1. 1
EIGHTH INTERNATIONAL ALUMINUM EXTRUSION TECHNOLOGY
SEMINAR AND EXPOSITION
Front-loading Technology With
Tandem Cylinder Design For High
Precision Extrusions
Tecalex

2. 2
INDEX
1. Introduction
2. Front loading principle
3. Advantages of front loading
4. Specific features of front loading
5. Tandem cylinder design
6. Advantages of the Tandem cylinder design
7. Conclusions

3. 3
Introduction
• Front loading = charging of billet between
stem and die and then moving container
over billet.
• Advantages but as well: problems that had
to be resolved.
• Tandem cylinder design = 2 pistons (main +
auxiliary) on the same axis.
• Precise extrusions + surface quality.

4. 4
General press design
• 1100 – 2800 MT
• Front loading +
tandem cylinder
• Variable hydraulic
flow
• Rotational die changer
• Lubricated butt shear
• Forged front plate
• (…)

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Front loading principle
Step 1: Hot shear cuts billet

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Front loading principle
Step 2: Billet lubrication

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Front loading principle
Step 3: Move billet to waiting position

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Front loading principle
Step 4: Container and stem move backwards

9. 9
Front loading principle
Step 5: Butt shear removes butt

10. 10
Front loading principle
Step 6: Move billet to extrusion axis

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Front loading principle
Step 7: Clamp billet between die and stem

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Front loading principle
Step 8: Close container and extrude

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Advantages of front loading
Comparison back loading vs. front loading
• Compact design with
50% less cylinder
stroke
• Reduced dead cycle
times
• No need of high speed
movements
• Less oil volume
Back loading
Front loading

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Advantages of front loading
Symmetrical upsetting of billet
Front loading
Back loading
• Front loaded billet in the
center line = no
perpendicular stresses.
• Less clearance between
container and billet.
• Symmetrical billet
deformation, no press
bending or die uplift.
• Higher precision of the
extruded profile.

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Special features of front loading
Loading 2 pieces is tricky !
2-piece billet waiting Clamping 2 piece billet

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Special features of front loading
Optimized warm shear to remain original section .
• 2-piece billet from
billet rest
management is easy
to load

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Special features of front loading
Feeder with movable shell to support different billet length.

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Tandem cylinder design
2 pistons (main + auxiliary) working on the same axis.
Main Piston
(Forged Steel F125)
Auxiliary Piston
(Forged Steel F125)
Billet clamp
Pre-fill valves
Shaft
(Forged Steel F125)
Nut
Bushing
Bodies
(Forget steel St52.3)

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Tandem cylinder design
Video clip: Working principle.

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Advantages of Tandem Cylinder
Forged steel plate flexion: Finite element analysis.
0,253
0,222
0,19
0,158
0,126
• Two cylinders on the main axis
= reduced cylinder diameter and
reduced front plate dimensions
and distance of tie rods,
compared to conventional
cylinder design.
• Due to the less distance
between the tie rods, a tandem
system press has 24% less
flexion than standard presses.

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Advantages of Tandem Cylinder
Alignment of the stem.
• The additional bearing points from the auxiliary cylinder improve
the alignment of the stem = more precise stem movement = more
precise extrusion.

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Conclusions
The combination of front-loading technology with tandem
cylinder design helps to improve the precision and
surface quality of extrusions because:
• Front loading = The billet is loaded exactly and
symmetrically onto the extrusion axis.
• Due to the tandem design, the bending of the front plate
is reduced and the die movement as well.

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Thank you for your attention!
www.tecalex.com