Job: cleaning of clutch transmission components | Challenge: complex gears and pinions to be cleaned | Implementation: different treatment stages on minimal footprint | Process: Spray cleaning, pressure flooding, ultrasound
No particle > 200 micrometers at a cycle time of 1 s per component.
At one of the largest automotive manufacturers, geometrically complex gears and pinions for dual-clutch transmissions have to be cleaned particle-free in high volumes. Cleaning is performed after surface compaction by blasting with steel beads. After cleaning, the components are sent directly to final assembly. Particles in the gearbox inevitably destroy the function of automatic shifting and thus lead to high follow-up costs.
For many years, the automotive manufacturer has been using spray cleaning systems with horizontal throughfeed technology to treat transmission components in its plants worldwide. The systems designed in this way can no longer withstand the ever-increasing demands on cleanliness, in conjunction with more complex part geometry and the cycle frequencies. As a consequence, new cleaning technology was sought. We have faced this task and solved it to the full satisfaction of the customer.
Cleaning trials in the technical center at PURIMA
Before a cleaning system for the treatment of complex components is designed, extensive washing tests and elaborate residual dirt investigations are required. PURIMA carried out this work in close cooperation with the project managers of the automobile manufacturer at its own technical center in Porta Westfalica. The task and the results to be achieved were defined by the customer as follows defined as follows :
- High cleanliness classes, no particles >200µm
- Cycle times max. 1 sec./component
- The components must be dry and protected against corrosion
- Continuous throughput operation with consistent, reproducible quality
- Fully integrated line chaining
- Minimization of ongoing operating costs
After numerous tests in the PURIMA pilot plant, incl. of residual dirt analyses in accordance with the requirements of the automotive industry based on VDA 19, the solution was successfully developed.
The plant technology developed by PURIMA of the type FLOWTRONIC® in modified design is able to fulfill all these criteria and defined parameters.
Maximum technology in a small space
The FLOWTRONIC® continuous flow system combines the technology of a system with immersion baths and effective spray cleaning in a minimal footprint. The juxtaposition of different treatment zones is possible in this technique in a very multilayered way and is individually designed and adapted according to the customer’s requirements.
Especially in this case, the final cleaning after blasting with steel beads, a dry pre-cleaning stage has been implemented. Since the components are heavily contaminated with adhering steel beads, especially in complex undercuts, the components are blown off in advance at different angular positions with air from high-pressure fans. The blown-off, dry blasting material is fed to a collection container via a screw conveyor. The advantage for the customer is that the blasting material can be partially reused and does not deposit in the wet zones. In the following diving zones as mechanical support ultrasound and pressure flooding In the spray zones above, intensive, targeted rinsing of the dissolved particles is carried out with a defined filtered medium. Before the components leave the treatment stage, they are cleaned by directed blowing of the components and transport chains bath carryover to a minimum reduced .
The treatment zones pre-cleaning, ultrasonic, rinsing 1, rinsing/passivation 2 and drying are set up in the system in such a way that angle/position changes occur when the components are moved in and out, thus ensuring extremely intensive sonication and pressure and spray rinsing from all sides is possible.
Due to the strict separation of the individual treatment zones the positional changes of the components and by targeted blowing-off, the bath service lives have been more than doubled compared to straight through systems. The cleaned particles quickly sink to the bottom of the tank. To prevent contact corrosion in the stainless steel basins, the basins are equipped with pyramid bottoms and additional bottom rinsing equipped. The liquid is extracted by powerful pumps at the deepest point and the particles are removed via multi-stage filter systems removed from the liquid.
At the customer’s request, a loading and unloading station which can be loaded automatically and alternatively manually, taking ergonomic aspects at the workplace into account.
Customer requirements met
WithFLOWTRONIC®-continuous cleaning system is the goal of a constant compliance of the specified cleanliness classes during the treatment of very high quantities of parts has been achieved. This proven plant technology can also be used for the treatment of similar series parts, e.g. shift forks or shift sleeves. The deburring of parts with high-pressure water and subsequent cleaning process is also already in FLOWTRONIC® – Continuous systems have been implemented.
