5.2.2.3 Net and Shape Forging

Net and near net shape forging represents some relatively recent developments of the conventional impression die forging process. Net and near net shape forgings are distinguished by geometric features that are thinner and more detailed, varying parting line locations, virtual elimination of draft, closer dimensional tolerances and with many as-forged surfaces. The resulting product benefits are much fewer machining operations, reduced weight and lower costs for raw materials and energy. In many cases, the only machining operations required are drilling of attachment holes.

Net and near net shape forgings in the as-forged and heat treated condition usually reflect a higher production cost than do their conventionally forged counterparts. They are often but not necessarily flashless. The cost advantage shifts to net shape forging as post-forging machining operations are eliminated.

A cost study for an aircraft aluminum forging made by four processes identifies the cost drivers and illustrates the trade-offs for this application. The four processes are hand forging, blocker type (forging to approximate shape and machining), conventional forging and net shape forging.

The cost drivers are charted and the effects calculated for various production quantities in Table 5-1. The cost is given in relative terms, rather than dollars, with the piece price of a conventional forging taken as 1. The advantage for net shape forging over hand forging begins at 110 units; at 140 or more units, net shape forging is the most economical of the four processes. Other applications will have different cost ratios. Actual values can be determined only by consultation with the forging company representative.

Table 5-1: Cost Comparison of Wide-Body Jet Forging.
Courtesy of FIA member company.

 

 

Forging
Process

 

Hand

 

Blocker
Type

 

Conventional
Finished

 

Net
Shape

Forging costs

---

 
 
 
Tooling
---
308
615
1000
Set-up
1.48
    30.8
     18.5
    23
Piece cost
 
         1.23
        1.0
         1.9
Machining costs
 
 
 
 
Tooling
1.46
123
92
31
Set-up
21
     15.4
   11.5
     2.3
Piece cost
8.5
      5.4
     3.5
       0.23

Return to Table of Contents

array ( '#markup' => '

Net and near net shape forging represents some relatively recent developments of the conventional impression die forging process. Net and near net shape forgings are distinguished by geometric features that are thinner and more detailed, varying parting line locations, virtual elimination of draft, closer dimensional tolerances and with many as-forged surfaces. The resulting product benefits are much fewer machining operations, reduced weight and lower costs for raw materials and energy. In many cases, the only machining operations required are drilling of attachment holes.

Net and near net shape forgings in the as-forged and heat treated condition usually reflect a higher production cost than do their conventionally forged counterparts. They are often but not necessarily flashless. The cost advantage shifts to net shape forging as post-forging machining operations are eliminated.

A cost study for an aircraft aluminum forging made by four processes identifies the cost drivers and illustrates the trade-offs for this application. The four processes are hand forging, blocker type (forging to approximate shape and machining), conventional forging and net shape forging.

The cost drivers are charted and the effects calculated for various production quantities in Table 5-1. The cost is given in relative terms, rather than dollars, with the piece price of a conventional forging taken as 1. The advantage for net shape forging over hand forging begins at 110 units; at 140 or more units, net shape forging is the most economical of the four processes. Other applications will have different cost ratios. Actual values can be determined only by consultation with the forging company representative.

Table 5-1: Cost Comparison of Wide-Body Jet Forging.
Courtesy of FIA member company.

 

 

Forging
Process

 

Hand

 

Blocker
Type

 

Conventional
Finished

 

Net
Shape

Forging costs

---

 
 
 
Tooling
---
308
615
1000
Set-up
1.48
    30.8
     18.5
    23
Piece cost
 
         1.23
        1.0
         1.9
Machining costs
 
 
 
 
Tooling
1.46
123
92
31
Set-up
21
     15.4
   11.5
     2.3
Piece cost
8.5
      5.4
     3.5
       0.23

Return to Table of Contents

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Net and near net shape forging represents some relatively recent developments of the conventional impression die forging process. Net and near net shape forgings are distinguished by geometric features that are thinner and more detailed, varying parting line locations, virtual elimination of draft, closer dimensional tolerances and with many as-forged surfaces. The resulting product benefits are much fewer machining operations, reduced weight and lower costs for raw materials and energy. In many cases, the only machining operations required are drilling of attachment holes.

Net and near net shape forgings in the as-forged and heat treated condition usually reflect a higher production cost than do their conventionally forged counterparts. They are often but not necessarily flashless. The cost advantage shifts to net shape forging as post-forging machining operations are eliminated.

A cost study for an aircraft aluminum forging made by four processes identifies the cost drivers and illustrates the trade-offs for this application. The four processes are hand forging, blocker type (forging to approximate shape and machining), conventional forging and net shape forging.

The cost drivers are charted and the effects calculated for various production quantities in Table 5-1. The cost is given in relative terms, rather than dollars, with the piece price of a conventional forging taken as 1. The advantage for net shape forging over hand forging begins at 110 units; at 140 or more units, net shape forging is the most economical of the four processes. Other applications will have different cost ratios. Actual values can be determined only by consultation with the forging company representative.

Table 5-1: Cost Comparison of Wide-Body Jet Forging.
Courtesy of FIA member company.

 

 

Forging
Process

 

Hand

 

Blocker
Type

 

Conventional
Finished

 

Net
Shape

Forging costs

---

 
 
 
Tooling
---
308
615
1000
Set-up
1.48
    30.8
     18.5
    23
Piece cost
 
         1.23
        1.0
         1.9
Machining costs
 
 
 
 
Tooling
1.46
123
92
31
Set-up
21
     15.4
   11.5
     2.3
Piece cost
8.5
      5.4
     3.5
       0.23

Return to Table of Contents

', )