Extrusion Specific Energy (SEC)
Calculate the extrusion specific energy consumption (SEC), SEC = power ÷ mass throughput, from the screw motor power (kW) and the mass throughput (kg/h). The result, in kWh/kg, is the energy to process each kilogram of polymer, and the main ENERGY-EFFICIENCY indicator of an extruder. Since extrusion melts and pumps plastic largely by VISCOUS heating (screw mechanical energy converted to heat by shear), specific consumption directly reflects how well the screw is doing its job. Typical values are 0.1-0.4 kWh/kg, varying with polymer (each has a melting enthalpy), screw geometry, speed and temperature. An abnormally HIGH SEC signals problems — wrong screw, excessive shear (which can degrade the material), poor temperature setting — and energy waste (the largest part of an extruder's operating cost). A very low SEC may indicate incomplete melting. Monitoring SEC is central to efficiency, quality and cutting cost and emissions in plastics processing. Enter the power consumed and the mass throughput.
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Extrusion specific energy (SEC)
The specific energy of extrusion (SEC — Specific Energy Consumption) is SEC = power ÷ mass throughput, from the power drawn by the screw motor (kW) and the mass output rate (kg/h). The result, in kWh/kg, is the energy spent to process each kilogram of polymer — the headline indicator of the energy efficiency of an extruder. Because extrusion melts and pumps the plastic largely through viscous heating (the mechanical energy of the screw converted into heat by shear), specific consumption is a direct readout of how well the screw is doing its job. Typical values fall between 0.1 and 0.4 kWh/kg, varying with the polymer (each one has its own heat of fusion), the screw geometry, the screw speed and the temperature profile. An abnormally high SEC points to trouble — the wrong screw design, excessive shear (which can degrade the material), poorly tuned barrel temperatures — and to wasted energy, the largest single item in operating cost. A very low SEC may signal incomplete melting. Tracking SEC is central to efficiency, product quality and the reduction of cost and emissions in plastics processing. Enter the power drawn and the mass throughput.
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Energy per Elevator Trip
Calculate the potential energy spent to raise a load, E = m·g·h, from the unbalanced mass m (net load after the counterweight, kg), gravity g and the lift height h (m). The result, in joules, is the minimum theoretical energy to hoist the load — a basis for estimating the elevator's electrical consumption and the energy-regeneration potential. Modern elevators with regenerative drives recover part of this energy on descent (when the counterweight descends with a light car), feeding it back to the grid. Actual consumption is higher, divided by the efficiency. Enter the unbalanced mass and the lift height.
Screw Degree of Fill
Calculate an extrusion screw's degree of fill, η = (actual flow ÷ drag flow) · 100, from the actual production flow and the screw's theoretical drag flow. Degree of fill measures how much of the screw's theoretical pumping capacity (the drag flow, which would occur with no back-pressure) is actually delivered as real flow — the difference is 'lost' to pressure flow (backflow from die resistance). It is thus a measure of the extruder's volumetric EFFICIENCY and operating point on the characteristic curve: a high fill (near 100%) means little back-pressure (open die, simple product); a low fill means strong back-pressure (restrictive die), with much internal backflow. In gravity-fed (flood-fed) extruders the screw runs full, and degree of fill reflects the drag-pressure balance; in metered-feed (starve-fed, common in twin-screw) extruders, degree of fill is deliberately controlled by the feed rate, decoupling flow from speed and giving independent control of residence time and shear. Knowing the degree of fill helps diagnose the process and optimize productivity. Enter the actual flow and the drag flow.
Aircraft Fuel Efficiency
Compute aircraft fuel efficiency = distance / fuel.
Screw Channel Shear Rate
Calculate the average shear rate in an extrusion screw channel, γ̇ = (π·D·N) ÷ H, from the barrel diameter D (m), screw speed N (rev/s) and channel depth H (m). Shear rate is the velocity gradient the molten polymer experiences between the moving screw surface and the fixed barrel, and it is central to plastics processing for a key reason: molten polymers are NON-Newtonian pseudoplastic fluids whose viscosity DECREASES as shear rate rises (shear thinning). Knowing the shear rate lets you estimate the material's real viscosity in the machine (via the power law) and thus pressure, power and viscous heating. Very high shear can degrade the polymer (chain scission by shear and heat); too low leaves melting incomplete. Each polymer has a suitable range. This screw-channel shear rate differs from the (much higher) die shear rate at the exit restriction. It is a basic processing-rheology calculation. Enter the diameter, speed and channel depth.
Extruder Head Pressure
Estimate an extruder's head pressure, ΔP = (Q·μ) ÷ K, from the volumetric flow Q (m³/s), the melt viscosity μ (Pa·s) and the die conductance constant K (m³, summarizing the head+die flow-resistance geometry). Head pressure is the pressure the melt reaches at the screw end, before being forced through the die that gives the product its final shape. It results from the balance between the screw's pumping capacity (drag flow) and the die's resistance: more restrictive dies (smaller orifices, longer narrower channels) need higher pressure for the same flow. Extrusion pressures are very high — typically 100-400 bar (10-40 MPa) — and measuring and controlling them is essential: pressure indicates process state (blockages, viscosity changes from temperature, screw wear), governs flow and product uniformity, and has safety limits (excessive pressure can rupture the head or trigger burst disks). The screw-die balance, shown in the extruder's characteristic curve, is the heart of process control. Enter the flow, viscosity and die constant.
Blow-Up Ratio (Blown Film)
Calculate the blow-up ratio (BUR) in blown-film tubular extrusion, BUR = D_bubble ÷ D_die, from the film bubble diameter D_bubble and the annular die diameter D_die. Blown-film extrusion makes most of the world's plastic films (bags, packaging, sacks, sheeting): the melt is extruded through an annular die forming a tube, which is then INFLATED with compressed air like an elongated balloon and pulled upward at once, stretching the film in two directions to its final thickness (a few micrometres). The blow-up ratio is how much the tube is inflated relative to the die diameter — typically 1.5:1 to 4:1. It controls molecular orientation in the TRANSVERSE (circumferential) direction: a higher BUR stretches the film more in width, balancing its properties in both directions (transverse by blowing and longitudinal by pulling). The balance between blow-up and draw (pulling) sets the biaxial orientation, which determines the film's strength, stiffness, clarity and tear behavior. Adjusting BUR is a main control variable in making blown films with the desired properties. Enter the bubble diameter and the die diameter.
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.