Standard blank diameter (ROUND_DIAMETERS), machining allowances, saw cut or multi-part bar. For rectangular parts from round stock — automatic 3D reorientation (variants A / B / C) to minimize diameter and chips.
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Часті запитання
How does 3D reorientation of a rectangular part from round bar work?+
The calculator checks part orientations in the bar (A / B / C) and picks the smallest standard diameter including turning allowances.
How does single-piece cutting differ from a multi-part bar?+
Single-piece saw cutting gives an exact length per part. A multi-part bar saves cut time but increases scrap — the calculator compares batch mass and UF for both.
Where do round bar diameters come from?+
The standard ROUND_DIAMETERS series: the smallest size that fits the part plus machining allowances.
Norming parameters
Material selection for round bar, hexagon, forgings and sheet. For sheet — standard thicknesses, commercial sheet nesting and a PDF report.
Step 1. Finished part geometry (clean drawing dimensions)
Lets you calculate UF and chip weight accurately when the part has large holes, pockets or lightening cut-outs.
Step 2. Machining allowances
Added to the clean Ø before selecting the nominal: minimum blank Ø = clean Ø + allowance, then the ROUND_DIAMETERS series.
Step 3. Blank cutting
Step 4. Round bar (blank)
Minimum Ø = clean Ø + allowance; smaller sizes from the ROUND_DIAMETERS series are unavailable.
Affects batch weight and UF.
Engineering report
Summary of material norming for the given batch
Finished part shape
Cylindrical
Cylindrical (round part) · min. Ø by envelope 21 mm
Required stock length
1.26 m (1260 mm)
D = 22 mm · 0.003 kg/mm · 380.133 mm²
Blank size (gross, 1 pc)
126 mm
Clean length + facing allowance + saw kerf width
Total blank weight per batch (gross)
3.78 kg
Material purchase mass for the entire batch
Clean weight of one finished part (net)
0.24 kg
Net: cylinder from clean diameter and length
Chip / waste weight
1.38 kg
Batch clean weight: 2.4 kg
Utilization factor (UF)
63.49%
Medium UF — check the allowances and the number of parts per bar.
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Calculation methodology and material consumption norming
The calculator selects the smallest standard round bar diameter from the nominal size series, accounts for process allowances and the cutting strategy — piece-by-piece on the saw or from a bar with a parting tool.
What the algorithm accounts for
Diameter selection: for a cylindrical part — clean Ø + diameter allowance; for a rectangular/prismatic part — 3D rotation (options A / B / C) and the smallest standard Ø that fits the part with allowances.
Cutting: piece-by-piece — facing + saw kerf width; from bar — parting tool width, end trimming and chuck remnant.
Mathematical basis of the calculation
The mass of a round bar piece is calculated from the circular cross-section area and density. Dimensions are in millimeters, ρ in g/cm³, the result in kilograms.
m [kg] = V [mm³] × ρ [g/cm³] / 10⁶
Reference density table
Material
ρ, g/cm³
Application
Structural steel
7.85
Round bar
Aluminum
2.7
Round bar
Brass / Bronze
8.5
Round bar
Formulas
Cross-section area
S = π × D² / 4
Mass of a piece of length L
m = S × L × ρ / 10⁶
Equivalent to: m [kg] = V [mm³] × ρ [g/cm³] / 10⁶, where V = S × L.
Minimum blank Ø
Cylindrical part: clean Ø + diameter allowance. Rectangular part — the minimum over the L×W×H orientations with a side allowance, then the smallest nominal from the ROUND_DIAMETERS series.
Blank length
Clean part length + facing + (saw kerf, or parting tool width + chuck remnant — depending on the cutting strategy).
Notation: D — bar diameter, L — length (mm), ρ — density (g/cm³), m — mass (kg). UF = batch net mass / batch gross mass.
