Success story of BMC/SMC/DMC fully automatic presses

From 0 to 100 with IAG special solutions

With the development of a complex IAG fully automatic press system concept including weighing & dosing technology, two global market leaders came together. 

This IAG special-purpose machine meant that, when introducing a new product technology, customers were able to guarantee the necessary process safety with an IAG machine. Thanks to the scaling of the technical i.e. laboratory operation to a fully automated mass production machine, the mass market can now also be served in a cost-effective manner with accordingly consistent quality. 

For the material feeding of a production machine for the production of brake linings with a back plate made of composite material (Duroplast-phenolic resin glass fibres), two appropriately portioned types of raw material (powdery resinous friction mix and flaked, fibre-reinforced plastic chips known as SMC chips/DMC chips) had to be made available according to the system cycle. This was carried out via weighing and dosing technology located on a platform above the main system, which following manual transfer to the machine, was fed in fully automatically via a central material transport system. The dosing and weighing procedure took place simultaneously for both material types:

 

For the powder material: 

  • Dosing via coarse and fine dosing screws from an agitator silo. 
  • Weighing – for provision of product-dependent material volumes 
  • Feeding into the hot press stations

 

For the composite material (CFK SMC chips/DMC chips): 

  • Coarse dosing for controlled filling of the fine dosing 
  • Fine dosing (vibrating spiral conveyor) 
  • Weighing - for provision of product-dependent material volumes
  • Insertion into a separate press tool with automatic tool changeover

 

The properties of the composite material presented a major challenge for automation. Through intensive pilot tests and a constant exchange of experiences with the customer, eventually the material supplier was able to develop a material with targeted properties for the automated processing. 

 

An overview of the process steps

Material feed 

1. Via a transport silo and a conveyor system, the two base materials (friction mix and composite material) are brought to the production machine in a fully automatic procedure. 

Dosing and weighing of the friction mix 

2. In a rotating agitator in the silo, the dosing takes place with the help of pairs of dosing screws (coarse and fine) into the 4 weighing pans situated below. 

3. The weighing itself is carried out using precision scales with intelligent controls for constant monitoring of the weighing process and independent implementation of any potentially necessary corrections. 

4. Upon conclusion of the 4 weighing processes running in parallel, the final portions are transferred to the next step. 

Coarse dosing of the composite material 

5. Via a central spiral drum, previously filled by the transport silo, the material is dosed into a mobile weighing pan. This pre-portioning exclusively serves the controlled feeding of the 4 vibrating spiral conveyors, thus preventing overfilling. 

Transport of the composite material 

6. This coarse portion is now carried by a 2-axle slide system and fed into the 4 vibrating spiral conveyors, as necessary. 

Fine dosing of the composite material 

7. According to the pre-set and product-dependent formula, in a first step the material is now transferred from the vibrating spiral conveyors and taken via tracks to the corresponding gutter of the vibrating feeder unit. 

8. The vibrating feeder unit gutters serve to extend the flow of material (decreasing the density) before it is transferred to the weighing pans, which is what actually enables correspondingly precise weighing. 

9. Finally, the weighing takes place in the 4 corresponding weighing pans.  

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