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HYDROFORMING:

Technological & Economical Aspects Page 5 & 6:

Dr.-Ing. Alfons Böhm, Siempelkamp Pressen Systeme, Krefeld
Anthony Abbey,
Siempelkamp Pahnke Engineering, Springfield

Contents

1.) Part design determines production costs: Example engine cradle
2.) How to reduce the number of production steps: Examples
3.)
Hydroforming processes and die design for high volume production
4.)
Cost studies for various part
5.)
ALLFORM Double Ram Press Systems (DRS) for high volume production
6.)
Achievable reliability and quality: Some selected aspects

5. ALLFORM Double Ram Press Systems (DRS) for high volume production

In comparison to stamping or deep drawing processes, hydroforming is still a slow process. This is important especially under economically since most systems currently in use for hydroforming are hydraulic presses with a similar capital investment costs to systems for stamping or deep drawing.

Typical cycle times, including loading and unloading, are within a range of 18 .. 20 seconds for smaller parts and 20 .. 30 seconds for larger parts; using the quick-filling system /6/ offers cycle times within a range of 18 .. 23 seconds for parts of any size.

The time for hydroforming itself ist only about 5..8 seconds; to optimise the use of the existing equipment under economic and volume aspects SPS introduced the first tandem press system in 1996.

The principle of the Allform - Double Ram Press System (DRS) is explained in Fig. 6.1:

- Two separate rams are integrated into one press frame of a hydraulic press.
- One hydraulic and high-pressure system is installed.
- One or more tools can be installed on each ram side.
- Whilst the first side is hydroforming, the second side is unloading, loading, filling, sealing, then the high pressure system switches from the first to the second side and hydroforming starts at the second ram side.
- Hydroforming of different parts with different process parameters on each ram is possible in general (excellent material flow for components, which are assembled together later)

By the described method the cycle time is reduced to about 15 seconds per part including loading and unloading.

The described mode is named "single mode". The DRS can also be driven in "coupled mode" while the rams are connected and working like a standard ALLFORM press system but with a higher press force (Fig. 6.1):

- A further amount of larger parts can be produced on the same system.

Fig 6.1: ALLFORM Double Ram Press System
Unloading / Loading / Filling / Sealing / (Pre-Forming)

Fig 6.1: ALLFORM Double Ram Press System for high volume hydroforming.

Further economic and technical advantages of the system are mentioned and quantified in Fig. 6.2. The figure shows also two examples of actual installations in mass production. The Allform DRS can be individually optimised for the customers needs (press force, platen size, etc.).

Fig 6.2 Advantages of the ALLFORM Double Ram Press System Fig 6.2 Advantages of the ALLFORM Double Ram Press System

CANADA:
1st and 2nd press: 2 X 6000t (6600 USt) ALLFORM system Canada

GERMANY:
2 x 800t (880 USt) ALLFORM System SPS R&D Center Germany

6. Achievable reliability and quality: Some selected aspects

Finally a few selected aspects are mentioned which are important to achieve the necessary reliability and quality which is offered by hydroforming:

  • The part has to be plasticized during hydroforming in all areas; consequently a minimum circumferential expansion of 3..7% for steel materials is recommended (Fig. 7.1);

  • A stiff press frame to avoid any opening of the dies and to reduce the elastic deflection of the system;

  • Press force control during the hydroform process to minimize influences of the elastic deflection of the press/tool-system;

  • Stiff die design including stiff guidance of upper and lower die halves to avoid any movement between the dies;

  • Wear resistant die material and coating including a cost effective wear and spare part strategy;

  • Water management of press and tool system with reference to part lubrication;

  • Hydroforming press control system allowing free but sensible programming of all process parameters and process monitoring.

Fig 7.1:Case quality study on hydroforming

Fig 7.1: Case quality study on hydroforming (1) /5/

Note (1)
There is no understanding of „high pressure hydroforming“ and „low pressure hydroforming“ for most technicians in europe because the height of any physical size is relative. Most important is the necessary internal pressure which can be calculated by different methods; one is shown in /2/.

Literature

/1/ Böhm, Alfons
"The production steps bending - annealing - hydroforming: Experience from mass production."
Technical paper of: EFB-Kolloquium "Hydroforming",
March 5-6 1996, Stuttgart/Germany.

/2/ Böhm, Alfons
Numerical simulation of hydroforming processes with a closer look to expanding within closed dies.
University of Paderborn, 1993.

/3/ Meyer, Werner
Hydroforming of Tubes; University of Magdeburg/Germany,
09/23-24/99; Technical Paper, page 188 ff.

/4/ Böhm, Alfons
"Hydroforming: State of the Art"
Technical paper of:
14th Annual World Tube Congress; Tube Fabricating Session, November 3, 1998, Cleveland/Ohio.

/5/ Seifert, M.
Magna Matag
Body & Chassis Systems Hydroforming of Tubes; University of Magdeburg/Germany,
09/23-24/99; Technical Paper, page 188 ff.

/6/ Böhm, Alfons
"Part cost reduction in the hydroforming process"
Technical paper of :
The 2nd International Conference on Innovations in Hydroforming,
September 15-17, 1997, Columbus/Ohio.

Select your page: (1) (2) (3) (4) (5)

With permission of Siempelkamp Pressen Systeme / Germany.
All rights are reserved.

   

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Last update: Januar 12, 2000
Letzte Änderung: 12 Januar 2000

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