# Cutting Parameters Reference

## Feed and Speed Formulas

### RPM from Surface Speed

```
RPM = (SFM x 12) / (pi x diameter_inches)
RPM = (SMM x 1000) / (pi x diameter_mm)
```

Where SFM = Surface Feet per Minute, SMM = Surface Meters per Minute.

### Feed Rate

```
Feed (mm/min) = RPM x Number_of_Flutes x Chip_Load_per_Tooth
Feed (in/min) = RPM x Number_of_Flutes x Chip_Load_per_Tooth
```

### Material Removal Rate

```
MRR = ADOC x RDOC x Feed_Rate
```

Where ADOC = Axial Depth of Cut, RDOC = Radial Depth of Cut.

## Depth of Cut Guidelines

### Roughing

| Parameter | Endmill Rule |
|-----------|-------------|
| ADOC (axial) | 1-2x tool diameter |
| RDOC (radial) | 40-60% of tool diameter |
| Step-over | 40-60% of tool diameter |

### Finishing

| Parameter | Endmill Rule |
|-----------|-------------|
| ADOC (axial) | 0.5-1x tool diameter |
| RDOC (radial) | 5-15% of tool diameter |
| Step-over | 5-15% of tool diameter |

### Adaptive/HEM Clearing

| Parameter | Rule |
|-----------|------|
| ADOC (axial) | Up to 3-4x tool diameter |
| RDOC (radial) | 5-15% of tool diameter |
| Engagement angle | < 40 degrees |
| Benefit | Constant chip load, reduced tool wear |

## Material-Specific Parameters

### Aluminum 6061-T6

| Tool Dia | RPM | Feed (mm/min) | Chip Load | SFM |
|----------|-----|---------------|-----------|-----|
| 3mm, 2-flute | 24,000 | 600-900 | 0.013-0.019mm | 750 |
| 6mm, 3-flute | 18,000 | 800-1200 | 0.015-0.022mm | 900 |
| 10mm, 3-flute | 12,000 | 720-1080 | 0.020-0.030mm | 1000 |
| 12mm, 4-flute | 9,000 | 720-1080 | 0.020-0.030mm | 900 |

### Steel 1018 (Mild)

| Tool Dia | RPM | Feed (mm/min) | Chip Load | SFM |
|----------|-----|---------------|-----------|-----|
| 6mm, 3-flute | 4,000 | 360-480 | 0.030-0.040mm | 250 |
| 10mm, 4-flute | 2,500 | 300-400 | 0.030-0.040mm | 250 |
| 12mm, 4-flute | 2,100 | 250-340 | 0.030-0.040mm | 250 |

### Brass (360 Free-Machining)

| Tool Dia | RPM | Feed (mm/min) | Chip Load | SFM |
|----------|-----|---------------|-----------|-----|
| 6mm, 2-flute | 10,000 | 600-800 | 0.030-0.040mm | 500 |
| 10mm, 3-flute | 6,000 | 540-720 | 0.030-0.040mm | 500 |

### Stainless Steel 304

| Tool Dia | RPM | Feed (mm/min) | Chip Load | SFM |
|----------|-----|---------------|-----------|-----|
| 6mm, 4-flute | 2,700 | 270-430 | 0.025-0.040mm | 170 |
| 10mm, 4-flute | 1,600 | 160-260 | 0.025-0.040mm | 170 |

### Plastics (Delrin/Acetal)

| Tool Dia | RPM | Feed (mm/min) | Chip Load | SFM |
|----------|-----|---------------|-----------|-----|
| 6mm, 1-flute | 18,000 | 1800-2700 | 0.10-0.15mm | 900 |
| 6mm, 2-flute | 18,000 | 900-1400 | 0.025-0.038mm | 900 |

Note: Single-flute preferred for plastics to prevent chip welding.

## Tool Selection Guidelines

| Operation | Tool Type | Notes |
|-----------|----------|-------|
| Roughing pockets | Endmill (3-flute for aluminum, 4-flute for steel) | Largest diameter that fits |
| Finishing | Endmill or Ballnose (for 3D surfaces) | Smaller for detail |
| Drilling | Drill bit or endmill helical plunge | Match hole diameter |
| Profiling | Endmill | Match corner radius requirement |
| Deburring | Chamfer mill (90 or 120 deg) | Match edge requirement |
| 3D surfaces | Ballnose | Step-over determines scallop height |

## Scallop Height (Ballnose Finishing)

```
Scallop Height = R - sqrt(R^2 - (stepover/2)^2)
```

Where R = ballnose radius. For 0.01mm scallop with 6mm ballnose: stepover = 0.49mm.

## Tool Life Considerations

- Aluminum: carbide endmills last 60-120 minutes at recommended parameters
- Steel: carbide endmills last 30-60 minutes
- Reduce feed by 15-20% for extended tool life
- Increase RPM and reduce chip load for better surface finish
- Coolant (flood or mist) extends tool life 2-3x in steel