478
B. Kianian and C. Andersson
(17%) costs account for more than half (52%) of the total PM gear manufacturing
cost calculated in this study. Hence, any improvement opportunities in these two
processes can benefit PM part makers both economically and environmentally to
a large extent, since both metal powders production and HT process are prominent
energy consumers. Discussion section (see Sects. 33.5.2 and 33.5.3 below) elaborates
on metal powder and HT process more in detail. Optimization of these processes
are dependent on the part’s material, weight, size and complexity (Kruzhanov and
Arnhold 2012).
Compaction cost (12%) is the next major cost driver for this study gearwheel,
and the main reason is its very high tool investment cost (e.g. basic and part specific
adoptions and helical gear drive system costs) generally and due to the complex
helical gear in this case. The equipment (e.g. hydraulic press) cost is high as well,
however because of the press high energy efficiency (Kruzhanov and Arnhold 2012)
and competitive cycle time (7 stroke/min in this case), the compaction operational
cost was only 25% of the total compaction cost in Fig. 33.3. Whereas its tool cost
accounts for 65% of the total compaction cost.
Gear rolling (7%) and sintering (4%) processes are the minor cost drivers in
this study. Rolling process tool (die and clamping accessories) cost accounts for
45% of the total gear rolling cost in Fig. 33.3, due to many die refurbishment and
replacement times for the annual production volume of 400,000 units. Whereas, gear
rolling operational cost accounts for 40% of the total gear rolling cost because of its
competitive cycle time and very short setup time. Sintering process is considered as
the most energy intensive process with rather low efficiency (less than 30%) due to
different loses (e.g. radiation, ineffective loading) (Kruzhanov and Arnhold 2012;
Zapf and Dalal 1983; Bocchini 1983). The sintering furnace utilized in this study is
a belt furnace with conveyor belt width of 0.6 m and sintering capacity of 300 kg/h.
33.5 Improvement Scenarios Simulation
It is mentioned earlier that the PPC model provides capability of designing and
simulating different production scenarios e.g. improvement opportunities. Different
improvement opportunities regarding gear rolling process automation, and OEE
improvement incl. sensitivity analyses were discussed with the interviewees at the
different companies. Based on the discussions, two different improvement scenarios
are presented, together with a scenario where the energy price is increased.
33.5.1 Gear Rolling Automation
One of the production improvement scenarios is automation of gear rolling process,
which increases the equipment investment cost by nearly 27% as/in the base case analysis in this study. Based on data obtained from interviews, the gear rolling automation
B. Kianian and C. Andersson
(17%) costs account for more than half (52%) of the total PM gear manufacturing
cost calculated in this study. Hence, any improvement opportunities in these two
processes can benefit PM part makers both economically and environmentally to
a large extent, since both metal powders production and HT process are prominent
energy consumers. Discussion section (see Sects. 33.5.2 and 33.5.3 below) elaborates
on metal powder and HT process more in detail. Optimization of these processes
are dependent on the part’s material, weight, size and complexity (Kruzhanov and
Arnhold 2012).
Compaction cost (12%) is the next major cost driver for this study gearwheel,
and the main reason is its very high tool investment cost (e.g. basic and part specific
adoptions and helical gear drive system costs) generally and due to the complex
helical gear in this case. The equipment (e.g. hydraulic press) cost is high as well,
however because of the press high energy efficiency (Kruzhanov and Arnhold 2012)
and competitive cycle time (7 stroke/min in this case), the compaction operational
cost was only 25% of the total compaction cost in Fig. 33.3. Whereas its tool cost
accounts for 65% of the total compaction cost.
Gear rolling (7%) and sintering (4%) processes are the minor cost drivers in
this study. Rolling process tool (die and clamping accessories) cost accounts for
45% of the total gear rolling cost in Fig. 33.3, due to many die refurbishment and
replacement times for the annual production volume of 400,000 units. Whereas, gear
rolling operational cost accounts for 40% of the total gear rolling cost because of its
competitive cycle time and very short setup time. Sintering process is considered as
the most energy intensive process with rather low efficiency (less than 30%) due to
different loses (e.g. radiation, ineffective loading) (Kruzhanov and Arnhold 2012;
Zapf and Dalal 1983; Bocchini 1983). The sintering furnace utilized in this study is
a belt furnace with conveyor belt width of 0.6 m and sintering capacity of 300 kg/h.
33.5 Improvement Scenarios Simulation
It is mentioned earlier that the PPC model provides capability of designing and
simulating different production scenarios e.g. improvement opportunities. Different
improvement opportunities regarding gear rolling process automation, and OEE
improvement incl. sensitivity analyses were discussed with the interviewees at the
different companies. Based on the discussions, two different improvement scenarios
are presented, together with a scenario where the energy price is increased.
33.5.1 Gear Rolling Automation
One of the production improvement scenarios is automation of gear rolling process,
which increases the equipment investment cost by nearly 27% as/in the base case analysis in this study. Based on data obtained from interviews, the gear rolling automation