Initial analysis of cost, energy and carbon dioxide emissions in single point incremental forming – producing an aluminium hat

Figures & data

Figure 1 SPIF configuration.

Figure 2 SPIF toolpath, showing 2D contours displayed using MasterCam™.

Figure 3 Screenshot of hat detail in MasterCam™ showing tool path.

Figure 4 Picture of finished hat.

Table 1 Summary of experimental parameters.

Parameter	Scenario 1 (S1)	Scenario 2 (S2)
Lubricant	Quaker state 75W-140	Used cooking oil ester^a
Tool size, mm (in.)	6.35 (0.25)	9.525 (0.375)
Spindle speed (RPM)	600	600
Feed rate, mm/min (in./min)	2032 (80)	4064 (160)
Step size, mm (in.)	0.254 (0.01)	0.508 (0.02)
^a Sample from Dr. C. Herrmann at Braunschweig Institute of Technology in Germany.

Figure 5 Power profile comparison of SPIF of hat with and without stock in Scenario 1.

Table 2 Energy profile data for hat made with SPIF process Scenario 1 on Bridgeport™ GX480.

	Average power (W)	Estimated total energy (kJ)
Machine breaker off	35	–
Average standby baseline	639	3824
SPIF hat (no stock) + baseline	758^a	4454
SPIF hat (stock) + baseline	778^a	4571
SPIF hat deformation energy	–	117 (4571–4454)
Average positioning (less standby baseline)	287^a	9
Total energy	–	4580 (4571+9)
Total direct energy	–	747 (4580–3824)
Total ancillary energy	–	3833
^a Average power calculated with total energy and time, not showing range for power spikes.

Table 3 Summary of energy use and time for two scenarios.

	S1	S2
Deformation energy, kJ (kWh)	117 (0.033)	33 (0.009)
Ancillary energy, kJ (kWh)	3834 (1.065)	1032 (0.287)
Direct energy, kJ (kWh)	746 (0.207)	385 (0.107)
Total energy, kJ (kWh)	4580 (1.272)	1420 (0.394)
Total energy standard error, kJ (kWh)	± 40 (0.012)	± 30 (0.009)
SPIF time (s)	5720	1456
Total time (with idling and positioning), (s)	5902	1636
Total time standard error (s)	± 2	± 2

Figure 6 Abridged process diagram for hat made from aluminium sheet via SPIF showing process area for CO₂ and cost of manufacturing analysis.

Table 4 Cost breakdown for manufacturing a hat using SPIF for two scenarios.

	Scenario 1 (S1)			Scenario 2 (S2)
Item	Cost rate	Used per hat	Final cost	Cost rate	Used per hat	Final cost
Stock (Al-3003 O)	$111.60 for 48” × 8′ × 0.059” sheet	12.875” × 12.875” × 0.059” (21% removed to create brim)	$4.01	Same	Same	$4.01
Lubricant	$20.00/L (Quaker State Full Synthetic 75W-140)	16.8 ml	$0.34	$2.80/L (Used cooking oil ester)	10.5 ml	$0.03
Direct energy	$0.088/kWh	1.065	$0.09	$0.088/kWh	0.287	$0.03
Ancillary energy	$0.088/kWh	0.207	$0.02	$0.088/kWh	0.107	$0.01
Tool	$25.00 for 1/4” Custom steel tool	(1000 hats per tool)	$0.03	$25.00 for 3/8” Custom steel tool	(1000 hats per tool)	$0.03
Total cost per hat (without labour)	–	–	$4.48	–	–	$4.10
Labour (design, set-up, machine and finish)	$60/h (1 hat process)	3 h	$180.00	$60/h (1 hat process)	1.81 h	$109.05
Total cost per hat (with labour)	–	–	$184.48	–	–	$113.15
Labour per hat (1000 hats)^a	$50/h (1000-hat process)	1.64 h	$82.00	$50/h (1000-hat process)	0.46 h	$22.84
Total cost per hat (with commercial labour charge)	–	–	$86.48	–	–	$26.94
^a Labour contribution reduces when more hats are created.

Table 5 CO₂ contribution breakdown for Scenario 1 (S1) SPIF hat process.

		Experimental/traditional inputs			Modified inputs
Item	Amount used	Material LCA reference assumption	Estimated EI	CO2 per hat (kg CO2)	Material LCA reference assumption	Estimated EI	CO2 per hat (kgCO2)
Stock (Al-3003 O)	0.346 kg	Rolled Al – virgin  raw materials	12.15 kg CO2e/kg	4.20	Rolled Al – 33%  recycled materials	8.72 kg CO2e/kg	3.02
Lubricant (75W-140)	0.017 L	Mineral gear oil	3.29 kg CO2e/L	0.06	Used cooking oil ester	0.512 kg CO2e/L	0.01
Direct energy	0.207 kWh	Ontario grid	0.17 kg CO2e/kg	0.04	Ontario grid	0.17 kg CO2e/kg	0.04
Ancillary energy	1.065 kWh	Ontario grid	0.17 kg CO2e/kg	0.18	Ontario grid	0.17 kg CO2e/kg	0.18
Tool (1/4” SPIF tool custom)	1.36E-4 kg	Generic HSS mill  tool – new	6.4 kg CO2e/kg	8.70E-4	Generic HSS mill  tool – remanufactured	1.3 kg CO2e/kg	1.77E-4
Total	–	–	–	4.48	–	–	3.24

Table 6 CO₂ contribution breakdown for Scenario 2 (S2) SPIF hat process.

		Experimental/traditional inputs			Modified inputs
Item	Amount used	Material LCA reference assumption	Estimated EI	CO2 per Hat (kg CO2)	Material LCA reference assumption	Estimated EI	CO2 per hat (kg CO2)
Stock (Al-3003 O)	0.346 kg	Rolled Al – virgin raw  materials	12.15 kg CO2e/kg	4.20	Rolled Al – 33% recycled  materials	8.72 kg CO2e/kg	3.02
Lubricant (used cooking oil ester)	0.0105 L	Used cooking oil ester	0.512 kg CO2e/L	0.01	Used cooking oil ester	0.512 kg CO2e/L	0.01
Direct energy	0.107 kWh	Ontario grid	0.17 kg CO2e/kg	0.02	Ontario grid	0.17 kg CO2e/kg	0.02
Ancillary energy	0.287 kWh	Ontario grid	0.17 kg CO2e/kg	0.05	Ontario grid	0.17 kg CO2e/kg	0.05
Tool (3/8” SPIF Tool custom)	1.09E-4 kg	Generic HSS mill  tool – new	6.4 kg CO2e/kg	6.98E-4	Generic HSS mill  tool – remanufactured	1.3 kg CO2e/kg	1.42E-4
Total	–	–	–	4.28	–	–	3.09

Figure 7 CO₂ contribution breakdown for SPIF hats without stock input.

Table 7 Summary of analysis for a hat manufactured with SPIF at two settings.

		Scenario
	Description	1	2
Time	Process time per hat (one–off), h	3.00	1.82
	Process time per hat (commercial 1000-hat line), h	1.64	0.46
Energy	Total process energy use (kJ)	4580	1420
Cost	Cost of process and inputs for hat (less labour), $	4.48	4.10
	Cost with labour (one–off), $	184.48	113.15
	Cost with labour (commercial 1000-hat line), $	86.48	26.94
CO2 emissions	Embodied CO2 of hat (experiment/traditional), kg CO2e	4.48	4.28
	Cost at $50/tonne CO2, $	0.22	0.21
	Embodied CO2 of hat (modified), kg CO2e	3.24	3.09
	Cost at $50/tonne CO2, $	0.16	0.15