Hot forming: Quick, precise and long-lived technologies

Hot forming, including press hardening, is used to produce high-strength car body parts. In the Front of Line, blanks are separated in the conventional manner and then transported through a furnace where they are heated to a temperature of over 900°C. They are then formed while still hot. Quick loading times are crucial for this process to prevent excessive cooling. That makes traversing feeder systems ideal for this application. Throughout the past decade, Strothmann has successfully automated numerous hot forming plants in a variety of standardised stages of expansion. Depending on the requirements Strothmann uses two different basic solutions – the feeder and the transfer concept.

System overview

Front of Line

Blank cart

Hot forming: Blank cart

Carriages on the RoundTrack system for feeding and discharging blank stacks in the Front of Line area guarantee an uninterrupted stack change. They are equipped with spreading magnets, the cover plate is equipped with specific alignment units and centring aids based on the customer’s requests. Fence elements at the cart ends close the protective circuit during the stack change.

Spreading magnets

Hot forming: Spreading magnets

Spreading magnets can either be placed as posts on pantograph arms with an approach function on the blank cart or arranged on the side of the blank cart with an automatic approach.

Destacking feeder

Hot forming: Destacking feeder

Traversing feeders with additional rotary axes are used for destacking the blanks. By using two feeder modules on a joint main axis, different types of blanks can be collected in one batch.

Marking stations

Hot forming: Marking stations

Strothmann’s hydraulic marking stations can perform up to four marking processes simultaneously. Depending on the product, the marking heads can be adjusted in relation to each other in two directions. An additional path measuring system is integrated in the hydraulic cylinders to act as a double blank detection.

Centring table

Hot forming: Centring table

Prior to entering the press, the heated blanks must be centred. The Strothmann centring table is equipped with automatically adjustable centring fingers for up to four blanks. Stops can be designed for manual or automatic adjustment and have a height adjustment function for disposal of reject parts.

Press loading and unloading

Feeder concept

Hot forming: Feeder concept

In systems with a press located directly in the throughfeed direction downstream of the furnace, the heated blanks are generally gripped by a feeder from above and inserted in the press. Large grippers with heat shielding are used for this process. The advantage of this system is its compact design and the installed power.

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Transfer concept

Hot forming: Transfer concept

If the press is arranged crosswise to the furnace throughfeed direction, two feeders on a joint main axis that grip the blanks from the sides can be used for loading and unloading. The narrow traversing axes make it possible for the unloading feeder to wait in the press compartment next to the tool during the pressing process, thereby significantly reducing the change time.

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Front of Line: Layout

Technical data

Front of Line

Cycle time

Up to 10 s

Max. load capacity

60 kg

Blank length

2500 mm

Max. stack weight pallet

6,000 kg

Rotary axis of destacker

± 135°

Number of blanks per feeder

2

Number of markings per blank

4

Pressing force for marking

120 kN

Process time for marking

approx. 1.5 s

Number of letters

up to 26

Press loading and unloading

Hot forming

Feeder concept 

  • Press in furnace throughfeed direction 
  • Loading and unloading by one feeder each with load-bearing capacity of 200 kg or 120 kg 
  • Large toolings with heat shielding 
  • Achievable change time approx. 4 s 
  • Advantage: compact space and lower installed power

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Hot forming

Transfer concept 

  • Press crosswise to furnace throughfeed direction 
  • Loading and unloading by two feeders each with 80 kg load-bearing capacity each 
  • Feeders wait in the press compartment next to the tools 
  • Achievable change time approx. 2.5 s  
  • Advantage: minimised cycle times 

Feeder concept

Transfer concept

Overall size

1

2

S

M

L

XL

Automation unit

3/200 (loader)
3/120 (unloader)

3/200

3/040

3/040

3/080

3/080

max. stroke X

3500 mm

up to 6000 mm

2500 mm

3300 mm

4000 mm

4700 mm

standard stroke Z

1100 mm

1100 mm

700 mm

700 mm

800 mm

800 mm

Load-bearing capacity

200 kg

120 kg

2 x 40 kg

2 x 40 kg

2 x 80 kg

2 x 80 kg

Achievable change time

4 s

4 … 4.5 s

2.5 s

2.5 s

2.5 … 3 s

3 s

What requirements do you have for your hot forming system?

Contact our experts for press automation.

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Hot forming