Turning Time
Calculate the cutting time of one turning pass, t = L ÷ (f·n), from the length to machine L (mm), the feed f (mm/rev) and the rotation n (rpm). The product f·n is the tool feed rate (mm/min); dividing the length by it gives the pass time. This is the PRODUCTIVE cutting time of a longitudinal turning operation (the tool traversing the part length), and the basis of total fabrication time and thus machining cost and production planning. Total time also includes non-productive times (tool approach and retract, part change, measuring, tool change) and the number of passes needed (depending on material to remove and depth per pass). Cutting time — by raising feed and rotation (and thus cutting speed) — is the path to productivity, always within tool life, machine power and required finish limits. This is essential to quote machined parts and size a machine shop's capacity. Enter the length, feed and rotation.
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Turning time
The cutting time of a single turning pass is t = L ÷ (f·n), computed from the length to machine L, the feed per revolution f and the spindle speed n. The product f·n is the tool feed rate (mm/min); dividing the length by it gives the time of the pass. This is the productive cutting time of a longitudinal turning operation (the tool travelling along the length of the workpiece) and it is the basis for the total manufacturing time and therefore for machining cost and production planning. Total time also includes the non-productive times (tool approach and retraction, part change, measurement, replacement of a worn tool) and the number of passes required (which depends on the stock to remove and on the depth of cut per pass). Cutting the machining time — by raising the feed and the spindle speed, and therefore the cutting speed — is the road to productivity, always within the limits of tool life, machine power and the required surface finish. This calculation is essential for quoting machined parts (machine time is a central cost) and for sizing the production capacity of a machine shop. Enter the length, the feed and the spindle speed.
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Material Removal Rate (Turning)
Calculate the material removal rate (MRR) in turning, Q = Vc·a_p·f, from the cutting speed Vc (m/min), the depth of cut a_p (mm) and the feed f (mm/rev). The result, in cm³/min, is the material volume removed per unit time — the direct measure of machining PRODUCTIVITY. Maximizing MRR (cutting fabrication time and cost per part) is the core goal in roughing, achieved by increasing any of the three factors: cutting speed, depth or feed. But there are limits and trade-offs: higher speed shortens tool life (Taylor); higher depth and feed raise the cutting force and power required (which may exceed machine capacity or cause chatter) and worsen finish. So the typical strategy uses high MRR in ROUGHING (productivity) and low in FINISHING (precision and roughness). MRR times the material's specific cutting energy gives the required power. Enter the cutting speed, depth of cut and feed.
Machining Spindle Speed
Calculate the spindle speed (RPM) needed in machining, n = (1000·Vc) ÷ (π·D), from the desired cutting speed Vc (m/min) and the diameter D (mm — workpiece in turning or tool in milling). It is the inverse of the cutting-speed calculation, and the most used on the shop floor: the operator knows the material, picks the recommended cutting speed from tables, and must convert it to the rpm to set on the machine. The relation reveals a key point: for the same cutting speed, SMALLER-diameter parts or tools require HIGHER rpm (and vice versa). So turning a part of varying diameter (facing, tapers) at constant cutting speed requires continuously varying the rpm — done automatically by CNC lathes (G96, constant surface speed), while on conventional lathes the operator adjusts by ranges. Getting rpm right is essential for tool life, finish and safety (excessive rpm on large parts creates dangerous centrifugal forces). Enter the cutting speed and the diameter.
Pomodoro Sessions Calculator
Compute total time for a Pomodoro session: 25 min focus + 5 min break, with long break every 4 rounds.
Injection Cycle Time
Compute the total cycle time of a plastic injection by adding the injection time (fill + pack), the cooling time and the mold open/eject time. Cooling is usually the largest share (50–80% of the cycle). The cycle time directly determines productivity: parts/hour = 3600/cycle × cavities. Reducing it is the constant focus of optimization. Enter the injection, cooling and opening times.
Cutting Force by the Kienzle Equation
Computes the main cutting force with the Kienzle equation, F_c = k_c1.1 · b · h^(1 − m_c), where k_c1.1 is the tabulated specific cutting force of the workpiece material for a reference chip section of 1 mm × 1 mm, b is the chip width and h the chip thickness, and m_c is the exponent describing the size effect. That is exactly where it differs from the direct calculation F_c = k_s·b·h: the latter treats specific pressure as a material constant, while Kienzle embeds the experimental fact that thin chips cost far more force per unit area, because the cutting edge radius stops being negligible next to the chip thickness. With k_c1.1 = 1500 N/mm² and m_c = 0.26, a 0.2 mm thick chip works at 2279 N/mm², 52 % above the tabulated value — which is why very low feeds raise the power spent per cubic millimetre removed, and the tool wear with it, instead of saving them — even though the absolute force falls. Since k_c1.1 carries a hidden millimetre raised to m_c, the equation is not dimensionally pure: thickness and width have to be entered in millimetres, and switching units is off by orders of magnitude. Enter the specific force k_c1.1, the exponent m_c, the chip width and the chip thickness.
Machining Cutting Speed
Calculate the machining cutting speed, Vc = (π·D·n) ÷ 1000, from the diameter D (mm — of the workpiece in turning or the tool in milling) and the rotation n (rpm). The result, in m/min, is the relative tangential speed between the cutting edge and the workpiece — the MOST important machining parameter, governing cutting temperature, tool wear, finish and productivity. Each workpiece-tool material combination has an optimal cutting-speed range recommended by makers: too high overheats and wears the tool fast (shortening life per Taylor's equation); too low cuts productivity and can cause built-up edge (BUE) and poor finish. Cutting speed is the starting point of any machining plan: from it and the diameter, the machine rpm is computed; it depends on material (steel, aluminum, titanium have very different ranges), tool material (HSS, carbide, ceramic) and operation. Enter the diameter and the rotation.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.