Machining Soft Magnetic Alloys – Hiperco® 50A & Core Iron (VIM VAR)
The Ed Fagan Guide to Machining Soft Magnetic Alloys reviews the machining of CarTech® Hiperco® 50A and Core Iron (VIM VAR).
Soft magnetic alloys can be machined by all of the common metal machining processes. No special equipment or procedures are required to produce parts with accurate dimensions with excellent finishes.
Soft magnetic alloys that are primarily nickel-iron alloys, e.g. EFI Alloy 79 (Magnifer 7904), HyMu 80, Hipernom, Moly-Permalloy, Permalloy 80, EFI Alloy 50 (Magnifer 50) and High Permeability 49 can be machined in accordance with the information found in our Machining Nickel-Iron Alloys Guide.
Guide to Machining CarTech® Hiperco® 50A
Tools
The choice between high-speed steel and carbide tools depends largely on production quantities. When using carbide tools, surface speed feet/minute (SFPM) can be increased between 2 and 3 times over the high-speed suggestions. Feeds can be increased between 50 and 100%.
The following charts include typical machining parameters used to machine CarTech Hiperco 50A. The data should be used as a guide for initial machine setup only.
Turning – Single Point & Box Tools
| SFPM | IPR | |
| High Speed Tools | 30 - 40 | 0.003 - 0.010 |
| Carbide Tools | 120 - 130 | 0.005 - 0.010 |
Turning – Cut-Off & Form Tools
| Cut-Off Tool Width | SFPM | IPR |
| 1/16" | 25 | 0.001 |
| 1/8" | 25 | 0.002 |
| 1/4" | 25 | 0.003 |
| Form Tool Width | SFPM | IPR |
| 1/2" | 25 | 0.004 |
| 1" | 25 | 0.0025 |
| 1-1/2" | 25 | 0.002 |
Die Threading
| Threads per Inch | SFPM |
| 3 - 7-1/2 | 8 |
| 8 - 15 | 10 |
| Over 16 | 15 |
Milling
| SFPM | IPR |
| 20 - 30 | 0.001 - 0.005 |
Drilling
| Drill Diameter | SFPM | IPR |
| 3/8" | 30 | 0.005 |
| 3/4" | 30 | 0.010 |
Reaming
| SFPM | IPR | |
| Under 1/2" | 65 | 0.005 |
| Over 1/2" | 65 | 0.010 |
Tapping
| Threads per Inch | SFPM |
| 3 - 7-1/2 | 6 |
| 8 - 15 | 7 |
| 16 - 24 | 11 |
| Over 25 | 15 |
Broaching
| SFPM | IPR | |
| Chip Load | 8 - 15 | 0.002 |
| Over 25 | 15 |
Guide to Machining Core Iron (VIM VAR)
The following charts include typical machining used to machine electrical iron. The data listed should be used as a guide for initial machine setup only.
Turning – Single Point & Box Tools
High Speed Tools
| Depth of Cut inches | Speed IPM | Speed IPR | Tool Material |
| 0.150 | 80 | 0.015 | M-2 |
| 0.025 | 110 | 0.007 | M-2 |
| Depth of Cut inches | Speed IPM Brazed | Speed IPM Throw Away | Feed IPR | Tool Material |
| 0.150 | 350 | 400 | 0.020 | C-6 |
| 0.025 | 400 | 490 | 0.007 | C-7 |
Turning – Cut-Off & Form Tools
Cut-Off Tool Feed IPR
| Speed FPM | Width | Width | Width | Tool Material |
| 1/16" | 1/8" | 1/4" | ||
| 70 | .001 | .015 | .002 | M-2 |
| 250 | .003 | .0045 | .006 | C-6 |
| Speed FPM | Width | Width | Width | Width | Tool Material |
| 1/2" | 1" | 1-1/2" | 2" | ||
| 70 | .0015 | .001 | .001 | .0007 | M-2 |
| 250 | .003 | .0025 | .0025 | .0015 | C-6 |
Drilling
Feed IPR
| Speed FPM | Hole Dia.* | Hole Dia.* | Hole Dia.* | Hole Dia.* | Hole Dia.* | Hole Dia.* | Hole Dia.* | Hole Dia.* | Tool Material |
| 1/16" | 1/8" | 1/4" | 1/2" | 3/4" | 1" | 1-1/2" | 2" | ||
| 70 | .001 | .002 | .004 | .007 | .010 | .012 | .015 | .018 | M-42 |
*Nominal Hole Diameter
Figures used for all metal removal operations covered are average. On certain work, the nature of the part may require adjustment of speeds and feeds. Each job has to be developed for best production results with optimum tool life. Speeds or feeds should be increased or decreased in small steps.
Items as supplied from the mill exhibit only a fraction of the soft magnetic properties which they are capable of attaining. To optimize their full magnetic properties, further heat treatment is a necessity.
Optimal heat treating procedures vary depending on the type of soft magnetic alloy – recommended heating temperatures, hold times, cooling rates, cycles, and types of atmospheres are all specific to each alloy. For the recommended heat treatment procedures refer to our Hiperco 50, 50A & 50 HS Ferromagnetic Annealing Guide, Core Iron (VIM VAR) Ferromagnetic Annealing Guide, EFI Alloy 50 Ferromagnetic Annealing Guide, or EFI Alloy 79 Ferromagnetic Annealing Guide.