPM? Multiply π by the diameter in inches and RPM, then divide by 12: SFM = (π × D × RPM) ÷ 12. Use this calculator for instant results.
What SFM should I use for carbide end mills in stainless steel? For stainless 304, use 250-400 SFM for roughing, 300-500 SFM for finishing. Lower end for heavier cuts, higher end for finishing passes.
The difference between SFM and RPM? SFM is cutting speed through material (process parameter). RPM is spindle rotation speed (machine parameter). RPM = (SFM × 12) ÷ (π × D).
Does workpiece hardness affect surface speed? Yes — harder materials require lower SFM. As a rule of thumb, reduce SFM by 20% for every 10 HRC increase above 35 HRC. Higher hardness also increases cutting forces, which must be accounted for in the 部品当たりのコスト.
Should I use coolant or dry at high SFM? At high SFM (above 600 SFM in steel), coolant is essential to manage thermal shock. With carbide tools, intermittent coolant application can cause micro-cracking. Use consistent flood or through-spindle coolant when running above 500 SFM.